This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Physiology
Cardiac event at the end of isometric relaxation phase: 
Select and explain. 
A. Atrioventricular valves open, B. Atrioventricular valves closes, C. Corresponds to peak of C wave in JVP, D. Corresponds to T wave in ECG
A: Atrioventricular valves open
Answer: A: Atrioventricular valves open 
Explanation: Isometric relaxation - Semilunar valves have closed. - AV valves yet to open In isometric relaxation ventricular muscle continues to relax without change in ventricular volume | Intraventricular pressure decreases back to the diastolic levels | AV valves open JVP correlation to cardiac cycle A wave: Atrial contraction C wave: Beginning of ventricular contraction bulging of AV valves back towards atria V wave: Towards end of ventricular contraction X wave: Ventricular contraction Y wave: Atrial emptying tricuspid valve opens