Long-term follow-up of the signal-averaged ECG in arrhythmogenic right ventricular cardiomyopathy: correlation with arrhythmic events and echocardiographic findings

AIMS: The aims of our study were to evaluate late potential changes during long-term follow-up in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and to correlate these results with echocardiographic findings and sustained ventricular tachycardia (VT) occurrence. METHODS AND RESULTS: We studied 31 patients (22 males and 9 females; mean age 29+/-16) during 8 years of follow-up by signal-averaged ECG (SAECG) and echocardiography. Ten subjects experienced episodes of sustained VT. During follow-up, all the SAECG parameters showed a progressive significant increase in late potentials. In contrast, echocardiographic indices did not show evidence of relevant modifications. Patients with sustained VT were characterized by significantly lower left and right ventricular ejection fractions, longer values of filtered QRS at 25/40/80-250 Hz filters, and longer high-frequency low-amplitude (HFLA) signals at 25-250 Hz at baseline. The analysis of SAECG modification during follow-up indicated that only HFLA signals at 25-250 Hz increased significantly in the sustained VT group. CONCLUSION: We detected a progressive increase in delayed ventricular conduction by SAECG not associated with significant echocardiographic changes. Therefore, the conduction disturbance seems to increase independently from anatomical alterations. The baseline SAECG and echocardiographic parameters, more than their modifications during follow-up, appear to be useful in identifying patients with sustained VT.