Persistence of spongy myocardium with embryonic blood supply in an adult.

Gross presence of the embryonic pattern of myoarchitecture and of a sinusoid blood supply was found in the apical part of the left ventricle in a man who had been diagnosed with nonobstructive hypertrophic cardiomyopathy during life and who died suddenly at age 21 years. This is a first description of this finding in an adult with an otherwise normal heart and coronary arteries. The features of the cardiac lesions provide support for the current embryological views on ontogenesis of human myocardial structure and blood supply.