Does Late Gadolinium Enhancement Predict Cardiac Events in Patients With Ischemic Cardiomyopathy?

Abstract

Despite improved clinical care and heightened public awareness, myocardial infarction (MI) and sudden cardiac death remain the leading causes of death in the United States.1 For this reason, clinical,2 laboratory,3 and electrocardiographic4 markers to identify those at risk for future cardiac events have been developed. In addition, both invasive (contrast angiography)5,6 and noninvasive (transthoracic echocardiography,7 radionuclide scintigraphy,8 magnetic resonance,9 and computer tomography10) imaging markers have been identified that further supplement the clinical markers to more accurately define cardiac risk. For the most part, these imaging markers rely on rest or stress measures of left ventricular (LV) ejection fraction,11 regional wall motion,12 myocardial perfusion,13 or the extent of coronary atherosclerosis.14 With the exception of coronary artery calcification scoring generated from computer tomography image datasets,15 there have been few new imaging markers (introduced during the past 15 years) that add incremental benefit to our ability to identify cardiac risk. Article p 2733 Late gadolinium enhancement (LGE) cardiac imaging was introduced by Saeed et al16 in 1989, to identify infarcted myocardial tissue during cardiovascular magnetic resonance (CMR). This technique incorporates the administration of relatively inert extracellular gadolinium contrast during gradient-echo inversion recovery imaging.17 On image acquisition, areas of noninfarcted tissue appear dark, and infarcted or fibrotic tissue appears bright because of reduced clearance and increased volume of distribution of the gadolinium.16 This fundamental aspect of delayed enhancement imaging has led to the recent expression, “bright is dead.” Combining the ability to characterize myocardial tissue with the heightened spatial resolution of CMR (voxel sizes are commonly acquired in the range of 1.5×1.5×6 mm), one can appreciate clear, crisp borders of infarct zones that are nearly identical to those observed histopathologically.18 In humans, the technique is reproducible, …