Cardiac Arrhythmia Drugs Flashcards Preview

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Flashcards in Cardiac Arrhythmia Drugs Deck (4)
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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.


How may arrhythmias present?

Changes in heart rate and rhythm


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



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

- circus movement
- reflection

Abnormal anatomic conduction
- Wolf-Parkinson-White Syndrome