Clinical and electrophysiologic features of syncope in chronic chagasic heart disease

Abstract

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 only an abnormal HV interval; and G-IV (n = 10) with both an inducible VT 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 prevalent (P = 0.0001) in G-I. The ejection fraction by echocardiography was higher in G-I (P = 0.0122). The density of premature ventricular complexes 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 electrocardiogram, was not different among groups. All deaths were sudden, prevalence was higher in G-II and absent in G-III, and recurrence of syncope 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 congestive heart failure, complexity of premature ventricular complexes by Holter, and absence of intraventricular heart block showed statistical correlation with normal electrophysiologic study, inducible VT, and normal HV interval, respectively.