Electrolyte addition to nonionic contrast media. Cardiac effects during experimental coronary arteriography

Although the incidence of serious adverse effects is low during clinical coronary arteriography, life-threatening cardiovascular complications occasionally occur. Ventricular fibrillation (VF) is most often seen during contrast media (CM) injection through a wedged catheter. A simulated wedged catheter model in dogs has therefore been developed. Further, patients with heart failure are at greater risk for CM-related side effects during coronary arteriography. Thus, an acute ischemic heart failure model has been used. The present thesis was designed to investigate the cardiac electrophysiologic and hemodynamic effects of CM during selective coronary arteriography in normal and failing hearts, and in particular the role of electrolyte addition to nonionic CM. The risk of spontaneously induced VF and the arrhythmogenic mechanisms were studied when using iso-osmolal and low-osmolal CM having different contents of electrolytes, and after pretreatment with antiarrhythmic drugs. Further, effects of adding electrolytes to nonionic CM during single and fast repeated injections in normal and failing hearts were studied. Also possible effects of oxygenating CM were studied. CM injection in a wedged catheter situation had a high risk for VF. Probably, VF was due to induced regional electrophysiologic changes in ventricular activation and repolarization. Pretreatment with antiarrhythmic drugs did not prevent VF. However, addition of low concentrations of electrolytes to nonionic CM reduced the risk for VF in a wedged catheter situation. The results indicate that side-effects of CM during coronary arteriography are related mainly to the passive washout of cardiac electrolytes. Electrolyte shifts during coronary arteriography may change the myocardial Na/Ca balance and cellular calcium control. The nonionic, iso-osmolal CM iodixanol, with a balanced content of sodium and calcium and the low-osmolal, nonionic CM iohexol, also with a balanced content of electrolytes, had about the same low risk for inducing VF and presented a much lower risk for inducing VF than did iohexol and ioxaglate in a wedged catheter situation. Single injection of iohexol with a balanced eletrolyte addition induced only minimal electro-physiologic changes and was well tolerated hemodynamically. Repeated intracoronary CM injections during ischemic heart failure were associated with similar additive electrophysiologic and hemodynamic changes as when using iohexol without electrolyte supplement. Oxygenated and nonoxygenated CM presented the same risk for inducing VF. Only minor electrophysiologic and hemodynamic differences could be detected during wedged catheter injection. In conclusion, addition of key electrolytes to nonionic CM can reduce the risk of cardiac complications during coronary arteriography. Oxygenation of CM does not seem to significantly further reduce the risk.