QT INTERVAL DISPERSION AS A PREDICTOR OF ARRHYTHMIC EVENTS IN CONGESTIVE-HEART-FAILURE

Aims Identification of patients with congestive Heart failure at risk of sudden death remains problematic and few data are available on the prognostic implications of QT dispersion. We sought to assess the pred ictive value of QT dispersion for arrhythmic events in heart failure s econdary to dilated cardiomyopathy or ischaemic heart disease. Methods and Results Twelve-lead ECGs calculated for QT dispersion, 24 h Holte r ECGs and signal-averaged ECGs were prospectively recorded in 705 hea rt failure patients in sinus rhythm. The 86 patients with ischaemic he art disease and the 119 with dilated cardiomyopathy were not significa ntly different as regards NYHA grades (51 vs 49% in grades III-IV), ca rdiothoracic ratio (57 +/- 7 vs 57 +/- 6%) and ejection fraction (28 /- 8 vs 29 +/- 9%). The mean QT dispersion (66 +/- 29 vs 65 +/- 27 ms) , the frequency of non-sustained ventricular tachycardia (37 vs 38%) a nd ventricular late potentials (41 vs 40%) were not significantly diff erent in patients with ischaemic or dilated cardiomyopathy. QT dispers ion was not significantly related to other arrhythmogenic markers. Dur ing follow-up (24 +/- 16 months), 66 patients died, 22 of them died su ddenly and seven presented a spontaneous sustained ventricular tachyca rdia. In patients with dilated cardiomyopathy, in multivariate analysi s, only a QT dispersion >80 ms was an independent predictor of sudden death (RR: 4.9: 95% CI 1.4-16.8, P<0.02) and arrhythmic events (RR: 4. 5, 95% CI 15-13.5, P<0.01). In patients with ischaemic heart disease, no studied parameter was found significantly related to sudden death o r arrhythmic events. Conclusions In congestive heart failure, abnormal QT dispersion can identify patients with dilated cardiomyopathy who a re at high risk of arrhythmic events.