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Murmurs for the Learners: An approach to pediatric heart murmurs

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Murmurs for the Learners: An approach to pediatric heart murmurs – A Medical Student Clinical Pearl

Luke MacLeod, Med IV

DMNB Class of 2022

Reviewed by Dr. Tushar Pishe

Copyedited by Dr. Mandy Peach

Case:

You are a senior medical student working in the emergency department and are asked to see Charlie, a 3-year-old boy who had a fall.  He is accompanied by his uncle Kevin, who gives you the history.  About one hour ago, Charlie was climbing onto a chair when he fell off and hit his head.  The chair was only a few feet off the ground and the floor was covered with a rug.  Charlie cried for several minutes after the fall, but there was no loss of consciousness or vomiting following the event.

Kevin tells you that Charlie is a healthy boy with no known medical issues or surgical history. There have been no concerns with his growth or development thus far.  He has no allergies, does not take any medications, and is up to date on his immunizations.  Kevin is unable to tell you much about Charlie’s family history.  He recently adopted Charlie, whose biological parents are no longer involved.

On exam, you observe an active and responsive 3-year-old.  He is afebrile with stable vital signs.  He has normal colour and shows no signs of respiratory distress.  There is a small bump on the top of his head, but no other injuries are noted.  His neurological exam reveals no focal neurological deficits.  To complete the exam, you feel his abdomen, which is soft and non-tender with no organomegaly, and auscultate his heart and lungs.  His lungs are clear with no crackles or wheeze. On auscultation of the heart, you detect a soft, non-radiating systolic murmur that seems to go away with inspiration.

You are reassured from the history and exam that Charlie’s head injury was very minor and that no further investigations or interventions are necessary, but you wonder about the significance of his heart murmur.

 

What is a heart murmur?

 

A heart murmur is an additional sound, often described as whooshing or blowing noise, heard between heart beats that is generated by turbulent blood flow in or near the heart.1,2  Heart murmurs are very common, with up to 90% of children having one either during infancy or later in childhood.  However, less than 1% of these murmurs are due to congenital heart disease.3  If the heart murmur is related to a serious underlying condition, the child may have signs or symptoms such as cyanosis, cough, shortness of breath, or light-headedness.1  Most murmurs are asymptomatic, but the absence of symptoms does not always mean that the murmur is benign.3 In some cases a murmur may be the only sign of an underlying heart condition.4

 

How to describe a murmur

 

Before picking up your stethoscope, you’ll want to make sure you have clean ear canals so you can pick up subtle murmurs.  The characteristics use to describe a murmur can be remembered with the pneumonic Q-TIP ROLS (note: this is not a recommendation to clean your ears with cotton swabs).

 

Quality

The quality of a murmur can be described as harsh, blowing, musical, rumbling, or vibrating.3

 

Timing

Timing describes when the murmur occurs in the cardiac cycle.  A systolic murmur occurs between S1 and S2.  These can be further categorized into four sub-types:

  • Early systolic: heard with or immediately after S1 and ends about halfway through systole.
  • Mid-systolic/systolic ejection murmur: heard midway between S1 and S2. Increases then decreases in volume (crescendo-decrescendo).
  • Mid-to-late systolic: heard about halfway through systole and ends before S2
  • Holosystolic/pansystolic: heard throughout systole.

Click here to listen to a holosystolic murmur: https://www.youtube.com/watch?v=MzORJbyHTT0

 

A diastolic murmur occurs between S2 and S1.  These can be further categorized into three sub-types:

  • Early diastolic: a high-pitched murmur heard with or immediately after S2.
  • Mid-diastolic: heard soon after S2 and ends before S1.
  • Late diastolic/presystolic: heard just before S1.

 

A continuous murmur is heard throughout the cardiac cycle.3

 

Intensity

A grading system from 1-6 is used to describe a murmur’s intensity, with higher values representing greater volumes.3  The following table details what each grade indicates:5

Pitch

A murmur can have low, medium, or high pitch.  High pitch murmurs are best detected using the diaphragm of the stethoscope, while low pitch murmurs are easier to hear using the bell.3

 

Radiation

This is the furthest point from the location (see below) where the murmur can still be detected.3

 

Other sounds

S3: heard in early diastole (shortly after S2).  S3 can be present in hyperdynamic states or with a large VSD.  This sound is best heard with the bell over the apex (for blood flow to the left ventricle) or the lower left sternal border (for blood flow to the right ventricle). When an S3 is present, the heart beat cadence is often described using the word “Kentucky” where “Ken” is S1, “tuc” is S2, and “ky” is S3.5

 

S4: heard late in diastole (just before S1) when there is turbulent blood flow into a stiff ventricle, such as in hypertrophic cardiomyopathy, myocardial dysfunction, semilunar valve stenosis, or tachycardia-induced cardiomyopathy.  S4 is best heard with the bell and is a pathologic exam finding.  When an S4 is present, the heart beat cadence is often described using the word “Tennessee,” where “Ten” is S4, “nes” is S1, and “see” is S2.5

 

Click below to listen to S3 and S4 heart sounds

https://www.youtube.com/watch?v=o8eqYHCy7dw

 

Ejection clicks

These are high pitch sounds that are often generated by abnormal heart valves.  The affected valve is determined based on the location, timing, and nature of the click as shown in the table below:5

Pericardial friction rub

A coarse grinding sound heard with pericarditis. This is best heard along the left sternal border.5

 

Location

This is the point where the murmur is most easily heard.3

 

Shape

Shape describes a murmur’s volume pattern. A few examples are shown below:6

What are the characteristics of benign and pathological murmurs?

 

Some red flag characteristics of pathologic murmurs are listed below.4,7

  • Holosystolic
  • Diastolic
  • Grade 3 or higher
  • Harsh quality
  • Systolic click
  • Max intensity at upper left sternal border
  • Abnormal S2
  • Greater intensity with standing

 

Characteristics of benign murmurs can be remembered using The Seven S’s.4,8

  • Systolic
  • Soft
  • Short (not holosystolic)
  • Small (non-radiating)
  • Sweet (not harsh)
  • Single (no clicks or gallops)
  • Sensitive (changes with position or respiration)

 

Click below to listen to an innocent heart murmur

https://www.youtube.com/watch?v=uFyWHPfrRak

 

Here are some examples to practice differentiating innocent from pathological murmurs:

https://teachingheartauscultation.com/pediatric-murmur-recognition-program-intro

 

What are some of the more common pediatric heart murmurs?

 

Innocent9

  • Classic vibratory parasternal-precordial stills murmur
  • Pulmonary ejection murmur
  • Systolic murmur of pulmonary flow in neonates
  • Venous hum
  • Carotid bruit

 

Pathologic4

  • Ventricular septal defect
  • Atrial septal defect (example: https://www.youtube.com/watch?v=W8gg2S-mvSQ)
  • Patent ductus arteriosus
  • Teratology of Fallot
  • Pulmonary stenosis
  • Coarctation of the aorta
  • Aortic stenosis
  • Transposition of the great arteries

 

Next steps

 

In patients with a heart murmur and an abnormal chest X-ray or ECG, an echocardiogram is indicated.  The echocardiogram is the gold standard test to diagnose congenital heart defects.  While the chest X-ray and ECG are low cost tests and can help rule out other diagnoses, they are not particularly useful in identifying the cause of a heart murmur. 3

An innocent heart murmur in an asymptomatic patient with an otherwise normal exam does not require referral to cardiology.  However, the patient should be followed by their family physician to monitor the murmur.

Patients who are symptomatic, have a pathologic murmur, and/or have other concerning exam findings should be referred to a pediatric cardiologist.10

 

Case Conclusion

 

Charlie’s heart murmur lacked any of the red flag characteristics.  It was soft (grade 2) systolic murmur that did not radiate and changed with inspiration, which are all reassuring signs.  He was also asymptomatic and had an otherwise normal exam.

You explain to Kevin that Charlie looks well and that there are no signs of serious head trauma.  You mention that you did notice a heart murmur that is likely benign.  Charlie does not need to see a specialist, but you recommend that he have a follow up appointment with his family doctor in the next few weeks to monitor the heart murmur.

 

 

References:

  1. Heart Pulse Sound Wave Icon Stock Vector – Illustration of blood, healthcare: 91331428. Accessed November 19, 2021. https://www.dreamstime.com/stock-illustration-heart-pulse-sound-wave-icon-background-image91331428
  2. Heart Murmur | NHLBI, NIH. Accessed November 18, 2021. https://www.nhlbi.nih.gov/health-topics/heart-murmur
  3. Heart murmurs: MedlinePlus Medical Encyclopedia. Accessed November 18, 2021. https://medlineplus.gov/ency/article/003266.htm
  4. Pediatric Heart Murmurs: Evaluation and management in primary care. Accessed November 18, 2021. https://oce-ovid-com.ezproxy.library.dal.ca/article/00006205-201103000-00006/HTML
  5. Frank JE, Jacobe KM. Evaluation and Management of Heart Murmurs in Children. Am Fam Physician. 2011;84(7):793-800.
  6. Approach to the infant or child with a cardiac murmur – UpToDate. Accessed November 18, 2021. https://www.uptodate.com/contents/approach-to-the-infant-or-child-with-a-cardiac-murmur?search=heart%20murmurs&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
  7. Physical Examination – Textbook of Cardiology. Accessed November 18, 2021. https://www.textbookofcardiology.org/wiki/Physical_Examination
  8. Pediatric Heart Murmur Recognition Program intro. Teaching Heart Auscultation to Health Professionals. Accessed November 19, 2021. https://teachingheartauscultation.com/pediatric-murmur-recognition-program-intro
  9. Bronzetti G, Corzani A. The Seven “S” Murmurs: an alliteration about innocent murmurs in cardiac auscultation. Clin Pediatr (Phila). 2010;49(7):713. doi:10.1177/0009922810365101
  10. Begic E, Begic Z. Accidental Heart Murmurs. Med Arch. 2017;71(4):284-287. doi:10.5455/medarh.2017.71.284-287
  11. McConnell ME, Adkins SB, Hannon DW. Heart murmurs in pediatric patients: When do you refer? Am Fam Physician. 1999;60(2):558-565.

 

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