[Experimental studies of the effects of contrast medium on left ventricular function (author's transl)]

The influence of contrast medium (0.63 ml/kg body weight Natrium-Methylglucamin-Jothalamat, Conray 70) on pressures and volumes of the left ventricle were studied in six anesthetized mongrel dogs (mean body weight 36 +/- 6 kg). Under closed-chest conditions radiopaque markers were implanted into the endocardium of the left ventricle by means of a special catheter via the right carotid artery. The positions of the markers were calibrated in terms of volume by injections of contrast medium during diastole (flow rate 14 ml/s). Thus it was possible to determine left ventricular volumes without additional administration of contrast medium. Before and during injection, volumes determined from the position of the markers and pressure (catheter-tip manometer) were evaluated in each cycle. After injection, the parameters were determined every minute over a period of ten minutes. Immediately after injection of contrast medium there was a short period in which the following parameters changed: decrease of ventricular systolic pressure, of mean aortic pressure, of maximal dp/dt, of minimal dp/dt, and, after a short increase, of enddiastolic pressure. About one minute after the end of injection, the parameters were about the initial values. These transitory changes were explained by the initial negative and vasodilating effect of the contrast medium. The chamber volumes and stroke volume did not change during and after injection. Because of the constant heart rate cardiac output did not change. The ejection fraction was diminished even before injection, no further changes were found. These experimental results show that, even in ventricles with reduced function, contrast medium injected with a slow flow rate during diastole only leads to small and transient changes of left ventricular hemodynamics.