Treatment of Arrhythmias Flashcards
What 3 factors contribute to the spontaneous electrical discharge of the SAN?
o Decrease in K+ outflow
o “funny” Na+ current
o Slow inward Ca2+ current
Which area of the heart are atrial dysrhythmias associated with?
Supraventricular
Which area of the heart are junctional dysrhythmias associated with?
AV node
What are the 4 broad categories of event that dysrhythmias usually arise from?
Heart block
After depolarisations (early or delayed)
Circuit re-entry
Ectopic pacemaker activity
Which class of arrhythmia treatment do potassium channel blockers belong to?
Class 3
Which class of arrhythmia treatment do calcium channel blockers belong to?
Class 4
Which class of arrhythmia treatment do sodium channel blockers belong to?
Class 1
Which class of arrhythmia treatment do beta-adrenoreceptor channel blockers belong to?
Class 2
Sotalol
Class 2
Verapamil
Class 4
Disopyramide
Class 1a
Flecainide
Class 1c
Amiodarone
Class 3
Lignocaine
Class 1b
What are the two important arrhythmia treating drugs that are ‘unclassified’?
Adenosine
Digoxin
What type of dysrhythmias are very effectively tackled by verapamil?
SVT
AF
How does diltiazem differ from verapamil?
Diltiazem has a greater effect on smooth muscle calcium channels
Think back to the different phases of heart muscle contraction:
Phase 0: rapid depolarisation (F-type Na+ open)
Phase 1: partial repolarisation (F-type Na+ close)
Phase 2: plateau (Ca2+ open)
Phase 3: repolarisation (Ca2+ close, K+ open)
Phase 4: stable (pacemaker potential)
Which phases do each of the classes of anti-arrhythmic drugs target?
CLASS 1: Phase 0 (rapid depolarisation)
CLASS 2: Inhibit action of beta agonists, which act on Phase 2 (plateau) and Phase 4 (pacemaker potential)
CLASS 3 & 1a: Phase 3 (repolarisation)
CLASS 4: Phase 2 (plateau)
NOTE:
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