Valves Flashcards
What kind of HR do you want with stenotic valves?
Slower
Desirable to increase transvalvular flow with stenotic lesions. (good to have slow HR)
What kind of HR do you want with regurgitant valves?
Faster, less time in diastole
What is contraindicated with severe AS?
Spinal anesthetic contraindicated in aortic stenosis - sympathectomy below level, cant produce sympathetic response, will drop BP..give neo.
Want slower HR
Do stenotic valves respond to changes in loading?
no - usually fixed
Do regurgitant valves respond to changes in loading?
The valve area in regurgitant lesions can respond to changes in loading conditions (preload, afterload)
1 cause of AS?
Calcific Aortic Stenosis
Normal AVA =
2.6 – 3.5 cm2
Mercedes benz?
healthy Tri-leaflet aortic valve
classic symptoms of AS
(AS) are heart failure (HF), syncope, and angina. However, these “classic” manifestations reflect end-stage disease.
Now, the most common presenting symptoms:
●Dyspnea on exertion or decreased exercise tolerance
●Exertional dizziness (presyncope) or syncope
●Exertional angina
Ischemia in AS causes
Relative decrease in myocardial capillary density- Hypertrophy not normal tissue.
Is pressure higher in the aorta or the LV with aortic stenosis?
LV!
stenosis of the aortic valve causes obstruction to blood flow from the left ventricle (LV) to the aorta. As a result, there is a systolic pressure gradient across the valve with a higher pressure in the LV than the aorta
What is th gradient for severe AS
<0.9
1 cause of aortic regurg
Rheumatic heart disease damages the valve
What happens to CPP with aortic regurg?
Reduced coronary perfusion pressure*
Lower diastolic pressure
Increased LVEDP
increased pulse pressure
Regurg saying
fast, full, forward
Goals for AS
increased preload, slow HR, maintain sinus rhythm
goals for regurg
fast, full, forward, lower afterload to improve forward flow
Normal MVA
4 – 6 cm2
causes of MS
Rheumatic
Women 4x > Men
Is lV function usually normal with MS?
Yes. LV function is usually normal
Is RV function usually normal with MS?
RV function is normal in absence of pulmonary hypertension (PAH)
Severe pulmonary hypertension will result in RV failure and secondary abnormalities of LV function
What to avoid with MS?
Frequently have elevated PA pressures. Avoid acidosis, hypercarbia, and/or hypoxemia.
Causes of MR
Rheumatic disease
Endocarditis
Mitral valve prolapse-ballooning back of leaflet
Mitral annular enlargement-prevents closure
Ischemia
Myocardial infarction
Trauma
Fenfluramine diet suppressants
Do measurements of the lV tend to be slightly elevated with MR?
Measurements of LV function tend to be slightly elevated
Moderately depressed ejection fraction in a patient with MR may be indicative of a severely depressed inotropic state
Goals for MR care
faster HR, increased contractility, afterload reduction, preload based on patient response to fluid load
Hypertrophic cardiomyopathy and SAM
May have Systolic Anterior Motion (SAM) of the mitral valve
The anterior leaflet of the mitral valve moves toward the septum during systole. Narrowing tract. This creates dynamic outflow tract obstruction and mitral regurgitation.
What to avoid in hypertrophic cardiomyopathy
Avoid anything that causes reduction in left ventricular volume
Avoid:
Decreased preload
Increased contractility
Decreased afterload
Higher heart rates
More on hypertrophic cardiomyopathy
Under some conditions (e.g., exercise training) remodeling is beneficial; however, under other conditions (e.g., heart failure) this remodeling is deleterious because it increases the oxygen demand of the heart and decreases mechanical efficiency. Certain drugs, such asbeta-blockers, angiotensin-converting enzyme inhibitorsandangiotensin receptor blockershave been shown to prevent or partially reverse remodeling under pathologic conditions.
Avoid hypovolemia
Decreased HR reduces oxygen demand of thickened myocardium. May also allow time for adequate LV filling.
Decreased contractility reduces gradient across LVOT. Beta-blockade is beneficial.
Want Increased afterload, it reduces the gradient across LVOT. Thickened myocardium requires increased diastolic BP.
