Left atrial mechanics and the risk of atrial fibrillation in patients with hypertrophic cardiomyopathy

Background Atrial fibrillation (AF) is a common complication in patients with hypertrophic cardiomyopathy (HCM) and is associated with increased morbidity and mortality. Speckle-tracking echocardiography enables quantitative assessment of left atrial (LA) function, but its prognostic value in HCM remains yet incompletely understood. Methods Between May 2018 and December 2024, 310 consecutive patients with HCM were prospectively enrolled at our medical university, Austria. The primary endpoint was defined as new-onset AF in patients without a prior history of AF. LA reservoir, conduit, and contraction strain were assessed using speckle-tracking echocardiography. Associations between LA strain components and incident AF were analyzed using Cox regression models, adjusted for age, sex, LA volume index, and serum NT-proBNP levels. Results Of the 310 enrolled patients, 225 (median age 55 years, 41% female) had no prior history of AF and showed adequate image quality for analysis. The median interventricular septal thickness was 21 mm (IQR 18–25), the relative wall thickness ratio was 1.71 (IQR 1.37–2.08), and the LV mass index was 156.0 g/m² (IQR 128.5–184.0). The mean LA reservoir strain was –22.3% (SD 9.21), conduit strain –12.2% (SD 6.77), and contraction strain –10.47% (SD 5.77), without any sex-specific differences. Over a median follow-up of 4.5 years, 36 patients (16%) developed new-onset AF. In adjusted Cox regression analyses, all three LA strain parameters were significantly associated with AF (HR per one-unit increase: reservoir strain 1.17 [95% CI 1.09–1.26], conduit strain 1.12 [95% CI 1.03–1.24], contraction strain 1.35 [95% CI 1.18–1.56], respectively). Conclusion LA mechanical function, defined by all three strain phases is independently associated with an increased risk of AF in patients with HCM. LA strain analysis may serve as a valuable tool for risk stratification, enabling closer monitoring (e.g. implantable loop recorder) and potential earlier intervention in high-risk patients.