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.
Diastolic Dysfunction. Diastolic dysfunction of the left ventricular occurs when the left ventricle becomes stiff. This can happen for a variety of reasons, but often doesn't affect systolic pump function (contraction), rather, it makes it more difficult for the heart to fill with blood and relax during diastole. Importance of Diastolic Function.