Valvular Heart Disease Flashcards
Sites of auscultation of the heart valves:
What is the most common vascular heart disease?
Aortic stenosis
What substance is responsible for the mechanical integrity of a valve?
Collagen is responsible for the mechanical integrity of a valve.
What role do interstitial cells have in heart valves?
The valve is populated throughout by interstitial cells, which produce and continuously repair the extracellular matrix (especially collagen), allowing the valve to respond and adapt to changing mechanical conditions.
Valves of the heart
Summarise valve stenosis:
- Stenosis is the failure of a valve to open completely, which impedes forward flow.
- Usually chronic and therefore well tolerated.
- Pressure overload.
Summarise regurgitation.
Regurgitation results from failure of a valve to close completely, thereby allowing reversed flow. • Can be chronic or acute • Volume overload.
Pathologic changes of valves are largely of three types:
- Damage to collagen that weakens the leaflets, eg. mitral valve prolapse.
- Nodular calcification beginning in interstitial cells, as in calcific AS.
- Fibrotic thickening, the key feature in rheumatic heart disease.
A systolic ejection murmur is a sign of what?
Aortic stenosis
Pressure volume loops reflecting valvular disease:
What are the three leaflets of the aortic valve?
Left
Right
Posterior
What causes aortic stenosis?
Usually caused by mechanical stress over time, which damages endothelial cells around the valves, causing fibrosis and calcification, which hardens the valve and makes it more difficult to open completely.
Aortic stenosis is most commonly seen in which population?
Patients over 60 years old.
What are the main risk factors of aortic stenosis?
Age
Bicuspid aortic valve (congenital abnormality).
Chronic rheumatic fever.
Chronic rheumatic fever
Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection.
How does chronic rheumatic fever cause aortic stenosis?
Causes chronic inflammation and repair, leading to fibrosis. In this case, the leaflets can fuse together, called commissural fusion.
What change to the heart occurs as a result of aortic stenosis?
Concentric hypertrophy of the left ventricle.
- in response to the higher pressure need to pump blood through the aortic stenosis.
What are the complications of aortic stenosis?
Developing heart failure.
Microangiopathic hemolytic anemia.
- reduction in blood flow to organs, decreased perfusion to different organs = different presentation of symptoms.
e. g:
decreased perfusion to the brain = syncope.
decreased perfusion to the heart = angina.
Microangiopathic hemolytic anemia
Damage to red blood cells as they’re forced through the smaller valve, splitting them into smaller fragments called schistocytes. This leads to hemoglobinuria, which is hemoglobin in the urine.
What is the treatment for aortic stenosis?
Replacement of the valve.
What are the symptoms of aortic stenosis?
Syncope
Angina
Dyspnoea
Aortic stenosis = SAD
What are the signs of aortic stenosis?
Slow rising pulse.
Narrow pulse pressure.
Soft S2
ESM (crescendodecrescendo)
Gallivardin phenomenon
Radiates to carotids
Heaving apex beat
How is aortic stenosis diagnosed?
ECG
CXR
Echocardiogram
When does aortic regurgitation occur?
Ventricular diastole
What are the causes of aortic regurgitation?
Aortic root dilation - (This is when the root dilates, or gets bigger, and in doing so pulls apart the leaflets, making it harder for the valves to fit snugly together and close all the way, letting some blood flow backward).
Infective endocarditis damaging the valves (causes fibrosis).
Chronic rheumatic fever (causes fibrosis).
What causes aortic root dilation?
Aortic dissection
Aneurysm
Syphilis
What causes chronic rheumatic fever to develop?
The disease typically develops two to four weeks after a streptococcal throat infection.
What type of murmur is heard in aortic regurgitation?
Early decrescendo diastolic murmur, caused by the blood flowing back through the valve.
How is blood pressure altered in aortic regurgiation?
Because blood is leaking back from the aorta into the left ventricle, the left ventricular blood volume increases, which increases the stroke volume, or the amount of blood that the left ventricle pumps out during contraction, or systole. More blood pumped out of the heart per squeeze requires more pressure, so systolic blood pressure increases. During diastole, though, there’s less blood volume in the aorta because some has leaked back into the ventricle, which means that diastolic blood pressure decreases.
Pulse pressure =
Pulse pressure = systolic pressure - diastolic pressure
How does a large pulse pressure present?
A large pulse pressure, meaning a large difference between systolic and diastolic pressure, is referred to as a hyperdynamic circulation. Patients with a hyperdynamic circulation have bounding pulses, or water-hammer pulses, because the blood, which is mostly composed of water, slams like a hammer against the walls of the arteries with each heartbeat.
What change occurs to the heart due to aortic regurgitation?
Eccentric ventricular hypertrophy.
What are the symptoms of aortic regurgitation?
Dyspnoea
Orthopnoea
Paroxysmal nocturnal dyspnoea