Auscultation at the upper right sternal edge in our patient demonstrated a single S1, followed by an ejection sound and a mid frequency, short systolic, diamond shaped murmur. Note that the ejection sound does not vary in intensity with respiration. S2 is single and accentuated, consistent with elevated aortic diastolic pressure. S2 is followed by a high frequency, grade two, early diastolic, decrescendo murmur. [Sounds]
Graphic image
By viewing a graphic image and simultaneously listening, we can further appreciate these auscultatory events. [Sounds]
Ejection sound
The ejection sound is caused by opening of thickened, but mobile bicuspid aortic valve leaflets. Sound is generated when movement of the valve leaflets is arrested at the limit of the valve's restricted excursion. The sound is analogous to the opening snap of a stenotic mitral valve. Intensity of an aortic ejection sound does not vary with respiration.
Systolic murmur
The systolic ejection murmur begins with the ejection sound. It rises to a peak in early systole, reflecting turbulent flow across the bicuspid valve during maximal ventricular ejection velocity. Murmur intensity falls off quickly, completing its crescendo-decrescendo shape. Early onset and termination of the murmur indicates absence of significant valve obstruction.
S2
The second heart sound is single and consists only of the aortic component, as expected, because the pulmonic component is not audible at the upper right sternal edge. It is accentuated, reflecting elevated diastolic pressure in the aorta.
Diastolic murmur
The diastolic murmur begins with the second heart sound, indicating flow back through the incompletely closed aortic valve. The murmur is high frequency, reflecting high diastolic pressure in the aorta. Its short duration suggests mild regurgitation.
Pressure curves
These simultaneous aortic and left ventricular pressure curves illustrate the relationship of the hemodynamic events to the acoustic events. The ejection sound occurs immediately after opening of the aortic valve. The murmur begins immediately after the ejection sound and rapidly reaches its peak, it then diminishes rapidly, reflecting maximal ventricular ejection early in systole. The aortic component of S2 occurs as left ventricular pressure falls below aortic pressure. The diastolic murmur begins immediately thereafter, as aortic valve closure is incomplete. Diastolic pressure in the aorta does not fall substantially, as aortic regurgitation is mild.