Efficacy and tolerance of intravenous flecainide in patients with chronic high frequency ventricular arrhythmias.

The effectiveness and safety of intravenous flecainide was evaluated in 33 patients with chronic high frequency premature ventricular complexes (mean value of PVCs 23.7 min-1). Flecainide was injected intravenously at a rate of 20 mg per 2 min until complete disappearance of ventricular arrhythmias or up to a total dose not exceeding 200 mg. Total suppression of PVCs occurred in 31 out of 33 patients at the end of the injection (mean dose 132 mg). The overall reduction of PVCs was 94 per cent (P less than 0.001) at the end of infusion and 74 per cent (P less than 0.001) 1 h later. The mean plasma drug level attained 1 h after administration was 287 ng ml-1 (range 82-984). Heart rate and blood pressure did not change, but a significant increase (P less than 0.001) in PR (+12%), QRS (+13%) and QTc (+4%) duration occurred after drug administration. Flecainide was well tolerated. An idioventricular tachycardia was induced in one patient and two patients experienced side effects of the central nervous type: dizziness, blurring of vision and a sensation of warmth. In view of its activity flecainide appears to be a valuable addition to the antiarrhythmic armamentarium.