EFFECTS OF CLASS-I DRUGS ON ATRIAL-FIBRILLATION

Effects of Class I Drugs on AF. This article reviews our knowledge abo ut the efficacy of Class I antiarrhythmic agents, especially quinidine , propafenone, and flecainide, for pharmacologic conversion of atrial fibrillation to sinus rhythm, When given intravenously or orally-for t he long term, conversion rates between 50% and 90% are reported for re storation of sinus rhythm as well as for maintenance of sinus rhythm a fter DC cardioversion, Based on transtelephonic monitoring of arrhythm ia recurrences as well as tolerance, Class IC agents appear to be espe cially effective for suppressing clinical symptoms in patients with pa roxysmal atrial fibrillation, For patients who develop atrial fibrilla tion following coronary artery surgery, Class I agents are the second choice of treatment only. The concept of single oral loading with Clas s IC agents for conversion of atrial fibrillation appears attractive, but more data are needed before we conclude that it is efficacious as well as safe when given to ambulatory patients, Because all Class I an tiarrhythmic agents have the potential for lethal proarrhythmia, the g reatest and as yet unsettled issue is safety. Until the advent of larg e-scale and long-term trials demonstrating the efficacy and safety of Class I agents for the treatment of patients with atrial fibrillation, this strategy, although very popular to suppress frequent and unpleas ant symptoms due to atrial fibrillation, cannot be regarded as firmly established.