Investigative radiology
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The effects of intracoronary administration of contrast materials were investigated in conscious and anesthetized dogs prepared with pressure gauges or catheters in the left ventricle for measuring aortic pressure (P), LVP, and dP/dt, and dimension crystals on opposing endocardial surfaces of the LV for measuring LV dimensions and its first derivative dD/dt (velocity of contraction). All contrast materials were tested at a concentration of 370 mg I/ml. Biphasic responses were observed with monomeric contrast materials; direct effects occurred within the first 10 seconds after injection, while secondary or indirect effects (reflex?) ensued near the end of the first 10 seconds or in the second 10-second period (Higgins, 1978). ⋯ Several nonionic materials also have been tested in this preparation: metrizamide, P-297, and iopamidol. These materials had similar effects on LV function; each caused a slight increase or no change in indexes of LV contractile state and no change in LV dimensions. A new monacid dimer (P-286) with a lower sodium content than monomeric materials produced effects on LV function which were less deleterious than standard monomeric materials, but more so than the nonionic materials.