Effects of ionic and nonionic contrast agents on left ventricular and extracellular fluid dynamics during angiocardiography in an infant model.

Concern for side effects of contrast materials limits the volume that can be used for angiocardiography in infants; many of these effects are related to hyperosmolality. The effects of intracardiac injections of ionic (meglumine sodium diatrizoate) and nonionic (metrizamide) contrast agents on the left ventricle and body fluids were compared in an infant model. Immediately after injection, meglumine sodium diatrizoate (MSD) caused increases in left ventricular peak systolic pressure (LVPSP) (+26 +/- 5%) (control (C) = 92 mmHg), LV dp/dt (+21 +/- 6%) (C = 2610 mmHg/sec), left ventricular end-diastolic dimension (LVEDD) (+31 +/- 5%) (C = 10.5 mm), and left ventricular end-systolic dimension (LVESD) (+28 +/- 6%) (C = 7mm). Subsequently, LVPSP and dp/dt decreased to -16 +/- 6% and -23 4 +/- 6% of control, while LVEDD and LVESD rose. Dimension changes resolved by 15 minutes. Metrizamide caused immediate increases in LVPSP (+27 +/- 4%) (C = 86 mmHg) and LV dp/dt(+25 +/- 4%) (C = 2640 mmHg/sec). These parameters never declined significantly below control levels and were at control level at 15 seconds. Initial increases in LVEDD (+17 +/- 3%) (C = 10 mm) and LVESD (+6 less than 4%) (C = 6.5 mm) with metrizamide were significantly less than with MSD (P less than 0.008). MSD caused greater and more persistent elevations of serum osmolalities than metrizamide. Differences between the two agents were accentuated during systemic hypoxemia. Thus, ionic contrast agents appear to have a greater propensity for inducing toxic cardiovascular effects in infants than nonionic agents.