Evaluation of Heart Murmurs in the Neonate

1. Evaluation of Heart Murmurs in the Neonate By Nikette Neal, MD

2. Definition • A heart murmur is am extra heart sound cause by turbulent blood flow • Murmurs may be common in the first 24-48 hours of life

3. Changes After Birth • Pulmonary Vascular Resistance begins to fall immediately • Foramen Ovale closes – within the first hour • Ductus Arteriosus closes – up to 48 hours can be normal • Left heart now the dominant side • Process continues for up to 6-8 weeks

4. Epidemiology • Murmurs have been reported in an many as 90% of newborns • The prevalence of structural disease is less than 1% • 25% of which requiring surgical intervention • Fewer than 50% of cases of CHD are identified on a prenatal ultrasound

5. Etiology • Murmurs in asymptomatic neonates may be caused by the following in a neonate: • Turbulent flow through a closing ductusarteriosus • Regurgitant mitral or tricuspid valves • Pulmonic stenosis • Aortic stenosis • Nonphysiologic peripheral pulmonary stenosis • Supravalvularaortic stenosis • Etc.

6. history • A detailed history is important in determining the need for further work up of murmur • History of Present Illness • Feeding History- infants with structural heart disease tend to have difficulty with tolerating feeds • Associated symptoms while feeding- this includes tachypnea, diaphoresis, fussiness, retractions, or cyanosis • Weight gain- infants with heart disease tend to have poor weight gain • Activity level- lethargy and/or irritability are both associated with murmurs in the newborn.

7. History con’t • Prenatal history • Prenatal ultrasound results • Medications taken during pregnancy • Alcohol or drug exposure • Comorbid conditions • Family history • Congenital abnormalities • Inheritable conditions related to cardiac conditions • Childhood deaths or first degree relatives with heart disease

8. Physical Exam • Physical exam is paramount in the diagnosis if cardiac disease in a newborn • Examination of the newborn should include a thorough assessment of the vitals • Especially heart rate, respiratory rate, blood pressure, and pulse oximetry • On general exam, note the patient’s dispositionand color • Central cyanosis is highly associated with cardiac disease. • Diminished or bounding pulses should increase our index of suspicion

9. Cardiac Examination • To determine if further evaluation is needed note • Presence of a precordial bulge, heave, or thrill • Abnormality of the second heart sound • Obscured S1 • Diastolic murmur • Intensity greater than II/VI • Harsh quality • If any of these are present, an echocardiogram is indicated

10. Innocent Murmurs • A murmur is characterized by timing, location, quality, intensity, pitch and presence or absence of clicks • An innocent murmur is characterized by the 7 S’s • Sensitive (changes with position) • Short duration • Single • Small(non-radiating) • Soft • Sweet (not harsh) • Systolic

12. Diagnostic Studies • Echocardiogram • Study of choice to diagnose CHD • Pulse Oximetry • Should be obtained in the right upper and lower extremities • An oxygen saturation of <90% is considered positive • Chest X-ray • EKG

13. References • Frommelt MA. Differential diagnosis and approach to a heart murmur in term infants. Pediatric Clinics of North America. 2004;51:1023–1032 • Yi MS, Kimball TR, Tsevat J, Mrus JM, Kotagal UR. Evaluation of heart murmurs in children: Cost-effectiveness and practical implications. The Journal of Pediatrics. 2002;141(4):504–510 • Silberbach M, Hannon J. Presentation of Congenital Heart Diseases in the Neonate and Young Infant. Pediatr. Rev. 2007;28;123-131