[Dependency of heart rate on contrast medium temperature and coronary angiographic severity in coronary angiography].

The influence of temperature (24 degrees C, 34 degrees C) of contrast medium (Urografin 76) on sinus frequency was studied during diagnostic coronary arteriographies in patients with different degree of coronary heart disease. 1. Injection of contrast medium in both coronary arteries was associated with a decrease of heart rate by 4.1-12.8%. There was no significant difference between the decrease in heart rate when injecting the contrast medium into the right or into the left coronary artery. 2. The change in heart rate during left and right coronary arteriography was independent from the temperature of the contrast medium (24 degrees C, 34 degrees C). Therefore, coronary arteriography made at 25 degrees C does not produce significant changes in heart rate when compared to coronary arteriography performed with contrast medium which has been warmed by 10 degrees C (34 degrees C). 3. Heart rate was decreased parallel to the increase in severity of coronary artery stenosis. The possible underlying mechanisms (changes in coronary artery perfusion pressure, hypoxic bradycardia) are being discussed.