Incidence and natural history of suspected innocent heart murmur in neonates at HRHPrincess Maha Chakri Sirindhorn Medical Centre

Abstract

This study aim is to determine the incidence and clinical significance of innocent heart murmur detected during neonatal examination and to define the origin and natural history of the innocent heart murmur in neonates. We investigated in neonates with the clinical diagnosis of an innocent heart murmur at HRH Princess Maha Chakri Sirindhorn Medical Centre. Each infant had a complete echocardiographic study and was followed up at 2 and 6 months respectively. Thirty neonates with innocent heart murmur were enrolled in this study. The incidence of innocent heart murmur in term neonates was 9:1,000 livebirths. Normal echocardiograms were found in 10 cases (33%), peripheral pulmonary branch stenosis (PPS) in 6 cases (20%), small patent ductus arteriosus (PDA) in 5 cases (17%), small ventricular septal defect (VSD) in 3 cases (10%), mild pulmonary valve stenosis in 1 case (3%), and isolated mild tricuspid valve regurgitation in 5 cases (17%). Only VSD and pulmonary valve stenosis were considered to be pathological findings. Two cases had missed the appointment. The heart murmurs had disappeared in 23 cases (82%) and in 26 cases (93%) at 2 and 6 months, respectively. The PDA and mild pulmonary stenosis had resolved in all patients, but peripheral pulmonary stenosis was still present in 1 of 6 cases. Two of the three with VSD still had a murmur and the defects were still patent. An innocent heart murmur in a neonate is often related to non clinical significant conditions. The suspected innocent heart murmur diagnosed at birth resolves within 6 months in most of the infants.