THE INEFFICACY OF INTRAVENOUS PROPAFENONE FOR RATE CONTROL IN ATRIAL-FIBRILLATION

The antiarrhythmic agent propafenone has been reported to prolong atri oventricular node conduction and may be suitable for rate control in a trial fibrillation (AF). To evaluate this, 10 patients (seven men and three women aged 29 to 67 years, mean +/- SD 48 +/- 14) were given int ravenous propafenone during AF in both the supine and upright position s. Intracardiac catheters measured local electrograms from the high ri ght atrium and right ventricular apex during AF. Atrial rate, ventricu lar rate and blood pressure were recorded in the control state and aft er head-up tilt with these measurements repeated after propafenone 1.5 mg/kg was infused over 5 mins. Four of 10 patients reverted to sinus rhythm. Propafenone increased the mean ventricular cycle length (496 /- 147 versus 556 +/- 152 ms, P = 0.1), although this did not reach si gnificance. In contrast, propafenone markedly increased the mean atria l cycle length (136 +/- 35 versus 226 +/- 39, P < 0.001). The mean ven tricular cycle length reverted to baseline after tilt (447 +/- 103 ms) while the mean atrial cycle length decreased but not to baseline leve ls (170 +/- 21 ms). The authors conclude that intravenous propafenone is generally inadequate for rate control in AF, especially in the upri ght position.