CARDIAC EFFECTS OF ADDING ELECTROLYTES AND OXYGEN TO IOHEXOL IN A DOG-MODEL OF CONTRAST MEDIA-INDUCED VENTRICULAR-FIBRILLATION

We investigated whether addition of a balanced electrolyte supplement and oxygen to the nonionic contrast medium iohexol reduces the risk of ventricular fibrillation (VF), and studied regional electrophysiology prior to the VF event. Twenty mi of each test solution were infused a t a rate of 0.5 ml/s into the left anterior descending coronary artery (LAD) in 8 anesthetized dogs. LAD was externally occluded during infu sion, to simulate a wedged catheter situation. ECG, hemodynamics, regi onal epicardial monophasic action potential duration (MAPD) and Ventri cular activation times (VAT) were calculated. All infusions with iohex ol caused VF within 27 a. Five of 12 infusions with iohexol + 30 mmol NaCl, 3 of 11 infusions with iohexol + electrolytes (IPE) (NaCl, KCl, CaCl2 and MgCl2) and 4 of 11 infusions with IPE with oxygen addition ( IPE + O-2) caused VF after 45 s. Iohexol did not change MAPD prior to the VF event. Iohexol + 30 mmol NaCl and the IPE solutions lengthened MAPD initially but at the time of the VF event MAPD were normalized or shortened. We conclude that electrolyte supplement to iohexol may pre vent VE probably by lengthening MAPD.