T-wave alternans negative coronary patients with low ejection and benefit from defibrillator implantation

Area of Science:

• Cardiology
• Electrophysiology
• Preventive Medicine

Background:

• Prophylactic defibrillator implantation offers a mortality benefit for patients with prior myocardial infarction and low ejection fraction (≤0.30).
• Identifying patients who will not benefit from defibrillators is crucial for optimizing treatment and resource allocation.

Purpose of the Study:

• To evaluate the utility of microvolt T-wave alternans (MTWA) testing in identifying patients at low risk for ventricular tachyarrhythmic events.
• To determine if MTWA testing can help select patients who may not require prophylactic defibrillator implantation.

Main Methods:

• Retrospective analysis of 129 patients from two clinical trials with prior myocardial infarction and left-ventricular ejection fraction ≤0.30.
• Prospective assessment of microvolt T-wave alternans testing.
• Follow-up for 24 months to assess rates of sudden cardiac death and cardiac arrest.

Main Results:

• No sudden cardiac death or cardiac arrest occurred in patients with negative T-wave alternans results at 24 months.
• An event rate of 15.6% for sudden cardiac death or cardiac arrest was observed in patients with positive T-wave alternans results.
• MTWA testing demonstrated a high negative predictive value for ventricular tachyarrhythmic events in this high-risk population.

Conclusions:

• Microvolt T-wave alternans testing is a valuable tool for risk stratification in patients with prior myocardial infarction and reduced ejection fraction.
• Negative MTWA results identify patients unlikely to experience ventricular tachyarrhythmic events, suggesting they may not benefit from prophylactic defibrillator therapy.