Ischemic HD Phys/Pharm Flashcards
non selective Beta blockers
propanolol, timolol
therapeutic effect Beta blockers
decrease contractility and heart rate > decrease O2 demand
slowing HR can improve ischemic area flow
oral availability nitrates
nitroglycerin - high first pass
isosorbide dinitrate - 25%
adverse effects and contraindications beta blockers
**Contra: **obstructed airway
acute decompensated heart failrue
marked bradycardia / heart block
caution insulin treated diabetics
**adverse: **fatigue, sexual dysfxn
pharmacokinetics Nitrates
nitroglycerin significant first pass
isosorbide dinitrate metabolized to mono
mononitrate not metabolized
at __% obstruction, cannot reach maximal flow
at ___% obstruction, distal perfusion pressure cannot maintain normal resting flow
70%
90%
B1 selective Beta blockers
metoprolol, atenolol
non-dihydropyridine Ca blockers
verapamil, diltizem
therapeutic effect nondihydropyridine Ca blockers (verapamil, dilitiazem)
decrease O demand by reducing contractility and HR
(less potent vasodilators than dihydropyridines nifedipine and amlodipine)
3 determinents of myocardial O2 demand
Wall stress
HR
contractility
electrocardiogram chronic stable angina during ischemia
ST segment depression and T wave inversion
(normalize quickly)
Therapeutic effect and mechanism Ranolazine
inhibit late sodium current in myocytes
decreases anginal episodes and increases exercise capacity
normal endocardial/epicardial blood flow ratio
1
major area of nitrate impact
venous circulation
therapeutic effect dihydropyridine Ca channel blockers (nifedipine, amlodipine)
decrease O demand via vasodilation > decrease afterload > decrease wall stress
increase coronary O supply via vasodilation
adverse effects Ca blockers
headache flushing
decreased contractility
Bradycardia
edema (esp nifedipine, diltiazem)
constipation (especially verapamil)
Unstable angina and MI
plaque rupture > platelet aggregation adn thrombosis > unopposed vasoconstriction
silent ischemia
cardiac ischemia without discomfort or pain
therapeutic effects of nitrates (not mechanism)
increase venous capacitance (decreasse preload)
small reduction in systemic art pressure (pos reflex tachy+contractility)
Coronary dilator
specific indications dihydropyridine Ca blockers (nifedinpine, amlodipine)
relief of vasospasm
syndrome X
typical signs of angina with no evidence of atherosclerotic stenoses
increase in coronary O2 demand is met via
increases in coronary flow
flow is matched with coronary need via ___
autoregulation
Q =
P/R
nitrates adverse effects
headache
hypotension
reflex tachy
flushing
wall stress
Pxr/2h
perfusion pressure dependent on ___ prssure
diastolic pressure
nitrate drugs
Nitroglycerin
isosorbide mono- **and **dinitrate
stable angina
lumen narrowed by plaque
inappropriate vascoconstriction
caution should be taken when combining ___
beta blocker and nondihydropyridine Ca blocker (cardiodepression)
dihydropyridine Ca channel blockers
Nifedipine, alodipine
