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.
If you wear contact lenses you must stop wearing them prior to surgeryâat least two weeks for soft contacts and one month for hard contacts. This is because contact lenses can cause mild warping of the corneal shape, which may interfere with the preoperative measurements of the eye and calculations for RLE surgery.