Ambulatory external Holter monitors (HMs) offers an alternate method of testing for heart disease. Traditionally, an exercise stress test has been used to diagnose or confirm heart disease. However, an exercise stress test is not foolproof, often producing false negative or positive results. Due to other medical conditions (such as arthritis), some patients are unable to undergo exercise stress tests. The HM provides continuous details during a 24- to 48-hour time span.
In 2009, a newer extended EKG monitor patch system for use from 48-hours to up to 14-days was approved by the FDA. The literature search through October 2011 reveals one clinical trial in Spain comparing a one-day HM use to a seven-day HM in 63 patients. The authors concluded that the seven-day HM did not significantly increase the detection of nonsustained atrial tachycardia or atrial fibrillation. They did concluded the seven-day HM improved in the detection and revealed better characterization of ventricular arrhythmic episodes, but was less useful for supraventricular events. Therefore, not all arrhythmias are detected by extending HM beyond 48 hours. Dagres et al. report a study published in 2010 of 215 patients using HMs for seven-days six-months after catheter ablation for atrial fibrillation. Analysis was done on patients who had a recurrence within the first 24-, 48-, and 72- hours, etc. up to the total of seven-days. During the complete 7-day recording, 30% had a recurrence. They speculated that 24-hours of detection would find 59% of recurrences, a 48-hour recording would find 67% and a 72-hour HM, 80% of patients would show recurrences. The authors concluded a HM duration of less than 4-days may miss recurrences, a 4-day recording “might offer a reasonable comprise” when compared to using a HM for 7-days.
Additional studies were also cited by the ZEUS system manufacturer, which compared standard HMs to delayed-time and/or auto-activated ambulatory event monitors (AEMs). These studies were retro-review of patient records, randomized cross-over trials, or case-series. In 2011, a clinical trial was started, NCT01382953, known as the “The Simple ECG Monitoring” for comparison of a sternal EKG patch system with the standard HM system. The investigators intent is to review the “very small innovative monitor patch system that relieves the patient a cumbersome and uncomfortable recording system”. The scientific evidence to date remains insufficient to conclude using an EKG monitor patch system beyond 48-hours up to 14-days improves health outcomes, when other AEMs are available for use beyond 48-hours. Therefore, the coverage position of the medical policy is not medically necessary.
Real-time AEMs reflect a trend in the medical device industry toward the miniaturization of large medical devices. The FDA cleared the device based on design controls used in the manufacture of the device and on a comparison to standard EKGs currently marketed. However, if a patient has a potentially serious event or a suspicion of a serious/life threatening event that requires the availability of constant 24-hour monitoring, that patient should not be managed in an outpatient setting where there is an inability to appropriately intervene immediately when the event occurs. In that circumstance, such patients should be appropriately monitored in a hospital cardiac care unit. The same applies to delayed-time monitoring supplemented with 24-hour technician or physician readout availability.
Delayed-time AEMs are a well-established technology that is typically used to evaluate episodes of cardiac symptoms (palpitations, dizziness, and syncope). AEMs also monitor other cardiac conditions requiring specialized management, which, due to their infrequency, would escape detection using a standard 24- or 48-hour HM and reduce the necessity of repeated Holter monitoring.
For auto-activated AEMs, a focus review was done for the 2006 policy update. Several studies, including an analysis of a database of 100,000 patients, compared the diagnostic yield of automatic- and patient-activated arrhythmia recordings, and reported an improved yield with auto-triggering devices. However, one comparative study of 50 patients noted that auto-activation may result in a large number of inappropriately stored events.
A phase II pivotal study (NCT00781118) is underway accessing the AngelMed Guardian System, a permanent implantable continuous intracardiac ischemia detection or monitoring system (IIDS). The ALERTS (AngelMed for Early Recognition and Treatment of STEMI [ST elevation myocardial infarction]) study is a prospective, randomized multi centered pivotal trial in 100 centers and 1,020 patients with a high-risk of having a myocardial infarction or heart attack, due to acute coronary syndrome or bypass surgery. The system is designed to detect acute ST elevation changes, to alert patients to seek medical attention, and store EKG traces for analysis. The ALERT trial began in 2008 and is estimated for completion in May 2015. The results of the study will be reviewed by the FDA for an investigational device exemption (IDE).
According to the National Institutes of Health, continuous monitoring of the culprit artery is mandatory to determine the correct therapeutic intervention. While coronary angiography reveals vessel anatomy, it is only for a brief moment; and, AEMs may be limited in the arrhythmia captured, based on the type of system used and/or inability to analyze acute ischemic events (ST-segment shifts), and patient compliance. The authors of a current perspective and future direction review of silent myocardial ischemia, Ahmed et al., stated, “The goal of therapeutic intervention is to reverse ongoing ischemia and to interrupt or prevent myocardial cell death”. They deduce that to get to therapeutic goal, use of implantable monitoring is one solution.
Currently no IIDS devices are approved by the FDA and are considered an emerging technology, the utilization of the devices are considered experimental, investigational and unproven.
Mobile cardiac outpatient telemetry (MCOT) real-time remote heart monitors. Although these devices have the added capability of real-time cardiac monitoring and may lead to timely physician notification in the event of a serious arrhythmia, it is unknown if this form of monitoring improves health outcomes or patient management, especially when compared to established ambulatory cardiac event monitoring devices. Patient selection criteria have not been adequately defined. Randomized clinical trials comparing health outcomes of established monitoring techniques to the ambulatory EKG detectors with automatic-real-time event notification are required to provide evidence of clinical benefit from this form of monitoring. A recent 2005 published study was identified that described the outcomes of a consecutive case series of 100 patients. Patients with a variety of symptoms were included, such as palpitations (47%), dizziness (24%), or syncope (19%), in addition to efficacy of drug therapy (25%). Clinically significant arrhythmias were detected in 51% of patients, but half of those patients were asymptomatic. The study authors comment that the automatic detection results in an increased diagnostic yield, but there was no discussion of the MCOT service unique features, such as real-time analysis, transmission, notification of arrhythmia, and potential contraindications when used for patients with history of or at risk of serious ventricular arrhythmias.
Rothman and colleagues recently reported results comparing MCOT to standard loop recording. This study involved 305 patients who were randomized to a LOOP recorder or MCOT and who were monitored for up to 30-days. The unblinded study enrolled patients at 17 centers for who the investigators had a strong suspicion of an arrhythmic cause of symptoms, including those with symptoms of syncope, presyncope, or severe palpitations occurring less frequently than once per 24 hours and a nondiagnostic 24-hour HM or telemetry monitor within the prior 45 days. Test results were read in a blinded fashion by an electrophysiologist. Study exclusions were Class IV heart failure, myocardial infarction within the prior three months, unstable angina, history of sustained VT or VF, and complex ectopy with an ejection fraction less than 35%.
While 305 patients were randomized, results from 266 were analyzed using patients who completed at least 25-days of monitoring, 132 in the LOOP group and 134 in the MCOT group. Of the 39 patients who did not complete the protocol, 20 did not complete (13 MCOT and seven LOOP) the study due to non-compliance (non-wearing) with the device. Patients were predominantly female with a mean age of 56 years. Approximately 20% had a history of heart disease, 50% hypertension, and 5% heart failure.
A diagnostic endpoint (confirmation or exclusion of arrhythmic cause of symptoms) was found in 88% of MCOT patients and 75% of LOOP patients (p = 0.008). The difference in rates was due primarily to detection of asymptomatic (not associated with simultaneous symptoms) arrhythmias in MCOT group consisting of rapid atrial fibrillation (AF) and/or flutter (15 patients versus one patient) and VT defined as more than three beats and rate greater than 100 (14 patients versus two patients). These were felt to be clinically significant rhythm disturbances and the likely causes of the patients’ symptoms. The paper does not comment on the clinical impact (changes in management) of these findings in patients where the rhythm disturbance did not occur simultaneously with symptoms. In this study, the median time to diagnosis in the total study population was seven days in the MCOT group and nine days in the LOOP group. Of note, prior studies of the auto-triggered loop recorder have also shown similar findings that are viewed as improvements over traditional LOOP recordings that require patient activation.
A subset of only 50 patients (related to device availability) received the newer auto-trigger loop recorders. In this subset, a diagnostic endpoint was found in 88% of the 24 MCOT patients and 46% of the auto-trigger LOOP group. The lower yield of the auto-trigger loop recorder noted in this study is surprising; others have reported increased yield with this feature.
The auto-trigger loop recorders have become a part of the standard diagnostic approach to patients who have infrequent symptoms that are felt likely to be due to arrhythmias. Therefore, this is the test to which newer technologies must be compared. Currently, the literature does not provide any adequate comparative data for the auto-trigger device compared to MCOT. Further study of MCOT is needed to replicate the Rothman study and to compare MCOT with the auto-trigger loop recorder. MCOT is considered experimental, investigational or unproven as a diagnostic alternative in patients who experience infrequent symptoms (less frequently than 48-hours) suggestive of cardiac arrhythmias, such as palpitations, presyncope, or syncope.
MCOT continues to be studied in the evaluation of patients who have had ablation procedures, in addition to being studied as a method to measure rhythm and rate control in patients with AF. Neither study compares MCOT with standard approaches.
There is insufficient evidence to show that outpatient cardiac telemetry or real-time event monitoring is more effective than conventional ambulatory event monitors or has a greater impact on patient management.
A literature search of MedLine database was performed through August 2008. No studies were identified that would change the coverage position of this medical policy.
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