EFFECT ON CARDIAC CONTRACTILE-FORCE FROM ADDITION OF CATIONS AND OXYGEN TO IOHEXOL - COMPARISON WITH OTHER LOW-OSMOTIC CONTRAST-MEDIA IN THE ISOLATED RABBIT HEART DURING NORMAL AND REDUCED PERFUSION-PRESSURE

The coronary arteries of the isolated rabbit heart were perfused with different contrast media (CM). The effects on cardiac contractile forc e (CF) from enriching iohexol solutions with sodium, calcium, potassiu m, magnesium and oxygen were investigated. The effects were studied du ring normal and reduced perfusion pressure; the latter was intended to simulate flow conditions distal to proximal stenotic processes of the coronary arteries. By adding the above mentioned cations to iohexol ( 175 mg I/ml) the smallest influence on CF was found when the CM contai ned 30 mM NaCl, 0.3 mM CaCl2, 0.9 mM KCl and 0.3 mM MgCl2 and this inf luence on CF was significantly less than caused by iohexol with 30 mM NaCl (p less-than-or-equal-to 0.01). The influence on CF was further r educed when this iohexol solution was oxygenated with 100% oxygen (p l ess-than-or-equal-to 0.001). This modified iohexol solution caused a s ignificantly smaller influence on CF than the low-osmotic media iohexo l, iopamiro, ioversol and ioxaglate (p less-than-or-equal-to 0.001). I oxaglate caused the greatest decrease in CF of all the CM (p less-than -or-equal-to 0.001) and to a greater extent during reduced flow than d uring normal flow (p less-than-or-equal-to 0.01). In conclusion, iohex ol enriched with a balanced electrolyte solution and saturated with ox ygen had a smaller adverse effect on contractility than iohexol, iopam idol, ioversol and ioxaglate.