Prevalence of Arrhythmias in Patients With Coronary Microvascular Dysfunction

Background: Coronary microvascular dysfunction (CMD) is an important cause of angina with nonobstructive coronary arteries (ANOCA). It is unclear whether CMD is associated with arrhythmia. Aims: This study aimed to evaluate the prevalence of arrhythmias in patients with ANOCA and CMD compared to those in patients with ANOCA without CMD. Methods: In this observational study of the Coronary Microvascular Disease Registry (NCT05960474), patients with ANOCA who underwent invasive coronary functional assessment for CMD were included. The diagnosis of arrhythmia was based on 12-lead electrocardiography (ECG), or clinical diagnosis accompanied by ECG evidence within 1 year before CMD evaluation. Results: The study included 262 patients; 66 (25.2%) were CMD-positive. Patients with CMD were older, and there was no difference in history of heart failure and baseline left ventricular ejection fraction compared to those without CMD. Premature atrial contractions (PACs) (25.8% vs. 5.6%; p < 0.001), supraventricular tachycardia (SVT) (24.2% vs. 6.6%; p < 0.001), premature ventricular complexes (PVCs) (43.9% vs. 10.7%; p < 0.001), nonsustained ventricular tachycardia (NSVT) (28.8% vs. 3.1%; p < 0.001), and accelerated idioventricular rhythm (9.1% vs. 2.6%; = 0.02) were more common in CMD-positive patients. In a multivariate analysis adjusting for baseline differences and other variables clinically associated with arrhythmia, CMD was associated with PACs (odds ratio [OR]: 4.7; 95% confidence interval [CI]: 1.8–11.9), SVT (OR: 3.5; 95% CI: 1.5–8.6), PVCs (OR: 5.9; 95% CI: 2.6–13.0), and NSVT (OR: 9.5; 95% CI: 3.2–27.7). Conclusion: Patients with ANOCA and CMD have a higher likelihood of arrhythmias, especially ventricular arrhythmias.