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DESCRIPTIONMicrovolt T-wave alternans (MTWA) refers to a beat-to-beat variability in the amplitude of the T wave. A routine electrocardiogram (ECG) cannot detect these small fluctuations, and thus this test requires specialized sensors to detect the fluctuations and computer algorithms to evaluate the results. T-wave alternans is a provocative test that requires gradual elevation of the heart rate to above 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 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 anything in between is considered indeterminate.
The presence of T-wave alternans has been investigated as a risk factor for fatal arrhythmias and sudden cardiac death in patients with a history of myocardial infarction, congestive heart failure, or cardiomyopathy. High-risk patients may be treated with drugs to suppress the emergence of arrhythmias or undergo implantation of cardiac defibrillators to promptly terminate tachyarrhythmias when they occur. Since sudden cardiac death is one of the most common causes of death after a myocardial infarction (MI) or in patients with dilated cardiomyopathy, there is intense interest in risk stratification to target therapy.
Patient groups are divided into those who have not experienced a life-threatening arrhythmia (primary prevention) and those who have (secondary prevention). Those who have already experienced an arrhythmia are already at high risk and probably do not require testing. T-wave alternans is one of many risk factors that have been investigated for identifying candidates for primary prevention. Others include left ventricular ejection fraction, arrhythmias detected on Holter monitor or electrophysiologic studies, heart rate variability, and baroreceptor sensitivity. Signal-averaged ECG (SAECG) is another technique for risk stratification. SAECG, addressed separately in another policy, measures beat-averaged conduction, while T-wave alternans measures beat-to-beat variability.
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.
POLICYT-wave alternans is considered investigational as a technique of risk stratification for primary or secondary prevention* of fatal arrhythmias and sudden cardiac death in patients with a history of myocardial infarction, congestive heart failure, cardiomyopathy or other cardiac disorders such as long QT syndrome (e.g., Brugada syndrome).
*Primary prevention refers to patients that have not experienced a life-threatening arrhythmia. Secondary prevention refers to patients that have experienced a life-threatening arrhythmia.
POLICY EXCEPTIONSFederal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
Investigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY11/2002: Approved by Medical Policy Advisory Committee (MPAC), CPT code 93025 added, ICD-9 diagnosis codes 410.0-410.92, 412, 414.00-414.9, 425.0-425.9 added
8/24/2005: Code References section updated, ICD-9 diagnosis codes 410.0-410.92, 412, 414.00-414.9, 425.0-425.9 deleted
3/10/2006: Policy reviewed, no changes
5/14/2007: Policy reviewed, description updated
10/7/2008: Policy reviewed, no changes
12/09/2009: Policy Exceptions revised to add FEP verbiage. Coding Section revised to add verbiage, "*This is not an all inclusive list".
04/20/2011: Policy reviewed; no changes.
06/06/2012: Policy reviewed; no changes to policy statement. Deleted outdated references from the Sources section.
SOURCE(S)Blue Cross Blue Shield Association policy # 2.02.13
CODE REFERENCEThis may not be a comprehensive list of procedure codes applicable to this policy.