Influence of arteriographic contrast media on the Na+/Ca++-ratio in blood.

To investigate the basis of cardiodepressive side effects in coronary arteriography, the isolated effects of different contrast media on electrolyte levels in blood (and blood fractions) were quantified in vitro. Due to their sodium content and calcium chelation, ionic media cause an imbalance in the extracellar Na+/Ca++-ratio that determines myocardial contractility. Ca++-chelation exceeded that due to stabilizing additives indicating a binding by the contrast agents themselves. The amount of calcium bound varied with different media and was greatest with Renografin. It is suggested that the degree of Na+/Ca++-imbalance in blood explains the extent of acute cardiodepression.