Question

Please describe for me how the events of the cardiac cycle align with the heart sounds and components of an ECG

Answer 1

The heart sounds are generated during cardiac cycle when blood flow through the heart.The heart sound are the sign of closure of valves. There are particularly two sounds can be heard -S1 and S2 .The S1 occurs when atrioventricular valve closes and S2 occurs when the semilunar valve closes.

It aligns with the ECG , the ventricular depolarization represented by the QRS peak in ECG. Due to ventricular contraction/systole ,the pressure rises and blood volume decreases within the ventricle above those in atria results into sudden closure of the atrioventricular valve.This event gives rise to the first heart sound s1 " Lub" . After reaching the threshould of the ventricular pressure, ventricular repolarisation T wave occurs after that sudden closure of the Semilunar valve when atrial systole occurs which sounds the second heart sound S2 as "Dub".