innocent murmurs Flashcards
What are innocent murmurs in children?
Innocent murmurs are heart sounds in children that are not due to structural heart problems.
List types of innocent murmurs heard in children.
Types include Ejection murmurs, Venous hums, and Still’s murmur.
What causes ejection murmurs?
Ejection murmurs are caused by turbulent blood flow at the outflow tract of the heart.
What causes venous hums?
Venous hums are caused by turbulent blood flow in the great veins returning to the heart, heard as a continuous noise below the clavicles.
Describe Still’s murmur.
Still’s murmur is a low-pitched sound heard at the lower left sternal edge.
What are the characteristics of an innocent ejection murmur?
Characteristics include a soft-blowing murmur, localised with no radiation, no diastolic component, no thrill, and no added sounds. It may vary with posture and the child is asymptomatic.
What should be noted about the condition of the child with innocent murmurs?
The child with innocent murmurs is typically asymptomatic with no other cardiac abnormalities detected.
A 2-year-old boy is brought to the surgery by his mother with earache and pyrexia. On examination of the precordium a murmur is heard. Which one of the following characteristics is not consistent with an innocent murmur?
Short buzzing murmur in the aortic area
Soft-blowing murmur in the pulmonary area
Varies with posture
Diastolic murmur
Continuous blowing noise heard just below the clavicles
The correct answer is Diastolic murmur. Innocent murmurs, also known as physiological or functional murmurs, are heart sounds produced when the blood flows rapidly through the heart and vessels. They are typically heard during systole - the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries. Diastolic murmurs, on the other hand, occur during diastole - when the heart relaxes and fills with blood. These are usually indicative of structural heart disease such as aortic or mitral stenosis or regurgitation.
Discussing each of the incorrect options:
Short buzzing murmur in the aortic area: This description is consistent with an innocent murmur. An innocent murmur can be described as short (less than half of systole), soft, and often vibratory or musical (‘buzzing’).
Soft-blowing murmur in the pulmonary area: This characteristic is also typical for an innocent murmur. They are often best heard at left upper sternal border (pulmonary area) and they have a soft blowing quality.
Varies with posture: The intensity and character of an innocent murmur can change with changes in body position. For example, it can become softer or disappear altogether when moving from standing to lying down.
Continuous blowing noise heard just below the clavicles: This could describe a venous hum, which is considered an innocent sound. It’s caused by turbulent blood flow in jugular veins and is typically heard just below clavicles.
Innocent murmurs are common in children and usually do not require treatment unless they cause symptoms or complications. However, any new-onset murmur should be evaluated carefully to rule out underlying cardiac pathology.
A GP incidentally discovers a murmur in an 8-year-old girl. The murmur is described as a ‘continuous blowing noise’ heard below both clavicles.
What is the most likely type of murmur diagnosed?
Aortic stenosis
Mitral stenosis
Venous hum
Still’s murmur
Pulmonary flow murmur
Venous hum is a benign murmur heard in children and sounds like a continuous blowing noise heard below the clavicles
Important for meLess important
This description is classical of a venous hum. A Still’s murmur is benign but is heard as a low-pitched sound on the lower left sternal edge. A pulmonary flow murmur is also benign but heard on the upper left sternal border. The other murmurs are pathological.
