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.
Fundamentally, however, in every other way NSTEMI and unstable angina are identical. In other words, the imminent risk of a full myocardial infarction (that is, a STEMI), with âan irreversible death of part of the heart muscle, is very high in both NSTEMI and unstable angina.