<prompt> At the end of isometric relaxation phaseAtrioventricular valves openAtrioventricular valves closeCorresponds to peak of C wave in JVPCorresponds to T wave in ECG  <response>: Ans. a Atrioventricular valves openRef: Ganong, 25th edp.539Isovolumetric relaxation ends by opening of Atrioventricular valves 