Left Atrial Strain as an Integrative Marker of Diastolic Dysfunction and Atrial Fibrillation in Hypertrophic Cardiomyopathy: A Retrospective Cross-Sectional Study

Background and Objectives: Echocardiographic assessment of left ventricular diastolic dysfunction (LVDD) in hypertrophic cardiomyopathy (HCM) is challenging, as conventional parameters correlate poorly with left ventricular filling pressure. Emerging evidence suggests that left atrial (LA) strain is associated with atrial fibrillation (AF). This study aimed to compare LA reservoir strain (LASr)-based and conventional LVDD grading, evaluate associations between LA strain and clinical and echocardiographic parameters, and explore its relationship with AF. Materials and Methods: This retrospective cross-sectional single-center study included 109 adult HCM patients with comprehensive echocardiographic data. LVDD was graded using conventional echocardiographic parameters and LASr-based thresholds (≥35% (grade 0), ≥24% to <35% (grade 1), ≥19% to <24% (grade 2), and < 19% (grade 3)). Results: LASr-based grading revealed a significantly greater prevalence of advanced LVDD compared with conventional assessment (grade 3: 39% vs. 3%, p < 0.001), with poor intermethod agreement (κ = 0.07). Overall, approximately 45% of patients were reclassified into higher LVDD grades using LASr, particularly among nonobstructive HCM patients. Higher LASr-based LVDD grades were associated with worse conventional diastolic indices, reduced biventricular strain parameters, and higher natriuretic peptide levels. Reduced LA reservoir and conduit strain were independently associated with documented AF after adjustment for age, LA volume index, and left ventricular mass index. Conclusions: LASr provides additional information on diastolic dysfunction in HCM patients and is associated with documented AF. LASr-based grading assigned more patients to advanced LVDD grades than conventional assessment. The observed association with AF requires prospective validation before LA strain can be used for risk stratification.