CLINICAL AND ELECTROPHYSIOLOGIC FEATURES OF SYNCOPE IN CHRONIC CHAGASIC HEART-DISEASE

Introduction: Syncope in patients with chronic Chagasic heart disease (CCHD) is a frequent but poorly studied problem. Methods and Results: Fifty-three patients with CCHD and recurrent syncope were followed for 2 to 127 months. They were classified into the following groups: G-I (n = 15) without inducible ventricular tachycardia (VT) and normal HV interval; G-II (n = 17) with only inducible VT; G-III (n = 11) with on ly an abnormal HV interval; and G-IV (n = 10) with both an inducible V T and an abnormal HV interval. Empiric pharmacologic therapy was given in G-I; pharmacologic therapy guided by electrophysiologic study in G -II; atrioventricular pacing in G-III; and empiric pharmacologic with atrioventricular pacing in G-IV. Age and sex were similar among groups ; New York Heart Association Functional Class I symptoms were more pre valent (P = 0.0001) in G-I. The ejection fraction by echocardiography was higher in G-I (P = 0.0122). The density of premature ventricular c omplexes by Holter monitoring was similar among groups. The complexity of premature ventricular complexes by Holter was significantly higher in G-II (P = 0.0270); this variable, analyzed from the exercise elect rocardiogram, was not different among groups. All deaths were sudden, prevalence was higher in G-II and absent in G-III, and recurrence of s yncope was similar among groups. Conclusion: The most probable causes of recurrent syncope were VT (43%) with poor prognosis, and paroxysmal atrioventricular block (21%) with a favorable prognosis. Absence of c ongestive heart failure, complexity of premature ventricular complexes by Holter, and absence of intraventricular heart block showed statist ical correlation with normal electrophysiologic study, inducible VT, a nd normal HV interval, respectively.