CARDIOVASCULAR EFFECTS OF AJMALINE

Ajmaline, a rauwolfia derivative, from Rauwolfia serpentina, possessed potent antiarrhythmic effects. Hemodynamic studies performed in anesthetized and conscious dogs demonstrated no significant changes in measured hemodynamic parameters at doses equal to or less than 2 mg/kg. Studies in isolated papillary muscle demonstrated no negative inotropic effects until concentrations of 1 .times. 10-4. Disparate results were obtained with regard to heart rate reflecting the state of autonomic tone. Electrophysiologic studies in both anesthetized and conscious dogs demonstrated a significant depression of intraventricular conduction with no significant effect on AV [atrio-ventricular] nodal conduction; ventricular automaticity was not affected. Ajmaline did not alter digitalis-induced AV nodal conduction prolongation. Ajmaline dramatically altered or abolished ventricular arrhythmias secondary to acute ischemia. Ajmaline specifically depresses intraventricular conduction, suggesting that this drug would be particularly effective in the treatment of re-entrant ventricular arrhythmias.