Left atrial remodeling parallels ventricular damage and predicts atrial fibrillation in chagas cardiomyopathy

Introduction Atrial cardiomyopathy is a frequent complication of Chagas disease, driven by chronic inflammation and fibrosis. We hypothesized that left atrial (LA) remodeling progresses in parallel with left ventricular (LV) damage and predicts new-onset atrial fibrillation (AF). Methods We studied 50 patients with chronic Chagas cardiomyopathy (age 51±9 years, 70% female), all in sinus rhythm at baseline, followed at a tertiary center (mean 83.5±40.7 months). New-onset AF was assessed by serial Holter and ECG. LA anteroposterior diameter, LV mass (Devereux), and LVEF (Teichholz) were obtained by echocardiography from the parasternal long-axis view at admission and follow-up. Paired echocardiograms were available in 34 patients. LA enlargement was defined as diameter >4.0 cm. Results At baseline, 37 patients (74%) had normal LA diameter. AF incidence was 2.55/100 person-years (95%CI 1.17–4.85) and new LA enlargement 1.73/100 person-years (95%CI 0.56–4.03); 9 patients died. LA diameter increased at 0.6±1.4 mm/year (p<0.001) and LV mass at 6.9±23.6 g/year (p=0.027). Over follow-up, LA diameter increased from 3.55±0.62 cm to 3.90±0.58 cm (p<0.001), LV mass from 153.8±51.7 g to 206.9±73.0 g (p<0.001), and LVEF declined from 69.3±16.3 % to 61.0±18.9% (p<0.001) (Figure 1). Patients who developed AF had larger baseline LA (4.0±0.6 vs 3.5±0.6 cm; p=0.019); and baseline LA > 4.0 cm predicted AF (OR=5.16; p=0.040). Non-survivors had LA larger at admission (4.0±0.7 vs 3.5±0.5 cm; p=0.031) and at follow-up (4.7±0.7 vs 3.8±0.4 cm; p=0.005). The annual rate of LA enlargement strongly correlated with LV mass increase (r=0.84, p<0.001). Conclusion In Chagas cardiomyopathy, progressive LA enlargement mirrors LV remodeling, and predicts new-onset AF, suggesting that atrial cardiomyopathy is not an isolated event but part of a global fibrotic process. Serial LA assessment may identify patients at higher risk of AF and death.