Quantification of fragmented ventricular depolarizations over the entire QRS complex for improving the identification of patients with ventricular tachycardia

Fragmented ventricular depolarizations (FVD) were assumed to be recorded as low amplitude deflections (5-100 μV) on the high resolution recordings of averaged unfiltered electrocardiograms. Scores that quantify FVD over the entire QRS complex and, respectively, in the terminal part of the QRS complex, in all the three X, Y and Z leads, were defined. In 55 patients with ventricular tachycardia, the detection of late potentials (at 40 Hz) was significantly related to the duration of the QRS complex and to the Score and duration of FVD in the terminal QRS complex. As compared to late potentials detection, a FVD Score >3 over the entire QRS complex, and not only a FVD Score >2 in the terminal QRS, significantly improved the identification of VT patients, without increasing the prevalence of false positive results in the control groups of hypertensive patients and of subjects without cardiopathy