Review : Electrophysiologic and Antiarrhythmic Effects of Propafenone: Focus on Atrial Fibrillation

Differential effects of dofetilide, amiodarone, and class Ic drugs on left and right atrial refractoriness and left atrial vulnerability in pigs

“…The frequency dependence of the atrial ERP found for flecainide, propafenone and dofetilide in our pigs is a confirmation of published data. The class Ic drugs tended to show a positive frequency-dependent effect (Wang et al 1990;Valderrabano and Singh 1999) whereas that of dofetilide tended to be reverse (Nattel and Singh 1999). Concerning amiodarone, which also tended to show a reverse frequency-dependent effect on ERP in both atria in our pigs, controversial statements can be found in the literature.…”

Maintaining Sinus Rhythm in Atrial Fibrillation by Drug Therapy: Single Agents or Combinations?

“…The respective therapeutic effects of the study drugs in the trial might differ somewhat in patients with persistent AF restored to sinus rhythm, an issue that requires further exploration. However, despite the fact that sotalol ( 15) and propafenone (13) are known to have vastly different rate-related effects on the ERP in the atria, their observed efficacy in the present study on preventing AF recurrence was very similar. This has also been reported previously (16,17) and is of particular interest (16,17).…”

“…It is now clear that the critical factor has been their associated property of prolonging the atrial action potential duration (a class III action), which reduces the probability of AF and AFL as has been substantiated in the case of sotalol and amiodarone (4,11). What might then be the fundamental mode of actions of powerful class Ic agents such as flecainide (12) and propafenone (13), which also exert powerful antifibrillatory actions in the atria? In ventricular tissue, they function as potent class 1 agents with little or no effect on APD or ERP.…”

“…Class Ic drugs (flecainide and propafenone) are thus of much interest, because their class III action in the atria develops only during fast heart rates ( 12), precisely when this action is most relevant for the control of AF. Such an ideal electrophysiologic action of the drugs can be used not only for the maintenance of sinus rhythm, but also for the acute conversion of atrial fibrillation and flutter to sinus rhythm either after parenteral or following larger single oral drug doses (13). Importantly, is it not now timely to explore the possibility that combining their unique properties of increasing the ERP as a function of rate with those of the most promising class III agents such as sotalol, amiodarone, or their derivatives to obtain optimal longterm effectiveness in maintaining stability of sinus rhythm in patients with AF and AFL?…”