Cardiac magnetic resonance of single ventricles.

The assessment of the patient with a single ventricle is an enormous challenge to medical science. Not only are there are varied types of single ventricles, nearly all patients require either heart replacement or reconstructive surgery, including an aortic to pulmonary connection. During the various phases of reconstructive surgeries which eventually leads to the Fontan procedure (1), there are varying loads placed on the ventricle (from a volume loaded ventricle to a volume unloaded one) as well as varying physiologies, such as one from a run-off lesion into the pulmonary circulation (e.g., Norwood Stage I reconstrucion (2)) to one without one (final Fontan reconstruction). Cardiac magnetic resonance (CMR) has come to play a major role in congenital heart disease, and the single ventricle is no exception (3). Because of the wide field of view and high resolution imaging of both 3-dimensional anatomy and physiology, CMR contributes to both the medical as well as surgical management in these patients. Since the single ventricle patient undergoes numerous surgeries (at least 2), the ability of CMR to detect myocardial scarring and regional wall motion abnormalities can aid in determining the etiology of poor ventricular performance. In conjunction with echocardiography, it can be used to avoid cardiac catheterization in many instances as patients progress through staged Fontan reconstruction (4). This manuscript will discuss the role CMR plays in the care and management of the patient with the single ventricle. A brief background on staged Fontan reconstruction will be presented followed by the typical CMR scanning protocol in these patients.