Experimental Assessment of Technique for Measurement of Valvular Regurgitation by Constant Infusion of Indicator

Abstract

The continuous infusion of indicator into the left ventricle at a constant rate, with comparison of indicator concentration in aortic and left atrial blood at equilibrium prior to recirculation, is theoretically a valid method for measurement of mitral regurgitation. When assessed in dogs with constantly metered left ventricular-atrial regurgitation, however, the method failed to measure regurgitation accurately and yielded values which, in general, were well below the true ones. The failure of the method appeared to be due to incomplete dispersion of dye in the ventricle and limited distribution of regurgitated blood within the atrium. Despite differences between the animal preparation and naturally occurring mitral regurgitation, the study casts doubt on the quantitative reliability of data on valvular regurgitation in man obtained by indicator methods utilizing left ventricular injection and left atrial sampling.