premature ventricular contraction causes early emptying of the left ventricle (lv) into the aorta. since the next ventricular contraction occurs at its regular time, the filling time for the lv increases, causing an increased lv end-diastolic volume. due to the frank–starling mechanism, the next ventricular contraction is more forceful, leading to the ejection of the larger than normal volume of blood, and bringing the lv end-systolic volume back to baseline.