Hemodynamic and electrocardiographic consequences of high- and low-osmolality contrast agents for left ventricular angiography.

The cardiovascular effects of two nonionic contrast agents with low osmolality (iohexol and metrizamide) were compared with one standard ionic, high-osmolality contrast agent (metrizoate) used for left ventricular (LV) angiography in patients with coronary heart disease. Metrizoate induced a marked elevation of LV end-diastolic pressure and LV systolic pressure and an increase in cardiac output after a delay of a few minutes. All these changes were significantly less severe with iohexol and metrizamide. Hypotension occurring 30 sec after LV angiography was observed only with use of metrizoate. All agents increased heart rate, but the increase after metrizoate was significantly more pronounced and prolonged. The PQ and QT interval was prolonged only by metrizoate. The subjective symptoms were significantly more marked with metrizoate than with the two other agents. Thus the new nonionic contrast agent iohexol and metrizamide produced markedly less hemodynamic and electrocardiographic disturbance than the ionic agent metrizoate.