[Cardiac arrhythmias and their clinical significance in mitral valve prolapse].

Among 160 patients with mitral-valve prolapse but no other illness there were 118 with cardiac arrhythmias. 30 had frequent or multifocal ventricular premature systoles, 21 had coupled ventricular extrasystoles, and seven had ventricular tachycardia. In six patients the prematurity index was under 1. Supraventricular premature systoles were registered in 56 patients, with seven each having paroxysmal atrial tachycardia and paroxysmal atrial flutter or fibrillation. Ventricular arrhythmias were significantly more frequent in late-systolic prolapse and with positive auscultation findings (systolic click or systolic murmur). Long-term ECG monitoring was more valuable than an exercise ECG. About half the patients with frequent arrhythmias had palpitations and rapid heart action. Coupled ventricular premature systoles and ventricular tachycardias, as well as R-on-T were relatively rare; our findings thus tend to suggest a relatively favourable prognosis for these arrhythmias.