Annual deaths from tornadoes, earthquakes and floods together total fewer than 200. The most deadly heat wave in recent years occurred in Chicago over a week in July 1995, when temperatures hovered around 100 degrees.
Cardiac Cycle: 1st Systole Phase. During the systole phase, the right ventricle receives impulses from the Purkinje fibers and contracts. The atrioventricular valves close and the semilunar valves open. The de-oxygenated blood is pumped into the pulmonary artery.
The mechanical events occurring during one systole and diastole. To study a particular phase of cardiac cycle, one should study what happens to atrium, ventricle, aorta/pulmonary vein, cardiac valves in that phase. Events that occur in left chambers of heart, similar events occur in right chambers of heart.