In systole, the heart volume reduces so that the blood is forcefully pumped out into arterial vessels for distribution throughout the body. During systole auricles contract simultaneously as wall as the two ventricles are also contract simultaneously. The contraction of auricles and ventricles occurs separately at different times. Auricular systole takes 0.1 second, while atrial diastole about 0.7 seconds. Ventricular systole takes 0.3 seconds, while ventricular diastole takes 0.5 sec.