Effects of flecainide on ventricular function: clinical and experimental correlations.

Flecainide has unusual electrophysiologic properties and a high potency for the suppression of ventricular tachyarrhythmias. Little is known about its inotropic and hemodynamic actions. In isolated rabbit papillary muscle, it produced a concentration-dependent depression of contractile force, the threshold concentration being 1.0 micrograms/ml. In patients undergoing coronary angiography for ischemic heart disease and given 1 (n = 11) and 2 mg/kg (n = 11) of flecainide acetate i.v., there was no change in heart rate or mean arterial pressure. The vehicle in which i.v. flecainide was suspended had no significant effects in 6 patients in whom it was tested. Both doses produced comparable hemodynamic effects irrespective of the level of the left ventricular ejection fraction. The mean right atrial pressure increased by 12% (p less than 0.05) after 1 mg/kg and by 15% (p less than 0.01) after 2 mg/kg of the drug. The corresponding increases in mean wedge pressure were 44% (p less than 0.05) and 33% (p less than 0.05), in mean pulmonary artery pressure 27% (p less than 0.01) and 28% (p less than 0.05), in systemic vascular resistance 10% (p less than 0.05) and 9% (not significant [NS]) and in pulmonary vascular resistance 6% (NS) and 49% (p less than 0.05). Significant decreases in cardiac index (8 and 12%, p less than 0.05), stroke volume index (11 and 15%, p less than 0.01) and stroke work index (12%, p less than 0.05, and 21%, p less than 0.01) as well as in left ventricular ejection fraction (15 and 16%, p less than 0.01) were also induced by the 2 doses of flecainide.(ABSTRACT TRUNCATED AT 250 WORDS)