Abstract
An elementary computational formula for estimating cardiac volume and stroke volume from either M-mode or bi-dimensional echographic data is developed from an analysis of retrospective catheterization, angiographic and echographic data. The proposed equation has the form, V=0.01D12/5, where V is the cardiac volume in ml, 0.01 is a unit conversion constant and D is the ventricular dimension in mm. The new model assumes the validity of the Teichholz correction factor to the volume of an ellipsoid of revolution as an approximation of left ventricular cardiac volume.
Application of this model to retrospective echographic data reveals that the new formula enjoys an identical domain of validity as the Teichholz formula, deviating from this model by less than 1% over a range of cardiac volumes from 20 to 180ml. Comparison of this cardiac volume formula with a series of 37 echographic and catheterization measurements of stroke volume yields a correlation of r=0.95 with a standard error of S.E.=14.3ml in comparison with the Fick principle method for cardiac stroke volume. The results of this study suggest that the present expression offers a computational simplification of the Teichholz formula, facilitating modifications for other configurations while retaining this expressions favorable correlation with invasive measurements of cardiac volume.
