Coronary microvascular dysfunction (CMD) is frequent in hypertrophic cardiomyopathy (HCM) and may predispose to arrhythmias. A study published in Circulation evaluated whether angiography-derived microvascular resistance (AMR) is linked to atrial fibrillation (AF) in HCM.

The retrospective cohort included 607 patients with HCM who underwent coronary angiography. AMR was calculated using a wire-free angiography method, with values ≥250 mmHg·s/m indicating CMD. Patients with CMD were more likely to be male, hypertensive, and smokers. AF prevalence was significantly higher in those with CMD (26.3% vs 11.0%; P < 0.001) and increased progressively across AMR quartiles (7.1%, 11.3%, 16.2%, and 26.8%; P for trend < 0.001). After adjustment for demographic and clinical factors, CMD (odds ratio [OR] 3.12; 95% CI: 1.89–5.18; P < 0.001) and the highest AMR quartile (OR 6.08; 95% CI: 2.76–13.38; P < 0.001) remained independently associated with AF.

The study concluded that CMD, quantified through AMR, represents a strong, independent marker of AF risk in HCM, highlighting the potential role of microvascular assessment in arrhythmic risk stratification.