99 MYOCARDIAL NECROSIS IN STRESSED NEWBORNS

Abstract

The recent association of transient tricuspid insufficiency of the newborn with papillary muscle necrosis prompted a detailed retrospective clinical and histologic analysis of all autopsied infants to find sites of myocardial necrosis. In a four year period, 19 of 80 autopsied infants who died within 7 days of birth were found to have one or more sites of significant myocardial damage. None of the 80 had congential heart disease. 10/19 pregnancies were classified as high risk. All were singleton births. Of 9/19 monitored during labor, 7 had abnormal monitor patterns. Seven infants had tricuspid insufficiency (TI) murmurs and one had the murmur of mitral insufficiency (MI). All those with the TI murmurs had distinct necrotic foci in the tricuspid valve papillary muscles. The infant with the MI murmur had moderate to severe damage of the mitral valve papillary muscles. Six of seven with TI murmurs were term infants. Thirteen of 19 had suffered asphyxia, 6 of them had had massive aspiration of meconium stained amniotic fluid. Six of nineteen infants had creatine phosphokinase studies and 5 of 6 had significant elevation of the MB fraction. The occurrence of a severe asphyxial episode or abnormal monitor pattern associated with the development of TI or MI murmurs and elevated CPK-MB fraction suggests that the infant has suffered a papillary muscle or other myocardial necrosis.