MECHANICAL AND BIOCHEMICAL CARDIAC DISTURBANCES INDUCED BY BOLUS ADMINISTRATION OF IODINATED CONTRAST-MEDIA AND NONIODINATED SOLUTIONS

RATIONALE AND OBJECTIVES. Bolus injection of iodinated contrast media has been observed to alter myocardial mechanical function, but the con sequences on cellular metabolism are poorly documented, Modifications of metabolic parameters (intracellular pH as well as adenosine triphos phate [ATP], phosphocreatine, and inorganic phosphate contents) and of mechanical function (coronary flow, heart rate, and left ventricular developed pressure) were simultaneously recorded on isolated rat heart s perfused over 2 minutes with a high osmolality contrast medium (HOCM ) and two low osmolality contrast media (LOCM). In addition, the effec ts of test solutions mimicking the ionicity and the osmolality of LOCM were evaluated. METHODS. Isovolumic rat hearts were submitted to a 2- minute perfusion with oxygenated Radioselectan, Hexabrix, and Omnipaqu e (320 mgI/mL) at 37 degrees C. Metabolic parameters were obtained by P-31 nuclear magnetic resonance spectroscopy at 4.7 Tesla, Noniodinate d ionic and nonionic solutions also were tested for comparison. RESULT S. HOCM irreversibly impairs the metabolic and mechanical functions, w hereas ionic and nonionic LOCM and test solutions induce transient car diac failure but no permanent alteration of the metabolic or mechanica l parameters. CONCLUSION. In this protocol, HOCM causes irreversible d egradation of the biochemical status and definitive heart failure, whe reas ionic and nonionic LOCM only induce transient changes of myocardi al function, Treatments with the LOCM do not induce any modification o f the ATP and PCr content, and, at the end of the reperfusion period, the mechanical function is equivalent to that of control hearts, Depen ding on the ionic content of the solutions (iodinated or not), the evo lution of the ventricular developed pressure after injection differs f rom one group of hearts to another, From these experiments, it is conc luded that ionic imbalance and viscosity of the solutions, rather than iodine content or hyperosmolality, should be considered the causes of heart failure.