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.