Term
| Determinants of cardiac O2 demand |
|
Definition
increased heartrate
myocardial contractility
LV wall tension |
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Term
| perfusion of cardiac muscle occurs during |
|
Definition
subepicardium - systole and diastole
endocardium - diastole |
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Term
| how to increase exercise tolerance |
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Definition
| decrease rate of rise of rate-pressure product (heart rate x systolib BP) |
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Term
| How to decrease cardiac O2 demand |
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Definition
prevent increase in HR and dp/dt
Decrease wall tension during diastole and systole by decreasing cardiac preload (decrease venous return)
Decrease wall tension during systole by decreasing afterload (diastolic BP) |
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Term
| How to increase O2 delivery |
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Definition
Dilation of large epicardial arteries and endocardial arterioles
Increase collateral blood flow in ischemic regions
Decrease wall tension during systole and diastole
Decrease heart rate |
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Term
|
Definition
Beta blockers "-olol"
Nitrate vasodilators
Calcium channel blockers
- diltiazem and verapamil
- dyhydropyridines "-lodipine" |
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Term
| Beta blockers stop angina by |
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Definition
decreasing HR
decreasing contractility
decreasing afterload (DBP)
increased blood flow to endocardium (decreased HR -> increased diastolic perfusion time) |
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Term
|
Definition
| organic nitrates are NO donors -> causes venodilation -> decreased preload -> decreased wall tension during diastole and systole -> decreased O2 demand and increased endocardial blood flow |
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Term
| Early CV effects of sublingual nitroglycerine |
|
Definition
Increase demand - increased HR and dp/dt
Decrease demand - decrease preload and afterload
Increase supply - increase epicardial flow, post occlusive flow, and collateral flow (minimal effect) |
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Term
| Late CV effects of sublingual nitroglycerine = oral nitrates |
|
Definition
Don't increase demand
Decrease demand - decrease preload
Increase supply - increase epicardial, post-cclusive, and collateral flow |
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|
Term
| Difference between acute effects of sublingual nitroglycerin and isosorbide mono/dinitrate |
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Definition
| sublingual nitroglycerin acutely decreases DBP and increases HR and dp/dt (which increases O2 demand - not good) |
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Term
| Primary effect of nitrates on angina |
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Definition
| reduction in myocardial work = reduction in O2 demand via venodilation -> decreased preload -> decreased wall tension |
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Term
| Nitrates effect on platelets |
|
Definition
inhibit platelet aggregation
nitrates are NO donors; NO prevents platelet aggregation
antiplatelet effect can help prevent MI |
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Term
| calcium channel blockers that primarily effect the heart vs resistance arterioles |
|
Definition
Heart: verapamil and diltiazem
Resistance arterioles: dihydropyridines (almodipine and felodipine) |
|
|
Term
Effect of blockade of L type Ca channels in the
-heart
-coronary vessels
-resistance arterioles
-aorta/large arteries
-veins |
|
Definition
Heart: decreases HR, AV conduction, and dp/dt
Coronary vessels: vasodilation
Resistance arterioles: vasodilation -> decrease TPR and DBP -> decrease afterload
Aorta/large arteries: increases compliance -> lowers SBP
Veins: no effect on venous return |
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Term
| Verapamil and diltiazem MOA |
|
Definition
| decrease HR, AV conduction, dp/dt -> decrease SV and CO |
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Term
| Amlodipine and felodipine |
|
Definition
| decrease in DBP -> baroreflexly mediated increase in sympathetic activity (so no effect on HR, AV conduction, contractility, SV and CO) |
|
|
Term
| How do calcium channel blockers decrease wall tension? |
|
Definition
Verapamil/diltiazem - decrease dp/dt + some decrease in afterload
Amlodipine/felodipine - decrease afterload (DBP) |
|
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Term
| Which drugs improve coronary blood flow? |
|
Definition
calcium channel blockers dilate epicardial and endocardial arterioles
nitrates don't |
|
|
Term
| How do verapamil and diltiazem resolve angina? |
|
Definition
Decrease O2 demand: decrease HR, dp/dt, afterlad, ventricular pressure during systole
Increase O2 delivery: dilation of epicardial arteries and endocardial arterioles |
|
|
Term
| How do amlodipine and felodipine resolve angina? |
|
Definition
Decreased O2 demand: decreased afterload -> decreased ventricular pressure during systole)
Increased O2 delivery: dilation of epicardial arteries and endocardial arterioles |
|
|
Term
| Which drugs do you use for Prinzmetal's angina? |
|
Definition
| calcium channel blockers because they prevent vasospasm in epicardial arteries |
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Term
| Adverse effects of verapamil and diltiazem |
|
Definition
Bradycardia
SA nodal failure
AV block
Heart failure in patients with systolic dyfunction |
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Term
| Adverse effects of dihydropyridines |
|
Definition
Pedal edema - dilation of precapillary sphincters (NOT expansion of ECF volume)
Paradoxical angina - excessive vasodilation, coronary steal, increased O2 demand
Increased risk of MI - excessive vasodilation -> increased sympathetics
Gastroesophageal reflux
Hypotension |
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