1. Valve Defects /Cardiac Cycle
UNM School of Medicine
CV/Pulmonary/Renal Block

2. Normal Cardiac Cycle and Heart Sounds
Refer to this normal cardiac cycle when studying the abnormal cycles in the following slides
View the PowerPoint in slide show mode in order for sound files to work.
Click here for normal heart sounds

3. Aortic regurgitation 1 Diastolic decrescendo murmur
Pressure gradient =
aortic pressure - left ventricular
Pressure
Pressure gradient decreases during
Diastole as aortic pressure falls and
LV pressure rises due to filling
Note the large pulse pressure due to
rapid “runoff” of blood to circulation
plus back into ventricle.
Blood begins filling ventricle before
Mitral valve opens (back flow from
Aorta).

4. Aortic regurgitation 2
There can also be a systolic murmur due to large stroke volume and turbulent flow
During ejection
EDM – early diastolic murmur
AFM – Austin Flint murmur – mitral leaflet displacement & turbulent back flow

5. Aortic stenosis
Murmur intensity depends on pressure gradient across aortic valve; LV pressure – aortic pressure.
P increases, then decreases, resulting in crescendo – decrescendo systolic murmur.
The time for left ventricular systole will be prolonged (while the time for left ventricular diastole is shortened).

6. Mitral regurgitation
Murmur depends on pressure difference across the mitral valve
P = LV – LA pressure
P remains large and relatively constant during ejection resulting in a holosystolic murmur.
LA pressure increases due to backflow across incompetent valve

7. Mitral Stenosis
Murmur intensity depends on pressure difference across mitral valve.
P = LA – LV
Highest at the beginning,
resulting in diastolic
decrescendo murmur with a rise in pressure
(crescendo) just before systole as atria contracts

8. Online resources

9. Practice Question: The cardiac cycle and murmur of a patient in the cardiac cath
lab is shown below. The valve defect in this patient is:
Aortic regurgitation
Aortic stenosis
Mitral regurgitation
Mitral stenosis