Abstract 10746: Left Atrial Strain and the Risk of Arrhythmias on Extended Ambulatory Cardiac Monitoring: The Multi-Ethnic Study of Atherosclerosis

Abstract

Introduction: Abnormalities in left atrial (LA) function can be identified before the development of overt LA structural changes. Little is known about the relationship between LA mechanics and the risk of subclinical atrial and ventricular arrhythmias. Methods: 1,441 participants of the Multi-Ethnic Study of Atherosclerosis completed speckle-tracking echocardiography and Zio Patch monitoring from 2016-2018 (mean age 73 years, 52% female); participants in atrial fibrillation (AF) during echocardiography or cardiac monitoring were excluded. Absolute values of LA reservoir, booster pump, and conduit strain were measured. We evaluated associations of LA strain measures with atrial arrhythmias (presence of monitor-detected AF, AF burden, frequency of premature atrial contractions [PACs], frequency of supraventricular tachycardia [SVT] runs) and with ventricular arrhythmias (frequency of premature ventricular contractions, presence of non-sustained ventricular tachycardia [NSVT], frequency of NSVT runs). Primary analyses adjusted for demographic variables, blood pressure, smoking, diabetes, and clinical cardiovascular disease (4%). Results: Cardiac monitoring (median 14 days) detected AF in 3%. Each standard deviation (5.4%) lower (worse) LA reservoir strain was associated with a 64% higher risk of monitor-detected AF (95% CI 16-137%), 33% higher PAC frequency (95% CI 22-46%), and 15% higher SVT frequency (95% CI 7-24%). Adjustment for kidney function, NT-proBNP, LA volume, and LV ejection fraction and global longitudinal strain had little impact on associations. Findings were similar for LA booster pump strain and null for LA conduit strain (Figure). Associations of LA reservoir and booster pump strain with ventricular arrhythmias were completely attenuated after adjustment for LV function. Conclusions: In a multi-ethnic community-based cohort, abnormal LA mechanics may be an important risk factor for subclinical atrial arrhythmias.