Effect of an anterior wall motion abnormality on the results of single-plane and biplane left ventriculography

Abstract

Although the biplane area-length method would be optimal for all left ventriculograms, 2 contrast injections are needed in laboratories with singleplane imaging equipment. The purpose of this study was to develop practical guidelines to identify the need for biplane left ventriculography in laboratories with single-plane equipment. From a retrospective analysis of 91 consecutive biplane ventriculograms (group 1), guidelines were identified that predicted when the ejection fraction calculated by the biplane method would differ significantly from the single-plane value. These guidelines were derived from information immediately available to the operator in the laboratory at the time of the procedure. Patients in group 1 were divided into 3 subgroups: biplane exceeding single-plane ejection fraction by ≥0.05 (n = 20); singleplane exceeding biplane ejection fraction by ≥0.05 (n = 14); and ejection fractions within ±0.04 by the 2 methods (n = 57). By multivariate analysis, the only predictor of a higher ejection fraction calculated by the biplane method was an anterior wall motion abnormality. This finding was tested prospectively in a separate group of 60 patients (group 2). Left ventriculograms in group 2 patients were stratified before analysis by the presence or absence of an anterior wall motion abnormality. In patients with anterior wall motion abnormalities, the biplane ejection fraction was greater than the single-plane value by 0.05 ±0.04 (range −0.03 to +0.15). In contrast, this difference in patients without anterior wall motion abnormalities was −0.01 ± 0.04 (range −0.09 to +0.06; p < 0.01). Therefore, in laboratories where only single-plane imaging is available, these data define a practical way to determine if a separate contrast injection in the left anterior oblique view would likely result in a higher value for the ejection fraction calculated by the biplane method.