Effects of encainide and amiodarone on the adaptation of ventricular refractoriness to an increase in rate

The ventricular effective refractory period (VERP) adapts gradually to an increase in rate, and up to several minutes may be necessary before the maximum shortening of VERP is realized when the rate increases.1,2 Quinidine and mexiletine have been demonstrated to have no effect on the adaptation of ventricular refractoriness to an increase in rate.3 However, the effects of class IC and class III antiarrhythmic drugs on the adaptation of refractoriness to an increase in rate are not known. Therefore, the purpose of this study was to evaluate the effects of encainide and amiodarone on the adaptation of the VERP to an increase in rate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28462/1/0000253.pd