Effects of lignocaine on intramyocardial conduction in nonischaemic and ischaemic canine myocardium

Abstract

The effect of lignocaine (USP: lidocaine) on intramyocardial conduction in ischaemic and nonischaemic areas of the left ventricular myocardium was determined in 11 mongrel dogs. Intramyocardial conduction times were assessed during control conditions, 15 min after coronary ligation, and following lignocaine administration. Coronary occlusion resulted in a disparity between the conduction velocities in the ischaemic and nonischaemic zones. Ater lignocaine administration conduction to the ischaemic area was further decreased. However, conduction to the nonischaemic area was decreased to a relatively greater extent, resulting in a significant decrease in the disparity of conduction velocities in the two areas. It is concluded (1) that lignocaine exerts dissimilar quantitative effects on the nonischaemic and acutely ischaemic myocardium and (2) that these differential effects decrease the inhomogeneity of intraventricular conduction. It is possible that this action may play a role in the suppression of re-entrant arrhythmias.