Silent Myocardial Ischemia

A heart attack commonly does not have apparent symptoms; silent myocardial ischemia can occur in the absence of chest discomfort or other anginal equivalent symptoms, e.g., dyspnea, nausea, diaphoresis, etc., with ST-segment changes on EKG, reversible regional wall motion abnormalities, or perfusion defects on scintigraphy studies. MI occurs due to multiple factors resulting in an imbalance between consumption and production of adenosine triphosphate (ATP), causing ATP depletion leading to a cascade of biochemical events. Silent myocardial ischemia (SMI) obtained recognition at the beginning of the 20th century. About 70% to 80% of transient ischemic episodes do not present with anginal chest pain or any other symptoms (silent ischemia). Lack of pain in silent myocardial infarction (MI) increases morbidity and mortality since patients do not seek medical treatment in a timely fashion.