During coronary angiography, some electrocardiographic changes occured due to contrast media, which do life threatening influences.

We compared the electrocardiographic changes which were induced by injection of three radiopaque contrast media during selective coronary angiography in 49 patients with chest pain. One of the contrast media was high osmolar ionic(Urografin_76) and the another was low osmolar ionic(Hexabrix) and the last was non-ionic(Ioversol). Electrocardiograms were obtained before, during and after selective coronary angiography.

The changes of S-T segment or T were decreased in non-ionic group rather than high osmolar or ionic group. And there was significant Q-Tc interval prolongation among all three groups except comparision of low osmolar ionic contrast dye and non-ionic contrast dye in left coronary angiography.

Non-ionic low osmolar contrast media was safer than high osmolar or ionic contrast medial because of lesser change of Q-Tc interval during selective coronary angiography.