Left atrial remodeling is common in hypertrophic cardiomyopathy (HCM) and is associated with atrial fibrillation (AF) and thromboembolic events. However, currently available AF risk prediction models perform poorly in patients with HCM. The left atrioventricular coupling index (LACI) is a novel imaging marker that integrates left atrial size and left ventricular filling properties and has emerged as a potential indicator of atrial remodeling and AF risk. This study aimed to evaluate the association between LACI and new-onset AF, transient ischemic attack, or ischemic stroke in patients with HCM.

We retrospectively analyzed 287 patients with HCM without a prior history of AF, transient ischemic attack, or ischemic stroke who underwent cardiac magnetic resonance imaging between 2014 and 2022. Left atrial and left ventricular volumes were measured, and LACI was calculated as the ratio of minimum left atrial volume to left ventricular end-diastolic volume. Patients were categorized into tertiles according to LACI. Left atrial strain analysis was performed. Cox proportional hazards models assessed the association between LACI and a composite endpoint including AF, transient ischemic attack, or ischemic stroke.

During a median follow-up of 60 months, 51 patients (17.9%) reached the composite endpoint. Patients in the highest LACI tertile (≥ 36%) had a significantly higher risk of AF or thromboembolic events (adjusted HR, 2.88; 95%CI, 1.27–6.51; P <.001). Left atrial booster strain was also independently associated with adverse outcomes.

LACI and left atrial booster strain are independently associated with new-onset AF and thromboembolic events in patients with HCM.