Follow-up by repeated signal-averaged surface QRS in patients with the syndrome of arrhythmogenic right ventricular dysplasia.

Repeated signal-averaged surface electrocardiograms were recorded with a mean interval of 32.5 months (range 14 to 55 months) in 12 patients with the syndrome of arrhythmogenic right ventricular dysplasia (ARVD). The mean differences in the amplitude and duration of the filtered QRS complex (FQRS), the root mean square voltage of the last 40 ms of the FQRS and the duration of the terminal potentials of less than 25 microV were not statistically significant between the recordings. A wide spectrum of changes in the voltage and duration of the terminal potentials was observed, irrespective of the clinical susceptibility to ventricular tachycardia. Three patients developed changes suggesting a progression, with a decreased voltage and prolonged duration of the terminal potentials, and four patients showed the opposite pattern. In five patients the signals were stationary. It is concluded that the properties of late potentials may change with time in patients with ARVD. Follow-up by repeated signal-averaged QRS does not appear to be useful in predicting the susceptibility to ventricular tachycardia in ARVD. Its application in predicting and following progressive right ventricular morphological changes remains to be determined.