Paediatrics: Heart murmurs

Heart murmurs

Heart murmurs should be characterized in terms of type, location, radia-tion, and quality of sound.

Murmurs are classified as follows:

•   Systolic: pansystolic; ejection systolic.

•   Diastolic: early diastolic; mid-diastolic.

The location where a murmur is best heard may give a clue to the underly-ing aetiology.

•   Lower sternal edge: VSD—often loud; innocent heart murmur—soft.

•   Upper sternal edge: aortic stenosis; pulmonary stenosis.

•   Base of neck: aortic valve lesion.

Pathological heart murmur

Characteristic features of pathological heart murmurs:

•   All diastolic murmurs.

•   All pansystolic murmurs.

•   Late systolic murmurs.

•   Loud murmurs >3/6.

•   Continuous murmurs.

•   If there are associated cardiac abnormalities.

•   Abnormal symptoms or signs:

o shortness of breath (SOB);

o tiredness/easy fatigue;

o failure to thrive (FTT);

o cyanosis;

o finger clubbing;

o hepatomegaly.

Innocent heart murmurs

This is the commonest cause of a heart murmur in children. It arises due to the rapid flow and turbulence of blood through the great vessels and across normal heart valves. It does not signify the presence of any under-lying cardiac abnormality or any other pathology.

Characteristics of innocent heart murmur

•   Systolic in timing—always. Never diastolic.

•   Short duration/low intensity sound.

•   Intensifies with increased cardiac output (e.g. exercise/fever).

•   May change in intensity with change in posture and head position.

•   No associated cardiac thrill or heave.

•   No radiation.

•   Asymptomatic patient.

Types of innocent heart murmur

Venous hum (uncommon)

•   ‘Machinery’ quality sound. Upper left sternal edge.

•   Due to blood flow in great veins.

Flow murmur

·  Short systolic murmur. Mid-left sternal edge.

·Often heard during acute illness with fever, disappears when fever resolves.

Musical murmur

Systolic murmur. Lower left sternal edge.