Frequency-Dependent Effects of Several Class I Antiarrhythmic Drugs on max of Action Potential Upstroke in Canine Cardiac Purkinje Fibers

Canine cardiac Purkinje fibers

Seven class I antiarrhythmic drugs: lidocaine (4 micrograms/ml), mexiletine (4 micrograms/ml), propranolol (0.9 micrograms/ml), procainamide (30 micrograms/ml), quinidine (5 micrograms/ml), flecainide (4 micrograms/ml), and disopyramide (3.1 micrograms/ml)

Vmax of the action potential upstroke and time constant of Vmax recovery at constant cycle lengths and after abrupt changes in cycle lengthsurrogate