Pre-ejection ventricular phase starts
C. i.e. (Aortic and pulmonary valve are open) (565-Ganong 2nd) (509-Ganong 23rd)* When the aortic and pulmonary valves open the phase of ventricular ejection begins. Ejection is rapid at first, slowing down as systole progress* The ejection fraction is valuable index of ventricular fraction*** The duration of each cardiac cycle is about 0.8 sec** (systole 0.27 sec & Diastole 0.53 sec)* Dicrotic notch - The pulmonary artery pressure curve also has a dicrotic notch produced by the closure of the pulmonary valve i.e. second heart sound*** Isovolumetric contraction - the first phase of ventricular systole. Immediately after atrial systole the A V are closed due to increase in ventricular pressure the semilunar valve are already closed**. Now the ventricles contracts as closed cavities. Only the tension increases in-ventricular* First heart sound occurs during the period of isovolumetric contraction**.* Fourth heart sound is caused by - Biventricular filling**
Aortic valve open pulmonary valve closed
Aortic valve closed pulmonary valve open
Aortic and pulmonary valve are open
Aortic and pulmonary valve closed
Heart, Circulation, and Blood