Drugs to treat cardiac arrhythmias Flashcards
Target of class 1 antiarrhythmics
Myocardial AP
What drugs fall under the class 1A antiarrhythmics?
Procainamide
Quinidine
Disopyramide
What effects to the class 1A drugs have on the myocardial AP?
Block Na+ channels leading to widened QRS
Block K+ channels leading to prolonged AP and thus a prolonged QT on ECG
What type of arrhythmias do class 1A drugs treat?
SVT
VT
Arryhthmias associated with MI (not first line)
What drugs fall under the class 1B antiarrhythmics?
Lidocaine
Mexiletine
What effects to the class 1B drugs have on the myocardial AP?
Block Na+ channels thus decrease the slope of phase ) and widen QRS on ECG
Do not bind to K+ channels, thus do not prolong AP. The AP is actually shortened
What drugs fall under the class 1C antiarrhythmics?
Flecainide
Propafenone
What effects to the class 1C drugs have on the myocardial AP?
Block Na+ channel thus decrease slope of phase 0 and widen QRS on ECG
Block certain K+ channels, but not ones that repolarize the AP, thus AP length is not changed
What type of arrhythmias do class 1C drugs treat?
SVT in patients with normal hearts
What type of arrhythmias do class 1B drugs treat?
VT in the setting of MI
Class 2 drugs used in treating arrhythmias are?
Beta-blockers (esmolol, propranolol)
Target of Class 2 antiarrhythmics
Pacemaker AP
Class 3 antiarrhythmics MOA
Block K+ channels thus prolong the AP duration and inducing prolonged QT on EKG.
They prolong the refractory period
What drugs fall under the class 3 antiarrhythmics?
Amiodarone
Sotalol (Beta-blocker)
Dofetilide
Ibutilide
Class 4 antiarrhythmic drug MOA and target
Cardioactive calcium channel blockers
Target the SA node
