Direct Effects of Amide-Type Local Anesthetics on Isolated Rat Ventricular Papillary Muscles

Abstract

The direct effects of 2 amide-type local anesthetics, lidocaine and bupivacaine, on myocardial contractility were studied in isolated rat heart muscles. Three different clinically equipotent doses of each agent were tested. In Tpd, +dp/dtmax, and - dp/dt-,», the cardiodepressive action of lidocaine seemed to be slightly more than that of bupivacaine, but bupivacaine showed a more depressive action on myocardial contractility from the results of Tr and RT90%. We might say that lidocaine exhibit significant cardiodepressive activity, which is at least similar with bupivacaine.