Abstract 18171: Post-Exercise T-Wave Alternans as a Predictor of Fatal and Non-Fatal Cardiovascular Events

Abstract

Purpose: T-wave alternans (TWA), a measure of beat-to-beat fluctuations in the ventricular repolarization, has been proposed to reflect the vulnerability to arrhythmic death in various populations. We tested the hypothesis that the presence of TWA may also predict non-arrhythmic cardiac events, such as heart failure and vascular events. Methods: Exercise electrocardiograms of 1017 patients with angiographically documented stable coronary artery disease (CAD) were analyzed for TWA with the modified moving average (MMA) method. End-points of the study were cardiac death, hospitalization due to heart failure, acute coronary event and stroke. Results: During a two-year follow-up, 21 patients experience cardiac death, 24 patients were hospitalized due to heart failure, 104 had acute coronary event, and 54 had stroke/transient ischemic event (TIA). TWA ≥ 23.5 μV during post-exercise recovery was predictive of cardiac death (hazard ratio [HR]: 6.72, 95% confidence interval [CI]: 1.93 - 23.37, P=0.003), but it did not predict hospitalization for heart failure (HR: 1.78, 95% CI: 0.74 - 4.29, P=0.201), occurrence of acute coronary event (HR: 1.06, 95% CI: 0.71 - 1.58, P=0.783), or stroke/TIA (HR: 1.16, 95% CI: 0.66 - 2.04, P=0.597). When adjusted with age, gender, diabetes, left ventricular ejection fraction (LVEF), maximum heart rate and baseline systolic blood pressure, maximum post-exercise TWA remained predictive of cardiac death with a multivariate hazard ratio of 5.28 (95% CI: 1.49 - 18.69, P=0.010). Conclusions: Post-exercise TWA is especifically associated with an increased risk of short-term fatal cardiac events in patients with stable CAD, but it is not a strong predictor of non-fatal cardiac events