Coronary microvascular dysfunction goes along with premature ventricular contractions

Abstract Background Coronary microvascular dysfunction (CMD) is highly prevalent in patients with angina and nonobstructive coronary artery disease. Still, since specific diagnostics are rarely performed, no tailored therapy is prescribed in these patients resulting in adverse cardiovascular outcomes in the short- and long-term. So far, the relationship between CMD and ventricular arrhythmias including premature ventricular contractions (PVCs) is unknown. Purpose Therefore, we aimed to analyze in a proof-of-principle dual-center study whether patients with CMD present with more PVCs than those without CMD. Methods First, a total of 150 patients with suspected ischaemic cardiomyopathy underwent stress cardiac magnetic resonance imaging with assessment of myocardial perfusion reserve index for the definition of CMD (<1.4). Second, 40 patients with stable angina and suspected CMD underwent intracoronary continuous thermodilution. CMD was defined as abnormal coronary flow reserve (<2) and/or index of microvascular resistance (≥25). The occurrence of ventricular and supraventricular arrhythmias in Holter electrocardiograms was compared between patients with vs. without CMD. Results Among all patients undergoing stress cardiac magnetic resonance imaging (median age 69 (IQR 57–76) years, 58.0% male), 59 (39.3%) were diagnosed with CMD. In Holter analysis, they had more PVCs per 24 hours (912 (IQR 78–7472) vs. 99 (IQR 6–429); p<0.0001), with a greater burden (1% (IQR 1–7) vs. 1% (IQR 1–1); p<0.0001) and more maximum PVCs per hour (123 (IQR 22–563) vs. 22 (IQR 2–122); p=0.0004) than patients without CMD (Fig. A). Also, they had more premature atrial contractions (PACs) per 24 hours (466 (IQR 37–2564) vs. 90 (IQR 20–549); p=0.0114), with a greater burden (1% (IQR 1–2) vs. 1% (IQR 1–1); p=0.0374) and more maximum PACs per hour (IQR 56 (9–425) vs. 27 (IQR 6–129); p=0.0264) (Fig. B). Among all patients undergoing continuous thermodilution (median age 71 (IQR 67–79) years, 52.5% male), 29 (72.5%) were diagnosed with CMD. In Holter analysis, they had more PVCs (1004 (IQR 162–2889) vs. 191 (IQR 77–591); p=0.0280) and PACs per 24 hours (221 (IQR 75–2461) vs. 52 (IQR 14–389); p=0.0239) than patients without CMD (Fig. C+D). Conclusion CMD goes along with PVCs as well as PACs which may have relevant implications for therapeutical approaches in these patients. Mechanistic insights need to be determined.CMD goes along with PVCs and PACs