Congestive heart failure, or simply heart failure, is progressive and should not be confused with a heart attack, which involves sudden tissue death of the heart muscle. Although heart failure may occur suddenly in some cases, gradual loss of function is more common.
I believe SI it stands for: Sacroiliac Joint Injections Sacroiliac (SI) joint injections are commonly used to determine what is causing back pain. SI joint injections are primarily diagnostic injections, meaning that they help your doctor determine the cause of your back pain but may not provide you with any long-term relief from the pain.
short procedures unit (short term care unit) a nursing unit where patients are briefly cared for following a medical or surgical procedure and are then discharged without spending the night. SI unit any unit of the International System of units (the metric system); see also si units. step-down unit a nursing unit designated to provide care for patients who are stable enough to be discharged from the intensive care unit but are not yet ready to be cared for on a medical-surgical unit.