Repolarization dispersion and sudden cardiac death in patients with impaired left ventricular function.

AIMS: Prolongation of repolarization dispersion measured from the 12-lead surface ECG has been associated with sudden cardiac death and ventricular tachyarrhythmia in a variety of heart disorders. This study tested the hypothesis that increased repolarization dispersion is of prognostic value in identifying chronic heart failure patients at high risk of sudden cardiac death and ventricular tachyarrhythmia.
RESULTS: In 163 patients, ischaemic (n = 126) and idiopathic dilated (n = 37) cardiomyopathy with a left ventricular ejection fraction < or = 40% were diagnosed by left ventricular angiography. During follow-up (26 +/- 15 months) 24 patients died suddenly, 10 experienced ventricular tachyarrhythmia, 19 died from pump failure, six died from acute myocardial infarction, and 97 survived. Bazett's formula rate-corrected JT-interval dispersion (JTc-d) was found to be 109 +/- 23 ms in sudden cardiac death/ventricular tachyarrhythmia patients, 57 +/- 20 ms in survivors, and 55 +/- 20 ms in patients who died from pump failure or acute myocardial infarction. Both univariate and multivariate analyses showed JTc-d to be the most important independent predictor of sudden cardiac death/ventricular tachyarrhythmia. A cut-off value of 85 ms for JTc-d had a 74% positive and a 98% negative predictive accuracy in identifying patients at risk for sudden cardiac death/ventricular tachyarrhythmia.
CONCLUSION: Analysis of repolarization dispersion from the 12-lead surface ECG seems to be a useful screening method for identifying chronic heart failure patients at high risk for sudden cardiac death/ventricular tachyarrhythmia.