Pharm - Arrythmias, IHD. Flashcards
What is an automatic arrythmia?
Impulse that’s formed from ectopic pacemaker or sinus disturbance
What is a re-entry arrythmia?
When the propagating impulse persists after the refractory period has ended.
What’s the difference between excitability and conductivity?
Excitability is the ability to RESPOND to an impulse
Conductivity is the ability to SEND an impulse.
Is conductivity the same thing as automaticity?
No, automaticity means the cells can generate the signal spontaneously and pass it along.
What phase of the AP cycle does Automaticity refer to?
Slope from RMP to threshold - actually phase 4 of the prior AP.
What phase does conduction velocity correspond to?
Phase 0: the slope of the line that shoots straight upwards. This is when Na is entering the cells.
What phase does the refractory period correspond with?
Phase 3: when the line is returning to the RMP. This is when the cells are repolarizing and K+ is entering the cells.
What phases exist in nodal cells?
Phases 0, 3 and 4.
Class II anti-arrythmics are what kind of drug?
Beta-blockers
When would you not want to use Class II anti-arrythmics?
Shock
ADHF (Acute Decompensated heart failure)
Bradycardia
Heart block
Asthma (they block action of bronchodilators)
What phases do beta blockers work on?
They:
Slow Phase 4 (automaticity):
Slow Phase 0
(Conduction velocity)
Increase phase 3
(Refractory period)
If a pt has Ischemic heart disease, they probably have…
Increased cholesterol.
What is the first manifestation of IHD in about half of patients?
CSA (chronic stable angina).
Lifestyle modifications for IHD?
Quit Smoking. No exposure to env’t smoke.
30-60m of exercise daily.
BMI less than 25.
Immunizations.
What medications are used to treat IHD?
B-blockers
CCBs
Nitrates
Ranolazine
Antiplatelet
Statins
ACEIs or ARBs
(These prevent remodeling).
Why are BBlockers useful in IHD? What BPM is target?
Decrease O2 demand. 55-60bpm.
Why are CCBs helpful in IHD?
Increases O2 supply in vasospastic angina pts. Dilates coronary vessels, relaxes smooth muscle.
Why are Organic Nitrates helpful in IHD?
Increase NO and decrease O2 demand. Improves collateral flow to ischemic areas.
What are the routes you can give nitroglycerin in?
tab, SL, spray, patch, paste, IV.
What would you tell a pt who takes nitro who is complaining about HA and lightheadedness?
It’s d/t vasodilation. They’ll go away unless you keep nitro going all the time.
When should you call 911 for chest pain, assuming the pt has a nitro prescription?
Right before the 2nd dose if chest pain is not relieved.
How might a person unintentionally hurt themselves when they take SL nitro?
Falling - tell them to sit down.
How likely is someone to have CAD if they have diabetes?
It’s almost 100%. Just assume, if they have DM, they also have CAD, IHD.
Why are antiplatelet useful in IHD?
B/c the aggregation of platelets is a huge part of blockage formation. Prevents CAD and acute MI.
What’s the difference between UA, NSTEMI and STEMI?
UA: partial blockage, ischemia.
NSTEMI: partial blockage, infarction.
STEMI: complete blockage, infarction.
“Every pt with chest pain meets MONA B. In the ED.”
What does this mean?
Pts who present with chest pain to the ED will get:
Morphine Oxygen Nitro (SL) Aspirin (325mg total). Beta-blocker.
After the ED (in the cath lab) what agents are used for acute chest pain?
P2Y12 inhibitors (platelet inhibitors)
Anticoagulants
GPIs (glycoproteins inhibitors): “super aspirin”
Thrombolytic agents.
How long can P2Y12 inhibitors be taken?
Up to 12mos post-MI if they had a stint placed. Up to 4 months if no stint.
