Coronary Microcirculation and Arrhythmias: The Two Faces of a Janus

Both supraventricular and ventricular arrhythmias may occur in patients without relevant epicardial coronary disease, significant structural heart disease or channelopathies. Their underlying mechanism is often unclear, and may sometimes be attributed to a preexistent coronary microvascular dysfunction which facilitates arrhythmias. Furthermore, arrhythmias may promote coronary microvascular dysfunction. We sought to clarify this relationship, starting from a clinical case of atrial fibrillation in a patient with coronary microvascular dysfunction and no epicardial coronary disease. We then explored various clinical scenarios which include ventricular arrhythmias, non-ischemic structural cardiac disease, cardiac pacing, bradyarrhythmias and conduction abnormalities.