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Can microvolt T-wave alternans testing reduce unnecessary defibrillator implantation?
Antonis A Armoundas1, Stefan H Hohnloser, Takanori Ikeda
1Massachusetts General Hospital, USA.
Nature Clinical Practice. Cardiovascular Medicine
|September 28, 2005
Summary
Microvolt T-wave alternans (MTWA) testing can identify patients with reduced ejection fraction unlikely to benefit from implantable cardioverter-defibrillators. Negative MTWA results suggest avoiding this invasive therapy, improving patient selection for defibrillator implantation.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Technology
Background:
- Prophylactic implantable cardioverter-defibrillator (ICD) therapy offers mortality benefits for patients with reduced ejection fraction, as shown in MADIT II and SCD-HeFT.
- However, only a small percentage of patients receive life-saving therapy, highlighting the need for better risk stratification due to the invasive and costly nature of ICDs.
Purpose of the Study:
- To review prospective clinical trials evaluating microvolt T-wave alternans (MTWA) testing.
- To assess MTWA's predictive value for ventricular tachyarrhythmic events in patients with reduced ejection fraction, similar to those in MADIT II and SCD-HeFT.
Main Methods:
- Analysis of prospective clinical trials on MTWA testing.
- Focus on patient populations with reduced ejection fraction, not pre-selected for ventricular tachyarrhythmias.
Main Results:
- Patients testing negative for MTWA had a low annual rate (around 1%) of fatal/nonfatal ventricular tachyarrhythmic events.
- Mortality was lower in MTWA-negative patients who did not receive ICDs compared to those who did in MADIT II and SCD-HeFT.
Conclusions:
- MTWA testing is a valuable tool for risk stratification in patients with reduced ejection fraction considered for ICD therapy.
- Negative MTWA results suggest that ICD therapy is unlikely to provide benefit and may be safely avoided.