At the end of isometric relaxation phase
Ans. (a) Atrioventricular valves openRef: Ganong, 25th ed/p.539Isovolumetric relaxation ends by opening of Atrioventricular valves
Atrioventricular valves open
Atrioventricular valves close
Corresponds to peak of "C" wave in JVP
Corresponds to T wave in ECG
Heart, Circulation, and Blood