From the Guidelines
When a new heart murmur is detected during a six-week postnatal check in general practice in New Zealand, the recommended approach is to first determine the clinical significance of the murmur through careful assessment, and if the infant appears well, refer for pediatric cardiology assessment within 4-6 weeks, unless the murmur has concerning features, in which case urgent or earlier referral is warranted, as supported by guidelines from the American College of Cardiology and American Heart Association 1.
Initial Assessment
Begin with a thorough clinical examination, including vital signs, oxygen saturation, and assessment for signs of heart failure such as poor feeding, tachypnea, hepatomegaly, or failure to thrive. If the infant appears well with normal growth, no cyanosis, normal pulses, and no signs of heart failure, the murmur may be innocent (physiological).
Referral Guidelines
All new murmurs should be documented and referred for pediatric cardiology assessment. In New Zealand, this typically involves referral to the nearest pediatric cardiology service or pediatrician with cardiac expertise. The timing of referral depends on clinical assessment:
- Urgent (same day) if the infant is symptomatic
- Within 1-2 weeks if asymptomatic but the murmur has concerning features (harsh, grade 3 or louder, diastolic, or associated with abnormal pulses)
- Routine (within 4-6 weeks) for well-appearing infants with soft systolic murmurs
Management While Waiting for Specialist Appointment
While waiting for the specialist appointment, parents should be advised to return promptly if the infant develops symptoms such as poor feeding, respiratory distress, color changes, or lethargy. No medications are typically prescribed at this stage unless there are signs of heart failure, in which case urgent referral is warranted.
Importance of Echocardiography
Echocardiography with color flow and spectral Doppler evaluation is an important noninvasive method for assessing the significance of cardiac murmurs, as noted in the guidelines 1. However, it is not recommended for patients who have a grade 2 or softer midsystolic murmur identified as innocent or functional by an experienced observer, unless other clinical factors suggest the need for further evaluation 1.
From the Research
General Practice Approach to New Murmurs in NZ
- In New Zealand, general practitioners play a crucial role in evaluating and managing heart murmurs in children, including those detected at the six-week check-up.
- The approach to managing new murmurs involves a thorough clinical examination, including a detailed history and physical examination, to determine the likelihood of a pathologic murmur 2, 3.
Evaluation of Heart Murmurs
- The clinical examination is an accurate means of assessing newly referred patients with murmurs, with a sensitivity of 96%, specificity of 95%, positive predictive value of 88%, and negative predictive value of 98% 4.
- Historical elements that suggest pathology include family history of sudden cardiac death or congenital heart disease, in utero exposure to certain medications or alcohol, maternal diabetes mellitus, history of rheumatic fever or Kawasaki disease, and certain genetic disorders 3.
- Red flags that increase the likelihood of a pathologic murmur include a holosystolic or diastolic murmur, grade 3 or higher murmur, harsh quality, an abnormal S2, maximal murmur intensity at the upper left sternal border, a systolic click, or increased intensity when the patient stands 3.
Referral and Further Management
- Referral to a pediatric cardiologist is indicated for newborns with a murmur, as neonatal murmurs have higher rates of pathology than in older children, and neonatal murmur characteristics are more difficult to evaluate during examination 2.
- In older children, referral to a pediatric cardiologist is indicated when a pathologic murmur is suspected, or when there are signs or symptoms of cardiac disease 2, 3.
- Electrocardiography, chest radiography, and other tests should not be reflexively performed as part of all murmur evaluations, as they can misclassify a murmur as innocent or pathologic, and are not cost-effective 2, 5.
- Echocardiography provides a definitive diagnosis and is recommended for evaluation of any potentially pathologic murmur, and for evaluation of neonatal heart murmurs because these are more likely to be manifestations of structural heart disease 3.