VENTRICULAR ARRHYTHMIAS AND ATHLETES HEART - ROLE OF SIGNAL-AVERAGED ELECTROCARDIOGRAPHY

The aim of this study was to assess the prevalence and the prognostic value of ventricular late potentials in apparently healthy top-level a thletes with ventricular arrhythmias, and the effect of physiological myocardial hypertrophy (athlete's heart) on the electrogenesis of the signal-averaged electrocardiogram (ECG). Two groups of asymptomatic at hletes without underlying heart disease were studied: group A consiste d of 35 athletes without arrhythmias and group B of 25 athletes with f requent and complex ventricular arrhythmias (ventricular ectopic beats >5000.24 h(-1) and ventricular couplets >15.24 h(-1)). Late potential s were present if athletes had significantly prolonged filtered QRS an d low amplitude signal duration and low root mean square voltages at b oth 25-250 Hz and 40-250 Hz filters. While late potentials were absent in all normal athletes of group A, they were present in seven of 25 ( 28%) athletes with arrhythmias of group B (P<0.003). Ten of 25 athlete s (five with and five without late potentials) of group B underwent pr ogrammed ventricular stimulation using a protocol comprising up to thr ee extrastimuli. No episode of sustained ventricular tachycardia was i nduced. In four of five athletes with late potentials and in one of fi ve without them? unsustained ventricular responses were induced. Echoc ardiographically determined left ventricular mass found in both groups of athletes did not influence the pathological result of the signal-a veraged ECG parameters. This study shows the applicability of the sign al-averaged ECG in identifying ventricular late potentials in a select ed population of top-level athletes with frequent and complex ventricu lar arrhythmias and without overt heart disease; it also shows that th e presence of late potentials is not influenced by left ventricular ma ss, even if extreme (>350 g), and it is correlated to a non-sustained ventricular response during an electrophysiological study.