Comparison of antiarrhythmic effects of oral prajmalium bitartrate and intravenous lidocaine in acute myocardial infarction.

In 35 patients with acute myocardial infarction premature ventricular complexes were quantified from stored continuous electrocardiographic tape recordings using a semiautomated arrhythmia detection system. Seventeen patients, separated at random, received no antiarrhythmic drug and formed the control group. In nine patients prajmalium bitartrate was given orally at a dose of 60 mg. (20 mg. every 4 hours). Nine patients had permanent infusions of 2.1 mg./minute lidocaine (corresponding to a daily dose of 3 g.). In both treated groups premature ventricular complexes decreased significantly as compared to the spontaneous frequency in the control group. Six hours after the onset of therapy premature ventricular complexes were reduced to 37% of the initial value in the prajmalium bitartrate group and to 51% in the lidocaine group, whereas in the control group frequency increased (169%). The peak effect was reached after ten hours when premature ventricular complexes were reduced to 5% under prajmalium bitartrate and to 20% under lidocaine administration. Runs of premature ventricular complexes were nearly completely suppressed after administration of prajmalium bitartrate. Under lidocaine administration runs were moderately and not significantly reduced. Eight hours after the onset of therapy, runs were reduced to 8% of the initial value under prajmalium bitartrate and to only 79% under lidocaine. The effect of prajmalium bitartrate on runs of premature ventricular complexes was significantly more pronounced than the effect of lidocaine. The present study documents that orally administered prajmalium bitartrate is an alternative to intravenous administration of lidocaine in the treatment of ventricular arrhythmias after acute myocardial infarction.