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.
An ECG will show the following characteristics for an NSTEMI: depressed ST wave or T-wave inversion; no progression to Q wave; partial blockage of the coronary artery; A STEMI will show: elevated ST wave; progression to Q wave; full blockage of the coronary artery