Incidence of ventricular fibrillation during left coronary arteriography in pigs:: Comparison of a solution of the nonionic dimer iodixanol with solutions of five different nonionic monomers

Background: Solutions of iodine contrast media (CM) used for selective coronary arteriography (CA) should have minimal propensity to cause ventricular fibrillation (VF). Commonly used CM for CA are nonionic monomers or dimers. Purpose: To compare VF propensity of ready-to-use solutions of one nonionic dimer, iodixanol, and five nonionic monomers, iobitridol, iopamidol, iomeprol, iopromide, and ioversol. Material and Methods: Twenty milliliters of each CM was injected into the left coronary artery (LCA) through an inflated balloon catheter (0.5ml/s) in 14 pigs; the longest period of injection was 40s. If VF occurred before 40s, the injection was stopped and the heart was defibrillated. After VF, there was a delay of 40min before the next injection. Hemodynamic parameters and vector electrocardiography (VECG) were monitored. A CM with a lower frequency of VF and a longer period between start of injection and start of VF was considered to have a lower VF propensity. Results: Following 14 injections, each of the five nonionic monomers caused 14 VF, whereas iodixanol caused three VF (P0.01). When VF occurred after iodixanol, it occurred later than after the other CM (P0.001). Iodixanol caused less prolongation in QRS time (P0.01) and QTc time (P0.05) than the other CM. Prolongations in QRS and QTc times caused by CM parallel the VF propensities of the CM. Conclusion: Ready-to-use solutions of the dimer iodixanol have lower VF propensity than solutions of the five monomeric CM. This is related to the fact that the solutions of the dimer iodixanol have lower osmolality, higher viscosity, and higher concentrations of NaCl and CaCl2 than solutions of the five monomers.