Class I Antiarrhythmics Flashcards
What vascular effects does Procainamide have?
Reduce peripheral vascular resistance, can cause hypotension
What are the cardiac effects of Procainamide? What does this look like on an EKG?
Slows upstroke of action potential generation via Na channel blockage and repolarization via nonspecific K channel blockage
Prolongs QRS complex and APD
What major toxicities does procainamide have? Prolonged use?
Acute: Torsades de pointes
Prolonged: Lupus like symptoms
Therapeutic use of procainamide?
Most ventricular and atrial arrhythmias
What are the cardiac effects of Quinidine? What does this look like on an EKG?
Slows action potential propagation, slows conduction
Prolongs QRS via Na channel blocking, repolarization via K channel blockage
Adverse effects of quinidine? Overdose symptoms?
Adverse effects: GI problems in 1/3 to 1/2 of patients
Overdose sx: headache, tinnitis, dizziness
Torsades de pointes
Therapeutic use of Quinidine?
Rarely used because so many people have problems with it
What are the cardiac effects of Disopyramide? EKG findings?
Same as the rest of the Class IA antiarrhythmics
Extracardiac effects of Disopyramide?
Atropine-like effects: Blurred vision, urinary retention, constipation, dry mouth
Serious side effects of Disopyramide?
Torsades de pointes, can precipitate heart failure in patients with left ventricular function depression.
Therapeutic use of Disopyramide?
Approved for supraventricular arrhythmias
What are the cardiac effects of Lidocaine? What does the EKG change to?
Selective depression of conduction in depolarized cells
Little effect seen in EKG
What are the indications for lidocaine use?
Agent of choice for ventricular tachycardia termination and prevention of V fib AFTER cardioversion
Should lidocaine be used prophylactically?
NO! Prophylactic use may actually increase total mortality
What are the cardiac effects of Mexiletine? EKG effects?
Orally active lidocaine, so the same as lidocaine.
