What Causes The Lub Dub Sound Of The Heartbeat Official

She drew a quick sketch on the exam paper: four rooms, four doors. “The lub is the first sound. It happens when your heart squeezes to push blood out. Those two big doors at the top—the mitral and tricuspid valves— snap shut. Hard. Like slamming two car doors at once.”

“All day, every day. Two pairs of doors, slamming in perfect sequence. Lub from the incoming valves. Dub from the outgoing ones.” She paused. “Unless something’s wrong. Then it’s not lub-dub . It’s lub-shhh-dub , or lub-dub-whoosh . That’s a murmur. A leaky or stiff door.” what causes the lub dub sound of the heartbeat

“Doors?”

Leo pressed his own palm to his ribs. “Mine sound okay?” She drew a quick sketch on the exam

Lub-dub. Lub-dub. Lub-dub.