Evolutionary Persistence of Spongy Myocardium in Humans
A15-year-old boy underwent successful cardiac transplantation for severe congestive heart failure. His sister had died at the age of 9 years of undefined congenital heart disease. At the age of 10 years, during a school medical screening, the patient was diagnosed with a cardiomyopathy. At cardiac catheterization, the right ventricle disclosed an increased trabecular pattern, mainly in the region of the apex, and the left ventricle showed an increased wall thickness, with mild hypokinesia. Subsequently, the patient complained of dyspnea on effort and presented signs of congestive heart failure. Five years later, the boy was admitted to an intensive care unit requiring a continuous inotropic drug infusion. Two-dimensional echocardiography disclosed biventricular dilatation with diffuse hypokinesia and a hyperechogenic coarse endocardial shape (a and b) interpreted as apical mural thrombi (arrow). The heart removed at transplantation was markedly dilated (weight, 720 g) and revealed the gross morphological features of noncompaction (spongy myocardium) with numerous, excessively prominent trabeculations and deep intertrabecular recesses penetrating into the endocardium (c). Histological examination confirmed that the spongy appearance was due to the deep intertrabecular recesses, lined by endothelium, which spread close to the epicardial surface (d). This feature strongly resembles the spongy myocardium pattern of nonmammalian vertebrates such as fish, amphibians, and reptiles.
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.
Circulation encourages readers to submit cardiovascular images to Dr Hugh A. McAllister, Jr, St Luke’s Episcopal Hospital and Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.
- Copyright © 1999 by American Heart Association