Cigna Ambulatory External and Implantable Electrocardiographic Monitoring - (0547) Form

The following Coverage Policy applies to health benefit plans administered by Cigna Companies. Certain Cigna Companies and/or lines of business only provide utilization review services to clients and do not make coverage determinations. References to standard benefit plan language and coverage determinations do not apply to those clients. Coverage Policies are intended to provide guidance in interpreting certain standard benefit plans administered by Cigna Companies. Please note, the terms of a customer’s particular benefit plan document [Group Service Agreement, Evidence of Coverage, Certificate of Coverage, Summary Plan Description (SPD) or similar plan document] may differ significantly from the standard benefit plans upon which these Coverage Policies are based. For example, a customer’s benefit plan document may contain a specific exclusion related to a topic addressed in a Coverage Policy. In the event of a conflict, a customer’s benefit plan document always supersedes the information in the Coverage Policies. In the absence of a controlling federal or state coverage mandate, benefits are ultimately determined by the terms of the applicable benefit plan document. Coverage determinations in each specific instance require consideration of 1) the terms of the applicable benefit plan document in effect on the date of service; 2) any applicable laws/regulations; 3) any relevant collateral source materials including Coverage Policies and; 4) the specific facts of the particular situation. Each coverage request should be reviewed on its own merits. Medical directors are expected to exercise clinical judgment where appropriate and have discretion in making individual coverage determinations. Where coverage for care or services does not depend on specific circumstances, reimbursement will only be provided if a requested service(s) is submitted in accordance with the relevant criteria outlined in the applicable Coverage Policy, including covered diagnosis and/or procedure code(s). Reimbursement is not allowed for services when billed for conditions or diagnoses that are not covered under this Coverage Policy (see “Coding Information” below). When billing, providers must use the most appropriate codes as of the effective date of the submission. Claims submitted for services that are not accompanied by covered code(s) under the applicable Coverage Policy Medical Coverage Policy: 0547 will be denied as not covered. Coverage Policies relate exclusively to the administration of health benefit plans. Coverage Policies are not recommendations for treatment and should never be used as treatment guidelines. In certain markets, delegated vendor guidelines may be used to support medical necessity and other coverage determinations. This Coverage Policy addresses the use of ambulatory electrocardiographic monitoring in the evaluation of patients with suspected arrhythmias, unexplained episodes of syncope and/or cryptogenic stroke. Coverage Policy Ambulatory External Cardiac Monitoring Ambulatory external cardiac monitoring from 48 hours to 30 days (Current Procedural Terminology [CPT®] codes 93241–93248, 93268, 93270, 93271, 93272, 0497T, 0498T) is considered medically necessary when EITHER of the following criteria are met: symptoms of presyncope, syncope, or severe palpitations when there is clinical suspicion of a significant bradyarrhythmia or tachyarrhythmia evaluation of atrial fibrillation for rhythm and/or rate control when the results will directly impact clinical decision-making Ambulatory external cardiac monitoring from 48 hours to 30 days is considered not covered or reimbursable for ANY other indication including ST segment analysis. Mobile Cardiac Monitoring with Telemetry Mobile cardiac outpatient telemetry (MCOT or MCT) (CPT codes 93228, 93229) is considered medically necessary when Holter monitoring is non-diagnostic or symptoms occur so infrequently and unpredictably that the length of the monitoring period would likely be inadequate to capture a diagnostic electrocardiogram (ECG) rhythm disorder and EITHER of the following criteria are met: symptoms of presyncope, syncope, or severe palpitations when there is clinical suspicion of a significant bradyarrhythmia or tachyarrhythmia evaluation of atrial fibrillation for rhythm and/or rate control when the results will directly impact clinical decision-making Mobile cardiac monitoring is not covered or reimbursable for ANY other indication. Ambulatory Implantable Cardiac Event Monitoring An implantable electrocardiographic event monitor (i.e., implantable loop recorder) (CPT code 33285; Healthcare Common Procedure Coding System [HCPCS] Code C1764, E0616) is considered medically necessary for EITHER of the following indications when the associated criteria are met: Medical Coverage Policy: 0547 Cryptogenic stroke with known or suspected atrial fibrillation when noninvasive ambulatory cardiac monitoring is inconclusive or non-diagnostic (e.g., patch monitors, external event monitors) Recurrent or unexplained syncope when BOTH of the following criteria are met:  non-arrhythmic causes have been excluded by appropriate testing (e.g., reflex syncope, orthostatic hypotension, volume depletion, dehydration, blood loss)  noninvasive ambulatory cardiac monitoring is inconclusive or non-diagnostic (e.g., patch monitors, external event monitors) The replacement of an implantable electrocardiographic event monitor is considered medically necessary for an individual who continues to meet ALL of the above criteria and the existing monitor is no longer under warranty and cannot be repaired (e.g., device is nearing the end of its battery life). The use of an implantable electrocardiographic event monitor (i.e., implantable loop recorder) for ANY other indication including routine monitoring of a documented arrhythmia or assessing the effectiveness of arrhythmia treatment is considered experimental, investigational or unproven. Cardiac Self-Monitoring Cigna does not cover ANY of the following for any indication because each is considered a convenience item and/or not medically necessary: a self-monitoring device that includes an ECG monitor combined with a cellular telephone, watch or other personal electronic device software or hardware required for downloading ECG data to a device such as personal computer, smart phone, or tablet General Background Cardiac arrhythmias or abnormal heartbeats represent a major source of morbidity and mortality among patients with cardiovascular disease. While some patients with arrhythmias may experience symptoms such as palpitations, weakness, dizziness, or syncope other patients may have no symptoms at all. Cardiac arrhythmias can be serious and life threatening and can lead to stroke and heart failure, including atrial fibrillation (AF), sustained ventricular tachycardia (VT), ventricular fibrillation, supraventricular tachycardia (SVT), sinus bradycardia/pauses and atrioventricular (AV) block. A history and physical examination may detect an arrhythmia and suggest possible causes. However, a diagnosis requires a 12-lead electrocardiography (ECG) or, less reliably, a rhythm strip, preferably obtained during symptoms to establish the relationship between symptoms and rhythm (Mitchell, 2021; Yenikomshian, et al., 2019). Ambulatory electrocardiographic (ECG) monitoring provides data over an extended period of time. The most common use of ambulatory electrocardiographic monitoring is for the diagnosis and assessment of cardiac arrhythmias, conduction abnormalities (symptomatic or asymptomatic) or the presence of potential arrhythmias (such as in patients with syncope or presyncope). The choice of initial ambulatory ECG monitoring for the symptomatic patient depends on the frequency and severity of symptoms. Continuous ECG (Holter) monitoring for 24 to 48 hours is used to monitor patients with daily or near daily symptoms, while those with less frequent symptoms are more likely to benefit from extended monitoring. Extended ambulatory monitoring can be Medical Coverage Policy: 0547 performed using an external monitoring device or an insertable cardiac monitor (Madias, 2020; Mittal, et al., 2011). There are various ambulatory ECG monitoring techniques and systems. The devices used for ambulatory cardiac monitoring include: Holter monitors continuously record all ECG data for a period of 24–48 hours • Patch monitors continuously record an ECG for up to 14 days • Event monitors may be worn continuously or applied during symptoms for up to 30 days and include post event monitors, event/loop monitors and auto-triggered event recorders Mobile cardiac outpatient telemetry monitors are worn continuously and are capable of real-time streaming, transmitting a loop, or a single-event electrogram directly to the reading center through a wireless link for up to 30 days Insertable cardiac monitors (ICM’s) are implanted in the left pectoral region and store events when the device is activated automatically according to programmed criteria or triggered by the patient Ambulatory External Cardiac Monitoring Ambulatory external cardiac monitoring devices provide recording of the electrical activity of the heart for more than 48 hours and up to 30 days. These devices are suggested to increase the detection of arrhythmias. A physician analyzes the recording to identify heart rhythm abnormalities. The devices used for ambulatory external cardiac monitoring for over 48 hours include patch monitors, event monitors and mobile cardiac outpatient telemetry. Patch Monitors: Patch monitors are small adhesive devices that do not require separate leads, wires, or battery packs. Patch monitors are capable of continuously recording an ECG for up to 14 days. An example of these devices is the Zio® Patch (iRhythm Technologies, Inc., San Francisco, CA), which can record up to 14 days of activity. The Zio® Patch device requires placing a patch on the left pectoral region. There is a button on the patch which the individual can press to mark a symptomatic episode although the patch does not require activation. At the end of the recording period the individual sends the device to the physician for analysis. According to the manufacturer, the Zio patch is indicated for use on patients who may be asymptomatic or who may suffer from transient symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, presyncope, syncope, fatigue, or anxiety (iRhythm Technologies, 2020; Mittal, et al., 2011). U.S. Food and Drug Administration (FDA): A number of ambulatory external continuous recording devices have been approved through the 510(k) process of the U.S. Food and Drug Administration (FDA) as Class II devices for extended ambulatory continuous ECG monitoring. The predicate devices upon which clearance was based are previous continuous ECG monitoring patches that can be worn for up to 14 days. The FDA does not necessarily require clinical data or outcome studies in making a determination of substantial equivalency for the purpose of device approval under section 510(k). There are several FDA-approved devices including, but not limited to: Zio PatchXT, Cardia Solo, and the Carnation Ambulatory Monitor. Literature Review – Patch monitors: There is evidence to support the clinical utility of ambulatory external continuous cardiac monitoring devices for 48 hours to 15 days in the diagnosis of cardiac arrhythmias in a specific subset of individuals (Barrett, et al., 2014; Schreiber, et al., 2014; Turakhia, et al., 2013; Rosenberg, et al., 2013). Randomized Controlled Trials: Eysenck et al. (2020) conducted a randomized control trial (RCT) to evaluate the accuracy of atrial fibrillation (AF) detection by comparing four external Medical Coverage Policy: 0547 ambulatory ECG monitors to permanent pacemaker AF detection. The Zio XT Monitor (ZM), NUUBO Vest (NV), Carnation Ambulatory Monitor (CAM) and Novacor ‘R’ Test 4 (RT) were all compared to a dual chamber rate adaptive permanent pacemaker (DDDRP PPM). Patients (n=21) with DDDRP PPMs and a history of AF were included and wore every external cardiac monitor (ECM) for two weeks in randomized order. The mean study duration was 77 days. All 21 patients had an episode of AF at least once during the 14-day observation period. The primary outcomes measured the AF burden and individual AF episodes when comparing device ECGs to permanent pacemakers. The secondary outcomes measured patient acceptability, wear time, costs and time expenditure. A total of 1108 individual AF arrhythmia episodes were identified by DDDRP pacemakers during the study. The Novacor ‘R’ Test 4 (RT) AF burden was significantly less accurate than the ZM, NV or CAM (p<0.05). The RT had a significantly higher probability of inaccurate AF diagnosis than ZM or CAM (p=0.025, p=0.042; respectively). The ZM wear time was longer than the RT and patient acceptability was significantly greater for CAM than RT (p=0.024). The authors concluded that the ZM, NV and CAM were more accurate in diagnosing atrial fibrillation compared to RT when using pacemaker AF arrhythmia episodes as the reference standard. The early prolonged ambulatory cardiac monitoring in stroke (EPACS) study was an open-label randomized controlled trial conducted by Kaura et al. (2019) that compared a 14-day ECG monitoring patch (Zio® Patch, iRhythm Technologies) with short-duration Holter monitoring for the detection of paroxysmal atrial fibrillation (PAF) following a transient ischemic attack (TIA) or ischemic stroke. Patients (n=116) were included in the study if they were age ≥ 18 years and were diagnosed by a stroke physician or neurologist with an ischemic non-lacunar stroke or TIA within the past 72 hours. Patients with a TIA were enrolled only if there were cortical symptoms of hemianopia or dysphasia at presentation or if their diffusion-weighted cerebral MRI scan was positive in a non-lacunar distribution. Patients were randomly assigned to either the patch-based monitoring group (n=56) or the short-duration Holter monitoring group (n=60). Patients assigned to the conventional medical therapy arm received current medical therapy of ambulatory Holter monitoring only (duration determined by treating physician, which was usually 24 hours). Patients assigned to the patch-based monitoring arm had the patch applied to the anterior chest wall with the device kept on for 14-days and had standard practice of short-duration Holter monitoring. Patients in both study arms had follow-up at day 28 and 90 using electronic hospital medical records data search and a phone call to the patient’s general practitioner in the community to collect endpoint data. End-point data included PAF documented on the ECG monitoring strategies or detected incidentally during usual clinical practice, such as during echocardiography. The study reported that patch-based monitoring strategy was significantly superior to short-duration Holter monitoring for the detection of PAF lasting 30 seconds or longer (p=0.026). The rate of detection of PAF at 28 days was not clinically significant between the groups (p=0.05). All patients who had newly diagnosed PAF were commenced on anticoagulation therapy by day 90. There was no difference in the rate of recurrent ischemic stroke/TIA or mortality (p=1.00, p=0.48; respectively) at 90 days. It was concluded that early, prolonged, patch-based monitoring after an index stroke or TIA is superior to short-duration Holter monitoring in the detection of PAF with an associated greater use of anticoagulation. Steinhubl et al. (2018) conducted a randomized controlled trail that evaluated effectiveness of a home-based self-applied wearable electrocardiogram (ECG) patch on the detection of undiagnosed atrial fibrillation (AF). Patients (n=2659) at increased risk for AF were randomized to active home- based monitoring to start immediately (n=1364) or delayed by four months (n=1291). The study concluded that immediate monitoring using a self-applied ECG patch, compared with delaying ECG monitoring for four months, led to a significantly higher rate of AF diagnosis at four months (3.9% vs 0.9%). Medical Coverage Policy: 0547 Comparative Studies: Rho et al. (2018) conducted a prospective comparative study to compare two FDA-approved monitors: the Zio Patch Monitor, Zio-XT (iRhythm Technologies, Inc, San Francisco, CA) and the Carnation Ambulatory Monitoring, CAM (BDx, Inc, Seattle,WA). The primary outcome compared the ECG signal clarity and determined whether there were differences in in rhythm types diagnosed between the two monitors. The secondary outcome assessed whether variances in the findings on the CAM or Zio-XT resulted in differences in clinical decision making and assessed the ease of use and comfort of each monitor. Patients (n=30) referred to a community cardiology practice had both ambulatory external monitors (AEM’s) placed with the intent of recording for seven days. After seven days, both monitors were returned to the manufacturer's reading center for processing and preparation of their standard ECG reports. During patch application and removal, a questionnaire to assess each device was completed by responsible medical technician. Additionally, the patients completed a questionnaire to assess both devices for comfort and ease of use. One patient was found to have no data recorded on the Zio- XT upon analysis by the Zio-XT reading center, and therefore, comparative ECG analysis was available for 29 of 30 patients. At the time of patch removal, both devices were considered user friendly. The CAM was slightly easier to attach and remove, was more stable, and was associated with less skin reaction. The patient experiences were comparable and favorable for both devices. When the managing physician was asked to recommend a specific clinical action based on the findings of each AEM separately, a difference in clinical decision making would have been made in 12 patients. The CAM recordings identified significantly more episodes of atrial tachycardia, atrial flutter, and nonsustained VT compared to the Zio-XT monitor (p<0.001, p<0.002, p<0.001; respectively). The CAM ECGs were ranked significantly higher in clarity compared to the Zio-XT (p<0.001). Differences in specific arrhythmias diagnosed between the two AEMs may result in differences in clinical decision making. Limitations reported included the small patient population, the study was not performed in a blinded fashion and the subjective nature of interpreting ECGs. Several prospective reviews, have compared the 24 hour Holter monitor to 14-day adhesive patch monitor (i.e., Zio® Patch, carnation ambulatory monitor) for the evaluation of cardiac arrhythmias. Smith et al. (2017) compared simultaneous recordings from an external patch system specifically designed to ensure better P-wave recordings (Carnation Ambulatory Monitor) and standard Holter monitor to determine diagnostic efficacy. The authors noted that in all 50 patients, the P-wave centric patch recording system identified rhythms in 23 patients (46%) that altered management, compared to six Holter patients (12%), (p<0.001). The patch ECG intervals PR, QRS and QT correlated well with the Holter ECG intervals and 48 patients (96%) preferred wearing the patch monitor. Study results in this review indicated that single-channel ambulatory patch ECG monitor, designed specifically to ensure that the P-wave component of the ECG be visible, resulted in a significantly improved rhythm diagnosis and avoided inaccurate diagnoses made by the standard 3-channel Holter monitor. Barrett et al. (2014) compared a 24-hour Holter monitor to the Zio® Patch. Over the total wear time of both devices, the adhesive patch monitor detected 96 arrhythmia events compared with 61 arrhythmia events by the Holter monitor (p<0.001). In a 24 hour period, the Holter monitor detected significantly more of the six types of arrhythmia events than the adhesive patch monitor. The Holter monitor detected 61 arrhythmia events compared with 52 arrhythmia events by the adhesive patch monitor (p=0.013). A total of 93.7% patients found the adhesive patch monitor comfortable to wear and 81% indicated they would prefer it over the Holter monitor. Rosenberg et al. (2013) also compared a 24-hour Holter monitor to the Zio® Patch for the evaluation of patients currently undergoing the management of paroxysmal AF. The authors reported no difference in AF burden estimated by the Zio® Patch and the Holter monitor, AF events were identified in 18 additional individuals, and the documented pattern of AF (persistent or paroxysmal) changed in 21 patients after Zio® Patch monitoring. Other clinically relevant cardiac events recorded on the Zio® Patch after the first 24 hours of monitoring, including symptomatic ventricular pauses, prompted referrals for pacemaker placement or changes in medications. As a result of the findings from the Zio® Patch, 28.4% of patients had a change in their clinical management. It was concluded that the Zio® Patch was well tolerated, and allowed Medical Coverage Policy: 0547 significantly longer continuous monitoring than a Holter, resulting in an improvement in clinical accuracy. Technology Assessment: A Hayes Medical Technology Directory (2019) report evaluated the evidence (n=74–122,454 adults/8 studies; n=332–3209 children/2 studies) which assessed the following: Zio Patch monitoring in adults with an arrhythmia or a suspected arrhythmia (six studies); Zio Patch monitoring in asymptomatic adults who are at risk of developing an arrhythmia (two studies); and Zio Patch monitoring in children (two studies). The review included one randomized controlled trial with matched cohort study, three prospective studies and six retrospective studies evaluating Zio Patch monitoring in children and adults. Follow-up timeframes ranged from 90 days to one year. In general adults or children were included who were referred for ambulatory cardiac rhythm monitoring to evaluate a known arrhythmia, to identify potential arrhythmia(s) suggested by symptoms or for screening. Definitive patient selection criteria have not been established for the Zio Patch continuous ECG monitor and the included studies did not provide adequate evidence to inform patient selection decisions. The most commonly reported adverse event was skin irritation which was mild in nature. A low-quality body of evidence in patients with known or suspected arrhythmias suggests continued detection of clinically significant arrhythmias (primarily AF) beyond 24 hours when using the Zio Patch monitoring system compared with another ECG monitoring system alone. There is insufficient evidence to draw conclusions regarding the clinical validity or utility of the Zio Patch in asymptomatic adults who are at risk of developing an arrhythmia or in children. The annual review in 2020 included four abstracts, (one randomized controlled trial, one prospective cohort study, one matched case- control study, and one systematic review) and did not identify any new evidence that would alter the existing findings (Hayes, 2019). Event Monitors: An external cardiac event monitor is used for patients with less frequent (i.e., weekly to monthly) symptoms of palpitations, presyncope, or syncope. Event monitors can be worn continuously or applied during symptomatic events. When an event is detected, ECG data are stored for a predefined amount of time prior to the event (looping memory) and a period of time after activation (Madias, 2020; Steinberg, et al., 2017). There are several types of event monitors: Post Event Monitoring devices are generally small, lightweight devices that can be placed on the patient’s chest upon the onset of symptoms. The patient's rhythm is stored for a specified amount of time after recording begins (e.g., 30 to 150 seconds). Event/Loop Recorders are devices that constantly record for a pre-specified period, but do not save the data until they are triggered to do so by the patient pushing an event button. The device will record and save the patient's rhythm for a pre-specified amount of time before and after activation of the device (e.g., 30 seconds prior to and 60 seconds after the event). Auto-triggered Event Recorders are more advanced devices. In addition to recording and saving symptomatic patient-triggered events, these devices have auto-detect features that will capture asymptomatic arrhythmias based on detection algorithms (e.g., atrial fibrillation events or bradycardia events). U.S. Food and Drug Administration (FDA) There are numerous manufacturers of external cardiac event monitoring devices which can be found on the FDA Center for Devices and Radiologic Health 510(k) database (FDA, 2021). An example of an FDA approved external loop monitor is the King of Hearts Express® AF (Card Guard Scientific Survival). The FDA approval granted 510(k) approval on 4/5/2002. It is indicated for diagnostic evaluation of patients who experience transient dizziness, palpitations, syncope or chest pain (FDA, 2002). Medical Coverage Policy: 0547 Literature Review - Event Monitoring: Evidence in the peer-reviewed scientific literature and professional society recommendations supports the clinical utility of ambulatory external cardiac event monitoring. Evidence in the published literature consists of systematic reviews, case studies and few well-designed clinical trials (Callum, et al., 2020; Gladstone, et al., 2014; Sivakumaran, et al., 2003; Krahn, et al., 2001; Krahn, et al., 1999). Randomized Controlled Trial: Gladstone et al. (2014) conducted a randomized controlled trial that evaluated if intensive ambulatory cardiac monitoring would increase the detection and treatment of atrial fibrillation in patients with unexplained stroke or TIA when compared to standard monitoring and follow-up. Patients (n=572) who had had a non-diagnostic cryptogenic ischemic stroke or TIA within the previous six months were randomly assigned to undergo ambulatory ECG monitoring with a 30-day event-triggered loop recorder (intervention group) (n=287) or an additional 24-hour Holter monitoring (control group) (n=285). Patients were included if they were 55 years of age or older, did not have known atrial fibrillation and had had an ischemic stroke or TIA of undetermined cause within the previous six months, diagnosed by a stroke neurologist after a standard workup, including 12-lead ECG, ambulatory ECG monitoring with the use of a Holter monitor for a minimum of 24 hours, brain and neurovascular imaging and echocardiography The primary outcome measured newly detected atrial fibrillation lasting 30 seconds or longer within 90 days after randomization. Secondary outcomes measured episodes of atrial fibrillation lasting 2.5 minutes or longer and anticoagulation status at 90 days. The detection of atrial fibrillation was statistically significant in the intervention group for atrial fibrillation lasting 30 seconds or longer and atrial fibrillation lasting 2.5 minutes or longer (p<0.001). By 90 days, oral anticoagulant therapy had been prescribed significantly more for patients in the intervention group than in the control group (p=0.01). The authors concluded that noninvasive ambulatory ECG monitoring for a target of 30 days significantly improved the detection of atrial fibrillation by a factor of more than five and nearly doubled the rate of anticoagulant treatment, as compared with the standard practice of short-duration monitoring. Mobile cardiac outpatient telemetry: Mobile cardiac outpatient telemetry (MCOT) devices are similar to external event monitors, except that the data are transmitted wirelessly in real time to a monitoring center that is monitored 24 hours a day. The transmitted data may be from preprogrammed arrhythmias or patient activation. This offers the potential for real-time, immediate feedback to a healthcare provider for evaluation. MCOT is useful for patients with severe intermittent symptoms or if the differential diagnosis includes a potentially dangerous arrhythmia that should be diagnosed expeditiously. These devices are worn continuously and can be embedded in a patch, necklace pendant, or a chest belt carrier (Olgin, 2020; Shen, et al., 2017; Steinberg, et al., 2017). U.S. Food and Drug Administration (FDA): Multiple MCOT devices have been approved by the U. S. Food and Drug Administration (FDA) through the Premarket Approval (PMA) process. Manufacturers of MCOT devices include, but are not limited to: CardioNet ambulatory ECG monitor with arrhythmia detection (San Diego, CA), HEARTLink™ II (Greensburg, PA) and LifeWatch Mobile Cardiac Telemetry 3 Lead LifeWatch MCT Literature Review - Mobile cardiac outpatient telemetry: There is evidence to support the clinical utility of mobile cardiac outpatient telemetry in the diagnosis of cardiac arrhythmia in a specific subset of individuals (Derkac, et al., 2017; Favilla, et al., 2015). Systematic Reviews: Sposato et al. (2015) conducted a systematic review and meta-analysis to estimate the proportion of newly diagnosed patients with atrial fibrillation after four sequential phases of cardiac monitoring following a stroke or transient ischemic attack. Fifty studies (n=11,658 patients) met the inclusion criteria. The criteria included studies that had the following Medical Coverage Policy: 0547 diagnostic methods: admission ECG, serial ECG, continuous inpatient ECG monitoring, continuous inpatient cardiac telemetry, Holter monitoring, mobile cardiac outpatient telemetry, external loop recording, and implantable loop recording. The diagnostic methods were placed into four phases. Phase 1 was acute assessment in the emergency room which consisted of admission ECG. Phase 2 included the in-hospital stay and consisted of serial ECG, continuous inpatient ECG monitoring, continuous inpatient cardiac telemetry, and in-hospital Holter monitoring. The third phase was the first ambulatory period which consisted of ambulatory Holter monitoring. The fourth phase was the second ambulatory period which used long-term, sophisticated monitoring methods (usually after previous diagnostic attempts with similar methods) and consisted of mobile cardiac outpatient telemetry, external loop recording, and implantable loop recording. The proportion of patients diagnosed with post-stroke atrial fibrillation was 7.7% in phase 1, 5.1% in phase 2, 10.7% in phase 3 and 16.9% in phase 4. The overall atrial fibrillation detection yield after all phases of sequential cardiac monitoring was 23.7% There were no differences (p=0.97) between the proportion of patients diagnosed with post-stroke atrial fibrillation by mobile cardiac outpatient telemetry, external loop recording, and implantable loop recording. The authors concluded that a combination of diagnostic methods could improve patient outcomes and guide future research. Hoefman et al. (2010) published a systematic review on diagnostic tools for detecting cardiac arrhythmias. Descriptive and experimental studies were found. The studies compared the yield of two or more devices or diagnostic strategies. The authors reported that Holter monitors had less diagnostic yield (33–35%) than event recorders. Automatically triggered recorders detected the more arrhythmias (72–80%) than patient-triggered devices (17–75%). Implantable devices are used for prolonged monitoring periods in patients with infrequent symptoms or unexplained syncope. Combined analysis was not performed due to the heterogeneity of the study populations and study designs. The limitations in the evidence base precluded any specific recommendations on selection of devices. The authors reported that the choice of device should be driven largely by the presence, type, and frequency of symptoms experienced by each individual. Retrospective Study: Kadish et al. (2010) retrospectively analyzed patient characteristics, diagnostic yield, and diagnoses of patients in a large commercial database (LifeWatch Services, Inc., Rosemont, Illinois). The purpose of the present study was to evaluate the potential advantage of the immediate response feature. All patients (n=26,438) who underwent monitoring from April to December 2008 at a single service provider formed the patient population of this study. Arrhythmic events noted in these patients were defined as those requiring physician notification and those that represented potentially life-threatening arrhythmias. Of the 26,438 patients included in the study, 5459 (21%) had arrhythmic events meeting physician notification criteria during a mean monitoring period of 21 days. Of these, 262 patients (1%) had arrhythmic events that could potentially be classified as emergent. These included 120 patients with wide complex tachycardia > 15 beats at > 120 beats/min, 100 patients with pauses > 6 seconds, and 42 patients with sustained heart rates < 30 beats/min. An additional 704 patients (3%) had narrow complex tachycardia > 180 beats/min at rest. Limitations of the study include lack of a comparison group, no information on patient outcomes and detailed information on the patient population was not reported. Ambulatory External Cardiac Monitoring – Other Indications: Ambulatory external monitoring has been proposed for the treatment of multiple other disorders including but not limited to: monitoring for post-operative atrial fibrillation and detecting arrhythmias after myocardial infarction in asymptomatic patients. Overall, improved health outcomes following ambulatory cardiac monitoring for the treatment of these conditions have not been established (Kwun, et al., 2022; Singh, et al., 2022; Ha, et al., 2021). Literature Review – Other Indications: Medical Coverage Policy: 0547 Randomized Controlled Trial: Ha et al. (2021) conducted a randomized controlled trial (RCT) that evaluated if continuous cardiac rhythm monitoring improves the detection of post-operative atrial fibrillation (POAF) among cardiac surgical patients during the first 30 days after hospital discharge compared to usual care. Cardiac surgical patients (n=336) with CHADS-VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes, prior stroke or transient ischemic attack, vascular disease, age 65–74 years, female sex) score greater than or equal to four or greater than or equal to two with risk factors for POAF, no history of preoperative AF, and POAF lasting less than 24 hours during hospitalization were included in the study. Patients were randomly assigned to the monitoring group (n=163) or to usual care (n=173). The intervention group underwent continuous cardiac rhythm monitoring with wearable, patch-based monitors for 30 days after randomization. Patients randomized to usual care did not undergo any protocol- mandated ECG monitoring within the first 30 days after randomization. The primary outcome measured cumulative AF and/or atrial flutter lasting six minutes or longer which was detected by continuous cardiac rhythm monitoring or by a 12-lead electrocardiogram within 30 days of randomization. Secondary outcomes included cumulative AF lasting six hours or longer and 24 hours or longer within 30 days of randomization, death, myocardial infarction, ischemic stroke, non-central nervous system thromboembolism, major bleeding, and oral anticoagulation prescription. Patients were followed up in-person at 1–3 months and six months after discharge from surgery. A telephone-based follow-up was conducted at nine months after discharge from surgery. The continuous cardiac rhythm monitoring group had significantly improved rate of AF detection during the first 30 days after hospital discharge (32/163; 9.6%) compared to usual care (3/173; 1.7%) (p<0.001). AF lasting six hours or longer was detected in 14 patients (8.6%) in the intervention groups and 0 patients in the usual care group (p<0.001). After discharge, major adverse cardiovascular events occurred in six patients (1.8%), two patients (1.2%) in the monitoring group and four patients (2.3%) receiving usual care. Author noted limitations included the short-term follow-up, preoperative cardiac monitoring was not done to rule out the presence of AF before surgery and subclinical AF could be prevalent among certain subsets of patients. Additionally, there was lack of compliance with monitoring by some patients that led to underestimation of AF. Lastly, the planned sample size and follow-up duration were not powered to detect for differences in major adverse cardiovascular outcomes, stroke rates in comparison with the presence of POAF, or whether oral anticoagulation therapy would alter the risk of such ischemic outcomes. No health disparities were identified by the investigators. Non-Comparative Study: Singh et al. (2022) conducted a prospective, multicenter, nonrandomized trial in India that assessed if early detection of arrhythmias using an external loop recorder (ELR) post myocardial infarction could predict one year mortality. The identifying high risk patients post myocardial infarction with reduced left ventricular function using external loop recorders (INSPIRE-ELR) trial included 249 patients within 14 days after MI with left ventricular ejection fraction (LVEF) ≤ 35% at discharge. Patients received a wearable external loop recorder (ELR) 5 ± 3 days after MI to monitor arrhythmias for seven days (phase 1 monitoring period) and again at 8–10 weeks after the index MI (phase 2 monitoring period). The primary outcome measured the incidence of pre-defined clinically significant arrhythmias in phase 1 monitoring period. Secondary outcomes measured 1) the incidence of clinically significant arrhythmias as recorded by ELR in phase 2 monitoring period; 2) the medical interventions performed and/or indicated based on ELR findings during phases 1 and 2 monitoring periods; 3) if patients with non- lethal arrhythmias documented by an ELR during phases 1 and 2 monitoring periods had a higher risk of all-cause mortality at 1 year; and 4) the association between ELR reported arrhythmias and incidence of SCD, resuscitated ventricular fibrillation (VF), and appropriate ICD shock. Enrolled patients were predominantly male (86%) with a mean age of 56 ± 12 years. In 82%, reperfusion had been done and all received standard of care cardiovascular medications at discharge. Of the 233 patients who completed monitoring, 81 (35%) experienced significant arrhythmias, including ventricular tachycardia/fibrillation (VT/VF): 10 (4.3%); frequent premature ventricular contractions (PVCs): 65 (28%); atrial fibrillation (AF): 8 (3.4%); chronic atrial flutter: 4 (1.7%); Medical Coverage Policy: 0547 2nd or 3rd degree atrioventricular (AV) block: 4 (1.7%); and symptomatic bradycardia: 8 (3.4%). In total, 26 patients died. Mortality was significantly higher in patients with clinically significant arrhythmia (p<0.0001). Of the163 patients who completed the phase 2 monitoring period, 61 (37.4%) had experienced clinically significant arrhythmias during the phase 2 monitoring, including VT/VF: 2 (1.2%); frequent PVCs: 54 (33.1%); AF: 3 (1.8%); 2nd or 3rd degree AV block: 1 (0.6%); and symptomatic bradycardia: 6 (3.7%). Mortality trended to be higher, but not clinically significant in patients with clinically significant arrhythmias (at 12 months after the monitoring period: p=0.057). Author acknowledged limitations included that the study only enrolled 250 patients of the planned 300 and the confidence interval for percentage of patients with clinically significant arrhythmia was wider than hypothesized. Additional limitations include the nonrandomized study design and the population only included patients in India and the results may not be applicable to other races or ethnic groups. The authors concluded that ELR applied in patients with acute MI and LV dysfunction at the time of discharge identifies patients with high mortality risk, however a prospective study is needed to evaluate whether ventricular arrhythmia is a major contributor to all-cause mortality and if early implantation of ICDs can be beneficial to manage these high-risk patients. Professional Societies/Organizations American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS): The ACC/AHA/HRS guidelines on the evaluation and management of patients with bradycardia and cardiac conduction delay stated that because of the prolonged monitoring duration, external loop recorders, transtelephonic event recorders, adhesive patch recorders, and mobile continuous outpatient telemetry monitoring provide a higher diagnostic yield than 24- or 48-hour Holter monitoring. These extended monitoring strategies can be useful in the evaluation of suspected bradycardia or conduction disorders (Kusumoto, et al., 2018). The ACC/AHA/HRS 2017 guideline for the evaluation and management of patients with syncope stated that there are several types of ambulatory cardiac rhythm monitoring devices. The selection and usefulness are highly dependent on the frequency of syncope and the likelihood of an arrhythmic cause of syncope. A patch recorder can considered as an alternative to an external loop recorder in select ambulatory patients with syncope of suspected arrhythmic etiology. The guideline also stated that the patch is less cumbersome than an external loop recorder. Patient-activated, transtelephonic monitor (event monitor) can be used when there are frequent, spontaneous symptoms that are likely to recur within 2–6 weeks. There is limited use in patients with frank syncope associated with sudden incapacitation. An external loop recorder (patient or auto triggered) is selected when there is frequent, spontaneous symptoms related to syncope, which are likely to recur within 2–6 weeks. Mobile cardiac outpatient telemetry (MCOT) is used when there are spontaneous symptoms related to syncope and rhythm correlation. High-risk patients whose rhythm requires real-time monitoring can benefit from MCOT (Shen, et al., 2017). International Society for Holter and Noninvasive Electrocardiology (ISHNE)/Heart Rhythm Society (HRS): The ISHNE and HRS consensus statement on ambulatory ECG and external cardiac monitoring/telemetry stated that accurate and timely diagnosis of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status (Steinberg, et al., 2017). The consensus statement made the following recommendations when selecting ambulatory ECG and external cardiac monitoring/telemetry: 24- to 48-hr Holter monitoring is recommended when frequent symptomatic events are anticipated to occur within the recording window Extended AECG monitoring (e.g., 15–30 days) is recommended when symptomatic event frequency is less than daily, or uncertain Medical Coverage Policy: 0547 Continuous monitoring (1–14 days) is indicated to facilitate quantification and trending of arrhythmia burden and patterns (e.g., ventricular ectopy, sinus tachycardia) Ambulatory Implantable Cardiac Event Monitoring An implantable electrocardiographic event monitor, also referred to as an implantable loop recorder (ILR), is used to continuously monitor a patient’s electrocardiogram for the detection of cardiac arrhythmias. ILRs are most commonly used in the evaluation of palpitations or syncope of undetermined etiology, particularly when symptoms are infrequent (e.g., less than once per month) and/or other ambulatory monitoring has been inconclusive. The goal is to capture the ECG at the time of the event and to distinguish a cardiac cause for transient loss of consciousness from other causes such as epilepsy, hypoglycemia, and transient ischemic attack (Benditt, et al., July 2022; Hayes 2016). ILRs are small leadless devices that are designed for subcutaneous implantation in the chest wall during a minimally-invasive surgical procedure. The preferred site for implantation is the left parasternal area of the chest. Sensing electrodes record a single-lead bipolar electrocardiogram (ECG), which can detect arrhythmias automatically or in response to patient activation. The episodes are recorded, stored and automatically transmitted wirelessly to the clinician through a cell phone, internet, or a patient monitor. According to the manufacturer, the battery has an estimated lifetime of 36–48 months. The device is removed when it is no longer needed, premature failure of the device or the battery is depleted. It may be replaced if clinically appropriate (Medtronic Inc, 2022; Galli, et al., 2016). U.S. Food and Drug Administration (FDA): There are numerous manufacturers of ILR’s which can be found in the FDA Center for Devices and Radiologic Health 510(k) database. Manufacturers of ILR devices include Abbott (Sylmar, CA), Biotronik (Lake Oswego, OR), Boston Scientific (Natick, MA), Sorin Group (Arvada, CO), Medtronic (Minneapolis, MN), Transoma Medical (St. Paul, MN) and St. Jude Medical (Sylmar, CA). Ambulatory Implantable Cardiac Event Monitoring - Cryptogenic Stroke: A stroke occurs in approximately 800,000 people each year in the United States; it can be a devastating diagnosis, associated with high morbidity and mortality. The standard evaluation of a patient presenting with stroke includes a comprehensive physical examination, basic hematologic tests, assessment of cardiac rhythm with cardiac and neurologic imaging. Despite these efforts, a definitive cause for stroke cannot be identified in 10%–40% of patients; these patients are considered to have suffered a cryptogenic stroke. A significant proportion of cryptogenic stroke survivors may have underlying atrial fibrillation (AF) which can be difficult to diagnose with conventional monitoring strategies since the arrhythmia is commonly asymptomatic and often occurs sporadically. Patients with a cryptogenic ischemic stroke or TIA without evidence of atrial fibrillation on electrocardiogram (ECG) and 24-hour cardiac monitoring, ambulatory cardiac monitoring is recommended for several weeks. Prolonged cardiac event monitoring increases the detection of subclinical AF in patients with TIA or acute ischemic stroke who present with sinus rhythm. Subclinical AF may be transient, infrequent, and largely asymptomatic and may be undetected on standard cardiac monitoring such as continuous telemetry and 24- or 48-hour Holter monitoring (Caplan, 2022; Prabhakaran and Elkind, 2022; De Angelis, et al., 2020; Musat, et al., 2018; Ringwala, et al., 2016). Literature Review - Cryptogenic Stroke: Evidence in prospective randomized controlled trials and observational studies support using ILR to detect atrial fibrillation in patients with cryptogenic stroke. Medical Coverage Policy: 0547 Randomized Controlled Trials: The Cryptogenic Stroke and Underlying AF (CRYSTAL AF) trial was a parallel group, randomized controlled trial conducted by Sanna et al. (2014) and compared the time to detection of atrial fibrillation using an implantable cardiac monitor or conventional follow-up in patients with cryptogenic stroke or transient ischemic attack (TIA). Patients (n=441) were randomized into two groups, the ICM group (Reveal XT; Medtronic) (n=221) or the control group (n=220). Patients assigned to the control group underwent assessment at scheduled and unscheduled visits, with ECG monitoring performed at the discretion of the site investigator. Patients eligible for the study were age 40 years and older without evidence of atrial fibrillation during at least 24 hours of ECG monitoring. Patients underwent randomization within 90 days after the index event that was supported by consistency between symptoms and findings on brain magnetic resonance imaging or computed tomography. Stroke was classified as cryptogenic after extensive testing did not reveal a clear cause. The primary end point was the time to first detection of atrial fibrillation (lasting > 30 seconds) within six months. Among the secondary end points was the time to first detection of atrial fibrillation within 12 months. Of the 441 randomly assigned patients, 416 (94.3%) completed six months of follow-up, two were lost to follow-up, five died, and 18 exited the study before six months. By six months, atrial fibrillation had been detected in 8.9% of patients in the ICM group (19 patients) versus 1.4% of patients in the control group (3 patients) (p<0.001). By 12 months, atrial fibrillation had been detected in 12.4% of patients in the ICM group (29 patients) versus 2.0% of patients in the control group (4 patients) (p<0.001). Of 208 ICMs that were inserted, five (2.4%) were removed due to infection at the insertion site or pocket erosion. The most common adverse events associated with the ICM were infection, pain and irritation or inflammation at the insertion site. The ICM remained inserted in 98.1% of patients at six months and in 96.6% of patients at 12 months. In 2016, Brachmann et al. published the long-term results of the Cryptogenic Stroke and Underlying AF (CRYSTAL AF) trial which were collected ≤ 36 months after randomization. Cumulative AF detection rates in the ICM arm increased progressively during this period (30.0%), but remained low in the control arm (3.0%). Among ICM patients with AF detected, the median time to AF detection was 8.4 months, 81.0% of first AF episodes were asymptomatic, and 94.9% had at least one day with > 6 minutes of AF. At study closure, 379 patients had completed the 12- month visit (n=194 ICM; n=185 control), 177 patients had completed the 24-month visit (n=88 ICM; n=89 control), and 48 had completed the 36-month visit (n=24 ICM; 24 control). Acknowledged limitations of the study included, uncertainty on whether the stroke was caused by atrial fibrillation, because not all cryptogenic strokes, are due to an arrhythmia. Additionally, the clinical significance of brief episodes of ICM detected atrial fibrillation is unknown and. not all episodes of atrial fibrillation can be accounted for, because the device has a limited memory. Finally, the algorithm for detection of atrial fibrillation is not infallible, although the accuracy is reported to be 98.5%. The authors concluded that ECG monitoring with an ICM was superior to conventional follow-up for detecting atrial fibrillation after cryptogenic stroke. In 2007, Giada et al. conducted a multicenter, prospective, randomized study to compare the diagnostic yield and the costs of an implantable loop recorder (ILR) with conventional treatment in patients with unexplained palpitations without severe structural heart disease. Patients (n=50) were randomized to conventional strategy (n=24) or to ILR implantation (n=26) with 1-year monitoring. Conventional treatment included 24 hour Holter recording, a four week period of ambulatory ECG monitoring with an external recorder, and electrophysiological study. The study included patients with infrequent (≤ 1 episode/month), sustained (> 1 minute) palpitations and a negative initial evaluation, including history, physical examination, and ECG. The primary end point was to establish the cause of the palpitations. A diagnosis was obtained in five patients in the conventional strategy group, and in 19 subjects in the ILR group (p<0.001). Despite the higher initial cost, the cost per diagnosis in the ILR group was lower than in the conventional strategy group. No adverse events were observed. Author noted limitations to the study included the highly specific study population preventing the results from being generalized to the entire Medical Coverage Policy: 0547 population with palpitations and the open label structure of the study. This study concluded that, in subjects with infrequent unexplained palpitations and without severe structural heart disease, ILR is a safe and cost-effective diagnostic approach. Non-Comparative Study: Ritter et al. (2013) investigated whether implantation of an insertable cardiac monitor (ICM) is feasible in patients with cryptogenic stroke, and compared the intermittent atrial fibrillation (iAF) detection rate of the ICM with seven day Holter monitoring. Sixty patients with acute cryptogenic stroke were included. All patients had to have embolic stroke patterns on cerebral imaging. ICM (Reveal XT) was implanted 13 days after the qualifying event. Seven-day Holter was performed after the ICM was implanted. The outcomes measured were the diagnosis of AF, time to first AF and recurrent stroke. The iAF was detected by the ICM in ten patients (17%) at 12 months. Only one patient (1.7%) had iAF during seven day Holter monitoring (P=0.0077). Episodes of iAF lasting two minutes or more were detected 64 days after implantation. There were no recurrent strokes during the observation period. The implantation procedure was well tolerated with no adverse events. The authors concluded that ICM implantation for the detection of iAF during outpatient follow-up is feasible in patients with cryptogenic stroke. ICMs offer a much higher diagnostic yield than seven day Holter monitoring. Technology Assessment: A Hayes Technology Brief on implantable cardiac loop recorders for detection of atrial fibrillation following cryptogenic stroke included nine clinical studies (n=22– 1247 patients) that evaluated ILRs for detection of atrial fibrillation (AF) following cryptogenic stroke. The review included a randomized controlled trial (RCT), a prospective cohort study, a retrospective database review, and six nested case-control studies. Overall, the quality of the evidence was moderate. Despite a number of poor-quality observational studies, a large, fair- quality randomized controlled trial (RCT) found that the ILR detected a higher number of AF events in patients with cryptogenic stroke compared with standard methods of monitoring. Results of the other studies, while of poor quality, had consistent findings suggesting that ILR detected AF in patients with a history of cryptogenic stroke. Use of the ILR in this patient population appears to be safe; the only reported complications included local irritation or infection. The annual review in 2019, did not change the conclusions of the original review (Hayes, 2017). Professional Societies/Organizations American Heart Association/Heart Rhythm Society (AHA/HRS): The 2021 AHA/HRS guideline for the prevention of stroke in patients with stroke and transient ischemic attack stated defined cryptogenic stroke as an imaging-confirmed stroke without a known source even with a full diagnostic assessment (including, at a minimum, arterial imaging, echocardiography, extended rhythm monitoring, and key laboratory studies such as a lipid profile and hemoglobin A1c [HbA1c]). Patients with a cryptogenic stroke who can take anticoagulation, long-term cardiac monitoring with mobile cardiac outpatient telemetry, implantable loop recorder, or other approach is reasonable to detect intermittent AF (Kleindorfer, et al., 2021). American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS): The 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation recommended that implantation of a cardiac monitor (loop recorder) is reasonable to optimize detection of silent AF in patients with cryptogenic stroke (i.e., stroke of unknown cause) in whom external ambulatory monitoring is inconclusive (January, et al, 2019). Ambulatory Implantable Cardiac Event Monitoring – Syncope: Syncope is a clinical syndrome characterized by transient loss of consciousness (TLOC) and postural tone, which can be caused by temporary cerebral hypoperfusion characterized by rapid onset, short duration, spontaneous, and complete resolution. (Bisignani, et al., 2018). Medical Coverage Policy: 0547 The initial evaluation of suspected syncope should include a comprehensive history, a physical examination and an electrocardiogram (ECG) (Benditt, July 2022). The comprehensive history should include the assessment of: pre-existing conditions: o structural heart disease o neurologic conditions o diabetes o alcohol/drug abuse o psychiatric disorders • medications that can cause syncope: o diuretics can cause hypovolemia and electrolyte disturbances o antihypertensive agents can induce or worsen orthostatic hypotension o beta blockers that can cause bradyarrhythmias family history that includes: o sudden death o o o seizure disorders or migraines familial cardiomyopathy familial predisposition to syncope The physical examination should include the assessment of: vital signs: o orthostatic vital signs o heart rate and rhythm o respiratory rate cardiovascular system o cardiac murmur o signs of pulmonary embolism neurological system Initial testing should include: an ECG should be done in all patients with suspected syncope o occasionally prolonged ambulatory cardiac monitoring is needed • an echocardiography if structural heart disease is known or suspected When the initial evaluation is undiagnostic, the patient is considered to have an unexplained diagnosis, this occurs in approximately 20 percent of cases. Ambulatory monitoring is indicated when a cardiac arrhythmia may be causing the syncope. The choice of the monitor system depends on the frequency of symptoms. Unless symptoms are occurring daily, a 24- or 48-hour Holter monitor is unlikely to make a diagnosis. Even in-hospital monitoring for one to three days may be nonproductive. In cases of significant but infrequent symptoms, longer-term ambulatory monitoring systems are more likely to be helpful. A patch monitor, external loop monitor or mobile cardiac outpatient telemetry (MCOT) may be selected for long term monitoring. ICMs are mainly used in the evaluation of palpitations or syncope of undetermined etiology, particularly when symptoms are infrequent and/or other ambulatory monitoring has been unrevealing or inconclusive (Benditt, May 2022). Literature Review – Syncope: The peer-reviewed medical literature supports the clinical utility of internal loop recorders for unexplained syncope. Evidence in the published literature primarily consists of systematic reviews and randomized controlled trials (Hindricks, et al., 2010; Giada, et al., 2007; Brignole, et al., 2006; Reiffel, et al., 2005; Farwell, et al., 2004; Sivakumaran, et al., 2003). Medical Coverage Policy: 0547 Randomized Controlled Trials: Sulke et al. (2016) conducted a prospective randomized controlled trial (RCT) to evaluate the use of a remotely monitored implantable loop recorder (ILR) as the first line investigation in unexplained syncope. The ILR (Sleuth, Transoma Medical Inc.) was compared to conventional therapy and a dedicated syncope clinic (SC). The study included patients > age 16 years with normal complete blood count, urea, electrolytes and blood glucose who had more than two episodes of recurrent unexplained syncope (RUS) in last 24 months. Patients (n=246) were randomized into four groups: ILR alone group (n=66), ILR + SC group (n=59), SC group (n=60) or conventional treatment group (n=61). The syncope clinic included computed tomography (CT), magnetic resonance imaging (MRI), external loop monitoring (ELR), echocardiography, electrophysiological study, and standard implantable loop recorder implantation. All patients randomized to attend the syncope clinic (SC and ILR + SC) were offered tilt testing (HUT). The primary outcome measured the time to ECG diagnosis and the secondary outcome was the time to the second syncopal event after randomization. Median follow-up was 20 months with five patients withdrawing from the study after enrollment and four patients declining ILR implantation. The time to electrocardiogram (ECG) diagnosis was significantly shorter with the ILR alone group and SC group when compared to the conventional group (p=0.0004 and p=0.002, respectively). Seventy-four percent of the first syncopal events documented in the SC groups occurred during provocative tilt testing. Twenty-two percent of patients who received an ILR were found to have a bradycardia indication for permanent pacing, compared with 3% of patients who did not receive an ILR. Overall, more investigative tests were undertaken in the conventional group than in any other. Only patients who received an ILR had a significant increase in time to second syncope (p=0.02), suggesting successful diagnosis and management of treatable causes of syncope. There were no implant related complications. An author noted limitation was head-up tilt induced syncope may not be the same as the initial syncopal episode, questioning if SC with or without HUT is beneficial. The authors summarized that implantable loop recorders offered rapid diagnosis, increased the likelihood of syncope being reported, demonstrated a high rate of intermittent bradycardia requiring pacing and reduced recurrent syncope. Furthermore, conventional management of syncope failed to achieve an ECG diagnosis despite a large number of investigative tests. Syncope clinic and provocative tilt testing delivered a rapid ECG diagnosis, but did not prevent recurrent syncope. Podoleanu et al. (2014) conducted a multicenter randomized open-label controlled trial (n=78) to evaluate the early use of an implantable loop recorder during a syncope evaluation. Patients were randomized into two groups. The ILR group (n=39) received a Reveal® or Reveal® Plus (Medtronic) ILR and the conventional (CONV) group (n=39) received a conventional evaluation commonly used by the attending physician, excluding the use of an ILR. The study included patients presenting with an unexplained single, severe, and recent (≤ 6 months) syncope or patients having ≥ 2 unexplained syncopal episodes with in the last 12 months. All syncopal events were unexplained by standard tests, including a 12-lead electrocardiogram (ECG), echocardiography and head-up tilt-test. The primary outcomes compared the diagnostic yield and costs of a common evaluation strategy for syncope with the early use of an ILR in low-risk patients and analyzed the quality of life (QoL) associated with the two strategies. The groups were followed for 14 months, with outpatient consultations scheduled at two, six, 10 and 14 months in the ILR group and at six and 14 months in the CONV group. After 14 months of follow-up, a certain cause of syncope was established in 18 (46.2%) patients in the ILR group and two (5%) patients in the CONV group (p<0.001). Patients in the ILR group were hospitalized for a non- significantly shorter period than patients in the CONV group and advanced cardiology tests were performed less frequently in the ILR group than in the CONV group (p=0.05). There was no difference between the two groups in terms of QoL. There were no adverse events related to syncope. Author noted limitations of the study included the small patient population and the cost of the device. It was concluded that in patients with unexplained syncope, the early use of an ILR Medical Coverage Policy: 0547 has a superior diagnostic yield compared with the conventional strategy, and lower healthcare- related costs. Da Costa et al. (2013) reported the results of a multicenter randomized prospective study that evaluated the clinical impact of the implantable loop recorder in patients with isolated syncope, bundle branch block (BBB) and a negative workup. Patients (n=78) were randomized into two groups, ILR with the Reveal ILR (n=41) or conventional strategy (n=37) for 36 months. Patients were included if they experienced one syncopal episode associated with any type of BBB with a QRS greater or equal to 120 millisecond; no evidence of second or third-degree AV block; and negative workup including an electrophysiological study (EPS). The primary endpoint was the time to occurrence of syncopal events associated with arrhythmias. Patients in the ILR group had follow-up visits every three months until the first symptomatic or asymptomatic episode was documented by electrocardiogram or until 36 months. Patients in the conventional strategy group were seen in the outpatient department at three, six, 12, 15, 18, 21, 24, 27, 30 and 33 months after randomization and at the study completion (36 months). At each visit, arrhythmic or cardiovascular events were recorded and a 12-lead electrocardiogram was obtained. Additionally, at each visit a Holter monitor was used for seven days, with analyses performed using the R Test Evolution (RTE) event recorder. ILR documented events occurred in 15 out of 41 patients after a median of six months; 11 (26.8%) patients presented with third-degree AV block; three (7.3%) presented with sick sinus syndrome (sinus arrest); and one (2.4%) presented with ventricular tachycardia. In the conventional group, three (8.1%) patients presented with third-degree AV block and one (2.7%) presented with sick sinus syndrome, after a median of nine months. Overall, 21 patients (27%) developed significant arrhythmic events: ventricular tachycardia (n=1; 1.3%); sudden death (n=2; 2.6%); third-degree (AV) block (n=14; 18%); and sick sinus syndrome (n=4; 5.1%). There was a clinically significant difference in relevant arrhythmias between the ILR group (n=15/41; 36.6%) and the conventional follow-up group (n=4/37; 10.8%) (p=0.02). Adverse events were not reported. Acknowledged study limitations included the small patient population, including patients after one episode of undiagnosed syncope and short term follow-up. The authors concluded this study demonstrated that ILR proved largely superior to conventional clinical follow-up in detecting recurrent events in patients with isolated syncope, BBB and negative EPS results, which may potentially impact therapeutic management. Systematic Reviews: A systematic review and meta-analysis of the literature (Solbiati, et al., 2017) analyzed the diagnostic yield of implantable loop recorders in patients with recurrent unexplained syncope in the absence of high-risk criteria and in high-risk patients after a negative evaluation. Prospective and retrospective studies with adults who underwent ILR implantation for undetermined syncope (49 studies; n=4381 patients) were included. The primary outcome was the overall diagnostic yield, defined as the proportion of patients with syncope recurrence and an available ILR recording or an automatic detection of a significant arrhythmia. Secondary outcomes were the proportions of patients with the specific etiologic diagnoses on the total of subjects and the proportion of an analyzable ECG recording during symptoms. The overall diagnostic yield was 43.9%. The proportions of subjects diagnosed with arrhythmic syncope, ventricular arrhythmias, supraventricular arrhythmias and bradyarrhythmias were 26.5%, 2.7%, 4.9% and 18.2%, respectively. The proportion of an analyzable ECG recording during symptoms was 89.5%. Median time to diagnosis was 134 days. The study concluded that about half of unexplained syncope subjects implanted with an ILR were diagnosed, and approximately 50% of them had an arrhythmia. A Cochrane review of four randomized controlled trials (RCTs) (n=579 patients) by Solbiati et al. (2016) assessed the incidence of mortality, quality of life, adverse events and costs of ILRs versus conventional diagnostic workup in people with unexplained syncope. All randomized controlled trials of adult participants (i.e., ≥ 18 years old) with a diagnosis of unexplained syncope comparing ILR with standard diagnostic workup were included. The primary outcomes were short Medical Coverage Policy: 0547 (i.e., within 30 days) and long-term all-cause mortality; other adverse events (cardiopulmonary resuscitation, intensive care unit admittance, major trauma, acute myocardial infarction, pulmonary embolism, major bleeding, aortic dissection ILR-related adverse events requiring either explant or treatment); and the quality of life during follow-up. The secondary outcomes were syncope relapse, economic costs and etiological diagnosis. The author concluded that all-cause mortality (death from any cause) was no different in people who received the ILR. Loop recorders did not seem to change quality of life, although people with an ILR had a significantly higher rate of diagnosis compared to participants in the standard assessment group. Moreover, data seemed to show a trend towards a reduction in syncope recurrences after diagnosis in people implanted with ILR. A Hayes Medical Technology Directory report on implantable cardiac loop recorders for the diagnosis and management of syncope in adults included 14 studies that evaluated the efficacy and safety of ILR implantation for recurrent syncope. The review included seven randomized controlled trials (RCTs) and seven observational cohort studies. Study sample sizes ranged from 60–939 patients. Included adult patients had unexplained, recurrent syncope or a suspicion of an underlying cardiac arrhythmia and structural heart disease, inherited cardiac condition or heart failure. Patients may have had negative or inconclusive results on standard tests that required confirmation or clarification. ILR results were compared to the results of standard tests (echocardiography, standard 12-lead ECG, 24-hour Holter monitoring, head-up tilt-table testing (TTT), electrophysiological (EPS) testing, external loop recorder (ELR), telemetry, etc.). Outcomes measured were diagnostic yield, syncope incidence and recurrence, treatment initiation based on ILR test results, outcomes of ILR-directed treatment for syncope, syncope-related trauma, quality of life, complications and mortality. Evidence from a moderate-quality body of evidence suggested that ILR is relatively safe. Additionally, when used as a part of a stepwise process, is superior to standard test strategies for patients with recurrent, unexplained syncope (RUS) and an inconclusive or negative diagnosis after initial clinical evaluation. The annual review in 2020, did not change the conclusions of the original review (Hayes, 2016). Professional Societies/Organizations American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS): The ACC/AHA/HRS guidelines on the evaluation and management of patients with bradycardia and cardiac conduction delay recommended that implantation of a cardiac monitor is reasonable if the initial noninvasive evaluation is non-diagnostic with infrequent symptoms (> 30 days between symptoms) and suspected to be caused by bradycardia (Kusumoto, et al., 2018). The ACC/AHA/HRS 2017 guideline for the evaluation and management of patients with syncope stated that implantable cardiac monitoring can be useful when evaluating select ambulatory patients with syncope of suspected arrhythmic etiology following a non-diagnostic initial workup (e.g., history & physical, 12 lead ECG). Further testing is recommended when the initial evaluation is unclear (e.g., orthostatic hypertension, tilt table testing) (Shen, et al., 2017). Heart Rhythm Society (HRS): The HRS expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope stated that implantable loop recorders (ILRs) can be useful for assessing recurrent and troublesome syncope in older patients who lack a clear diagnosis and are at low risk of a fatal outcome (Sheldon, et al., 2015; Reaffirmed 2020). Ambulatory Implantable Cardiac Event Monitoring - Other Indications: An implantable electrocardiographic event monitor (i.e., implantable loop recorder) has been proposed for the treatment of multiple other disorders including: routine monitoring of documented arrhythmias, screening asymptomatic patients or assessing the effectiveness of treatment. Medical Coverage Policy: 0547 ILR placement has been investigated as a tool to monitor for arrhythmias after a cardiac ablation and to guide anticoagulation. Surveillance for recurrence of atrial arrhythmias is important in patients who have undergone cardiac ablation. The optimal method for screening for episodes of AF after ablation is unknown (Lee and Mittal, 2018). However, serial or symptom-initiated standard ECGs, Holter monitoring (24 hours to 7 days) and transtelephonic recordings, patient- activated and automatically activated devices, and external loop recorders are among the commonly used noncontinuous monitoring tools. Although implantable loop recorders appear promising for the long-term assessment of AF burden, important limitations include less than 100% specificity due to myopotentials and atrial and ventricular premature beats, as well as limited memory, resulting in unretrievable electrograms that cannot be used to verify the correct rhythm diagnosis (Di Biase, et al., 2018; Ciconte, et al., 2017). Postablation anticoagulation is recommended in all patients for at least two months. After this two-month period of mandatory oral anticoagulation, the anticoagulant regimen in place prior to the procedure is restarted. For those patients without evidence of recurrent AF and whose risk for embolization is very low, anticoagulation can be stopped (Passman, 2022; Di Biase, et al., 2018). ILR placement has been investigated as a screening tool to detect subclinical AF. Subclinical AF is AF that is asymptomatic and not clinically apparent. Screening the general population for AF among persons > 65 years of age has not shown improved clinical outcomes when compared to the standard of care (e.g., pulse palpation on physical examination) (Kumar, 2022; Nasir, et al., 2017, Reiffel, et al., 2017). Literature Review – Other Indications Randomized Controlled Trials: Svendsen et al. (2021) conducted a randomized controlled trial (RCT) that assessed if atrial fibrillation screening using an implantable loop recorder (ILR) and use of anticoagulants can prevent stroke in individuals at high risk (The LOOP Study). Adults (n=6004) aged 70–90 years without atrial fibrillation and at least one additional stroke risk factor (i.e., hypertension, diabetes, previous stroke, or heart failure) were included in the study. Patients were randomly assigned in a 1:3 ratio to ILR monitoring (n=1501) or usual care (n=4503) (control). The primary outcome measured the combined endpoint of stroke or systemic arterial embolism. Secondary outcomes measured: (1) the combined endpoint of ischemic stroke, transient ischemic attack, or systemic arterial embolism; (2) the combined endpoint of stroke, systemic arterial embolism, or cardiovascular death; (3) cardiovascular death; and (4) all-cause death. Additional outcomes measured the diagnosis of atrial fibrillation, initiation of anticoagulation and major bleeding. No participants were lost to follow-up. All participants receiving ILR were followed up daily by continuous ECG monitoring with automated remote transmissions reviewed by a physician. If atrial fibrillation lasting at least six min was detected, oral anticoagulation was recommended. The ILR group had in-person follow-up visits annually for three years with subsequent follow-up by telephone contact and medical records. The control group had in-person follow-up at year three in the hospital and other visits took place by telephone contact and medical records. Remote monitoring continued until the end of service of the device, patient withdrawal, or death. During a median follow-up of 64·5 months, the diagnosis of atrial fibrillation and the initiation of oral anticoagulation occurred significantly more often in the ILR group (n=477, 31.8%; n=445, 29.7%, respectively) compared to the control group (n=550, 12.2%; n=591, 13.1%, respectively) (p<0.0001 for both). The endpoint of stroke or systemic arterial embolism and major bleeding was not significantly different between the two groups (p=0·11 for both). A potential study limitation included that the population only included patients in Denmark and the results may not be applicable to other races or ethnic groups. The authors concluded that ILR screening resulted in a three-times increase in atrial fibrillation detection and anticoagulation initiation but no significant reduction in the risk of stroke or systemic arterial embolism. The study Medical Coverage Policy: 0547 suggests that not all atrial fibrillation is worth screening for, and not all screen detected atrial fibrillation merits anticoagulation. No health disparities were identified by the investigators. Mamchur et al. (2020) conducted a randomized controlled trial that evaluated the efficacy of noninvasive ambulatory ECG monitoring (NIAM) compared to implantable loop recorder (ILR) in patients with atrial fibrillation (AF). Thirty Included patients had paroxysmal AF of different etiologies and the absence of the other types of rhythm or conduction disorders, a high European Heart Rhythm Association (EHRA) symptoms rate, and all of them were selected for scheduled catheter ablation due to the ineffectiveness of antiarrhythmic therapy. Patients were randomized into two groups. Group I (n=15) received the Reveal XT ILR for invasive ECG monitoring for up to three months and group II (n=17) used the Spyder noninvasive ambulatory ECG monitoring (NIAM) for up to 14 days. Scheduled visits were planned for a period of 14 days and three months after implantation. Unscheduled visits occurred after documentation of at least two episodes recorded manually, or when indicating the presence of automatic records on the patient's assistant. The outcomes measured the detection of symptomatic and asymptomatic AF episodes, as well as symptomatic and asymptomatic episodes of other arrhythmias. In both groups, at least one AF episode was detected during 14 days of monitoring. The overall count of AF episodes was 25 in NIAM group and 28 in ILR group. The mean time between AF start and its registration by a physician was significantly higher in the NIAM group at eight hours compared to 20 hours in ILR group (p=0.005). The NIAM group had a sensitivity of 80.1%, specificity of 73.1%, positive predictive value of 74.1%, and negative predictive value of 79.2%. Corresponding values for the ILR group were 78.6%, 69%, 71%, and 77%. At the same time, continued monitoring with ILR for longer than two weeks did not lead to a significant change in the sensitivity and specificity of the method. An author noted limitation was that both methods were compared in different patient groups instead of simultaneous ECG recording of both types of devices in the same patients. The author concluded that in patients with paroxysmal AF, the diagnostic value of both NIAM and ILR is comparable. An increase in the duration of ECG monitoring for longer than two weeks does not provide additional diagnostic information. two patients with AF were included in the study. ‐ Kapa et al. (2013) conducted a prospective, randomized trial (ABACUS study) to evaluate utility of an implantable loop recorder (ILR; Reveal XT, Medtronic, Inc) versus conventional monitoring (30- day transtelephonic monitors at discharge and after five months) for assessing arrhythmia burden and patient management post AF ablation. After AF ablation, patients (n=44) received ICMs and conventional monitoring. Conventional monitoring (CM) was monitored for 12 months which included wearing a monitor over three separate 30-day periods over the first year post-ablation and daily pulse checks. The conventional monitoring strategy was used for the first six months post-ablation. During the next six months, patients were monitored using the data from the Reveal device, transmitted from home every 30 days. The ILR was explanted in four patients. Over a mean follow-up of 6±1 months, 28 of the remaining 40 pts (70%) experienced AF (most within six weeks after ablation), which was correctly detected by ILR in 27 (96%) and by CM in 16 pts (57%). Patients with AF recurrences detected by both ILR and CM had a significantly higher AF burden than those with AF recurrences detected by ILR only (p<0.05). In eight patient (20%) ILR misclassified sinus rhythm with frequent premature atrial/ventricular complexes as AF. Additionally, signal under-sensing resulted in ILR rhythm misclassification as asystole or bradycardia in 10 patients (25%). ILR did detect true bradycardia or asystole in six pts (15%) which resulted in pacemaker implant in two patients and drug modification in three patients. Pokushalov et al. (2011) conducted a prospective, randomized study to identify the optimal treatment of patients with AF recurrences after the first ablation. Two hundred eighty-six patients with highly symptomatic, drug-refractory paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions) and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic). Patients without AF recurrences during the three month Medical Coverage Policy: 0547 postablation period were assigned to group 1; those with AF recurrences to group 2. Patients in group 2 were randomly assigned to group 3 or group 4. Group 3 patients were treated only with antiarrhythmic drugs for six weeks, with no early reablation during the three month postablation period. In the case of AF recurrence after the 3-month postablation period, patients underwent reablation. Group 4 patients were treated according to the onset mechanism of AF recurrences, as detected and stored by the implantable cardiac monitor: antiarrhythmic drug therapy, but no reablation if AF was not preceded by triggers; early reablation if premature atrial beats or atrial tachycardia’s or flutter triggered AF. The measured outcome this study was to identify the most appropriate strategy for treating patients with AF recurrences after the first ablation, through the diagnostic data stored by a subcutaneous AF monitor. All patients were followed up for one year to assess maintenance of sinus rhythm in each group. On 12-month follow-up examination, of the 119 (42%) patients in group 1, 112 (94%) had no AF recurrences. Among the 83 patients in group 3, only 27 (33%) had no recurrences. Of the 84 group 4 patients, 67 (80%) had no AF recurrences (p<0.0001 versus group 3). Author noted limitations included small patient population and the usual definition for failures (>30 seconds of AF) was not used, which could result in a different result. Evidence in the published, peer-reviewed scientific literature is inadequate to support improved clinical outcomes. A majority of the studies lack control groups, large sample populations, and measurement of long-term outcomes, therefore no conclusions can be made regarding the safety and efficacy of an implantable loop recorder to treat these conditions. Professional Societies/Organizations Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society/ Asia Pacific Heart Rhythm Society/Latin American Society of Cardiac Stimulation and Electrophysiology. (HRS/EHRA/ECAS/APHRS/SOLAECE): The 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation recommended that arrhythmia monitoring for efficacy of catheter ablation is typically delayed for at least three months postablation unless required to evaluate arrhythmia symptoms during the early postablation period. The two main reasons to perform arrhythmia monitoring following catheter ablation are clinical care and as part of a clinical research trial. Additionally, the consensus statement recommended that adherence to atrial fibrillation anticoagulation guidelines is recommended for patients who have undergone an AF ablation procedure, regardless of outcome of the procedure. If anticoagulation is needed for more than two months post ablation, the patient’s stroke risk profile should be used and not the perceived success or failure of the ablation procedure (Calkins, et al., 2017). U.S. Preventive Services Task Force (USPSTF): According to an USPSTF recommendation statement on screening for atrial fibrillation, there is a lack of evidence to assess the balance of benefits and harms of screening for AF. As such, the USPSTF cannot recommend screening for AF in asymptomatic adults (USPSTF, et al., 2022). Cardiac Self-Monitoring Some cardiac event monitors combine a cellular phone with a heart monitor. This type of self- monitoring device can be used without a physician’s prescription. One example is the AliveCor Heart Monitor (AliveCor, Inc., San Francisco, CA). This is an iPhone-enabled heart monitor that has been known as the iPhoneECG. It is in a thin case with two electrodes that snap onto the back of an iPhone. To obtain an ECG recording, the individual holds the device while pressing fingers from each hand onto the electrodes. It has been proposed that the device can obtain an ECG from the patient's chest. The AliveCor ECG iPhone application can record rhythm strips of any duration Medical Coverage Policy: 0547 to be stored on the phone and uploaded securely for later analysis, sharing, or printing through AliveCor's website. The AliveCor Heart Monitor operates for about 100 hours on a 3.0 V coin cell battery. These self-monitoring devices and/or software applications that are used for downloading ECG data to a device such as personal computer, smart phone, or tablet are considered convenience items for the individual and not medically necessary for any indication. U.S. Food and Drug Administration (FDA): A number of remote and wearable ECG devices have been approved through the 510(k) process of the U.S. Food and Drug Administration (FDA) as Class II devices for diagnostic use. There are several FDA-approved devices including, but not limited to: AliveCor, KardiaMobile, and the Zeus System (Zio Watch). Literature Review – Cardiac Self-Monitoring: Koh et al. (2021) conducted a randomized controlled trial that evaluated smartphone electrocardiogram for detecting atrial fibrillation after a cerebral ischemic event. Patients (n=203) were randomized to undergo one additional 24-h Holter monitoring (control group, n=98) or 30-day smartphone ECG monitoring (intervention group, n=105) using KardiaMobile (AliveCorVR, Mountain View, CA, USA). Included patients were age ≥ 55 years, not known to have AF and had an ischemic stroke or TIA of undetermined cause within the previous 12months. The primary outcome measured the detection of one or more episodes of ECG-documented AF lasting 30 seconds or longer within three months after randomization. Detection of AF outside the monitoring period but within three months from randomization was also included. Secondary outcomes measured the usage of anticoagulation therapy at three months and the performance of KardiaMobile. AF lasting more than 30 seconds was detected in 10 of 105 patients in the intervention group and two of 98 patients in the control group (p=0.024). After the 30-day smartphone monitoring, there was a significantly higher proportion of patients on oral anticoagulation therapy at three months compared with baseline in the intervention group (p=0.002). Author noted limitations included using a single-lead ECG to monitor for AF and even though the secondary outcome showed a significantly higher number of patients prescribed anticoagulation therapy in the intervention group, the proportion of patients on anticoagulation therapy was not statistically significantly different at three months when compared between the two groups. No health disparities were identified by the investigators. In 2020 Hayes, Inc. published an evidence analysis research brief evaluating patient use of mobile medical applications for the detection of cardiac arrhythmias. The review included 24 abstracts, including one randomized controlled trial (RCT), one prospective comparative study, seven prospective controlled studies, three prospective uncontrolled studies, two retrospective comparative studies, three retrospective controlled studies, four retrospective uncontrolled studies, one systematic review, one meta-analysis and one literature review. Rhythm data was collected by a variety of app users including clinicians, pharmacists, and patients across multiple care settings including intensive care units, interventional cardiology labs, pharmacies, and outpatient centers. Hayes concluded that there is sufficient published evidence to evaluate this technology. The study abstracts present conflicting findings regarding mobile medical apps (MMAs) for patient use in detecting cardiac arrhythmias. The overall the findings are conflicting for improvement of health outcomes, and until reviewed further conclusions regarding the safety and effectiveness could not be made. Use Outside of the US In 2022, the European Stroke Organisation (ESO) published a guideline on screening for subclinical atrial fibrillation after stroke or transient ischemic attack of undetermined origin. The guideline recommended prolonged cardiac monitoring instead of standard 24 hour monitoring to increase the detection of subclinical AF, however it is unknown if longer monitoring improves clinical outcomes. Additionally the guideline stated that “although insertable loop recorders (ILR) increase AF detection based on their longer monitoring duration, comparison with non-implantable ECG devices for similar monitoring time is lacking.” The ESO suggested using implantable devices, Medical Coverage Policy: 0547 if available, for AF detection instead of non-implantable devices to increase the detection of subclinical AF (Rubiera, et al., 2022). In 2022, the National Institute for Health and Clinical Excellence (NICE) (United Kingdom) published a medical technologies guidance on KardiaMobile for detecting atrial fibrillation. NICE stated that the “KardiaMobile is recommended as an option for detecting atrial fibrillation (AF) for people with suspected paroxysmal AF, who present with symptoms such as palpitations and are referred for ambulatory electrocardiogram (ECG) monitoring by a clinician” (NICE, 2022). ESC guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with European Association for Cardio-Thoracic Surgery (EACTS) recommended using short-term ECG recording for at least the first 24 hours, followed by continuous ECG monitoring for at least 72 hours to monitor for AF in patients with acute ischemic stroke or TIA without previously known AF. Additionally, in select stroke patients without known AF, additional ECG monitoring using long- term non-invasive ECG monitors or insertable cardiac monitors can be considered, to detect AF. The guideline recommended that oral anticoagulation is continued for at least two months post ablation. Long-term continuation of anticoagulation beyond two months post ablation is based on the patient’s stroke risk profile and not on the success or failure of the ablation procedure (Hindricks, et al., 2021). In 2020, the National Institute for Health and Clinical Excellence (NICE) (United Kingdom) published a medical technologies guidance on the Zio XT for detecting cardiac arrhythmias. NICE stated that Zio XT is convenient and easy to wear, with an improved diagnostic yield when compared to standard 24-hour Holter monitoring. The “Zio XT is recommended as an option for people with suspected cardiac arrhythmias who would benefit from ambulatory electrocardiogram (ECG) monitoring for longer than 24 hours. The NHS organizations need to collect information on the resource use associated with using the Xio XT and the long-term consequences for those who use this monitoring” (NICE 2020). The National Institute for Health and Clinical Excellence (NICE) (United Kingdom) diagnostics guidance on Lead-I ECG devices for detecting symptomatic atrial fibrillation using single time point testing in primary care stated that there is a lack of evidence to recommend the routine adoption of lead-I electrocardiogram (ECG) devices (imPulse, Kardia Mobile, MyDiagnostick and Zenicor- ECG) to detect atrial fibrillation when used for single time point testing in primary care for people with signs or symptoms of the condition and an irregular pulse. Further research is needed to determine how using lead-I ECG devices in this way affects the number of people with atrial fibrillation detected, compared with current practice and how ECGs generated by the devices would be interpreted in practice, including staff time needed to interpret the ECG traces and associated costs (NICE, 2019). The European Society of Cardiology (ESC) guidelines for the diagnosis and management of syncope, updated in 2018, included recommendations for implantable loop recorders. ILR is recommended during an early phase of evaluation in patients with recurrent syncope of uncertain origin, absence of high-risk criteria and a high likelihood of recurrence within the battery life of the device. ILR is indicated in patients with high-risk criteria (e.g., new onset chest pain, palpitations, syncope during exertion, severe structural or coronary artery disease) when a comprehensive evaluation (e.g., H&P, ECG, supine and standing BP, echocardiogram, tilt table testing) does not demonstrate a cause of syncope or lead to a specific treatment, and without conventional indications for primary prevention ICD or pacemaker indication. ILR should be considered in patients with suspected or certain reflex syncope presenting with frequent or severe syncopal episodes. Additionally, ESC recommended that ILR may be considered in patients in whom epilepsy was suspected but the treatment has proven ineffective and in patients with unexplained falls (Brignole, et al., 2018). Medical Coverage Policy: 0547 European Heart Rhythm Association (EHRA), Heart Rhythm Society (HRS), and Asia Pacific Heart Rhythm Society (APHRS) guidelines for the management of patients with ventricular arrhythmias (VAs) addressed the indications for diagnostic testing, the present state of prognostic risk stratification, and the treatment strategies that have been demonstrated to improve the clinical outcome of patients with VAs. The consensus recommendations on general diagnostic work-up stated that prolonged ECG monitoring by Holter ECG, prolonged ECG event monitoring, or implantable loop recorders should be considered when documentation of further, potentially longer arrhythmias would change management (Pedersen, et al., 2014). The National Institute for Health and Clinical Excellence (NICE) (United Kingdom) clinical guideline on transient loss of consciousness ('blackouts') for patients aged 16 years or older stated that for people with a suspected cardiac arrhythmic cause of syncope, the type of ambulatory ECG offered should be chosen on the basis of the person's history (and, in particular, frequency) of TLoC. For people who experience TLoC infrequently (less than once every two weeks), offer an implantable event recorder (NICE, 2010; updated 2016).