Ectopic beat (or cardiac ectopy) is a disturbance of the cardiac rhythm frequently related to the electrical conduction system of the heart, in which beats arise from fibers or group of fibers outside the region in the heart muscle ordinarily responsible for impulse formation (i.e. , the sinoatrial node).t is a form of cardiac arrhythmia in which ectopic foci within either ventricular or atrial myocardium, or from finer branches of the electric transduction system, cause additional beats of the heart.