Implication of Angio-based Microvascular Resistance, A Measure of Coronary Microvascular Dysfunction Severity, for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy.

Coronary microvascular dysfunction (CMD) is a common feature in patients with hypertrophic cardiomyopathy (HCM). CMD is a risk factor for atrial fibrillation (AF) in the general population. However, the relationship between CMD and AF prevalence in HCM patients has not been fully explored. This study aimed to investigate whether angio-based microvascular resistance (AMR), as an index of coronary microcirculatory function, is associated with the prevalence of AF in a large cohort of HCM patients. A total of 607 patients with HCM who underwent coronary angiography were included. AMR was retrospectively calculated using a wire-free angiography method in coronary arteries, and an average value of AMR ≥250 mmHg*s/m was defined as indicative of CMD. Our results showed that patients with CMD were more often male, with higher smoking rates and a higher prevalence of hypertension The prevalence of AF increased in patients with CMD (26.3% vs 11.0%; p <0.001), or across AHI quartiles (7.1%, 11.3%, 16.2%, and 26.8%, respectively; P for trend <0.001). After adjusting for age, sex, BMI, Hyperlipidemia, hypertension, left atrial diameter, creatinine and obstructive HCM, the presence of CMD (odds ratio, 3.12; 95% CI 1.89 to 5.18, p <0.001) or highest AMR quartile (odds ratio, 6.08 95% CI 2.76 to 13.38, p <0.001) were significantly associated with AF. In conclusion, AMR, as a marker of microvascular dysfunction, is independently associated with the prevalence of AF in patients with HCM. For HCM patients, these findings suggest that evaluating AMR could provide valuable insights into the risk of AF.