Arrhythmias Flashcards
Types of Channels
- Fast sodium channel
- Potassium channels
- Calcium channels
- “Funny” sodium channels (If channels)
Fast sodium channel
- Voltage dependent
- Lets sodium in, keeps potassium from going out and keeps calcium from blocking channel
Potassium channels
Contribute to regulation of action potential duration
Calcium channels
- T-type channels initiate action potential (short)
- L-type channels sustain action potential (long)
“Funny” sodium channels (If channels)
In SA and AV nodes
Voltage clocks influenced by?
Autonomic Nervous System
Divisions of Autonomic Nervous System and their function?
- Sympathetic: increases activity
2. Parasympathetic: decreases activity
Antiarrhythmic drugs are used to
- decrease or increase conduction velocity
- alter the excitability of cardiac cells by changing the duration of the effective refractory period
- suppress abnormal automaticity
Antiarrhythmic drugs treat which arrhythmias?
- Supraventricular arrhythmias: atrial fibrillation
- Ventricular arrhythmias: ventricular fibrillation
Class I do what?
- Fast sodium channel blockers
- Slows Phase 0 depolarization
Example of Class I?
lidocaine
quinidine
Class II do what?
- Beta blockers
- Suppresses Phase 4 depolarization
Example of Class II?
metoprolol
Class III do what?
- Repolarization prolongation
- Prolongs Phase 3 repolarization
Example of Class III?
amiodarone
Class IV do what?
- calcium channel blockers
- shortens action potential
Example of Class IV?
verapamil
diltiazem
Class V do what?
- calcium accumulation
- vagal effect
Example of Class V?
digoxin
Quinidine uses
- Atrial tachyarrhythmias
- AV-junctional and ventricular arrhythmias
ADR of Quinidine
Diarrhea Hemolytic anemia, thrombocytopenia Aggravate heart failure Liver failure Digoxin interaction
How Quinidine works
Slow Phase 0 depolarization, prolong action potential, slow conduction
What Vaughn Williams class is Quinidine
IA
uses for Lidocaine
Ventricular arrhythmias
ADR of Lidocaine
Worsen certain arrhythmias
Seizures
CNS effects
Contraindicated in second degree or complete heart block
How Lidocaine works
Shorten Phase 3 repolarization and decrease duration of action potential
What Vaughn Williams class is Lidocaine
Vaughn-Williams-IB
Dose for Lidocaine
Prefilled syringe of 100 mg IV bolus
uses for Propafenone (Rhythmol™)
- Life-threatening ventricular tachycardia or ventricular fibrillation
- Refractory supraventricular tachycardia
How Propafenone (Rhythmol™)works
Slow Phase 0 depolarization
What Vaughn Williams class is Propafenone (Rhythmol™)
Vaughn-Williams-IC
Prescription for Propafenone (Rhythmol™)
225 mg
One tablet every 8 hours