HYPERTROPHIC CARDIOMYOPATHY - VALUE OF ATRIAL PROGRAMMED ELECTRICAL-STIMULATION IN PATIENTS WITH OR WITHOUT SYNCOPE WITH SPECIAL REFERENCE TO THE ROLE OF ATRIAL ARRHYTHMIAS

Hypertrophic cardiomyopathy may be associated with both supraventricul ar and ventricular arrhythmias, which may play a role in the genesis o f syncope. The aim of this study was to assess the findings of electro physiological study and programmed atrial and ventricular stimulation and their possible role in syncope. Programmed atrial and ventricular stimulation using up to two extrastimuli in right atrium and three in right ventricle at three cycle lengths (600, 400 ms and spontaneous) w as systematically performed in 56 patients with hypertrophic cardiomyo pathy. Thirty seven had unexplained dizzinesses or syncopes (group I) and 19 did not present loss of consciousness (group Il). Patients with syncopes had a higher prevalence of induced sustained supraventricula r tachyarrhythmia (73%) than those of group II (16%) (P<0.05). Inducib le supraventricular tachycardia was the only finding in 16 patients wi th syncopes. During the follow-up (3 years+/-6 months), empirical anti arrhythmic therapy suppressed the symptoms, except in two patients who developed atrial fibrillation despite therapy. The high incidence of inducible atrial tachycardia of these patients was not correlated with particular Holter findings or echocardiographic data. However, their mean age was rather high (58+/-12 years). In conclusion, atrial tachya rrhythmias may play a role in syncopes of middle-aged patients with hy pertrophic cardiomyopathy. Moreover programmed atrial stimulation is a n useful means to identify this syncope mechanism. (C) 1997 Elsevier S cience Ireland Ltd.