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.
What is a STEMI? ST-Elevation Myocardial Infarction (STEMI) is a very serious type of heart attack during which one of the heartâs major arteries (one of the arteries that supplies oxygen and nutrient-rich blood to the heart muscle) is blocked. ST-segment elevation is an abnormality detected on the 12-lead ECG. It is a profoundly life-threatening medical emergency and usually associated with a disease process called atherosclerosis (coronary artery disease). You can find a useful video about heart disease and heart attacks at the Khan Academy.