S1 and S2 are the normal heart sounds you hear when the heart valves close. Heart murmurs are extra sounds that can be heard during systole, diastole, or as a continuous sound. S3 and S4 are abnormal ...

“Lub-dub…lub-dub…lub-dub…” That’s the sound a healthy heart makes as its valves close after each pump. Your doctor wants to hear this sound when listening to your heartbeat with a stethoscope. But if ...