Functional and metabolic effects of bupivacaine and lidocaine in the perfused working rat heart.

The effects of bupivacaine (2.5, 5, 10, and 12.5 mg/L) and lidocaine (12.5, 25, 40, and 50 mg/L), on spontaneous heart rate, mean pressure development, cardiac output, and coronary flow were compared after 15 minutes' exposure in the isolated perfused working rat heart preparation. In addition, myocardial oxygen consumption, glucose utilization, lactate production, tissue content of glycogen, adenine nucleotides, and creatine phosphate content were measured. The relative potency of bupivacaine to lidocaine, calculated from slopes of regression equations, as indicated by the four mechanical variables and oxygen consumption, was 4.59. When the bupivacaine concentration was "normalized" using this value, bupivacaine and lidocaine showed indistinguishable effects on glucose utilization, lactate production, and tissue glycogen. Neither of the local anesthetics had any influence on energy charge or creatine phosphate content.