Treating arrhythmia (Lecture 13) Flashcards
What are some major causes of arrhythmias?
1) Defects in impulse generation (may result in tachy or brady arrhythmias).
2) Defects in impulse conduction (may result in dropped beats or heart block).
What is the risk of having atrial fibrillation?
Blood stasis in the atria, formation of thrombus which could embolise and cause an ischemic stroke.
What are the important anti-arrhythmic drugs to remember?
Metoprolol (class 2), amiodarone (class 3), diltiazem (class 4) and digoxin (unclassified).
Pharmacological treatment of AF has 2 aims:
1) Treatment of rate/rhythm
2) Prevention of embolic complications.
What is the scoring system that we use to assess if someone is at risk of a stroke?
CHA2DS2 VASc
How do class 1 through to class 4 agents work?
What are the drugs that we have to know in there?
How do class 1 AA drugs work?
This reduces the rate and magnitude of depolarisation during phase 0, decreasing conduction velocity in non-nodal tissue.
- Adjacent cells depolarise more slowly.
How do class 2 AA drugs have an effect?
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What are the main uses of class 2 AA agents?
Rate control such as atrial fibrillation.
What is the mechanism of action of class 3 AA agents and the effect that they have?
Block K+ channels involved in repolarisation therefore prolongs atrial and ventricular repolarisation.
How do class 4 AA drugs work?
When would you use a class 4 drug?
What drug would you not use with it?
What 2 effects does digoxin have?
How does digoxin have a positive ionotropic effect?
how does digoxin have an antiarrhythmic effect?
What are its main indication?
Rate control in patients with heart failure.
Why is digoxin dangerous?
How can digoxin cause arrhythmias?
What do you do if someone does develop a dysrhythmia with digoxin?
