Murmur of persistent ductus arteriosus in premature infants.

A long-term survey of the repeated clinical examination of premature newborn infants is reported. There were 52 infants in whom there was well-documented clinical and phonocardiographic evidence of delayed closure of the ductus arteriosus. The ductus is believed to have closed spontaneously in 47 of them before 6 months of age and to have persisted in 5. Nine infants developed heart failure and all were treated medically. 8 recovered and the ductus subsequently closed spontaneously. The ninth (birthweight 1132 g) died in heart failure with a widely patent ductus. The characteristics of the various murmurs ascribed to the persistent ductus arteriosus are described and discussed. Extreme lability of the factors determining flow through the duct is suggested by the rapidly changing characteristics of the murmurs recorded.