The Cardiac Cycle Flashcards
Overview of the cardiac cycle
What causes the heart sounds S1 and S2?
S1 - Mitral valve closing
S2 - Aortic valve closes
Why does an ejection systolic murmur occur
This is a murmur when the heart is in systole, so contracting. The murmum is turbulent blood flow over the aortic valve
What is isovolumetric contraction and where is it on the cardiac cycle?
This is when the ventricle is contraction and pressure is rising, but the mitral valve and aortic valves are closed so the volume remains the same
What is isovolumetric relaxation?
This occurs from the closure of the aortic valve to the opening the mitral valve.
The valves are closed and the ventricle relaxes but there is no change in volume
What is the dicrotic notch?
This is a slight increase in aortic pressure just after the aortic valve closes
What are the four main stages of the ventricular cycle and what happens in each?
- Filling - The mitral valve is open and it fills passively in atrial diastole and actively in atrial systole. The P wave and the start of the QRS are here
- Isvolumetric Contraction - Mitral valve closes (S1) and the ventricle starts to contract and pressure increases
- Ejection - Aortic valve opens and closes (S2) and the T wave is here as it repolarises
- Isovolumetric relaxation - Aortic and mitral valves are closed nd the ventricle starts to relax
What would cause a pan systolic murmur?
Mitral regurg
What would cause an early diastolic murmur?
Aortic regurg
May have signs of aortic stenosis there too
What would cause a diastolic murmur?
Mitral stenosis
What are the heart sounds for Aortic regurg and aortic stenosis?
Aortic stenosis - Ejection systolic murmur
Aortic regurg - early diastolic
What are the heart sounds for mitral regurg and mitral stenosis?
Mitral regurg - Pan systolic
Mitrol stenosis - diastolic
Where are the chambers of the heart on x ray?
