Mitral valve closes
Aortic valve opens
A wave - atrial contraction
C wave - closure of the valve
V wave - atrial filling during ventricular contraction
The A-wave and the V-wave generate 2 "up-beats" for every heartbeat.
80% is passive, before atrial contraction
20% is atrial "kick"
Normally, atrial contraction contributes 20% to ventricular filling.
In diseased states, the atrial contraction often contributes much more than 20%.
Loss of atrial contraction (like in atrial fibrillation) can result in significant reductions of ventricular filling in diseased states, but usually not in normal states.
Stroke Volume Formula
SV = EDV - ESV
First sound (S1) is the mitral valve closing and the aortic valve opening.
Second sound (S2) is the aortic valve closing and the mitral valave opening.
Sometimes get S3 and S4 in diseased states.
S3 and S4
S3 occurs in early diastole. This is caused by rapid "overfilling" of the ventricle, usually occuring in heart failure.
S4 occurs in late diastole. This is caused by atrial contraction plus a stiff ventricle.
Pressure Volume Loop
4-1 is ventricular filling
1-2 is mitral valve closing and aortic valve opening (contraction)
2-3 is ejection
3-4 is aortic valve closing and mitral valave opening (relaxation)
P x V is work. The area inside the lines is work.