Abstract 14237: Left Atrial Dynamics Predict Incident Atrial Fibrillation in Hypertrophic Cardiomyopathy

Abstract

Introduction: Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM) and is associated with an 8-fold increased risk of stroke. However, the ability to predict incident AF remains limited. Methods: At a single referral center, we identified HCM patients with paired transthoracic echocardiograms (TTEs) performed at least 12-months apart and both prior to a diagnosis of AF. Baseline clinical characteristics and the occurrence of incident AF was obtained from a clinical registry and the electronic medical record. Comprehensive analysis of TTEs was performed by an experienced reader who was blinded to clinical events and included total atrial emptying fraction (LA EF) and its individual components, including LA volume at end-systole. Changes in parameters over time were determined by comparing results between each TTE. Univariate and multivariate regression, Cox proportional hazard, and Kaplan-Meier methods were used to analyze factors associated with the subsequent incidence of AF. Results: We studied 202 patients (mean age 45 years, 42% female, 27% hypertensive, 39% with sarcomere mutation, 37% NYHA II or greater). Of all factors examined, the initial LA EF, as well as the rate of LA remodeling as defined by the change in LA end-systolic volume over time, were most significantly predictive of AF development (Figure 1). These results were robust to multivariate regression with other factors significant in HCM (Figure 1C), including baseline LA diameter. Conclusions: Reduced LA function (the LA EF) and increased rate of LA dilation predict incident AF in HCM. Future studies are needed to identity factors associated with adverse LA dynamics in HCM and whether these can be mitigated with pharmacotherapy.