41Coronary Heart Flashcards
What are the 4 general things we do to decrease O2 demand and increase O2 supply?
decrease work of heart
inhibit platelet aggregation/thrombus
prevent or inhibit vasospasm
mechanical interventions
What are the 4 main antianginal agents?
nitrovasodilators
beta adrenergic blockers
calcium channel blockers
ACEI/ARB
What happens to heart rate contractility with nitrovasodilators? Wall stress and MVO2? after load? preload?
- reflex increase in contractility
- decrease wall stress and MVO2
- decrease preload
4 decrease afterload
[this all reduces O2 demand]
What nitovasodilator goes through the mitochondria to become NO? smooth ER? Which one does not need metabolized?
- GTN
- ISDM,ISMN
3nitroprusside
What are the 3 main mechanisms of actions for nitrovasodilators?
Relaxes large arteries
Relaxes all veins
inhibit platelet aggregation
What happens if you don’t take off your transdermal nitrate patch at night?
build tolerance quickly
Does isosorbide denigrate or isosorbide mononitrate have the shorter half life?
ISDN-administered 3-4 times daily
What is the order of headache intensity for the nitrates?
GTN>ISDN>ISMN [it is a sign that they are working!!]
When are nitrates contraindicated?
erectile dysfunction pills- PDE5
What does NO and nitrates enhance?
sGC which takes GTP to cGMP
Which PDE5 inhibitor has the longest half life? shortest? longest onset? shortest onset?
- tadalafil 2. vardenafil/sildenafil
3. sildenafil 4. avanafil
What is the mechanism of action of beta adrenergic receptor agonists? beta 1 blocker effects? beta 2 blocker effects
- inhibit sympathetics
- decrease HR and contractility, decrease renin
3 potentiate alpha adrenergic effects- vasoconstrict
beta 2 selective antagonists have receptors where?
blood vessels, bronchioles and pancreas
Can beta blockers cause impotence?
yes
Do beta blockers cause hyperglycemia and hyperlipidemia?
hypoglycemia and hyperlipidemia
Do beta blockers prolong survival in patients with compensated HF? what may worsen HF?
- Yes by decreasing MVO2
2. negative ionotropic effects
What is the rebound phenomenon with beta receptor antagonists?
worsening of MI with abrupt discontinuation of use due to up regulation of beta adrenergic receptors
What do calcium channel blockers do to vasculature? cardiac?
- relax arteries- minimal vein effect
2. decreases contractility of myocytes
How do calcium channel blockers reduce O2 demand?
decrease arterial pressure
decrease contractility
decrease heart rate
How do calcium channel blockers increase O2 supply
dilate epicardial arteries and stenoses
prevent vasospasm
Is nifedipine good in acute MI?
No, can worsen
Are calcium channel blockers better for secondary MI prevention than Beta blockers?
No
should we use valium channel blockers in heart failure?
no–due to negative inotropic effect
Do inhibitors of RAS prevent secondary MI?
Yes
