Quantification of valvar regurgitation by cardiac gated pool imaging.

Fifty patients with aortic and/or mitral regurgitation underwent gated pool imaging and cardiac catheterisation to quantify the severity of valvar regurgitation. Gated pool imaging was performed in the left anterior oblique projection and an estimate of regurgitant fraction derived by comparison of the left ventricular to right ventricular stroke volume expressed as a ratio. In 17 normal subjects the stroke volume ratio averaged 1 -07±O0 11. Angiographic regurgitant fraction was derived from measurement of total and forward stroke volume. The patients were divided into four groups. Group 1 consisted of 15 patients with moderate to severe aortic regurgitation, group 2 of 14 patients with moderate to severe mitral regurgitation, and group 3 of eight patients with severe combined aortic and mitral regurgitation. Comparison of gated and angiographic regurgitant fraction showed good correlation in each of these groups. Group 4 consisted of 13 patients. Seven had mixed aortic valve disease and six mixed mitral valve disease; correlation between the two techniques was good in the latter but poor in the former. To assess the reproducibility of gated pool imaging, 15 patients with either aortic or mitral regurgitation underwent a second study. The two results were closely comparable. To evaluate the influence of impaired left ventricular function on stroke volume ratio, 33 patients with varying degrees of left ventricular dysfunction and no angiographic evidence of valvar regurgitation underwent gated pool imaging. The ejection fraction in this group varied between 0O08 and 0O68. The stroke volume ratio averaged 1 12±018 and showed no relation to the ejection fraction. Gated pool imaging is a reliable and reproducible technique for the quantification of valvar regurgitation and is not influenced by the degree of left ventricular dysfunction. The method may be less reliable in patients with mixed aortic valve disease and in the quantification of minor degrees of