Abstract 2854: Lack of Time Dependence of Microvolt T-Wave Alternans Prediction
Background: Microvolt T-wave alternans (MTWA) has been proposed as an effective tool for risk stratification in patients with ischemic cardiomyopathy. Its prognostic utility at different follow-up time periods remains unknown.
Objective: To determine whether the predictive value of MTWA declines over 3 years.
Methods: We developed a prospective cohort of 768 patients with ischemic cardiomyopathy (LVEF≤35%) and no prior sustained ventricular arrhythmia, of which 392 (51%) received ICDs. Mean follow up was 27±12 months. MTWA results were categorized as negative and non-negative (positive and indeterminate). Multivariable Cox regression analyses, which controlled for ICD status, demographics, clinical, and electrophysiologic variables, evaluated the prognostic utility of MTWA in predicting all-cause mortality at discrete 6-month intervals over 3 years.
Results: We identified 514 (67%) patients with a non-negative MTWA test. After multivariable adjustment, patients screening MTWA nonnegative were at higher risks for all-cause death at 6 months [Hazard Ratio (HR)= 2.47 (95% CI: 0.82, 7.45; p=0.11)], 12 months [HR=1.73 (0.83, 3.64); p=0.15], 18 months [HR=2.01 (1.06, 3.80); p=0.03], 24 months [HR=2.59 (1.41, 4.79); p=0.002], 30 months [HR=2.54 (1.45, 4.45); p=0.001], and 36 months [HR=2.07 (1.23, 3.49); p=0.006]. The predictive power of MTWA was similar across time periods (p for trend=0.46).
Conclusions: MTWA is a robust predictor of all-cause mortality in patients with ischemic cardiomyopathy, with no decline in its predictive power at 36 months.