PO-05-218 ATRIAL MYOPATHY FORMS THE SUBSTRATE FOR ISCHEMIC STROKE IN PATIENTS WITHOUT ATRIAL FIBRILLATION: SECONDARY ANALYSIS OF TOPCAT TRIAL.

Abstract

Around 25% of all ischemic strokes do not have an etiology despite a complete standardized diagnostic workup. Recent studies emphasized the effect of atrial dysfunction on arrhythmogenesis and thrombogenesis. At present, there is a lack of a direct link between atrial myopathy and ischemic stroke independently of atrial fibrillation (AF). This study aims to explore a potential association between atrial myopathy and ischemic stroke in patients without AF. This is an exploratory, post-hoc analysis of the TOPCAT trial. We included patients with sinus rhythm documented at baseline ECG and not known to have AF. Atrial myopathy was defined as (left atrial diameter > 46mm or left atrial volume index > 36 mL/m2) or natriuretic peptides (BNP > 100 pg/mL or NT-Pro-BNP > 400 pg/mL). We used cox regression with covariate adjustments to investigate the effect of atrial myopathy on incident ischemic stroke over the study period. Among 3445 patients in the TOPCAT trial, 2226 (mean age 67.5± 4.9 years; female 54.8%) had echocardiographic and/or laboratory data and were included in this analysis. Atrial myopathy was present in 752 (33.7%) patients. During a median follow-up of 2 years, 56 (2.5%) patients developed ischemic stroke, including 25 with atrial myopathy. Atrial myopathy increased the risk of ischemic stroke [HR=1.91 (95% CI 1.08 to 3.38; p=0.013; Figure], independent of age, BMI, history of prior stroke, sex, race, hypertension, and vascular disease. There was a significant interaction with diabetes status. Atrial myopathy predicted risk in non-diabetics (HR=2.32 95% 1.04 to 5.19; p=0.03), but not in diabetics. Among patients with heart failure with preserved ejection fraction, atrial myopathy increases the risk of ischemic stroke, in the absence of AF. Further investigations are needed to better characterize this association and implement stroke prevention strategies.