[Changes in the morphology of the normal left ventricle during the phases of isovolumic contraction and relaxation. Consequences on the calculation of the volume and cardiac output by cineangiocardiographic methods].

It is well known that the left ventricular volume, as measured by the cineangiographic method, decreases during the phase of isometric contraction. What is more, the cardiac index and the ejection fraction measured by this method are definitely larger than those derived from dilution methods. These discrepancies can be explained by movements of the mitral valve during the phases of isometric contraction and relaxation. The systolic ejection volume (SEV) was measured by three different methods: 1. End-diastolic volume (EDV) -end-systolic volume (ESV) ; 2. EDV - pre-filling volume (PFV) ; 3. Pre-ejection volume (PEV) - ESV. It has emerged that the results given by the methods (2) and (3) correspond closely, and differ significantly from those given by method (1); they are also close to those obtained by the dilution method. This difference seems to arise from the fact that the movements of the mitral valve during the phase of isometric relaxation are diametrically opposite to those which occur during isometric contraction; thus, when the values EDV-ESV are used in the calculation of SEV, an overestimate is made because the mitral valve is not to be found in the same position within the ventricular cavity for both values.