[Effects of contrast media on left ventricular function. Comparison with iohexol and diatrizoate]

To investigate the effects of a low-osmolar nonionic (Iohexol: I) and a high osmolar ionic contrast media (Diatrizoate: D) on left ventricular (LV) function after left ventriculography (LVG), we studied 19 patients with coronary artery disease (I: 9 cases, D: 10 cases) during diagnostic cardiac catheterization. The first LVG was performed by injecting 40 ml of I or D at a rate of 12 ml/sec, measuring simultaneous LV pressure with a catheter tip manometer (Millar instruments). At 4 minutes after the first LVG, we repeated hemodynamic measurements and LVG. Single-plane volumes (RAO 30 degrees) were calculated every 20 msec (50 frame/sec) using the area-length method. LV systolic function was estimated by ejection fraction (EF), ratio of end-systolic pressure to end-systolic volume (ESP/ESV) and maximal (+)dP/dt. LV relaxation was assessed by the time constant (T) of LV pressure decay. LV diastolic compliance was evaluated by the diastolic pressure-volume (PV) relationship. Results. 1. LV end-diastolic pressure and volume were augmented more significantly in D than in I group, probably due to the difference of their osmolarity. 2. EF increased in D group with increase of LV preload after the first LVG, but didn't change in I group. ESP/ESV and maximal(+)dP/dt were not changed after the first LVG in both groups. 3. LV isovolumic relaxation remained unchanged with I and D. 4. LV diastolic PV relation curve shifted upward more in D than I group. We conclude that Iohexol has less influences on LV function than Diatrizoate and may be used in high risk patients.