antiarrhythmics Flashcards
3 reason a person may get an arrhythmia?
- disease
- cardiac injury
- drugs
Cardiac arrhythmias result from
- abnormal impulse _____ - arise from non-traditional ____
- abnormal impulse _____ - abnormal pathways due to _____
- _______ of both
- formation - locations
- conduction - blockages
- combination
name 8 types of arrhythmias
- at nodal level
- at conduction level
- premature contractions
- tachycardia
- flutters
- fibrillations
- bradycardia
- heart block
At the conduction level, there are 4 types of arrhythmias, what are they?
- normal pattern of conduction but conduction splits and goes two ways
- re entry
- unidirectional block
- prolonged refractory period
_____ heart block = His/Purkinje system cut in half, atria and ventricles work indpendently
Complete
generally, why are antiarrhythmias used?
Used to modify/restore aberrant electrophysiologic properties of cardiac muscle to normal aka depress parts of the heart that are beating abnormally
What are the 3 pharmacologic effects of antiarrhythmias?
- change slope of depolarization
- raise threshold for depolarization
- alter conduction velocity in different parts of the heart
What are 4 NON- pharmacologic effects for arrhythmias?
- electrical cardioversion
- automatic implantable cardioverter devices
- ablation therapy
- pacemakes
what are 4 contraindications to giving an antiarrhythmia?
- complete AV heart block
- CHF
- hypotension
- known hypersensitivity to the drug
5 indications that a person needs an antiarrhythmia
- paroxysmal atrial tachycardia
- paroxysmal ventricular tachycardia
- atrial fibrillation
- ventricular ectopic arrhythmias
- digoxin-induced arrhythmias
antiarrhythmic medications work on 1 of 5 trans membrane phases of the cardiac cycle which alter the phases to control rhythm, what are the 5 phases?
Phase 0 - influx of Na ions -> depolarization
Phase 1 - partial repolarization through efflux of K ions
Phase 2 - plateau where net influx of Ca is slightly more than the efflux of K
Phase 3 - efflux of K
Phase 4 - restoration of ionic concentrations via Na/K & Na/Ca exhange pumps
What phases of the cardiac cycle are part of the absolute (effective) refractory period? (-50mV)
Phases 0, 1, 2, and most of 3
What is the name in the cardiac cycle during the middle of phase 3 to beginning of phase 4?
Relative refractory period
What happens in the absolute refractory period?
synonymous with depolarization
cells cannot respond to a stimulus, its a mechanism that protects the heart from all other ectopic impulses
When is the only time that a strong stimulus can cause depolarization?
Relative refractory period - occurs when repolarization is almost complete (cells may all respond differently)