The effects of radiographic contrast media on myocardial contractility and coronary resistance: osmolality, ionic concentration, and viscosity.

With the ongoing development of new contrast agents, questions develop concerning the cardiac effects of these drugs. We used the perfused rat heart model to investigate the effects on cardiac and coronary function of hypertonic ionic (sodium chloride) and nonionic (glucose) solutions and conventional and low osmolality radiographic contrast media (RCM). We also evaluated the concurrent effects of RCM on prostacyclin and adenine nucleotide/nucleoside release. Hypertonic solutions of glucose had little effect on myocardial contraction (increase up to 7.7 +/- 0.9%), while NaCl solutions of similar osmolality were negatively inotropic (contractile force decreased up to 76.1 +/- 9.2%). Conventional RCM were negatively inotropic (decrease of 59.6 +/- 5.6% with Conray (Mallinckrodt Pharmaceuticals, St. Louis, MO), 32.2 +/- 3.2% with Angiovist 282 (Berlex Laboratories, Cedar Knolls, NJ]; two nonionic RCM, Iopamidol and Iotrol had little effect on myocardial contraction (reduction of 6.9 +/- 1.4% and increase of 12.0 +/- 2.9%, respectively). Hypertonic solutions of glucose and NaCl reduced coronary resistance in direct relationship to hyperosmolality. Conventional RCM also reduced coronary resistance, while the nonionic media caused minor alteration. None of the solutions tested altered prostacyclin or adenine nucleotide/nucleoside efflux from the heart. A solution of Ficoll 70 with a viscosity similar to that of RCM increased myocardial contraction by 9.6 +/- 3.6% and had no effect on coronary resistance, indicating that viscosity per se did not contribute to the negative inotropic effects or the reduction in coronary resistance. Hypertonic solutions, including conventional RCM, reduce coronary resistance as a result of their hyperosmolality Negative inotropic effects, however, are more related to high ionic concentration than to osmolality.