Cardiology

Heart Murmurs

At the one year check-up of a patient you have followed since birth you detect a 2/6 systolic murmur at the LLSB that you had not noted before.

The blood pressure and pulses are normal and the child has gained and grown well.

How would you decide that this is an innocent murmur and what do you tell the parents?

The above scenario is not an uncommon one for the general pediatrician, and the majority of murmurs heard by the pediatric practitioner are functional or innocent. By history, physical exam, careful examination, one should be able to make the differentiation between those that require further intervention and those that should be noted and followed over time.

History

  1. Child's overall health and growth.  Poor weight gain/FTT
  2. Family history of cardiac lesions, early or unexplained death or drowinging under 35 years of age
  3. In infants- feeding difficulties, tachypnea, irritability, sweating
  4. Older children- exercise intolerance, syncope, presyncope, palpitations, chest pain
  5. Birth history- prenatal conditions, exposure to drugs in pregnancy 
  6. History of other anomalies
  7. History consistent with underlying anemia or symptoms of hyperthyroidism

Physical Exam - Click on the links to listen

  1. Presence of non-cardiac malformations. Incidence of congenital heart disease increase with other anomalies
  2. Active or hyperdynamic precordium. You must palpate the chest.
  3. Signs of hypoxia - Cyanosis / digital clubbing
  4. Pulses - decreased or bounding.
  5. BP and difference in upper and lower extremities
  6. Signs of CHF - tachypnea, liver enlargement, rales, periorbital edema
  7. Intensity of murmur, location
  8. Changes with position (i.e., valsalva, standing)
  9. Second heart sound - intensity, splitting of 2nd heart sound (physiologic splitting vs fixed splitting). Usually with increased pulmonary pressure, the 2nd sound will become louder and single.
  10. Timing in Cycle - All diastolic heart murmurs with the exception of venous hums, are pathologic
  11. Gallops
  12. Clicks
  13. Need to reevaluate the patient when they are cooperative and quiet. Examine the child while asleep or relaxed and not tachycardiac.
     

  Innocent/ Functional Murmurs - Click on links to listen

  1. Venous hums - usually continuous and disappear in supine position. Heard best under clavicles. Due to turbulence in the jugular venous system.
  2. Pulmonary flow - ULSB. Due to turbulence from the pulmonary artery ejection 
  3. Vibratory - LLSB- high pitched and less than grade 2.  Doesn't radiate. Changes with position of the child. Intensity will increase with exercise, fever, and excitement.(all associated with increased HR)

Most children at some point in their lives have a heart murmur, and it is the job of the general pediatrician to differentiate functional from pathologic conditions. It is not unusual for an innocent murmur to sound pathological when the heart rate increase during exercise or the presence of a fever.

It is essential to inform the parents and the patient that they have an innocent murmur and if they see a new physician, they will not be sent for an unnecessary evaluation. The explanation must emphasize that the child's activities should not be limited and the murmur will not affect the child's future growth and health. Also, there is no special follow-up required. Anxious parents may insist on a consultation by a pediatric cardiologist.  Providing parents with appropriate-tarageted information may help to answer their questions and assuge their fears, such as the link below. 

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Often, infants with murmurs detected in the nursery most commonly later have normal exams as a result of a closed ductus or foramen ovale, however the provider should be aware of subtle findings that may point towards underlying cardiac disease. Tachypnea and a hyperdynamic precordium, and feeding problems should also trigger consideration of an underlying cardiac lesion thus attention to the cardiac exam in neonates is very important.

References

  1. Birkebaek, N.N. et. al. (1999). Chest roentgentogram in the evaluation of heart defects in asymptomatic infancts and children with a cardiac murmur: reproducibility and accuracy. Pediatrics, 103(2):e15.
  2. Cincinnati Children's. Signs and symptoms: heart murmur. 
  3. Harris, J.P. (1994). Evaluation of heart murmurs. Pediatrics in Review, 15(12).
  4. Menasahe, V. (2007). Heart murmurs. Pediatrics in Review, 28(4), 19-22. 
  5. McConnell, M.E. et. al. (1999). Heart murmurs in the pediatric patient: when do you refer?  American Family Physician, 60(2), 558-565.
  6. Sapin, S.O. (1997). Recognizing normal heart murmurs: a logic-based mnemonic. Pediatrics, 99(4), 616-619.
  7. Swenson, J.M. et. al. (1997). Are chest radiographs and electrocardiograms still valuable in evaluating new pediatric patients with heart murmurs or chest pain? Pediatrics, 99(1), 1-3.