Phasic coronary flow

Coronary capillary blood flow in the left ventricle muscle falls to a low value during systole, which is opposite to flow in vascular beds elsewhere in the body. The reason for this phenomenon is strong compression of the intramuscular blood vessels by the left ventricular muscle during systolic contraction. During diastole, the cardiac muscle relaxes and no longer obstructs blood flow through the left ventricular muscle capillaries, so blood flows rapidly during all of the diastoles.