Angina/Arrythmia/HF Flashcards
Angina denotes chest pain caused by accumulation of ___________ resulting from myocardial ischemia
metabolites
What can cause steal syndrome?
Nitrates
What is steal syndrome?
Occluded vessel naturally dilates to comphensate for occlusion to increase blood flow. By dilating all of the vessels, blood flow is directed to clean vessels that are dilated and less flow is sent through the vessel with the occlusion
You can increase coronary flow by ___% by dilating coronary arteries
15%
Whats the equation for CPP
AoDP-LVEDP / Coronary vascular resistance
What are the 4 ways to cause myocardial vascular tone relaxation?
-decrease Ca++
-Increase cGMP
-Increase cAMP
-Stabilize cell membrane (aka hyperpolarize the cell)
How does cGMP cause relaxation?
De-phosphorylates (de-activating) myosin light chain (MLC). Then the myosin light chain combines with actin to cause contraction
*(think actin and myosin interacting in the sarcomere of cardiac muscle)
How does cAMP cause relaxation?
It phosphorylates (de-activating) the enzyme myosin light chain kinase, keeping it from activating the myosin light chain
How do B2 agonists cause relaxation in the vasculature?
Increase cAMP acting on MLCK
With angina, _______ control is paramount
HR control
How do B2 agonists cause myocardial contraction?
B2 agonists cause cAMP to activiate PKA, which phosphorylates the L-type Ca++ channel causing increased influx of Ca++
With angina/MI you want HR below ____
100
What 3 drugs used to tx angina?
-Nitrates
-CCBs
-BBs
How does sildenafil cause smooth muscle relaxation?
Its a PDE inhibitor. PDE breaks down cGMP so if we inhibit PDE then we have more cGMP
Why do we give morphine in angina?
-Decreases myocardia demand by decreasing pain, which will decrease HR
-vasodilation = decreased preload and decreased workload on heart
(t/f) NTG has a high 1st pass effect
Yes
*this is why it’s given sublingual & transdermal patches
Does NTG dilate coronary arteries?
Yep
Which CCB is best for angina?
Verapamil (almost exclusive cardiac effects)
CCBs (particularly non-dihydropyridines) can be effective in HR control with ______
SVT
Afib
*atria arrhythmias that pass through the AV node
What is MOA of class 1 antiarrythmics
Na+ channel blockers
What is MOA of class 2 antiarrythmics
BBs
What is MOA of class 3 antiarrythmics
K+ channel blockers
What is MOA of class 4 antiarrythmics
Ca++ channel blockers
What electrolyte depolarizes cardiac nodal cells?
Ca++
What electrolyte depolarizes myocardial cells?
Na+
In a myocardial cell, what phase is resting membrane potential?
Phase 4
In a myocardial cell, what phase is depolarization?
Phase 0
In a myocardial cell, what phase is early repolarization?
Phase 1
In a myocarial cell what phase is the plateau phase?
Phase 2
In a myocardial cell, what phase is repolarization?
Phase 3