Anti Arrhythmics Flashcards
Which pacemaker node has the highest rate of automaticity?
The SA node
List two mechanisms of cardiac arrhythmias
Slowed conduction causing reentry circuits, altered rate of spontaneous discharge (ectopic pacemaker)
List class 1A, 1B, and 1C antiarrhythmics
1A: quinidine, disopyramide, procainamide
1B: lidocaine, mexiletine, tocainide, phenytoin
1C: Flecainide, propafenone
List three features of class 1 antiarrhythmics
Sodium channel blockers, cause slow depolarization, contain MSA
Describe the difference between lidocaine given injection and given IV
Injection – numbing effect
IV – antiarrhythmic effect
Which type of class one antiarrhythmics are rarely used due to increased mortality in post MI patients?
Class 1C – slow sodium channel blockers (Flecainide, propafenone)
Describe class II antiarrhythmics and list five examples
Beta adrenergic blockade used for atrial and ventricular arrhythmias
Propanolol, sotalol, esmolol, metoprolol, atenolol
Describe class III antiarrhythmics and list 3 examples
Potassium channel blockers used for ventricular and atrial arrhythmias
Amiodarone, dofetilide, sotalol
Describe class IV antiarrhythmics and list 2 examples
Calcium channel blockers used in supraventricular arrhythmias
Diltiazem and verapamil
List 4 side effects of class 1A antiarrhythmics
Tachycardia, sedation, constipation, dry mouth
Which class of antiarrhythmics are anti-cholinergic drugs?
IA: quinidine, procainamide, disopyramide
What is one particular side effect of procainamide?
Lupus like syndrome: butterfly rash, arthralgias
Which antiarrhythmic causes a lupus like syndrome?
Procainamide (IA)
Which IB antiarrhythmic is IV, and which is PO?
IV – lidocaine
PO – mexiletine
What is CAST & which class of drugs does it involve?
Cardiac arrhythmia suppression trial: showed increased mortality in post-MI patients with ventricular arrhythmias (class 1C)
Which class II antiarrhythmic is given IV?
Esmolol – short half-life, metabolized by plasma esterases
List four adverse effects of amiodarone
Visual disturbances, blue discoloration to skin, thyroid disturbances (contains iodine), pulmonary fibrosis
List reasons why amiodarone is commonly used to treat arrhythmias
Treats atrial and ventricular arrhythmias, can be used in heart failure, can be administered IV or PO, long half life with large volume of distribution
What is Dronedarone?
Prodrug of amiodarone used in atrial arrhythmias
How is Dronedarone different from amiodarone?
Lacks iodine that contributes to toxicity, cannot be used in patients with heart failure, only used in atrial arrhythmias
Which antiarrhythmic class is sotalol, and what is special about sotalol?
Class III
Has beta blocking properties and potassium channel blocking properties
What is digoxin mainly used to treat?
A fib and A flutter
What is the drug of choice for torsades?
Magnesium sulfate
What is the pharmacological rule about antiarrhythmic drugs?
All antiarrhythmics are arrhythmogenic
