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.
The symptom index (SI) for the chief complaint of heartburn or chest pain in 100 consecutive patients referred for ambulatory 24-h esophageal pH monitoring. Note the predominance of SI values in the two extremes (77%). There was a good association between high SI and an abnormal 24-h pH test (97.5%), as well as low SI and normal 24-h pH test (81.1%). (From [19].) index should be set lower than 75%. A few patients with normal 24 pH have positive symptom index, which in itself gives valuable information.