ECG abnormalities during excretory urography: the effect of stress

ECG alterations occurring during IV infusion of contrast agents have been well documented, although the specific causes of these alterations are unknown. Stress and anxiety have been considered important factors, but no prospective evaluation of their impact on ECG alterations has been reported. In order to separate ECG changes resulting from anxiety associated with the procedure itself from those caused by the contrast agent, ECG monitoring was done during IV urography, first when patients were given saline and then again during and after contrast infusion. In both circumstances, the patients were told that they were being given contrast material. One hundred fifty patients undergoing infusion excretory urography with meglumine diatrizoate were studied. Preliminary 12-lead ECGs identified those with initially normal (71) and abnormal (79) tracings. Lead II rhythm strip ECGs were then obtained at 1 and 3 min during a saline infusion and again during contrast infusion; final 12-lead ECGs were done after the contrast infusion. During contrast infusion, PR prolongation (greater than 0.02 sec) occurred in 44% of patients, a change in heart rate (greater than +/- 10 beats/min) occurred in 26%, and benign arrhythmias (premature atrial and ventricular contractions, less than 5/min) occurred in 9%. Saline alone caused no statistically significant ECG alterations (only a single instance of premature atrial contractions). The hypothesis that stress or anxiety may adversely affect ECG reactivity in IV urography is unproved. Although we do not offer proof that it cannot occur, we found no evidence in a study of 150 patients to confirm that stress is an important factor. Only the contrast agent, not saline, produced measurable ECG changes during urography.