Cardiovascular reactions to myelography with watersoluble contrast media

Summary Arterial blood pressure and heart rate were recorded for 5 to 7 h during myelography with iothalamate meglumine and metrizamide in 23 rabbits. After 0.6 ml iothalamate meglumine containing 280 mg I/ml a significant decrease in blood pressure and signs of circulatory failure were found. After identical doses of iothalamate meglumine to 0.4 ml containing 140 mg I/ml no significant fall in blood pressure was recorded. A decrease of blood pressure was always accompanied by a decrease of heart rate. Arterial blood pressure and heart rate during experimental myelography are suggested as useful variables in the evaluation and comparison of new contrast media for myelography.