Must antidysrhythmic agents be given to all patients with new-onset atrialfibrillation?

We investigated the spontaneous conversion rate of new-onset atrial fibrill ation (AF) in emergency department patients and the recurrence rate of AF d uring al month follow up period. Sixty-six consecutive hemodynamically stab le patients presenting to a university hospital emergency department with n ew-onset atrial fibrillation (less than 72 hours duration) comprised the st udy population. Patients were initially monitored for 8 hours and observed for spontaneous conversion of AF to sinus rhythm. If conversion did not occ ur in the first 8 hours, an oral loading dose (600 mg) of propafenone was g iven, and patients were observed for an additional 8 hours. All patients we re reevaluated at 24 hours and at 1 month, The spontaneous conversion rate in patients presenting within 6 hours of AF onset during the initial 8-hour observation period was 71%. The spontaneous conversion rate for ail patien ts during the initial observation period was 53%, The conversion rates betw een patients presenting "early" (less than 6 hours) and "late" (7-72 hours) were significantly different (P < 0.001). Many patients with new-onset AF, especially those with atrial fibrillation duration less than 6 hours, may need observation only, rather than immediate intervention, to treat their d ysrhythmia, (Am J Emerg Med 1999;17:659-662. Copyright (C) 1999 by W.B. Sau nders Company).