Cardiac Effects of Adding Electrolytes and Oxygen to Iohexol in a Dog Model of Contrast Media-Induced Ventricular Fibrillation

Abstract

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 ml of each test solution were infused at a rate of 0.5 ml/s into the left anterior descending coronary artery (LAD) in 8 anesthetized dogs. LAD was externally occluded during infusion, to simulate a wedged catheter situation. ECG, hemodynamics, regional epicardial monophasic action potential duration (MAPD) and ventricular activation times (VAT) were calculated. All infusions with iohexol caused VF within 27 s. 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 + O₂) 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 prevent VF, probably by lengthening MAPD.