Mechanical cardiac remodeling and new-onset atrial fibrillation in long-term follow-up of subjects with chronic Chagas' disease

Atrial fibrillation (AF) affects subjects with Chagas' disease and is an indicator of poor prognosis. We investigated clinical, echocardiographic and electrocardiographic variables of Chagas' disease in a long-term longitudinal study as predictors of a new-onset AF episode lasting >24 h, nonfatal embolic stroke and cardiac death. Fifty adult outpatients (34 to 74 years old, 62% females) staged according to the Los Andes classification were enrolled. During a follow-up of (mean +/- SD) 84.2 +/- 39.0 months, 9 subjects developed AF (incidence: 3.3 +/- 1.0%/year), 5 had nonfatal stroke (incidence: 1.3 +/- 1.0%/year), and nine died (mortality rate: 2.3 +/- 0.8%/year). The progression rate of left ventricular mass and left ventricular ejection fraction was significantly greater in subjects who experienced AF (16.4 +/- 20.0 g/year and -8.6 +/- 7.6%/year, respectively) than in those who did not (8.2 +/- 8.4 g/year; P = 0.03, and -3.0 +/- 2.5%/year; P = 0.04, respectively). In univariate analysis, left atrial diameter >/=3.2 cm (P = 0.002), pulmonary arterial hypertension (P = 0.035), frequent premature supraventricular and ventricular contraction counts/24 h (P = 0.005 and P = 0.007, respectively), ventricular couplets/24 h (P = 0.002), and ventricular tachycardia (P = 0.004) were long-term predictors of AF. P-wave signal-averaged ECG revealed a limited long-term predictive value for AF. In chronic Chagas' disease, large left atrial diameter, pulmonary arterial hypertension, frequent supraventricular and ventricular premature beats, and ventricular tachycardia are long-term predictors of AF. The rate of left ventricular mass enlargement and systolic function deterioration impact AF incidence in this population.