Heart sound 1 (S1) is the normal systolic heart sound. It is the first heart sound and is the "lubb" sound in lubb-dupp. The S1 sound is made when the mitral and tricuspid valves close ...

The first heart sound (S1) results from the closing of the mitral and tricuspid valves. The sound produced by the closure of the mitral valve is termed M1, and the sound produced by closure of the ...

A systolic ejection click frequently indicates a bicuspid aortic valve. This sound is heard just after the 1st heart sound (S1). Usually, the opening of the aortic valve is not audible ...