antiarrhythmic agents1 Flashcards
what is the MOA of drugs on EKG for treating arrhythmias
interrupting QT interval
what part of ekg depicts atrial depolarization?
p wave
what part of ekg depicts ventricular depolarization
qrs wave
what part of ekg depicts refractory period
qt interval
what is the term for regular rhythm of heart; between 60-100 bpm.
normal sinus rhythm (NSR)
what is torsade de pointes
a polymorphous ventricular tachycardia with prolonged QT interval
what is a palpitation
an awareness of the heartbeat; with or without an irregular rhythm
what are the 3 primary MOAs of antiarrhythmics
- changing conduction velocity
- changing refractory peiod
- changing automoticity
what are the effects of VW type 1a on:
- conduction velocity
- refractory period
- automaticity
- decrease velocity
- increase refractory period
- decrease automoticity
what are the effects of VW type 1b on:
- conduction velocity
- refractory period
- automaticity
- decrease velocity
- decrease refractory period
- decrease automoticity
what are the effects of VW type 1b on:
- conduction velocity
- refractory period
- automaticity
- strongly decrease velocity
- no change on refractory period
- decrease automoticity
anything that works on K channel is likely to cause what?
torsades
what subtype of of type 1 antiarrhythmics prolong ventricular refractoriness and QT interval by blocking K channels
type 1a
what VW class antiarrhythmic increases mortality in structural heart disease
class 1a and 1c
what is a classic example of a VW type 1b drug?
what does it work best for
lidocaine
MI’s with ventricular arrhythmias
why shouldnt lidocaine be used for a long period
metabolites have competitive action at site of action
what are type 2 antiarrhythmics
Beta blockers
what are the B-1 antagonists antiarrhythmic MOA
lowers HR and FOC, decreasing oxygen demand.
what is the primary MOA of amiodarone
blockade of potassium channels
what is the major type 1a drugs
- quinidine
- procainamide
- disopyramide
what drug consistently proves superior to treating atrial fibrillations
amiodorone
what is the lowest effective dose of amiodorone for atrial fibrillation
200 mg/ day
what is the lowest effective dose of amiodorone for ventricular tachycardia
400 mg/ day
why are daily doses of amiodorone divided
adverse GI effects; not due to half life!
what are the contraindications for amiodorone?
what doasage adjustment bust be made for renal dysfunction
kidney
no changes in dosing for renal dysfunction
what is the most common antiarrhythmic agent?
why?
amiodorone
lowest proarrhythmic potential
what is important with kinetics of amiodorone?
highly distributed in tissue; blood levels are useless
what is the half life of amiodorone
53 days
what determines how adverse effects will be seen in patients on amiodorone
amount taken and time on the drug
what is the #1 concerning adverse effect of amiodorone
pulmonary fibrosis; rapidly progressive and potentially fatal
what is the effect on the thyroid of amiodorone
usually hypothyroidism; sometimes hyperthyroidism
