ANTI-ARRHYTHMIC DRUGS QUIZ WITH
100% CORRECT ANSWERS [GRADED
A+]
Are class I anti-arrhythmics state dependent? - ✔✔Yes; they have high
affinity for activated or inactivated channels, and low affinity for resting
channels.
Are class I anti-arrhythmics rate dependent? - ✔✔Yes; they work best at
fast heart rates and lease during bradycardia
Are class I anti-arrhythmics acids or bases and what impact does this have
on their efficacy? - ✔✔They are weak bases (except phyntoin); this means
that acidosis will amplify Na+ channel blockade and thus their efficacy and
alkalosis will diminish their efficacy
Name the Class Ia anti-arrhythmics - ✔✔Quinidine and procainamide
©morren2025/2026.Year published 2026.
,What are the four mechanisms of quinidine action? - ✔✔Blockade of 1)
activated Na+ channels (main action), 2) inactivated Na+ channels, 3) K+
channels, 4) Ca++ channels, 5) Alpha-1 receptors, and 6) muscarinic
receptors
What are the major anti-arrhythmic effects of quinidine? - ✔✔decreased
conduction, increased refractoriness, increased AP duration (due to K+
channel blockade), and decreased automaticity
all effects are more evident on fast fibers than slow fibers
What effect does quinidine have on AV conduction? - ✔✔has a variable
effect on AV conduction time
Clinical use of quinidine? - ✔✔second choice drug in PVCs, atrial flutter
and atrial fibrillation, SVTs and VTs
©morren2025/2026.Year published 2026.
, What are the major adverse effects of quinidine? - ✔✔Causes torsades de
pointes, digitalis toxicity in patients on digoxin, and cinchonism
Contraindications of quinidine? - ✔✔complete heart block, bb block, VA
with long QT, prolonged QRS, torsades de pointes, cardiac failure, digoxin
induced arrhythmias
What is the mechanism of action of procainamide? - ✔✔blocks activated
Na+ channels (main mechanism) and K+ channels
How is procainamide different that quinidine? - ✔✔less prominent
antimuscarinic action, no effect on Ca++ channels or alpha receptors
What are the uses for procainamide? - ✔✔Acute treatment of some
arrhythmias associated with Wolff-Parkinson-White syndrome, SVTs, and
VAs when other drugs are poorly tolerated or not effective
What are the side effects / contraindications for procainamide? - ✔✔Same
as quinidine without cinchonism
©morren2025/2026.Year published 2026.
100% CORRECT ANSWERS [GRADED
A+]
Are class I anti-arrhythmics state dependent? - ✔✔Yes; they have high
affinity for activated or inactivated channels, and low affinity for resting
channels.
Are class I anti-arrhythmics rate dependent? - ✔✔Yes; they work best at
fast heart rates and lease during bradycardia
Are class I anti-arrhythmics acids or bases and what impact does this have
on their efficacy? - ✔✔They are weak bases (except phyntoin); this means
that acidosis will amplify Na+ channel blockade and thus their efficacy and
alkalosis will diminish their efficacy
Name the Class Ia anti-arrhythmics - ✔✔Quinidine and procainamide
©morren2025/2026.Year published 2026.
,What are the four mechanisms of quinidine action? - ✔✔Blockade of 1)
activated Na+ channels (main action), 2) inactivated Na+ channels, 3) K+
channels, 4) Ca++ channels, 5) Alpha-1 receptors, and 6) muscarinic
receptors
What are the major anti-arrhythmic effects of quinidine? - ✔✔decreased
conduction, increased refractoriness, increased AP duration (due to K+
channel blockade), and decreased automaticity
all effects are more evident on fast fibers than slow fibers
What effect does quinidine have on AV conduction? - ✔✔has a variable
effect on AV conduction time
Clinical use of quinidine? - ✔✔second choice drug in PVCs, atrial flutter
and atrial fibrillation, SVTs and VTs
©morren2025/2026.Year published 2026.
, What are the major adverse effects of quinidine? - ✔✔Causes torsades de
pointes, digitalis toxicity in patients on digoxin, and cinchonism
Contraindications of quinidine? - ✔✔complete heart block, bb block, VA
with long QT, prolonged QRS, torsades de pointes, cardiac failure, digoxin
induced arrhythmias
What is the mechanism of action of procainamide? - ✔✔blocks activated
Na+ channels (main mechanism) and K+ channels
How is procainamide different that quinidine? - ✔✔less prominent
antimuscarinic action, no effect on Ca++ channels or alpha receptors
What are the uses for procainamide? - ✔✔Acute treatment of some
arrhythmias associated with Wolff-Parkinson-White syndrome, SVTs, and
VAs when other drugs are poorly tolerated or not effective
What are the side effects / contraindications for procainamide? - ✔✔Same
as quinidine without cinchonism
©morren2025/2026.Year published 2026.
