Electrophysiological and antiarrhythmic effects of Lidocaine in canine acute myocardial ischemia

Abstract The electrophysiologic effects of temporary (15 minute) ligations of the left anterior descending coronary artery were examined in 16 dogs. Monophasic action potential duration (APD) and effective refractory period (ERP) were determined in the ischemic and normal zones. Intervals (Q-EG) were measured from the onset of the QRS in a standard ECG lead to the major deflection of electrograms recorded in these zones. Control ligations were compared to those in which a 2 mg./Kg. intravenous bolus of lidocaine was administered immediately after ligation followed by a constant rate intravenous infusion of 70 μg/Kg./minute. Lidocaine reduced the number of ventricular beats per minute (17 to 8) (p APD ERP in the ischemic zone (1.12 to 1.01; p APD ERP may explain the demonstrated antiarrhythmic properties in acute myocardial ischemia.