Physiology Heart, Circulation, and Blood bd40c453 At the end of isometric relaxation phase A Atrioventricular valves open B Atrioventricular valves close C Corresponds to peak of "C" wave in JVP D Corresponds to T wave in ECG High-Yield Explanation Ans. (a) Atrioventricular valves openRef: Ganong, 25th ed/p.539Isovolumetric relaxation ends by opening of Atrioventricular valves