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Clinical and electrophysiologic features of syncope in chronic chagasic heart disease
M Martinelli Filho1, E Sosa, S Nishioka
1Heart Institute, Medical School, University of São Paulo, Brazil.
Insights
Recurrent syncope in chronic Chagasic heart disease (CCHD) is often caused by ventricular tachycardia (VT) or atrioventricular block. Identifying these causes aids in prognosis and treatment strategies for CCHD patients.
Area of Science:
- Cardiology
- Electrophysiology
- Chagasic Heart Disease
Background:
- Syncope is a frequent, yet understudied, complication in patients with chronic Chagasic heart disease (CCHD).
- Understanding the underlying mechanisms of syncope is crucial for improving patient outcomes in CCHD.
Purpose of the Study:
- To investigate the causes and prognostic implications of recurrent syncope in patients with CCHD.
- To correlate electrophysiologic findings with clinical presentation and outcomes.
Main Methods:
- A cohort of 53 patients with CCHD and recurrent syncope were followed and classified into four groups based on inducible ventricular tachycardia (VT) and HV interval.
- Treatment strategies included empiric pharmacologic therapy, VT-guided therapy, atrioventricular pacing, or a combination.
- Ejection fraction, Holter monitoring, and exercise electrocardiograms were analyzed.
Main Results:
- Ventricular tachycardia (VT) was identified as the cause of syncope in 43% of patients, associated with a poor prognosis.
- Paroxysmal atrioventricular block was the cause in 21%, with a favorable prognosis.
- Absence of congestive heart failure correlated with a normal electrophysiologic study, while complex ventricular ectopy on Holter correlated with inducible VT.
Conclusions:
- Recurrent syncope in CCHD is primarily attributed to VT or atrioventricular block, each with distinct prognoses.
- Electrophysiologic study findings are valuable in stratifying risk and guiding therapy in CCHD patients presenting with syncope.
- Early identification of VT or conduction abnormalities can inform therapeutic interventions and improve outcomes.
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.