T wave alternans can decrease after coronary revascularization

Clinical observations and animal experiments indicate that T wave alternans (TWA) is associated with an increased propensity for ventricular fibrillat ion, and thus it may be considered as a noninvasive marker of life-threaten ing ventricular arrhythmias. There is substantial evidence indicating that TWA is an intrinsic property of ischemic myocardium. This study was perform ed to determine the role of percutaneous transluminal coronary angioplasty (PTCA)-induced myocardial ischemia in the development of TWA and the effect s of revascularization. The authors recorded bipolar X, Y, and Z leads of 1 11 consecutive patients (mean age: 56 years) undergoing PTCA before, during , and 24 hours after the procedure. T wave alternans signal was calculated in 97 patients (43 left anterior descending, 26 right coronary artery, and 28 circumflex or major obtuse margin branch) by fast Fourier transformation technique after signal processing. Twenty-four hours after the procedure, the mean and peak X, Y, and Z values for TWA had all been significantly red uced from baseline and during balloon inflation (p<0.01). The findings poin t out that induced ischemia could be a trigger for T wave alternans, and su ccesful revascularization can reduce alternans.