Previous studies have indicated that idiopathic dilated cardiomyopathy (IDCM) is associated with a high incidence of lethal ventricular arrhythmia and sudden cardiac death (due to arrhythmic events). The objective of this study was to evaluate predictive factors of arrhythmic events in IDCM.

A total of 174 patients with IDCM were evaluated for the measurement of multiple parameters such as PR interval, QRS duration, rate corrected QT dispersion, bundle branch block, atrial fibrillation, left ventricular end diastolic dimension, ejection fraction, left atrial size, and left ventricular hypertrophy. The patients were divided into 2 groups:group A with and group B without arrhythmic events.

Over an observation period of 38±19 months, arrhythmic events developed in 39 of the 174 patients (4 VT, 1 VF and 34 sudden cardiac death, 22.4%). In multivariate analysis, only QTDc was found to be an independent predictor of arrhythmic events (RR:1.03, 95% CI:1.01 - 1.04, p<0.01). The positive and negative predictive values of arrhythmic events in patients with QTDc>108 ms were 43.8% (7/16) and 85.6% (83/97) respectively. The positive predictive value of arrhythmic events in patients with QTDc>108 ms and EF<28% was 66.6% (8/12).

The extent of repolarization dispersion and LV systolic function was determined to have value as a useful screening test for the prediction of arrhythmic events in IDCM.