Blood leaks back into the chambers rather than flowing forward through the heart or into an artery. In the United States, backflow most often is due to prolapse. Prolapse is when the flaps of the valve flop or bulge back into an upper heart chamber during a heartbeat. Prolapse mainly affects the mitral valve.
NSTEMI is a shorthand medical term for non-ST segment elevation myocardial infarction. It is one type of myocardial infarction also called heart attack.
Pathophysiology of NSTEMI vs STEMI: Pathophysiologically, NSTEMI is somewhat different from STEMI. NSTEMI occurs by developing a complete occlusion of a minor coronary artery or a partial occlusion of a major coronary artery previously affected by atherosclerosis. This causes a partial thickness damage of heart muscle.