A heart attack or acute myocardial infarction (MI) occurs when one of the arteries that supplies the heart muscle becomes blocked. Blockage may be caused by spasm of the artery or, more commonly, by atherosclerosis with acute clot formation. The blockage results in damaged tissue and a permanent loss of contraction of this portion of the heart muscle.
Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-
A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.