New non-invasive approaches for the diagnosis of cardiomyopathy: magnetic resonance imaging.

Cardiac magnetic resonance imaging (CMR) permits a detailed look at the myocardium in patients with recent onset heart failure. Late-enhancement CMR provides information that is similar to that obtained by the naked eye of a pathologist. Myocardial scarring is endocardial in myocardial infarction, but it is epicardial in myocarditis and intramyocardial in hypertrophic cardiomyopathy. Thus, the distinction between these entities is possible by depicting scar via late-enhancement CMR and observing myocardial function by cine magnetic resonance imaging. Moreover, non-invasive follow-up--and hence observation of the healing or remodelling process--can be achieved using CMR. New CMR pulse sequences also permit depiction of myocardial oedema, which may occur early in patients with myocarditis and may be the only sign of the disease in the absence of necrosis. It is anticipated that cardiac MRI will become a standard diagnostic technique in patients with new onset of heart failure, left-ventricular hypertrophy or clinical symptoms suggestive of myocarditis.