Heartbeat 1 Jun 2026
Heartbeat 1 is caused by the sudden closure of the at the beginning of systole (contraction). As the ventricles fill with blood and begin to squeeze, the pressure slams these valves shut.
Heartbeat 1 is caused by the sudden closure of the at the beginning of systole (contraction). As the ventricles fill with blood and begin to squeeze, the pressure slams these valves shut.