Medically reviewed by Jeffrey S. Lander, MD Heart sounds are the noises made as blood moves through the heart with each heartbeat. When the heart valves close, they make a distinct lubb-dupp sound.

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 ...

What causes a split S1 heart sound and/or a widened split S1 heart sound? The first heart sound results from the closing of the mitral and tricuspid valves. The sound produced by the closure of ...