Question

Why does ventricular volume drop after ventricular pressure reaches its peak? Can you correlate anything to the QRS complex? Does anything else on the other graphs line up or happen at the same time?

Answer 1

Ventricular pressure increases during the ventricular systole due to filling of ventricles priorly and there is a stretching of ventricular musculature. At the end of ventricular diastole the ventricle is filled with blood and the pressure rises abruptly and the atrioventricular valves close.

​​​​​​Due to increase in ventricular pressure and decrease in aortic pressure there is a pressure gradient created and the semilunar valves open. Thus peak ventricular pressure results in the opening of semilunar valves and thus the blood flows into the aorta resulting in the drop of ventricular volume.

The ventricular systole is a mechanical event which starts at the peak of QRS Complex and in the the end of T wave. QRS Complex indicates ventricular depolarization and T wave indicates ventricular repolarization.

At the same time i.e., at the starting of ventricular systole the first heart sound is recorded on phonocardiogram. Aortic blood flow goes to a peak and corresponds to ventricular pressure peak. Aortic pressure exceeds ventricular pressure at its peak which results in closing of aortic valve.