RISK STRATIFICATION FOR ARRHYTHMIC EVENTS IN PATIENTS WITH NONISCHEMIC DILATED CARDIOMYOPATHY AND NONSUSTAINED VENTRICULAR-TACHYCARDIA - ROLE OF PROGRAMMED VENTRICULAR STIMULATION AND THE SIGNAL-AVERAGED ELECTROCARDIOGRAM

Objectives, This study investigated prediction of arrhythmic events by the signal-averaged electrocardiogram (ECG) and programmed stimulatio n in patients with nonischemic dilated cardiomyopathy. Background. Ris k stratification in patients with nonischemic dilated cardiomyopathy r emains controversial. Methods. Eighty patients with nonischemic dilate d cardiomyopathy and spontaneous nonsustained ventricular tachycardia underwent signal-averaged electrocardiography (both time-domain and sp ectral turbulence analysis) and programmed stimulation. All patients w ere followed up for a mean of 22 +/- 26 months. Results. Sustained mon omorphic ventricular tachycardia was induced in 10 patients (13%), who all received amiodarone. The remaining 70 patients were followed up w ithout antiarrhythmic therapy. Of the 80 patients, 15% had abnormal fi ndings on the time-domain signal-averaged ECG, and 39% had abnormal fi ndings on spectral turbulence analysis. Time-domain signal-averaged el ectrocardiography had a better predictive accuracy for induced ventric ular tachycardia than spectral turbulence analysis (88% vs. 66%, p < 0 .01). During follow-up, there were 9 arrhyth mic events (5 sudden deat hs, 4 spontaneous ventricular tachycardia/fibrillation) and 10 nonsudd en cardiac deaths. Cox regression analysis showed that no variables pr edicted arrhythmic events or total cardiac deaths. The 2 year actuaria l survival free of arrhythmic events was similar in patients with or w ithout abnormal findings on the signal averaged ECG or induced ventric ular tachycardia. Conclusions. In patients with nonischemic dilated ca rdiomyopathy, 1) there is a strong correlation between abnormal findin gs on the time domain signal-averaged ECG and induced ventricular tach ycardia, but both findings are uncommon; and 2) normal findings on the signal averaged ECG, as well as failure to induce ventricular tachyca rdia, do not imply a benign outcome.