Clinical usefulness of the combination of T-Wave alternans and late potentials for identifying high-risk patients with moderately or severely impaired left ventricular function

Ventricular tachyarrhythmia (VT) is an independent risk factor for an incre ased overall mortality in patients with impaired left ventricular (LV) func tion, but there is not an established noninvasive tool to detect such patie nts. The present study aimed to clarify the most useful noninvasive approac h for identification of patients with moderately or severely impaired LV fu nction complicated by VT. Sixty-seven patients in New York Heart Associatio n (NYHA) classes I-III with an LV ejection fraction (LVEF) less than 40% an d an LV end-diastolic dimension (LVDD) of at least 55 mm on echocardiograph y were enrolled. Impaired LV function was caused by either ischemic (n=30) or nonischemic dilated cardiomyopathy (n=37). T-wave alternans (TWA), QT di spersion (QTD), and late potentials (LP) on signal-averaged electrocardiogr aphy were sequentially determined without using antiarrhythmic drugs. VT wa s defined as more than 6 consecutive ventricular ectopic beats, The mean NY HA class was 1.9 +/-0.7, mean LVEF was 31 +/-8%, and mean LVDD was 65 +/- 1 0 mm. A history of VT was present in 26 of the patients (39%). Univariate a nd multivariate logistic analysis showed that TWA and LP were closely relat ed to VT, whereas NYHA greater than or equal to III, LVEF <30%, LVDD <great er than or equal to>70 mm, and QTD greater than or equal to 90 ms were not. The combination of TWA and LP had the most significant value (p=0.0004, od ds ratio=8.44) by univariate analysis, and only this combination had signif icant value in multivariate analysis (p=0.04). Therefore, the combination o f TWA and LP could be a useful index for identifying those patients with im paired LV function who are at risk for VT.