Fibrillation and atrial flutter. Immediate control and conversion to sinus rhythm with intravenous propafenone

The safety and efficacy of intravenous Propafenone, in the treatment of atrial fibrillation (a.f.) or flutter (A.F.) of recent onset (15 days), were assessed. Propafenone (2 mg/kg) was administered to 36 consecutive patients (mean age 60.8 years), 28 with a.f. and 8 with A.F. Nineteen patients (52.7%) reverted to sinus rhythm within 85 min (mean 27.2 min): 17 of 28 (60.7%) with a.f. and 2 of 8 (25%) with A.F. The efficacy of the drug was significantly influenced by the time elapsed from the onset of the arrhythmia: 14/21 (66.6%) patients with the arrhythmia lasting less then 48 hours and only 5/15 (33.3%) of those with the arrhythmia lasting more than 48 hours or of unknown onset, were converted (p less than 0.05). 18 patients underwent echocardiographic control: mean left atrial dimensions were 41.4 +/- 11.4 mm in converters and 47.4 +/- 11.2 mm in non converters (p = NS). Mean QRS lengthening observed was 16% (from 89 +/- 35.1 to 103.5 +/- 48.8 msec) (p = NS); QTc interval increased from 390 +/- 64.3 to 403 +/- 36.2 msec (p = NS). Arterial blood pressure showed significant changes only in two patients in whom a serious hypotension developed, needing infusion of adrenergic drugs. Non converters showed a reduction of the ventricular rate from 141.8 +/- 29.4/min to 101.8 +/- 18/min (p less than 0.01) meanwhile the shortest RR interval increased from 359.5 +/- 60.8 to 450 +/- 81.5 msec (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)