Association of relative wall thickness of left ventricle with incidence of thromboembolism in patients with non-valvular atrial fibrillation: The Fushimi AF Registry

AIMS: Atrial fibrillation (AF) increases the risk of thromboembolism, such as ischaemic stroke or systemic embolism (SE). The aim of this study was to investigate the relationship between left ventricular relative wall thickness (RWT) and the risk of thromboembolism in patients with non-valvular AF. METHODS AND RESULTS: The Fushimi AF Registry is a community-based prospective survey of the patients with AF in Japan. Analyses were performed on 3067 non-valvular AF patients, in which RWT values determined by transthoracic echocardiography were available at the baseline. The high-RWT group (RWT above the median) was more often female, older, and had higher systolic blood pressure, CHADS2 and CHA2DS2-VASc scores, as compared with low-RWT group. During the median follow-up period of 1309 days, there was a higher incidence of ischaemic stroke/SE in the high-RWT group [unadjusted hazard ratio (HR), 1.91; 95% confidence interval (CI), 1.42-2.59]. On multivariate Cox regression analysis, including the components of CHA2DS2-VASc score, left atrial diameter, oral anticoagulant prescription at baseline, and type of AF, high RWT was independently associated with ischaemic stroke/SE (adjusted HR, 1.81; 95% CI, 1.34-2.47). Stratified analysis demonstrated no significant interaction for any subgroups. In Kaplan-Meier analysis, ordinal RWT quartiles stratified the incidence of ischaemic stroke/SE. Finally, addition of RWT to CHA2DS2-VASc score increased the performance of risk stratification for the incidence of stroke/SE. CONCLUSION: Relative wall thickness was independently associated with ischaemic stroke/SE among Japanese patients with non-valvular AF, suggesting the importance of left ventricular morphology in contributing to adverse outcomes, particularly thromboembolism.