USE OF SIGNAL-AVERAGED ELECTROCARDIOGRAPHY FOR PREDICTING INDUCIBLE SUSTAINED MONOMORPHIC VENTRICULAR-TACHYCARDIA IN PATIENTS WITH BUNDLE-BRANCH BLOCK WITH AND WITHOUT A HISTORY OF SYNCOPE

The aim of this study was to examine the utility of signal-averaged electrocardiography in relation to inducible sustained monomorphic ventricular tachycard ia in patients with bundle branch block. One hundred fourteen patients with bundle branch block underwent signal-averaged electrocardiography in the time domain and programmed ventricular stimulation. Sustained monomorphic ventricular tachycardia was induced in 17 patients. The mean values of the three signal-averaged electrocardiographic variables analyzed differed significantly between the inducible and the noninducible group. The filtered QRS duration showed the most prominent difference between the two groups, and a filtered QRS duration greater than or equal to 155 msec had a sensitivity of approximately 80%, a specificity of 60%, and a total predictive value of 65%. In the subgroup of patients with syncope, a combination of these criteria with a history of coronary artery disease had a sensitivity of 100% and a specificity of 90%.