Cardiac II: Valvular Heart Disease Flashcards
What do you want HR and rhythm to be with AS?
70-80 bpm and NSR
What will tachycardia cause with AS?
tachycardia leads to decreased time for ventricular filling which causes decreased LVEDV that then causes decreased SV and decreased CO
What is the problem with bradycardia and AS?
bradycardia causes a decrease in CO which will cause LV over distension which compresses the sub endocardium which causes myocardial oxygen supply to decrease
In a patient with AS what will you want your preload to be and why?
Increased
You need adequate LVEDP (volume) to fill the non-compliant LV
What happens to the LV in aortic stenosis?
aortic stenosis is increased pressure needs to overcome the stenotic valve, thus the L ventricle wall becomes thicker , this is known as concentric hypertrophy
How can you ensure adequate intravascular volume with AS?
Administer IVF
Formula for BP?
SVR X CO
SVR that you want with a patient who has AS?
Maintain or increase
Tell me about stroke volume and CO in the AS patient?
stroke volume is fixed by the stenotic aortic valve, therefore CO is dependent on HR
(BP = SVR X CO)
Do you want hypotension with AS?
NO!
Hypotension decreases aortic root pressure which decreases CPP which leads to myocardia ischemia
How should you treat hypotension in the AS patient?
treat with an alpha 1 agent, this will increase SVR and CPP without increasing HR
CPR in the patient with AS….??
Chest compressions during CPR won’t generate sufficient intracardiac pressure to overcome the stenotic aortic valve.
Where is afterload set in the AS patient?
at the aortic valve (which is stenotic)
Regional anesthesia and AS?
Spinal is avoided in severe AS (<0.8) because it rapidly reduces SVR which leads to profound hypotension (BP = SVR X CO).
A reduction in SVR reduces CPP which leads to cardiovascular collapse
Can you do epidural anesthesia in a patient with AS?
If the patient does not have severe AS epidural can be done on a individual basis.
Slow onset LA should be used and a lower block height tends to cause a less dramatic drop in hemodynamics.
What does the AS patients arterial waveform look like?
typically no dicrotic notch
slower systolic upstroke (pulsus tardus)
small amplitude with narrow pulse pressure due to reduced SV (pulsus parvus)
dampened waveform overall
Most common cause of Aortic Stenosis?
Bicuspid aortic valve and calcification
Tell me your goals /concerns with the aortic stenosis patient?
You are concerned with rate, volume, and afterload.
Maintain NSR
Increase Preload
Afterload is kept high
WHY?
Tachycardia reduces filling time. Bradycardia creates LV distension
Volume: increase preload, keep CVP and PAOP high /normal
Afterload is set by the stenotic aortic valve. SVR must be kept high to help perfuse the coronary arteries (CPP = AoDBP - LVEDP)
Stenosis requires full, fast, and forward or slow, full, and tight?
Stenosis = Slow, full, and tight
Regurgitation requires full, fast, and forward or slow, full, and tight?
Regurgitation = Fast, Full, forward
What dysrhythmia is common with mitral valve disease associated with left atrial enlargement?
A - fib
Which cardiac lesions require a slow heart rate to prolong the duration of diastole and improve left ventricular filling and coronary blood flow?
aortic and mitral stenosis
Which valvular lesions require a faster heart rate and afterload reduction?
aortic and mitral regurgitation
Which induction drug do you want to avoid and why if a patient has mitral stenosis?
Ketamine because it typically increases the HR
