Antiarrhythmic action of lignocaine in early myocardial infarction. Plasma levels after combined intramuscular and intravenous administration.

In an attempt to find a regimen suitable for pre-hospital prevention of arrhythmias following myocardial infarction, the antiarrhythmic and pharmacokinetic effects of combining intravenous and intramuscular lignocaine have been studied. In nine patients with acute myocardial infarction, 100 mg of lignocaine was administered intravenously and 300 mg into the deltoid muscle. The antiarrhythmic effect was observed by continuous tape monitoring of the patients' rhythm before and after treatment. Plasma levels above 2 microng/ml were achieved within 1 min and maintained for 1 h in all patients; in seven this level was maintained for 2 h. A marked reduction in the occurrence of ventricular ectopic beats was observed in the first 15 min after treatment and was maintained for 90 min, but a significant effect was still present at 3 h. No serious side-effects were noted.