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.
Next, you should try to discern if the murmur occurs in systole or diastole by timing it against S1 and S2. Then, listen carefully to tell if the murmur completely fills that phase of the cycle (i.e., holosystolic), or if it has discrete start and end points.