Identification of the ischemic etiology of heart failure by cardiovascular magnetic resonance imaging: diagnostic accuracy of late gadolinium enhancement.

Background: A large proportion of patients with heart failure (HF) have a large and poorly contracting left ventricle. The noninvasive recognition of the ischemic etiology of such patients is difficult, and for this purpose, usually patients undergo coronary angiography. It has been shown that cardiovascular magnetic resonance (CMR) imaging can detect myocardial scarring by evaluating late gadolinium enhancement (LGE). The diagnostic accuracy of such method in differentiating the etiology of HF has not been previously tested in an unselected HF ambulatory population.

Methods: We studied 60 ambulatory patients consecutively enrolled from a specialized HF clinic. We included HF patients who were found to have increased left ventricular (LV) dimensions and reduced function. CMR was performed in these patients by operators who were unaware of patients' history and clinical conditions. LV dimensions and global and regional function, as well as the pattern of LGE, were obtained in each subject. Coronary angiography was subsequently performed in all the patients. The diagnostic accuracy of clinical history and electrocardiographic patterns, as well as regional wall motion abnormalities, wall thinning, and LGE, in differentiating coronary artery disease (CAD) from non-CAD patients were evaluated.

Results: The majority of CAD patients (98%) showed LV contrast hyperenhancement with respect to non-CAD HF subjects (16%). The detection of LGE by CMR had a sensitivity of 98% and a specificity of 84% and an overall accuracy of 93% in detecting CAD etiology among HF patients.

Conclusions: LGE is able to accurately differentiate CAD from non-CAD etiology of HF and may represent a clinically useful noninvasive tool for this purpose. As it provides relevant functional information as well as insight into the etiology, CMR may be included among the most important diagnostic tools in the workup of patients with HF.