SODIUM-CALCIUM RELATIONSHIPS AND CARDIAC-FUNCTION DURING CORONARY BOLUS PERFUSION - A PHYSIOLOGICAL APPROACH

The present review deals with the side-effects of contrast media (CM) on cardiac function during coronary angiography. A physiological appro ach is used to redefine existing concepts of CM osmotoxicity and chemo toxicity in terms of osmolal, ionic and molecular effects. The main id ea conveyed is that purely ionic effects are of central importance dur ing and immediately following the transit of a brief coronary bolus. I onic effects result largely from rapid transient washout of normal ext racellular ions, but are also influenced by ions present in the CM. In particular, the calcium (Ca) and sodium (Na) ions controlling cardiac function are easily affected. The myocardial Na-Ca exchange, which is mainly a physiological mechanism for cellular Ca efflux during cardia c relaxation, is therefore highlighted in detail. The importance of av oiding a potential Na-Ca mismatch is shown by examples from basic phys iology, cardiac surgery and coronary angiography and by results of exp eriments with Visipaque. In the isosmolal and isotonic CM Visipaque, w hich is based on the dimer iodixanol (320 mg I/ml), an available osmol al space is filled with an appropriately balanced supplement consistin g of NaCl (19 mM) and CaCl2 (0.3 mM).