The comparative antiarrhythmic effects of mepivacaine and lignocaine.

A comparison of the antiarrhythmic effects of 2 mg/kg of mepivacaine and lignocaine, as measured by elevations in the end-diastolic ventricular stimulation threshold (EDVST), was made in open-chest dogs. Both mepivacaine and lignocaine increased the EDVST significantly. The peak elevation of EDVST occurred within 2 minutes after injection and averaged 0.013 mA (13 ,uA) with mepivacaine and 0.022 mA (22 fjA) with lignocaine. The greater early response to lignocaine as compared with mepivacaine was significant. After 4 minutes the rate of decreasing effect was approximately 0.001 mA/ min for both mepivacaine and lignocaine. The studies provide new evidence demonstrating the antiarrhythmic properties of mepivacaine and support the continued evaluation of related compounds in the search for better antiarrhythmic agents.