Antiarhythmics Flashcards
What are the 3 catergories of arrhytmias origin?
Atrial (Supraventricular)
Nodal (Supraventricular)
Ventricular
What are 3 types of supraventricular tachyarrhythmias?
Paroxysmal supraventricular tachycardia (PSVT)
Atrial Fibrillation
Atrial Flutter with variable AV conduction
What are 3 common types of ventricular arrhythmias?
Monomorphic ventricular tachycardia
Torsades de pointed
Ventricular fibrillation
What are 2 drug classes that reduce automaticity of cardiac myocytes by decreasing the phase 4 slope?
Beta blockers
Calcium channel blockers
What are 2 drug classes that reduce automaticity of cardiac myocytes by increasing the threshold of action potentials?
Sodium blockers
Calcium channel blockers
What drug class reduces automaticity of cardiac myocytes by increasing action potential duration?
Potassium channel blocker
What drug class reduces automaticity of cardiac myocytes by increasing the maximum diastolic potential?
Adenosine
What are 2 mechanism by which reentry can be abolished by cardiac drugs?
Slowing depressed conduction
Lengthening refractory period
What are 2 drugs that can be used to lengthen the refractory period?
Sodium channel blockers
Potassium channel blockers
Regarding cardiac drugs, what is a “state / use” dependent drug? What is an example of a sodium channel blocker to which this principle applies?
A drug that only affects channels in the open state
Lidocaine
What are the 4 classes of antiarrhythmics and what are the component drug classes?
I - Sodium channel blockers
II - Beta blockers
III - Potassium channel blockers
IV - Calcium channel blockers
Among the sodium channel blockers, what are the 2 major mechanisms of action?
Slow phase 0 depolarization
Slow conduction
Among class 1A, 1B and 1C sodium channel blockers, which bind / unbind with slow, medium and fast kinetics? Which are considered the “smart / use-dependent” drugs?
1A - Medium
1B - Fast (Smart drugs)
1C - Slow
Among class 1A, 1B and 1C sodium channel blockers, which will prolong the action potential? Have no effect on the action potential? Shorten the action potential?
Prolong - 1A
Shorten - 1B
No Effect - 1C
What are the 3 examples of type 1A sodium channel blockers? Which should be avoided in heart failure? What are they used for (2)?
Procainamide Quinidine Disopyramide (Avoid in heart failure) - Ventricular arrhythmia - Recurrent Atrial arrhythmia
What are the 2 examples of class 1B sodium channel blockers? What is their shared major side effect? How are the used differently?
Lidocaine (acute ventricular arrhythmias)
Mexiletine (Chronic ventricular arrhythmias)
- CNS toxicity is shared side effect
What are the 2 class 1C sodium channel blockers? What are their major side effect? What are they used for?
Flecainide
Propafenone
- Both arrhythmogenics
- Used for recurrent atrial arrhythmias
What is a major consideration when using class 1C sodium channel blockers? What patient population should not use these drugs (2)?
Can cause life threatening arrhythmias
Don’t use in patients with underlying structural heart disease or after MI
What is the major mechanism by which beta blockers work as antiarrhythmics?
They reduce automaticity (slow the action potential)
What are the 4 beta blockers used in the treatment of arrhythmias? What are their shared side effects?
Propranolol Metoprolol Atenolol Esmolol - Bradycardia - Negative ionotrope
What are the 2 beta 1 selective beta blockers used to treat arrhythmias?
Metoprolol
Atenolol
Among the beta blockers used to treat arrhythmias, propranolol has a specific side effect not shared by the others. What is it? Why does it have this property?
It can cause bronchospasm
It blocks beta 2 receptors
What are the 2 therapeutic uses of beta blockers?
Atrial arrthythmias
Slow AV node conduction
What is a therapeutic use of the beta 1 selective beta blockers not shared by the other agents?
Prevent sudden cardiac death post MI
