WAVELET DECOMPOSITION ANALYSIS OF THE SIGNAL-AVERAGED ELECTROCARDIOGRAM USED FOR RISK STRATIFICATION OF PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY

Aims To study the predictive value of wavelet decomposition, as demons trated by the signal-averaged EGG, in order to identify patients with hypertrophic cardiomyopathy at increased risk for malignant ventricula r arrhythmias or sudden death. Methods and Results Two hundred and for ty-six patients with hypertrophic cardiomyopathy were studied. During a mean follow-up of 68 +/- 17 months 32 patients died, of whom 17 died suddenly. Patients with sudden death, together with eight patients wi th a history of ventricular fibrillation (sudden death/ventricular fib rillation group) were analysed and compared to the other 221 patients as well as to a subgroup of 82 patients without a history of syncope, ventricular arrhythmias on a long-term ECG recording or a family histo ry of sudden death. There were no differences in mean values of the fo ur wavelet decomposition parameters among patients in the sudden death /ventricular fibrillation group, those without sudden death/ventricula r fibrillation or patients in the low risk group. There were, however, significant differences between patients dying non-suddenly and patie nts being alive at the end of follow-up. Eighty-seven patients (35%) d emonstrated evidence of non-sustained ventricular tachycardia on a lon g-term EGG. Analysis of wavelet decomposition resulted in abnormal fin dings in these patients more often than in those without ventricular a rrhythmias.Conclusion The usefulness of wavelet decomposition analysis in predicting sudden death or ventricular fibrillation is limited in patients with hypertrophic cardiomyopathy. It may, however, play a rol e in identifying patients at risk of dying non-suddenly and of patient s with nonsustained ventricular tachycardia.