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.
OSI Open Sytem Interconnection (ISO defined communications architecture used in data link to permit heterogeneous data communication systems to be interconnected in order to allow the reliable exchange of messages without regard to the implementation of the networks and physical media through which the messages pass).