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24 Cards in this Set
- Front
- Back
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patients with what type of angina usually have narrowing of an epicardial coronary artery and ischemia presents upon exertion or stress
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stable angina
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what typically episodically reduces coronary flow on various occasions to trigger angina or acute MI
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coronary artery vasospasm
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patients with what type of angina typically have a rupture of an atherosclerotic plaque, with consequent platelet adhesion and aggregation with decreased coronary blood flow
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unstable angina
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What does Laplace's Law state
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the tension (T) in a vessel wall is equal to pressure (P) x radius (r) over vessel wall thickness (mu)
T = Pr/mu |
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__ induces vascular contraction
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Ca
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__ induces vascular relaxation
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NO
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how do nitrates, like nitroglycerin, work
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relax smooth muscle in veins at low doses and arteries at higher doses- release NO -> activates guanylyl cyclase -> cGMP -> activates myosin light chain phophatase -> dephosphorylate myosin light chain -> uncouples myosin and actin in smooth muscles (especially venules)
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what are the three mechanisms by which organic nitrates relieve angina
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1. dilation of venules -> dec prelaod -> increasing coronary blood flow
2. reduced oxygen demand of cardiac muscle by decreasing tension in cardiac walls 3. vasodilate large coronary arteries allowing mechanisms to act and preferentially increase blood flow to inadequately perfused areas with a high concentration of metabolites and ischemia |
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Name three uses for organic nitrates
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angina
CHF MI |
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name four contraindications for organic nitrates
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patients on sildenafil (all PDE5 inhibitors)
hypotension hypertrophic obstructive cardiomyopathy diastolic heart failure |
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When should organic nitrates be taken; what is the importance of overnight interruptions of dosing
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should be taken during anginal attack or in anticipation of exercise or stress
interrupt at night to restore efficiacy- otherwise marked attenuation of responses occurs |
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why is nitrogylycerin given sublingually
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bioavailability low due to high capacity hepatic organic nitrate reductase; sublingual administration avoids first pass effect
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what substance is a highly volatile liquid which can be packaged in a glass ampule protected with a cloth covering; and can be crushed to be delivered rapidly via inhalation
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amyl nitrite
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what organic nitrate is chewable
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isosorbide dinitrate
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What works on both vascular smooth muscle and myocardium
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calcium channel blockers
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What are the different calcium channel classifications
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T (low threshold)
L N P/Q R (high thresholds) |
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which channel is critically involved in both cardiac cells and vascular smooth muscle cells
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L type
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name three L channel blockers
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verapamil and diltiazem
nifedipine |
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What does Ca normally do in vascular smooth muscle
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released from SR -> binds calmodulin -> activates myosin light chain kinase -> phophorylates myosin light chain -> interactions between myosin and actin -> increased strength of contraction and vasoconstriction
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name a non selective beta blocker and a beta1 selective blocker
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non selective- propranolol
beta1 blocker- atenolol |
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what type of beta blocker is more useful in treatment of exertional angina
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all equally effective
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in what type of angina are beta blockers not helpful
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vasospastic
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name two antiplatelet and antithrombotic agents helpful in angina
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aspirin and heparin
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nitroglycerin is a donor of ___ that activates guanylyl cyclase to produce ___ leading to relaxation of vasculature
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NO
myosin light chain phosphatase |
