Conversion of Recent‐Onset Atrial Fibrillation to Sinus Rhythm: Effects of Different Drug Protocols

Abstract

(1) I.v. propafenone resulted in a higher conversion rate within 1 hour compared with the oral loading regimens of propafenone or flecainide, but the conversion rates at 3 and 8 hours were comparable, approximately 75% at 8 hours; 2) i.v. amiodarone was not different from placebo until 8 hours when it was associated with 57% of conversions; (3) conversion to sinus rhythm at 8 hours was observed in 37% of the placebo treated patients. Serious adverse effects occurred in few patients: two patients treated with flecainide and one treated with i.v. propafenone experienced left ventricular decompensation; one patient treated with placebo and two treated with flecainide had atrial flutter with rapid ventricular response. In conclusion, single-dose, oral loading with propafenone or flecainide are acceptable alternatives to conventional drug regimens in selected hospitalized patients. In addition, the measure of a placebo effect is mandatory in studies of recent-onset AF.

Intravenous amiodarone for cardioversion of recent‐onset atrial fibrillation

“…It has been shown in other studies that the efficacy of amiodarone in the termination of AF of different duration is significantly lower than that of class Ic drugs when assessed within the first 3 h of treatment. 6,11,14 In our study, the difference between efficacy of amiodarone and control treatment started to be significant after 8 h of treatment, when 50% of patients receiving amiodarone were converted to sinus rhythm. This is not surprising because intravenous amiodarone exerts different electrophysiologic effects than oral formulation.…”

“…[11][12][13][14] These discrepancies, perhaps, may occur by chance, as the study groups were small. The differences in patients' baseline characteristics, duration of index AF episode, and mode of 332 Table I.…”

“…17,18 In some other reports, the conversion rate in the amiodarone-treated patients assessed within 8 h of therapy was similar and did not exceed 59%. 6,9,14 Lack of difference between efficacy of amiodarone and control treatment during the first 8 h of therapy may be explained in part by the above-mentioned delayed onset of amiodarone class III antiarrhythmic action, and in part by the well-known fact that the highest rate of spontaneous termination of AF is seen within the first 8 h of AF. 14,19 …”

“…The results of these studies are discordant: the efficacy rate varies from only 59% to as much as 92%. The remaining published studies [11][12][13][14][15][16] dealt either with patients with longer AF duration or oral loading of amiodarone.…”

Atrial fibrillation: review of current treatment strategies

“…There is also synergism between these drugs and digoxin (64). Antiarrhythmic drugs have been highly effective in converting AF to normal sinus rhythm if promptly administered following onset of AF and at an adequately high dosage (65). Constant electrocardiographic monitoring of the patient has been recommended for the first 48 to 72 hours following the initial anti-arrhythmic drug dose (4).…”