Cardiac Arrhythmia Drugs Flashcards Preview

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Flashcards in Cardiac Arrhythmia Drugs Deck (4)
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1

What are arrhythmias?

Heart condition where there are disturbances in:
- pacemaker impulse formation
- contraction impulse conduction
- combination of the two

Results in rate and/or timing of contraction of heart muscle that is insufficient to maintain normal cardiac output.

2

How may arrhythmias present?

Palpitations
Syncope/pre-syncope
Changes in heart rate and rhythm

3

What are the classes of antiarrhythmic drugs?

Class 1 - Sodium Channel Blockers

Class 2 - Beta-Blockers

Class 3 - Potassium Channel Blockers

Class 4 - Calcium Channel Blockers

Digoxin

4

What are the mechanisms of arrhythmogenesis?

1) Abnormal impulse generation:
Automatic rhythms
- enhanced normal automaticity- increased rate of AP from SA node (e.g. raised heart rate when nervous)
- ectopic focus - AP arises from sites other than the SA node

Triggered rhythms
- delayed afterdepolarisation (arises from the resting potential)
- early afterdepolairsation (arises from the plateau)

2) Abnormal conduction
Conduction block
- impulse not conducted from the atria to the ventricles
- 1st, 2nd or 3rd degree

Re-entry
- circus movement
- reflection

Abnormal anatomic conduction
- Wolf-Parkinson-White Syndrome