An aortic ejection click is produced by thickened aortic valve leaflets. These clicks can be generated in a bicuspid aortic valve, which is a congenital abnormality with two aortic valve leaflets instead of the three normal leaflets.
A single first heart sound (S1) followed by an aortic ejection click (AEC) can mimic a split first heart sound. An AEC follows S1 by 50 milliseconds. An AEC will have a higher pitch and shorter duration than S1. The recommended auscultation point is the aortic valve area where splitting of S1 is not heard.
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The patient's position is sitting.