Flashcards in Treatment of Arrhythmias Deck (19)
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?
Which area of the heart are junctional dysrhythmias associated with?
What are the 4 broad categories of event that dysrhythmias usually arise from?
After depolarisations (early or delayed)
Ectopic pacemaker activity
Which class of arrhythmia treatment do potassium channel blockers belong to?
Which class of arrhythmia treatment do calcium channel blockers belong to?
Which class of arrhythmia treatment do sodium channel blockers belong to?
Which class of arrhythmia treatment do beta-adrenoreceptor channel blockers belong to?
What are the two important arrhythmia treating drugs that are 'unclassified'?
What type of dysrhythmias are very effectively tackled by verapamil?
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)