Our patient has a systolic, early peaking, high frequency murmur that is crescendo-decrescendo in shape. The murmur begins after S1 and builds rapidly to a peak, suggesting ventricular outflow obstruction. It then gradually decreases in intensity, ending in S2. Location of the murmur suggests that its origin lies in the right ventricle. Note that S2 is single, suggesting absence of the pulmonary component, as may occur with abnormally low pulmonary artery pressure. These findings are most consistent with right ventricular infundibular obstruction. Note also presence of a systolic ejection sound that does not vary with respiration, indicating aortic origin. This is consistent with augmented systolic expansion of the aortic root due to increased ejection volume into it. [Sounds]
Graphic
By viewing a graphic image and simultaneously listening, we can further appreciate these auscultatory events. [Sounds]
LLSE murmur
The murmur heard at the lower left sternal edge is sytolic, early peaking, crescendo-decrescendo and high frequency. Such murmurs typically result from turbulent flow when the majority of blood is ejected from the right ventricle. Rapid build up of the murmur suggests rapid rise in right ventricular systolic pressure. The high frequency of the murmur suggests that it originates within the body of the right ventricle, rather than at the pulmonic valve.
Differential diagnosis
Differential diagnosis of an ejection murmur heard at the lower left sternal edge in our patient includes an innocent Still's murmur, the murmur from increased right ventricular output due to an intracardiac left-to-right shunt and the murmur due to obstruction to systolic flow out of the right ventricle into the pulmonary arteries. Such an obstruction can lie within the right ventricle, at the pulmonary valve or in the pulmonary arteries.