Prognostic value of the left atrioventricular coupling index for adverse cardiac outcomes in hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) involves left atrial remodeling linked to adverse outcomes such as death, heart failure, and atrial fibrillation (AF). The left atrioventricular coupling index (LACI) reflects atrial-ventricular interaction, but its prognostic role in HCM is unclear. The objective of this study is to evaluate the prognostic value of cardiac magnetic resonance imaging (CMR)-derived LACI and identify optimal cut-offs for predicting adverse outcomes in HCM. Methods: This retrospective cohort study included HCM patients who underwent CMR with at least 1 year of follow-up. LACI was calculated as the ratio of left atrial to left ventricular end-diastolic volume. Associations between LACI and outcomes were analyzed using Cox regression. The primary outcome was a composite endpoint of all-cause death and hospitalization for heart failure (HHF). Secondary outcomes included all-cause death, HHF, and new-onset AF. Receiver operating characteristic (ROC) analysis determined optimal LACI cut-offs. Results: Among 183 patients (median age 61 years; 59 % male) followed for 4.2 years, 53 (29 %) reached the primary endpoint. Elevated LACI independently predicted the primary composite endpoint (≥0.41: aHR 2.24, 95 %CI: 1.19, 4.24, p = 0.013), HHF (≥0.44: aHR 4.54, 95 %CI: 1.69, 12.19, p = 0.003), and new-onset AF (≥0.44: aHR 3.06, 95 %CI: 1.26, 7.43, p = 0.003) but not all-cause death. Conclusion: CMR-derived LACI independently predicted adverse outcomes in HCM, offering a reproducible marker for improved risk stratification.