Acute effects of lidocaine on repolarization and conduction in patients with coronary artery disease

Right ventricular repolarization and refractoriness were studied during continuous infusion of lidocaine in patients with coronary artery disease. Compared with baseline the duration of monophasic action potential was shortened (p less than 0.01) at constant and premature stimulation. Early premature action potentials were less shortened (p less than 0.05). Therefore the difference between the longest and shortest action potential duration elicited 2 to 150 msec after refractoriness decreased during lidocaine infusion (p less than 0.01). The right ventricular effective refractory period was shortened similarly to the action potential duration. Lidocaine did not change the conduction of constant paced beats, whereas the more rapid conduction of the midrange premature beats was inhibited (p less than 0.01). The inhibition of premature conduction 50 to 150 msec from the right ventricular effective refractory period may be attributed to the effect of lidocaine on the rate-dependent recovery from inactivation. The effect on the restitution curve indicates that lidocaine may influence the dispersion of premature action potentials in human beings.