Optimal examination of the normally formed perinatal heart.

Because infants rarely suffer coronary artery thrombosis, it is mistakenly assumed that they seldom have significant ischemic myocardial injury. However, ischemic myocardial necrosis (INM) is common in the papillary muscles and subendocardium of stressed newborns and other infants. Standard dissection methods encourage only routine examination and limited sampling of the small perinatal heart, and most myocardial injury is never discovered. After evaluating published methods, a simple technique was developed to open and prepare the normally formed infant heart for optimal macroscopic and microscopic evaluation. Symmetrical anterior incisions of the atria and ventricles allow the atria, ventricles, and outflow tracts to be viewed almost simultaneously. A single change allows the heart to be "unrolled" into a plane for roentgenographic study of injected coronary arteries. The method for sampling the myocardium and the conduction system allows identification of more than 90 per cent of the IMN sites without adding significant costs. The recognition of significant IMN plays a valuable role in evaluating and explaining certain infant deaths.