drugs for ischemic heart dz Flashcards
evidence based tx for ischemic heart disease
Lipid-lowering drugs Anti-platelet agents
ACEI (HOPE and PEACE trials - CAD without HF)
Beta-blockers – reduce mortality post-MI
SX control for ischemic heart disdease
Nitrates Calcium antagonists
Beta-blockers
what two things do you need to consider when tx ischemic heart dz
reducing disease process and sx control
sxs of myocardial ischemia is usually secondary to
atherosclerosis of the coronary arteries
prinzmetals variant angina
normal coronary arteries but with spasms
seen in younger women in the morning
can be seen with CAD variant
New angina at rest or an increase in angina intensity, frequency, or duration
Unstable angina:
Occurs in patients without coronary artery disease and is due to a spasm of the coronary artery resulting in decreased myocardial blood flow
Classic Prinzmetal’s variant angina or vasospastic angina:
Coronary vasospasm occurring at the site of a fixed atherosclerotic plaque
Mixed angina:
Transient change in myocardial perfusion, function, or electrical activity; can be detected on an ECG in most anginal patients; patient does not experience chest pain or other signs of angina
Silent myocardial ischemia:
<50% asthersclerotic plaques will present with what sxs
Usually asymptomatic < 50%
Symptomatic at >70% obstructed
50-70% obstructed +/- sx
most txs for ischemic heart dz work by
decreasing oxygen demand
myocardial oxygen demand is determined by
wall stress
heart rate
and contractility
which are all variants of workload
wall stress that determines work load
Intraventricular pressure = blood pressure
Wall force – ventricular volume
Wall thickness
MLCK
how does it work and what drugs act on this
myosin-LC kinase when active can promote the phosphorylation of myosin LC and when phosphorylated they combine with actin to cause contraction
dephosphorylation causes relaxation
Ca activates this phosphorylation
which is how CCB and BB work in this way as well
how do nitrates work
increase cycle cGmP and increase dephosphorylation of myosin –> vasodilation
Decreasing intracellular Ca++ -
increase dephosphorylation
cause vasodilation
if we can block calcium in the cell what effect will it have on the cell
decrease contractily
alpha 1
heart
alpha 2
all over
beta 2
increase deactivation and cause vasodilation
Nitrates cause what effect in the body
Decrease venous return to heart, and therefore decrease workload
Promote coronary vasodilation, even with atherosclerosis
nitrates contraindicated with viagra why?
sidenafil increases cGMP
through another mechanism
can’t take with nitrates b/c of unsafe drops in blood pressure
BB would cause a higer risk or orthostatic HTN with nitrates because
blocks compensatory tachy response
sxs of nitrates
Orthostatic hypotension, syncope, temporal artery pulsations, throbbing headache d/t meningeal artery pulsations, compensatory sympathetic response (tachycardia, increased cardiac contractility), compensatory renal response (Na and water retention)
Isosorbide mononitrate
metabolite of isosorbide dinitrate