Dispersion of ventricular depolarization-repolarization: a noninvasive marker for risk stratification in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: We retrospectively investigated the value of clinical and ECG findings as well as QT-QRS dispersion in predicting the risk of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). METHODS AND RESULTS: Duration and interlead variability of the QT interval and QRS complex were measured manually from standard ECGs in 20 sudden death victims with ARVC diagnosed at autopsy (group I), in 20 living ARVC patients with sustained ventricular tachycardia (group II), in 20 living ARVC patients with </=3 consecutive premature ventricular beats (group III), and in 20 control subjects (group IV). QT and QRS dispersions were greater in group I (77.5+/-10.6 ms for QT and 45.7+/-8.1 ms for QRS) compared with group II (64.5+/-13.9 ms for QT [P=0.001] and 33.5+/-8.7 ms for QRS [P=0.0004]) and in group II compared with group III (48+/-8.9 ms for QT [P<0.0001] and 28+/-5.2 ms for QRS [P<0.0001]) and group IV (33.5+/-4.8 ms for QT [P<0.0001] and 18.5+/-3.6 ms for QRS [P<0.0001]). Negative T wave beyond V(1) and syncope were statistically more frequent in group I (P=0.02 and P=0.007, respectively). On multivariate analysis, QRS dispersion remained an independent predictor of sudden death (P<0.0001), followed by syncope (P=0.09). In assessing risk of sudden death, QRS dispersion >/=40 ms had a sensitivity and specificity of 90% and 77%, respectively; QT dispersion >65 ms, 85% and 75%, respectively; negative T wave beyond V(1), 85% and 42%, respectively; and syncope, 40% and 90%, respectively. CONCLUSIONS: QRS dispersion (>/=40 ms) was the strongest independent predictor of sudden death in ARVC. Syncope, QT dispersion >65 ms, and negative T wave beyond V(1) refined arrhythmic risk stratification in these patients.