Abstract 13820: Association of Cardiothoracic Ratio With Heart Failure Events in Atrial Fibrillation Without Heart Failure: The Fushimi AF Registry

Abstract

Background: The cardiothoracic ratio (CTR) is a readily available and non-invasive tool with which to assess cardiac volume status. We previously reported that N-terminal pro-B-type natriuretic peptide (NT-proBNP) level was associated with higher incidence of clinical events in patients with atrial fibrillation (AF) without pre-existing heart failure (HF). However, it remains unknown whether CTR on chest radiography is associated with the incidence of HF events in AF patients without HF. Methods: The Fushimi AF Registry is a community-based prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. After excluding patients with pre-existing HF (defined as having one of the following; prior HF hospitalization, New York Heart Association class ≥2, or left ventricular ejection fraction <40%), we divided 1,049 patients into four groups according to their CTR and NT-proBNP level (median value: 495 ng/L) at baseline, and compared the incidence of HF events (composite of cardiac death or HF hospitalization) among the groups; G1 (Lower CTR<50% and Lower NT-proBNP<495, n=256), G2 (Higher CTR≥50% and Lower NT-proBNP<495, n=268), G3 (Lower CTR<50% and Higher NT-proBNP≥495, n=117) and G4 (Higher CTR≥50% and Higher NT-proBNP≥495, n=408). Results: During the median follow-up of 5.4 years, the incidence rates of HF events in the groups either having higher NT-pro BNP group or higher CTR group were higher, as compared with patients with lower CTR and lower NT-proBNP (G1: 0.5% per person-year, G2: 1.3%, G3: 1.6% and G4: 2.5%; p<0.01) (Figure). Multivariate Cox regression analysis revealed that higher CTR (≥50%) was independently associated with the incidence of HF events in AF patients without prior HF hospitalization (hazard ratio: 1.47, 95% confidence interval: 1.09-2.00). Conclusion: In Japanese AF patients without pre-existing HF, higher CTR was associated with higher incidence of HF events irrespective of NT-proBNP level.