Left atrial function and left atrioventricular coupling indices for atrial fibrillation prediction in hypertrophic cardiomyopathy

Abstract Background In hypertrophic cardiomyopathy (HCM), atrial fibrillation (AF) is a marker of disease progression and worse outcome, increasing the risk of thromboembolic events. Identification of HCM patients (pts) at risk of AF is pivotal for their clinical management and follow-up. Purpose We aimed to explore whether a detailed echocardiographic evaluation of the left atrium (LA) remodeling and function in HCM pts might improve the predictive value for new AF compared to standard parameters. Methods In consecutive HCM pts referred to our Cardiomyopathy Clinic between 2020 and 2023, we assess left ventricular (LV) and LA volumes and strain by two-dimensional echocardiography (2DE), and LV and LA volumes and total LA emptying fraction (EF) by three-dimensional (3DE) echocardiography. 3DE left atrioventricular coupling index (LACI) was calculated as the ratio of respective LA to LV end-diastolic volumes and expressed as percentage %. Clinical, ECG, and 48h ECG Holter data were also collected. Results A total of 180 HCM pts (58±18 years, 55% men) were followed for 23±13 months. Twenty-seven patients experienced at least one episode of AF during follow-up. They were older and had more impaired LV global longitudinal strain (GLS) (-13±4% vs -15±4%, p=0.004), total LA EF (31±12 vs 42±11%, p=0.001) and LA reservoir strain (LASr, 10±6 vs 16 ±8%, p=0.001) compared to pts without AF. In addition, larger values of 3DE LACI (75±51% vs 43±25%p=0.009) were found in the HCM pts with new AF episode during follow-up. At Cox univariable analysis, 3DE LACI, LA EF and LASr were associated with AF (AUC 0.68, 0.69 and 0.72, respectively, p<0.001 for all). The optimal cutoffs for predicting AF were > 59% for 3DE LACI and < 26% for LA EF with significant discriminative value in Kaplan-Meier analysis. The addition of 3DE LACI and LA EF to a model including LV GLS and 2DE LA volume had a significant incremental value for predicting the occurrence of AF (Figure 1). Conclusions In HCM patients, the advanced evaluation of LA function and left atrio-ventricular coupling by 3DE may improve the identification of patients at risk for subsequent AF episodes within 1 year follow-up. Predictive Model