Pending Policies - Medicine
Risk Stratification Tests for Determining Arrhythmias (Signal-Averaged Electrocardiography [SAECG] and Microvolt T-Wave Alternans [MTWA])
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Microvolt T-wave alternans (MTWA) as a technique of risk stratification for primary or secondary prevention of fatal arrhythmias and sudden cardiac death (SCD) may be considered medically necessary in patients who are at risk for developing life-threatening ventricular arrhythmias (e.g., known cardiac dysrhythmias, history of myocardial infarction [MI], congestive heart failure, or cardiomyopathy).
MTWA testing is considered experimental, investigational, and/or unproven for all other indications.
Signal-averaged electrocardiography (SAECG), as a technique of risk stratification for arrhythmias after prior MI, is considered not medically necessary.
Other applications of SAECG are considered experimental, investigational and/or unproven, including but not limited to the following:
• Use in patients with cardiomyopathy,
• Use in patients with syncope,
• Assessment of success after surgery for arrhythmia,
• Detection of acute rejection of heart transplants,
• Assessment of efficacy of antiarrhythmic drug therapy, or
• Assessment of success of pharmacological, mechanical, or surgical interventions to restore coronary artery blood flow.
Signal-averaged electrocardiography and microvolt T-wave alternans have been investigated as techniques of risk stratification for arrhythmic events in patients with a variety of cardiac conditions, including history of myocardial infarction (MI), congestive heart failure, or cardiomyopathy. Patients with these disorders at high-risk of sudden cardiac death (SCD), may be treated with drugs to suppress the emergence of arrhythmias or may undergo implantation of cardiac defibrillators to terminate tachyarrhythmias when they occur. Because SCD, whether from arrhythmias or pump failure, is one of the most common causes of death after a MI or in patients with dilated cardiomyopathy, there is substantial interest in risk stratification to target therapy.
Microvolt T-Wave Alternans (MTWA)
MTWA refers to a beat-to-beat variability in T-wave amplitude. Because a routine electrocardiogram (EKG) cannot detect these small fluctuations, this test requires specialized sensors to detect the fluctuations and computer algorithms to evaluate the results. T-wave alternans is measured by a provocative test that requires gradual elevation of the heart rate to more than 110 beats per minute. The test can be performed in conjunction with an exercise tolerance stress test. Test results are reported as the number of standard deviations (SDs) by which the peak signal of the T-wave exceeds the background noise. This number is referred to as the alternans ratio. An alternans ratio of 3 or greater is typically considered a positive result, an absent alternans ratio is considered a negative result, and other values are indeterminate.
T-wave alternans has also been investigated as a diagnostic test for patients with syncope of unknown origin and as a noninvasive test to identify candidates for further invasive electrophysiology testing of the heart.
Signal-Averaged Electrocardiography (SAECG)
SAECG is a technique involving computerized analysis of small segments of a standard EKG to detect abnormalities, termed ventricular late potentials (VLPs), that would be otherwise obscured by “background” skeletal muscle activity. VLPs reflect aberrant, asynchronous electrical impulses arising from viable isolated cardiac muscle bordering an infarcted area and are thought to be responsible for ventricular tachyarrhythmias.
There are several devices and processing software that have received U.S. Food and Drug Administration (FDA) 510(k) clearance for the recording and measurement of MTWA. As far as devices for SAECG, numerous ECG devices are equipped with enhanced technology that allows signal averaging.
This medical policy was originally created in 1998 and has been updated periodically with searches of the MEDLINE database. Following is a summary of the key literature to date.
Prognostic or risk stratification test evaluation consists of:
• Appraising test technical performance, including definitions of positive and negative results and reproducibility of the test;
• Determining how accurately the test discriminates patients who will, from those who will not, experience the event of interest; and
• Evaluating the impact of test results on clinical management of the patient and a determination whether changes in clinical management result in an improvement of overall health outcomes.
Microvolt T-Wave Alternans (MTWA)
Primary prevention implantable cardioverter-defibrillators (ICD) trials (e.g., MADIT-II and SCD-HeFT) have changed the perspective on selection and risk stratification for use of ICDs. (1) In the MADIT-II trial, implantable defibrillators were shown to be effective in patients selected on the basis of prior myocardial infarction (MI) and reduced ejection fraction; SCD-HeFT inclusion criteria required reduced ejection fraction but not previous MI. Prior studies of implantable defibrillators had selected patients using results of electrophysiologic testing and symptoms. (2, 3) Given results from these trials, it is critical whether any additional risk stratification tool(s) can identify with sufficient accuracy patients who might or might not benefit from ICD implantation. For example, can T-wave alternans testing identify patients who would otherwise be appropriate for an ICD based in trial inclusion criteria, but who would actually not benefit from an ICD? The rationale for T-wave alternans testing is primarily that patients with a negative result will not benefit from an ICD. Evidence from prospective cohort studies can accurately define the predictive ability of MTWA for sudden cardiac death. This evidence on risk may impact clinical management, if there are well-defined levels of risk that are linked to different management strategies.
Blue Cross Blue Shield Association (BCBSA) Technology Evaluation Center (TEC) Assessments
A June 2005 BCBSA TEC Assessment evaluated the use of MTWA to risk stratify patients in whom ICDs would be used for primary prevention of sudden cardiac death. (4) The TEC Assessment identified 18 studies using MTWA to prospectively stratify the risk of a subsequent event (total N=2,931). Most studies interpreted MTWA blinded to other information. The incidence of endpoints (either ventricular tachyarrhythmic events [VTEs] or death) ranged from 3% to 51% across studies. Six studies included patients with ischemic cardiomyopathy, 4 nonischemic cardiomyopathy, and 8 patients selected by a variety of means, such as those referred for electrophysiologic testing.
Two patient indications were considered: 1) patients eligible for ICD placement for primary prevention of sudden death, and 2) patients not eligible for ICD placement. It is possible that the negative or positive predictive value (NPV, PPV) of MTWA results might be used to support decision making regarding ICD placement. Specifically, for the first patient indication, negative MTWA results might be used to identify a subset of patients at low likelihood of subsequent VTEs and thus unlikely to benefit from ICD placement. While a few studies found that MTWA testing had high sensitivity and high NPV for future VTE, there was considerable variation in diagnostic performance in the published literature. Reported sensitivities ranged from 75% to 100%, negative predictive values from 73% to 100%, and likelihood ratios for a negative test result varied between 0 and 0.42. The reasons for variation in diagnostic performance characteristics are not well-established. Differences in pretest risk of VTE would most influence NPV; however, the Assessment also noted that it would also be important to understand whether MTWA diagnostic performance might vary according to population characteristics, such as etiology of cardiomyopathy.
The 2005 TEC Assessment concluded the evidence insufficient to determine whether the use of MTWA leads to improved net health outcomes or whether it is as beneficial as any established alternatives.
A 2006 BCBSA TEC Assessment (5) reviewed a smaller number of studies addressing the question of whether MTWA can identify patients who would otherwise meet clinical indications for ICDs but whose risk of death is so low that they would not benefit. The critical evidence sought was the absolute risk of VTE or sudden death in those patients who have a negative MTWA test, and whether it can be determined whether this risk is consistent with no potential benefit from ICD therapy. Three studies were reviewed restricting analyses to patients who met criteria for ICD therapy.
Bloomfield et al. (6) followed 177 patients over an average of 20 months for all-cause mortality. Hohnloser et al. (7) selected ICD-eligible patients from two previously published studies and followed them over 2 years for sudden cardiac death or cardiac arrest. Among those with a negative MTWA test, the actuarial 2-year mortality rate was 3.8%. For those with a non-negative MTWA test, the actuarial 2-year mortality rate was 17.8%. Arrhythmic outcomes were not reported in this study.
In Hohnloser et al. (7), patients who met MADIT-II criteria were pooled from two previously published studies. The study reported all-cause mortality, rates of sudden cardiac death or cardiac arrest, and rates of VTE. For all-cause mortality estimated at 2 years, those with negative MTWA tests had a mortality rate of 12.5%, whereas those with non-negative MTWA tests had a mortality rate of 21.4%. For the primary outcome of sudden death or cardiac arrest, patients with negative MTWA tests had a 0% rate, and those with non-negative MTWA tests had a 15.6% rate. For the secondary outcome of all ventricular arrhythmic events, those with a negative MTWA test had a 5.7% rate, and those with non-negative tests had a 31.1% rate.
In Chow et al. (8), a total of 768 consecutive patients with ischemic cardiomyopathy (left ventricular ejection fraction [LVEF] <35%) and no prior history of ventricular arrhythmia were followed up for a mean of 18 months. Because event rates in the patients with and without ICDs are not comparable, only outcomes for the 376 patients who received only medical therapy were reported in the TEC Assessment. Thus, the results might be accompanied by potential selection bias. It appeared that the MTWA-negative patients who did not receive ICDs compared to the MTWA-negative patients who did receive ICDs had less severe heart failure (mean LVEF: 29.3% vs. 26.9%, respectively). At 18 months’ mean follow-up, the all-cause mortality rate was 8.4% in MTWA-negative patients and 21.8% in MTWA non-negative patients. For arrhythmic deaths, the rate was 3.4% in MTWA-negative patients and 11.2% in MTWA non-negative patients.
The 2006 TEC Assessment concluded that although MTWA does stratify risk in ICD-eligible patients, evidence of sufficient accuracy to infer clinical utility was lacking.
Verrier et al. (2011) prepared a consensus guideline on behalf of the International Society for Holter and Noninvasive Electrocardiology. (9) The guideline discussed the electrocardiographic phenomenon of T-wave alternans (TWA) (i.e., a beat-to-beat alternation in the morphology and amplitude of the ST-segment or T-wave), with a focus on its physiological basis and measurement technologies and its clinical utility in stratifying risk for life-threatening ventricular arrhythmias. Overall, the authors concluded that it is reasonable to consider MTWA evaluation whenever there is suspicion of vulnerability to lethal cardiac arrhythmias. However, there is as yet no definitive evidence from interventional trials that it can guide therapy.
In 2013, Chen et al. systematically reviewed current literature and carried out a meta-analysis to determine the ability of MTWA to predict the outcome severity after ischemic cardiomyopathy (ICM). (10) Major endpoints include composite endpoint of cardiac mortality and severe arrhythmic events in primary prevention of patients with ICM, as well as all-cause mortality (cardiac death, and/or non-cardiac death). Seven trials were included by using MTWA for risk stratification of cardiac events in 3385 patients with ICM. All patients were distributed into two groups according to the results of MTWA tests: non-negative group included positive and indeterminate, and negative group. Compared with the negative group, non-negative group showed increased rates of cardiac mortality or severe arrhythmic events (RR=1.65, 95%CrI=1.32, 2.071), SCD (RR=2.04 95%CrI=1.11, 3.75), and all-cause mortality (RR=2.11, 95%CrI=1.60, 2.79). The funnel plot revealed that there might be bias within current publications. The fail-safe number of composite endpoint and all-cause mortality was 14.42 and 18.93, respectively (when P=0.01). The fail-safe number of SCD was 1.07 (when P=0.05), which may be caused by the small case number of included studies and some patients with ICD included. Reviewers concluded that the non-negative group of MTWA had a nearly double risk of severe outcomes compared with the negative group. Therefore, MTWA represents a potential useful tool for judging the severity of ICM.
Quan et al. (2014) reviewed data regarding 24-hour ambulatory electrocardiogram (AECG)-based MTWA and its potential role in risk stratification of fatal cardiac events across a series of patient risk profiles. (11) Data were accumulated from 5 studies involving a total of 1,588 patients, including 317 positive and 1,271 negative TWA results. Compared with the negative group, positive group showed increased rates of SCD (hazard ratio [HR]: 7.49, 95% confidence interval [CI]: 2.65 to 21.15), cardiac mortality (HR: 4.75, 95% CI: 0.42 to 53.55), and composite endpoint (SCD, cardiac mortality, and severe arrhythmic events, HR: 5.94, 95% CI: 1.80 to 19.63). For the 4 studies evaluating TWA measured using the modified moving average method, the HR associated with a positive versus negative TWA result was 9.51 (95% CI: 4.99 to 18.11) for the composite endpoint. The positive group of AECG-based TWA had a nearly six-fold risk of severe outcomes compared with the negative group. Therefore, AECG-based TWA provides an accurate means of predicting fatal cardiac events.
Practice Guidelines and Position Statements-MTWA
American Heart Association (AHA)/American College of Cardiology (ACC) Foundation/Heart Rhythm Society (HRS)
A 2008 consensus document from the AHA, ACC Foundation, and HRS indicates that a moderate amount of data suggests that MTWA may be useful for risk stratification for SCD, but that further information will be needed to determine the clinical applicability of this test. (12)
Signal-Averaged Electrocardiography (SAECG)
Use of signal-averaged ECG in risk stratification for ventricular arrhythmias
SAECG has been thoroughly studied as a risk stratification tool for potentially fatal arrhythmias in patients with a previous MI. As reviewed by the Agency for Health Care Policy and Research (AHCPR) in 1998, SAECG is associated with a low positive predictive value, ranging from 8–44%, depending on the population studied. (13) In contrast, the negative predictive value (i.e., the ability to identify those patients who will not experience ventricular arrhythmias) ranges from 88–97%, suggesting that the negative predictive value may be used to identify patients who would not benefit from antiarrhythmic therapy. However, a key statistic underlying the negative predictive value is the underlying incidence rate of the outcome. Although sudden cardiac death is the most common cause of death in the 1-year period after infarction, it is relatively uncommon (2.5–11.3%) and declining, as a result of increasing use of thrombolytic therapy, aspirin, and beta-blockers. (14) Thus, given the relative low incidence rate of ventricular arrhythmias, the high negative predictive value is not surprising.
Grimm and colleagues reported on the results of the Marburg Cardiomyopathy study, a prospective observational study designed to determine the clinical value of potential noninvasive arrhythmia risk predictors among 343 patients with idiopathic dilated cardiomyopathy and followed up for 52 +/- 21 months for major arrhythmic events. (15) Reduced LVEF and lack of beta blocker use were important risk factors, but results of SAECG and T-wave alternans were not. Results of SAECG were found to only be a weak predictor of sudden cardiac death in a consecutive series of 700 patients with a history of acute myocardial infarction (AMI). (16) In another study of 1,800 consecutive survivors of AMI who underwent reperfusion therapy, late potentials identified by SAECG were not significantly associated with the endpoints of cardiac death or serious arrhythmias. (17)
Use of signal-averaged ECG to select patients for anti-arrhythmic treatment
The ultimate validation of any diagnostic test is to determine how it is used in the management of patients and whether the management decisions result in improved health outcomes. The following discussion focuses on the clinical use of SAECG as a selection criterion for antiarrhythmic therapies in clinical trials.
A large number of randomized clinical trials (RCTs) have evaluated the effectiveness of either antiarrhythmic drugs or implantable cardiac defibrillator (ICD) implantation in post- MI patients. These trials have generally used a variety of risk stratification criteria to positively select patients for intervention. By selecting patients with a sufficiently high risk of arrhythmia, the benefits of treating arrhythmia will hopefully outweigh any adverse effects of the treatment. For the purposes of this discussion, the most relevant studies are those that look at patients who have not experienced a prior episode of near fatal ventricular arrhythmia or aborted sudden death. Patients with a prior history of a potentially fatal arrhythmia are already at sufficiently high risk and are considered candidates for either antiarrhythmic therapy or ICD.
The Coronary Artery Bypass Graft (CABG) Patch trial used SAECG as a positive patient selection criterion. (18) The CABG-Patch trial recruited patients scheduled for CABG who had an EF of less than 36% and abnormalities on SAECG. The use of SAECG was based on a pilot study that showed that an abnormal finding on SAECG was associated with a mortality rate that was double that seen in those with a normal SAECG in the 2 years after CABG. (19) Patients were randomly assigned to a defibrillator group or a control group, and all received CABG. After an average follow-up of 32 months, there was no evidence of improved survival among those in the defibrillator group. However, it cannot be determined whether the failure of this trial was due to the selection criteria or the treatments being compared.
Other trials investigating the use of ICD in post-MI patients have not provided clarity regarding the issue of risk stratification. The MADIT-II trial selected patients solely on the basis of LVEF and showed a survival benefit among those randomly assigned to ICD. (20) No additional data have directly linked risk stratification information provided by SAECG to improved patient outcomes, improved efficiency, or reduced costs.
Use of signal-averaged ECG for other indications
Data are inadequate to evaluate the impact on patient management of other applications of SAECG including, but not limited to, its use in patients with cardiomyopathy; assessment of success after surgery for arrhythmia; detection of acute rejection of heart transplants; assessment of efficacy of antiarrhythmic drug therapy; assessment of success of pharmacological, mechanical, or surgical interventions to restore coronary artery blood flow; or risk stratification of patients with Brugada syndrome. Regarding the use of SAECG to identify patients with syncope who may have inducible ventricular tachycardia, even though an ACC consensus document from 1996 concluded that SAECG had an established role, data from the report reported only modest sensitivity (73%) and poor positive predictive values. (21) Thus, if used to determine who should have electrophysiologic studies, the test will fail to detect many patients who have positive electrophysiologic studies.
In 2011, studies were also published on the utility of signal-averaged ECG for arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, and epilepsy. (22-24) Kamath et al. (22) tested the utility of signal-averaged ECG in diagnosing arrhythmogenic right ventricular cardiomyopathy. These authors reported a sensitivity ranging from 47-69%, using different criteria for a positive test, and a specificity of 95%. Schuller et al. (24) reported a sensitivity of 52% and specificity of 82% for detecting cardiac involvement in patients with sarcoidosis. Rejdak et al. (23) studied 45 consecutive patients with epilepsy and compared results of signal-averaged ECG with 19 healthy controls. An abnormal signal-averaged ECG was found in 48% (22/45) of patients with epilepsy compared with 5% (1/19) of control patients.
In 2016, Dinov et al. looked at the correlation between SAECG and endocardial scar characteristics in patients with ischemic ventricular tachycardia (VT). (25) Fifty patients (42 male; aged 67±10 years, ejection fraction 34±12%) with ischemic VTs were prospectively enrolled. SAECG was performed before and after catheter ablation (CA). Patients with at least 2 abnormal criteria (filtered QRS ≥114 ms; root mean square 40 <20 μV, and low-amplitude potentials 40 >38 ms) were defined as having positive SAECG. There was a linear correlation between endocardial scar area (<1.5 mV) and filtered QRS (r=0.414; P=0.003). CA resulted in normalization of the SAECG in 6 patients. In patients with filtered QRS ≤120 ms, 13 (40.6%) patients had normal SAECG after CA compared with 7 (21.9%) before ablation (P=0.034). Patients with normal or normalized SAECG after CA had better VT-free survival compared with those whose SAECG remained abnormal. Abnormal SAECG after CA was a predictor for VT recurrence: hazard ratio=3.64; P=0.039 for the overall population, and hazard ratio=5.80; P=0.022 for patients having QRS ≤120 ms. Authors concluded that there is a significant correlation between the surface SAECG and endocardial scar size in patients with ischemic VTs. A successful CA can result in normalization of SAECG that is associated with more favorable long-term outcomes. SAECG can be useful to assess the procedural success of VT ablation. However, study was limited by the small number and the relatively short follow-up of patients.
Practice Guidelines and Position Statements-SAECG
American Heart Association (AHA)/American College of Cardiology Foundation (ACC)/Heart Rhythm Society (HRS)
A 2008 consensus document from the AHA, ACC Foundation, and HRS indicates that an abnormal SAECG may identify patients with prior MI at risk for SCD. (12) Given the high
negative predictive value of this test, it may be useful for the identification of patients at low risk. Routine use of the SAECG to identify patients at high risk for SCD is not adequately supported at this time. Further studies are required to assess the utility of this test.
Microvolt T-wave alternans (MTWA) is one available method to risk stratify patients who may be at risk for sudden cardiac death and has been proposed to assist in selecting patients for implantable cardioverter-defibrillators (ICD) treatment. Although results from prospective multicenter studies are insufficient to infer clinical utility, there is some evidence that MTWA may be useful in stratifying risk.
Signal-averaged electrocardiography (SAECG) has some ability to risk-stratify patients at risk for ventricular arrhythmias. However, this predictive ability is modest, and this technique has not been used to stratify patients into clinically relevant categories of risk. Some randomized controlled trials have used signal-averaged ECG for selection of patients at high risk of ventricular arrhythmias, but these studies have not demonstrated outcome benefits for the treatments under study. SAECG has also been tested as a diagnostic test for a variety of cardiac-related disorders, but the evidence is insufficient to demonstrate clinical utility for any of the conditions tested.
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Disclaimer for coding information on Medical Policies
Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.
The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers. Only the written coverage position in a medical policy should be used for such determinations.
Benefit coverage determinations based on written Medical Policy coverage positions must include review of the member’s benefit contract or Summary Plan Description (SPD) for defined coverage vs. non-coverage, benefit exclusions, and benefit limitations such as dollar or duration caps.
The following codes may be applicable to this Medical policy and may not be all inclusive.
ICD-9 Diagnosis Codes
Refer to the ICD-9-CM manual
ICD-9 Procedure Codes
Refer to the ICD-9-CM manual
ICD-10 Diagnosis Codes
Refer to the ICD-10-CM manual
ICD-10 Procedure Codes
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The information contained in this section is for informational purposes only. HCSC makes no representation as to the accuracy of this information. It is not to be used for claims adjudication for HCSC Plans.
The Centers for Medicare and Medicaid Services (CMS) does have a national Medicare coverage position on microvolt T-wave alternans (MTWA). Within patient groups that may be considered candidates for implantable cardioverter defibrillator (ICD) therapy, a negative MTWA test may be useful in identifying low-risk patients who are unlikely to benefit from, and who may experience worse outcomes from, ICD placement. (26)
The national coverage position for Medicare may have been changed since this medical policy document was written. See Medicare's National Coverage at <http://www.cms.hhs.gov>.
1. Moss AJ, Zareba W, Hall WJ, et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002 Mar 21; 346(12):877-83. PMID 11907286
2. Moss AJ, Hall WJ, Cannom DS, et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. Multicenter Automatic Defibrillator Implantation Trial Investigators. N Engl J Med. 1996 Dec 26; 335(26):1933-40. PMID 8960472
3. Buxton AE, Lee KL, Fisher JD, et al. A randomized study of the prevention of sudden death in patients with coronary artery disease. Multicenter Unsustained Tachycardia Trial Investigators. N Engl J Med. 1999 Dec 16; 341(25):1882-90. PMID 10601507
4. Microvolt T-Wave Alternans Testing to Risk Stratify Patients Being Considered for ICD Therapy for Primary Prevention of Sudden Death. Chicago, Illinois: Blue Cross Blue Shield Association – Technology Evaluation Center Assessment Program (2005); 20(9).
5. Microvolt T-Wave Alternans Testing to Risk Stratify Patients Being Considered for ICD Therapy for Primary Prevention of Sudden Death. Chicago, Illinois: Blue Cross Blue Shield Association – Technology Evaluation Center Assessment Program (2006); 21(14).
6. Bloomfield DM, Steinman RC, Namerow PB, et al. Microvolt T-wave alternans distinguishes between patients likely and patients not likely to benefit from implanted cardiac defibrillator therapy: a solution to the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II conundrum. Circulation. 2004; 110(14):1885-9. PMID 15451804
7. Hohnloser SH, Ikeda T, Bloomfield DM, et al. T-wave alternans negative coronary patients with low ejection and benefit from defibrillator implantation. Lancet. 2003; 362(9378):125-6. PMID 12867114
8. Chow T, Kereiakes DJ, Bartone C, et al. Prognostic utility of microvolt T-wave alternans in risk stratification of patients with ischemic cardiomyopathy. J Am Coll Cardiol. 2006; 47(9):1820-7. PMID 16682307
9. Verrier RL, Klingenheben T, Malik M, et al. Microvolt T-wave alternans physiological basis, methods of measurement, and clinical utlity—consensus guideline by International Society for Holter and Noninvasive Electrocardiology. J Am Coll Cardiol. 2011 Sep 20; 58(13):1309-24 PMID 21920259
10. Chen Z, Shi Y, Hou X, et al. Microvolt T-wave alternans for risk stratification of cardiac events in ischemic cardiomyopathy: a meta-analysis. Int J Cardiol. 2013 Sep 1; 167(5):2061-5 PMID 22683284
11. Quan XQ, Hong LZ, Lei R, et al. Ability of ambulatory ECG-based T-wave alternans to modify risk assessment of cardiac events: a systematic review. BMC Cardiovasc Disord. 2014; 14:198. PMID 25528490
12. Goldberger JJ, Cain ME, Hohnloser SH, et al. American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society scientific statement on noninvasive risk stratification techniques for identifying patients at risk for sudden cardiac death: a scientific statement from the American Heart Association Council on Clinical Cardiology Committee on Electrocardiography and Arrhythmias and Council on Epidemiology and Prevention. Circulation. 2008 Sep 30; 118(14):1497-1518. PMID 18833586
13. Signal-averaged electrocardiography. US Department of Health and Human Services, Health Technology Assessment. 1998; Number 11 (Publication No. PB98-137227).
14. Hohnloser SK, Zabel M. Identification of patients after myocardial infarction at risk of life-threatening arrhythmias. Eur Heart J. 1999; 1(suppl C):C11-20.
15. Grimm W, Christ M, Bach J, et al. Noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy: results of the Marburg Cardiomyopathy Study. Circulation. 2003; 108(23):2883-91. PMID 14623812
16. Huikuri HV, Tapanainen JM, Lindgren K, et al. Prediction of sudden cardiac death after myocardial infarction in the beta-blocking era. J Am Coll Cardiol. 2003; 42(4):652-8. PMID 12932596
17. Bauer A, Guzik P, Barthel P, et al. Reduced prognostic power of ventricular late potentials in post- infarction patients of the reperfusion era. Eur Heart J. 2005 Apr; 26(8):755-61. PMID 15673543
18. Bigger JT Jr. Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary-artery bypass graft surgery. Coronary Artery Bypass Graft (CABG) Patch Trial Investigators. N. Engl J Med. 1997 Nov 27; 337(22):1569-75. PMID 9371853
19. Gregoratos G, Cheitlin MD, Epstein AE, et al. ACC/AHA guidelines for implantation of cardiac pacemakers and antiarrhythmia devices: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Pacemaker Implantation). J Am Coll Cardiol. 1998; 31(5):1175-209. PMID 9570207
20. Moss AJ, Zareba W, Hall WJ, et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002; 346(12):877-83. PMID 11907286
21. Cain ME, Anderson JL, Arnsdorf MF, et al. Signal-averaged electrocardiography. J Am Coll Cardiol. 1996 Jan; 27(1):238-49. PMID 8522703
22. Kamath GS, Zareba W, Delaney J, et al. Value of the signal-averaged electrocardiogram in arrhythmogenic right ventricular cardiomyopathy/dysplasia. Heart Rhythm. 2011 Feb; 8(2):256-62. PMID 20933608
23. Rejdak K, Rubaj A, Glowniak A, et al. Analysis of ventricular late potentials in signal-averaged ECG of people with epilepsy. Epilepsia. 2011 Nov; 52(11):2118-24. PMID 21933183
24. Schuller JL, Lowery CM, Zipse M, et al. Diagnostic utility of signal-averaged electrocardiography for detection of cardiac sarcoidosis. Ann Noninvasive Electrocardiol. 2011 Jan; 16(1):70-6. PMID 21251137
25. Dinov B, Bode K, Koenig S, et al. Signal-averaged electrocardiography as a noninvasive tool for evaluating the outcomes after radiofrequency catheter ablation of ventricular tachycardia in patients with ischemic heart disease: reassessment of an old tool. Circ Arrhythm Electrophysiol. 2016 Sep; 9(9). PMID 27635068
26. National Coverage Determination (NCD) for Microvolt T-Wave Alternans (MTWA) (20.30) (2015 Jan 13). Prepared by Centers for Medicare and Medicaid Services. Available at <http://www.cms.gov> (accessed on June 7, 2018).
27. Signal-Averaged Electrocardiography-Archived. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (December 2012) Medicine 2.02.04.
28. T-Wave Alternans-Archived. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (May 2013) Medicine 2.02.13.
|11/1/2018||Document updated with literature review. Added the following statement to Coverage: “MTWA testing is considered experimental, investigational, and/or unproven for all other indications.” References modified, with the following new references added: 5-12, 17, 22-26.|
|10/15/2017||Reviewed. No changes.|
|10/1/2016||Document updated with literature review. Coverage unchanged.|
|8/1/2015||Reviewed. No changes.|
|11/15/2014||Document updated with literature review. Coverage unchanged. CPT/HCPCS code(s) updated|
|10/15/2013||Literature reviewed. No changes.|
|2/15/2009||Revised/updated entire document, this policy is no longer scheduled for routine literature review and update.|
|11/1/2006||Revised/updated entire document|
|8/15/2003||Revised/updated entire document|
|3/1/2002||Revised/updated entire document|
|4/1/1999||Revised/updated entire document|
|9/1/1998||Revised/updated entire document|
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|Risk Stratification Tests for Determining Arrhythmias (Signal-Averaged Electrocardiography [SAECG] and Microvolt T-Wave Alternans [MTWA])||11-01-2018||11-14-2019|
|Risk Stratification Tests for Determining Arrhythmias (Signal-Averaged Electrocardiography [SAECG] and Microvolt T-Wave Alternans [MTWA])||10-15-2017||10-31-2018|
|Risk Stratification Tests for Determining Arrhythmias (Signal-Averaged Electrocardiography [SAECG] and T-Wave Alternans)||08-15-2003||10-31-2006|