The relationship between coronary microvascular dysfunction, atrial fibrillation and heart failure with preserved...

Coronary microvascular dysfunction (CMD) is a new frontier in cardiovascular disease and an important contributor to myocardial ischemia. A high prevalence of CMD is shown in heart failure, however, the cause-and-effect relationship between CMD and atrial fibrillation (AF) is unknown. We hypothesize that CMD is associated with AF and increases susceptibility to the co-existence of AF and heart failure with preserved ejection fraction (HFpEF).

Our study examined the relationship between CMD, AF, and HFpEF in all patients who underwent invasive coronary physiology studies for assessment of chest pain or dyspnea. CMD was defined as impaired coronary flow reserve (CFR) without obstructive coronary disease.

A total of 80 patients (mean age 60±12 years, 68.8% female, median follow up of 2.2 years) were studied. Patients with AF (61%) or HFpEF (62%), or both (71%) were more likely to have CMD than those patients without these conditions. Of the patients with AF and abnormal CFR, 91% had HFpEF. CMD was a predictor of AF with concomitant HFpEF (OR 4.38, P=0.02). Our clinical outcome analysis demonstrated that patients with CMD, AF or HFpEF had lower survival free of HF hospitalization than those patients without (P<0.05). AF (OR 5.5, P=0.02), diabetes, older age, female gender, and higher heart rate were predictors of CMD.

CMD is highly prevalent in patients with AF with or without HFpEF. CMD is associated with poor clinical outcomes and the co-existence of AF and HFpEF. Understanding of the association between CMD and AF is important for developing an effective treatment strategy and the risk stratification for the prevention of AF in patients with CMD and vice versa.