Reduced Kidney Function and Left Atrial Dilatation as Predictors of Incident Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background Atrial fibrillation (AF), the most frequently occurring sustained arrhythmia in patients with hypertrophic cardiomyopathy (HCM), is linked to poor quality of life and increased thromboembolic risk. Chronic kidney disease (CKD) and reduced kidney function are known cardiovascular risk factors; however, their contributions to new‐onset AF in patients with HCM remain unclear. Estimated glomerular filtration rate (eGFR) is a key marker for CKD management. This study aimed to elucidate the incidence of new‐onset AF and to identify predictive factors in patients with HCM. Methods We analyzed 198 patients with HCM (121 men; mean age, 58 ± 17 years) without prior AF. The incidence and predictors of new‐onset AF were evaluated with a focus on kidney function and left atrial (LA) size. Cox proportional hazards modeling was used to assess the associations. Results Impaired kidney function (eGFR < 60 mL/min/1.73 m 2 ) was present in 35 patients (17.7%). Over a median follow‐up of 7.52 years, 43 patients (21.7%) developed new‐onset AF for an incidence rate of 2.8 per 100 person‐years. The multivariate analysis identified reduced eGFR and increased LA diameter (LAD) as independent predictors of AF. Kaplan–Meier curves showed a significantly higher cumulative AF incidence among patients with an eGFR ≤ 76.1 mL/min/1.73 m 2 or an LAD ≥ 48.0 mm. Conclusions Decreased kidney function and LA dilatation were significantly associated with new‐onset AF among patients with HCM. These findings suggest that this patient population requires closer monitoring for the early detection of AF.