VALUE OF SINGLE ORAL LOADING DOSE OF PROPAFENONE IN CONVERTING RECENT-ONSET ATRIAL-FIBRILLATION - RESULTS OF A RANDOMIZED, DOUBLE-BLIND, CONTROLLED-STUDY

Aims To evaluate the efficacy and safety of a single loading oral dose of propafenone in the interruption of recent-onset atrial fibrillatio n. Methods After a complete medical history, physical examination, 12- lead EGG, chest X-ray, and routine biochemical laboratory testing, 55 consecutive patients with recent-onset atrial fibrillation were random ized double-blind in the emergency department for the administration o f either a single oral dose (450 to 750 mg) of propafenone (29 cases) or a placebo (26 cases). After the 24-h observation period, comprehens ive echocardiographic examination was performed. Results The groups we re homogeneous as regards biological, clinical and echocardiographic c haracteristics. Two hours after treatment, 12 patients (41%) on propaf enone bur only two (8%) on placebo had converted to sinus rhythm (P=0. 005). This striking difference was maintained 6h after treatment (65 v s 31%; P=0.015) but lessened at 12h (69% vs 42%; P=0.060) and was insi gnificant at the end of the 24-h treatment period (79% vs 73%; P=0.752 ). Apart from hypotension, transient in three cases and sustained in o ne whose later echocardiographic examination demonstrated left systoli c ventricular dysfunction, propafenone was well tolerated. Conclusion Although there is no significant difference in the rates of conversion 24 h after treatment, propafenone works faster than placebo in achiev ing sinus rhythm. This rapid action of oral propafenone can be useful to solve quickly the clinical problems of a high proportion of patient s arriving at the emergency department with acute atrial fibrillation.