Effects of contrast material on dimensions and hemodynamics of the newborn heart: a study in conscious newborn lambs.

Abstract

Injections of contrast material (Hypaque M-75%) and normal saline into the left ventricle (LV) of 1- to 3-month-old conscious lambs, during continuous monitoring of LV internal dimensions and pressures, revealed instaneous increases in LV end diastolic and end systolic volumes and LV end diastolic pressure. After contrast material, these alterations were sustained. Contrast injections were also accompanied by a mild depression in LV contractile state (dp/dt/P), systemic vasodilatation and persistent augmentation of cardiac output. The immediate effects on LV dimensions are primarily a consequence of acute volume expansion of the LV by the injection while the sustained changes likely reflect an expanded intravascular volume.