Valvular Disease - Aortic Regurgitation Flashcards
What is Aortic regurgitation?
https://www.youtube.com/watch?v=JorBOLNzfUY
Aortic regurgitation is reflux of blood from the aorta through the aortic valve into the left ventricle during diastole
How does the heart compensate for aortic regurgitation?
Net cardiac ouput is reduced - total volume of blood pumped into the aorta must increase, and consequently the left ventricular size must enlarge
What happens to diastolic BP in aortic regurgitation?
Decreases due to diastolic backflow
What happens to coronary perfusion in Aortic regurgitation?
Decreases
What are causes of acute aortic regurgitation?
- Acute rheumatic fever
- Infective endocarditis
- Aortic dissection
- Ruptured sinus of valsalva
- Prosthetic valve failure
- Chest trauma
What are causes of chronic aortic regurgitation?
- Rheumatic heart disease
- Syphilis
- Seronegative Arthitidies
- Hypertension
- Bicuspid Aortic valve
- Takayasu’s Arteritis
- Connective tissue disorders
- RA
- Osteogenesis imperfecta
What seronegative arthritidies can cause chornic aortic regurgitation?
- Ankylosing spondylitis
- Reiter’s syndrome
- Psoriatic arthritis
What connective tissue disorders can cause Aortic regurgitation?
- Marfan’s syndrome
- Ehler’s danlos syndrome
When do symptoms begin to develop in aortic regurgitation?
When there is significant left ventricular failure
What are symptoms of aortic regurgitation?
- Exertional dyspnoea
- Orthopnoea
- Paroxysmal nocturnal dyspnoea
- Palpitations
- Angina
- Syncope
- CCF
Why do those with Aortic regurgitation suffer from PND and orthopnoea?
Due to the development of CHF
Why does angina occur in Aortic regurgitation?
Due to a combination of decreased perfusion due to regurgitation and increased work from the heart to maintain cardiac output
What signs might you see in someone with Aortic Regurgitation?
- Collapsing pulse
- Wide pulse pressure
- Displaced, hyperdynamic apex beat
- High pitched, early diastolic murmur
- Eponymous Signs
Why would you get a collapsing pulse in AR?
As the ventricle finishes contracting, blood regurgitates back through the incompetent valve rather than being maintained
Why is pulse pressure widened?
The high pulse pressure can be attributed to the high-volume flow from the left ventricle into the ascending aorta during systole. The diastolic decay of the pulse is attributed to the backflow into the ventricle and to forward flow through peripheral arterioles
Why does someone with aortic regurgitation have a displaced, hyperdynamic apex?
Due to both concentric and eccentric hypertrophy
When is the murmur of AR heard?
Diastole
What is the mechanism behind the murmur of aortic regurgitation?
The characteristic murmur is the sound of blood moving back across the damaged aortic valve.
What is Quincke’s sign?
Exaggerated pulsations of the capillary nail bed. May be accentuated by depressing and releasing the distal end of the nail
What is Demusset’s sign?
Rhythmic head bobbing in synchrony with the heart beat
What are pistol shot femorals?
A sharp bang heard on auscultation over the femoral arteries in time with each heart beat.
What investigations might you do in someone with suspected AR?
- ECG
- CXR
- ECHO
- Cardiac MRI
What might you see on ECG in someone with AR?
LVH - tall R waves and deeply inverted T waves in the left-sided chest leads, and deep S waves in the right-sided leads
What might you see on CXR in someone with AR?
- Left ventricular enlargement +/- dilatation of the ascending aorta
- Calcified ascending aortic wall - Syphilis
How would you manage someone with Aortic Regurgitation?
Main goal is to reduce hypertension to delay surgery
- ACEi
Surgery
- Aortic valve replacement
What happens to LV end systolic and end diastolic volume in AR?
Both increase
What happens physiologically in acute AR?
The LV does not have sufficient time to dilate, resulting in LV end-diastolic pressure increases rapidly. This causes an increase in pulmonary venous pressure and altering coronary flow dynamics.
As pressure increases throughout the pulmonary circuit, the patient develops dyspnea and pulmonary oedema. In severe cases, heart failure may develop and potentially deteriorate to cardiogenic shock. Decreased myocardial perfusion may lead to myocardial ischemia.
What happens physiologically in Chronic AR?
Causes gradual LV volume overload that leads to LV enlargement and eccentric hypertrophy. The LV becomes larger and more compliant, with greater capacity to deliver a large stroke volume that can compensate for the regurgitant volume. The resulting hypertrophy is necessary to accommodate the increased wall tension and stress that result from LV dilation (Laplace law).
Eventually, the LV reaches its maximal diameter and diastolic pressure begins to rise, resulting in symptoms (dyspnea) that may worsen during exercise. Increasing LV end-diastolic pressure may also lower coronary perfusion gradients, causing subendocardial and myocardial ischemia, necrosis, and apoptosis. Grossly, the LV gradually transforms from an elliptical to a spherical configuration.
What changes occur to the ejection fraction in chronic AR?
During the early phases of chronic AR, the LV ejection fraction (EF) is normal or even increased (due to the increased preload and the Frank-Starling mechanism). As AR progresses, LV enlargement surpasses preload reserve, with the EF falling to normal and then subnormal levels. The LV end-systolic volume rises.
What is Corrigan’s pulse?
Collapsing pulse in the arm
What mnemonic can you use to remember the main causes of aortic regurgitation?
- Rheumatic heart disease
- Endocarditis
- Ankylosing SPondylitis
- Luetic heart disease (syphilis)
- Marfans Syndrome
