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.
Inclusion terms of ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction are included to mirror the national standard guidelines of The American College of Cardiology and the American Heart Association for classifying patients with acute coronary syndrome.