Editors

JuhaniAiraksinen

Innocent Heart Murmurs in Adults

Innocent murmurs include
- murmurs of physiological origin
- occasionally murmurs originating from haemodynamically insignificant cardiac defects.
Innocent murmurs caused by accelerated blood flow are common in young adults.
Fever, anaemia, tachycardia and a thin or flat chest wall may intensify flow sounds making them resemble a murmur of a valvular disease.
Innocent nature of the murmur is suggested by the following features:
- short early systolic or mid-systolic murmur, grade 1-2
- point of maximum intensity beside the sternum on the left and attenuates in a recumbent position
- systolic ejection murmur in the pulmonary valve auscultation area
- normal S2 (not constantly split)
- no other abnormalities on auscultation
- good performance status, normal ECG and chest x-ray.
A murmur must not be considered innocent until the patient has undergone thorough investigation.
- If necessary, an echocardiography Echocardiography as an Outpatient Procedure should be carried out to confirm diagnosis.
Diastolic murmurs always originate from an organic abnormality which may, nevertheless, be haemodynamically insignificant.

The most common innocent murmur
Heard in the second or third left intercostal space
Intensity of the murmur is usually of grade 1-2/6.
Heard in early systole
The closure of the pulmonary valve is not delayed and the heart sound split widens on inspiration. No ejection click is heard.
Echocardiography is usually unnecessary.

A flow sound originating form the aorta, comparable to the pulmonary flow murmur
- In young adults
- Heard in the aortic valve area
- More notable after strenuous exercise when the stroke volume is particularly high
A murmur associated with a calcified aortic valve
- In elderly patients
- Resembles the murmur of aortic stenosis Aortic Stenosis (ejection click may be heard), but its intensity is of grade 2.
- No significant aortic stenosis or other signs suggesting stenosis are detected.
- Echocardiogram is often warranted in differential diagnostics.

Common innocent murmur in children, audible still in adolescence
Heard in mid-systole, musical (vibratory) in quality, intensity usually 2/6
Heard in the 3^rd or 4^th left intercostal space parasternally, typically better when the patient is in sitting position

In children and young adults
Heard as a continuous hum in the neck and supraclavicular fossa, particularly in the right
Disappears when pressure is applied to the internal jugular vein or when the patient is lying in the supine position. Louder during inspiration.