Left atrial size trajectories and outcome over a 35-year follow-up in patients with hypertrophic cardiomyopathy

Background In Hypertrophic cardiomyopathy (HCM) increasing evidence suggests left atrial (LA) remodelling plays a critical role in disease progression. Traditional static LA size measurements, while established as risk markers, do not reflect the dynamic nature of LA changes over time. Objectives This study aimed to define long-term LA remodelling trajectories in HCM and assess their prognostic value for predicting atrial fibrillation (AF), sudden cardiac death (SCD), and heart failure (HF) death. Methods A cohort of 210 HCM patients with at least 5 LA measurements (36 % women, mean age 45 ± 17 years) was followed over a 35-year period. Group-based trajectory modelling identified distinct longitudinal patterns of LA size. Clinical endpoints included incident AF, SCD, and a composite of heart failure-related death or transplantation. Cox regression analyses compared the predictive value of these trajectories against static baseline LA measurements. Results Three LA remodelling trajectories were identified. Over a mean follow-up of 21.8 ± 7.8 years, 73 patients developed AF, 25 experienced SCD, and 9 died from HF. Moderate (Cluster B) and severe (Cluster C) remodelling trajectories were associated with significantly increased AF risk (log-rank p  < 0.001), with Cluster C showing a markedly elevated adjusted hazard ratio (aHR 9.30 vs. 5.03 for baseline size). Cluster C was also significantly associated with higher risk of SCD (aHR 3.61, p  = 0.031) and HF death ( p  = 0.028). Conclusions Longitudinal LA remodelling patterns offer superior prognostic value over static measurements in HCM, enabling improved risk stratification and personalized care.