EFFECTS OF CLASS-III DRUGS ON ATRIAL-FIBRILLATION

Effects of Class III Drugs on Atrial Fibrillation. The Class III antia rrhythmic drugs have been used for the treatment of atrial fibrillatio n (AF); however, each has specific electrophysiologic properties that delineate different safety and/or effectiveness profiles. First-genera tion Class III agents seem to be more effective in preventing recurren ce of AF than in converting AF to sinus rhythm. The high incidence of major cardiac and noncardiac side effects in the long term often requi res discontinuation of the chronic antiarrhythmic therapy. The second- generation Class III drugs, ibutilide and dofetilide, have demonstrate d interesting clinical applications, especially in the setting of atri al flutter, However, their favorable antiarrhythmic effect is counterb alanced by the high incidence of severe proarrhythmias. New promising experimental data suggest that the new I-kr-I-ks blockers may be free from these dangerous limitations, thus extending the indication of Cla ss III drugs in the treatment of AF.