Direct myocardial effects of intracoronary administration of new contrast materials with lost osmolality.

The effects of LV dynamics of the intracoronary administration of three new contrast materials with reduced osmolality were compared with those of a monomeric ionic material, sodium iothalamate, and the nonionic material, metrizamide. In eight anesthetized dogs, the monacid dimer, P286, caused increases in LV dimensions and decreases in LV systolic pressure and parameters of the contractile state. The changes were less than those caused by sodium iothalamte. The alterations in LV function tended to be greater, but not significantly so, during systemic hypoxemia compared to the normal state. The nonionic materials, P297 and iopamidol, like metrizamide, caused no deleterious effects on LV dynamics in either the normal or hypoxemic state. Nonionic materials actually caused a slight increase in parameters of the LV contractile state.