Cardiac effects of non-depolarizing neuromuscular blocking agents pancuronium, vecuronium, and rocuronium in isolated rat atria

Pancuronium, vecuronium, and rocuronium produce different cardiac effects. Using spontaneously beating right and electrically stimulated left rat atria, while measuring developed force, effective refractory period, and heart rate, we determined and compared the concentration-dependent cardiac effects of the compounds. The preparations were exposed to five progressively increasing concentrations of these compounds (10(-9), 10(-8), 10(-7), 10(-6), and 10(-5) mol/L). Pancuronium increased heart rate; vecuronium and rocuronium produced positive inotropic effects; and vecuronium shortened refractoriness. These effects may be the result of a blockade of the M-2 muscarinic receptors. However, the concentrations required to produce changes were higher than those observed in patients under neuromuscular blockade. (C) 1999 Elsevier Science Inc. All rights reserved.