Diagnosis of acute myocardial infarction.

A number of new techniques have been shown to be superior to creatine kinase and the 12-lead ECG for the diagnosis of acute myocardial infarction. Myoglobin and heart fatty acid-binding protein are more sensitive than creatine kinase for the diagnosis of acute myocardial infarction; myoglobin is also a superior marker for estimating infarct size. Cardiac troponin is a protein specific for the myocardium. It can be used to differentiate myocardial necrosis when creatine kinase levels are elevated from other clinical conditions. Body surface potential mapping and vectorcardiography are better for localizing the site of acute myocardial infarction than the standard 12-lead ECG. Although echocardiography is frequently used for evaluating infarct remodeling, in the future it could be replaced by ultrafast computed tomography or magnetic resonance imaging. Two excellent techniques for the determination of myocardial viability are late thallium redistribution imaging and positron-emission tomography with 18F-fluorodeoxyglucose.