MRI of Uhl’s Anomaly
Uhl’s anomaly of the right ventricle is an unusual cardiac disorder with almost complete absence of right ventricular myocardium, normal tricuspid valve, and preserved septal and left ventricular myocardium.1
We report MRI of the heart from a 17-year-old boy with Uhl’s anomaly. He presented as a neonate with severe hypoxemia (arterial Po2 of 29 mm Hg) and functional pulmonary atresia. He was treated with prostaglandins until the pulmonary vascular resistance decreased and forward flow across the pulmonary valve was established. His cyanosis resolved with closure of the foramen ovale and ductus arteriosus. His follow-up examinations have shown persistent right ventricular dilation and restrictive right ventricular physiology but normal left ventricular function. Despite right atrial enlargement, he remains free of arrhythmias.
The MR images depict an extremely thin-walled right ventricle with almost complete absence of right ventricular free wall myocardium (Figure 1A⇓), with a paucity of apical trabeculations (Figures 1A⇓ and 3A⇓) with normal left ventricular myocardium (Figures 1A⇓, 2A⇓, and 3A⇓). There is an absence of fibrofatty infiltration of the right ventricular free wall (Figure 2A⇓), which may serve to differentiate Uhl’s disease from arrhythmogenic right ventricular dysplasia (Figure 2B⇓).2 The tricuspid valve hinges normally, is not dysplastic, and serves to exclude Ebstein’s anomaly of the tricuspid valve as the cause of a dilated and thin-walled right ventricle (Figure 3A⇓). The right atrium is dilated and hypertrophied as a consequence of the right ventricular restrictive cardiomyopathy3 and dependence on atrial contraction to augment pulmonary artery forward flow (Figure 3A⇓).
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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