Left ventricular ejection time. multiple relation to physiological and biometrical data; prediction of reference standards.

The relationship between left ventricular ejection time, and physiological or biometrical data, is submitted to multivariate statistical analysis. Methodology is intended to attain three objectives: 1) to simulate a controlled-condition experiment in clinical research, by using the statistical method of multiple regression; 2) to get a wide inference of conclusions, by selecting a sample of two hundred subjects whose biological data cover a wide field; 3) to check the really prospective value of results, by applying the formula worked out in a group of a hundred subjects to another independent group of a hundred subjects. The prediction formula of ejection time takes into account: stroke volume, cardiac cycle duration, body height, sex, age, pulse pressure, blood capacity in oxygen, presence or absence of digitalis treatment or atrial fibrillation. The first aim of the formula is to better evaluate the normal relationship between considered variables. Secondarily it leads to a proposal for estimating mechanical performance of the left ventricle.