Left atrial dimension and new-onset atrial fibrillation in chronic Chagas disease: A competing-risk analysis of the SEARCH-Rio cohort.
TL;DR
In CCD, baseline LA diameter predicts new-onset AF over 25 years, with 4.0 cm acting as a dynamic threshold, and P-SAECG is unrelated to LA size and poorly predicts AF.
Abstract
Background
Atrial cardiomyopathy and atrial fibrillation (AF) complicate chronic Chagas disease (CCD). We assessed whether baseline left atrial (LA) diameter predicts new-onset AF during long-term follow-up, relates to ventricular remodeling, and whether P-wave signal-averaged ECG (P-SAECG) adds predictive value. Methods Fifty patients from the SEARCH-Rio study, in sinus rhythm at enrolment (age; 51 ± 9 years; 70% female), were followed for up to 25 years. AF incidence was estimated with death as a competing event and strata compared by log-rank test. Correlation analysis linked LV mass and LA diameter changes; baseline P-SAECG was tested for incident AF. Results Eleven patients (22%) developed AF over 25 years. Patients with AF had larger LA diameter compared to the non-AF group, at baseline (4.01 ± 0.51 vs. 3.47 ± 0.58 cm; p = 0.008) and at 25 years (4.75 ± 0.35 vs. 3.60 ± 0.63 cm; p = 0.028). AF incidence above vs. below baseline LA 4.0 cm was 39% vs. 18% (HR 5.81; log-rank p = 0.024). From LA crossing 4.0 cm, incidence was 42.5% in crossers vs. 13.6% in non-crossers (p = 0.026). LV mass and LA diameter changes correlated (r = 0.505, p = 0.002). P-SAECG predicted neither AF nor LA diameter.
Conclusions
In CCD, baseline LA diameter predicts new-onset AF over 25 years, with 4.0 cm acting as a dynamic threshold. LA enlargement correlates only moderately with ventricular remodeling, and acts as a manifestation of independent atrial cardiomyopathy. P-SAECG is unrelated to LA size and poorly predicts AF.