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.
The non-ST elevation acute coronary syndromes (ACS; unstable angina [UA] and non-ST elevation [non-Q wave] myocardial infarction [NSTEMI]) occur in a variety of clinical settings. The definitions of and classification systems for UA and NSTEMI and their use to assess risk will be reviewed here.