Reduced risk of ventricular fibrillation by balancing sodium, calcium, potassium and magnesium added to nonionic contrast media. An investigation in the isolated rabbit heart.

The effect of addition of calcium, potassium and magnesium to iohexol (350 mg I/ml) enriched with 30 mM sodium was investigated with regard to ventricular fibrillation (VF) in isolated rabbit hearts. Enriching iohexol containing 30 mM sodium with increasing amounts of calcium (0-1.2 mM) caused an increase in the frequency of VF. Increasing amounts of potassium (0-3.8 mM) to iohexol with 30 mM Na + 0.15 mM Ca + 0.1 mM Mg reduced the risk of VF. However, this protective effect of potassium on VF was reduced if magnesium was removed from the test solution. Furthermore, increasing amounts of magnesium (0-1.2 mM) to iohexol with 30 mM Na + 0.15 mM Ca + 0.4 mM K led to an increased frequency of VF. Iohexol with 30 mM Na + 0.3 mM Ca + 0.9 mM K + 0.3 mM Mg caused no VF. It is of interest to add multiple cations to sodium-containing nonionic media to improve cardiac contractility following coronary perfusion. The present study indicates that it is possible to enrich iohexol 350 mg I/ml + 30 mM Na with calcium, potassium and magnesium in small amounts, and balanced with respect to each ion, without changing the risk of VF.