Echocardiographic observations of hemodynamic differences between mitral and aortic regurgitation. Quantitative interpretation of functional state by multivariate statistical analysis.

The hemodynamic differences between chronic mitral (MR: n = 30) and chronic aortic regurgitation (AR: n = 37) at various functional stages were investigated by echocardiography and compared with the findings in healthy subjects (n = 20). The ordinary statistical analysis revealed that in MR myocardial contractility and afterload to the left ventricle (LV) well preserved even at the stage of decompensation, while in AR the contractility deteriorated and the afterload was elevated even at the asymptomatic stage. By the multivariate statistical analysis, the functional differences and characteristics of the 2 diseases were clarified with 2 statistic factors derived from 6 hemodynamic parameters (LV end-diastole and end-systolic dimensions, mean velocity of circumferential fiber shortening, LV mid-systolic stress, LV mass, and left atrial dimension). In the differentiation between the 2 diseases by the multivariate analysis, left ventricular size tended to be smaller, contractility was preserved and loading of the left atrium was increased in MR more than in AR. Furthermore, a quantitative system which could explain the functional state by these echocardiographic parameters was derived from this multivariate analysis. The functional states was found to be strongly affected by LV end-systolic dimension and left atrial dimension. This quantitative method of determining the functional state, along with an accurate assessment of cardiac symptoms, provides a useful guideline for the clinical evaluation of the 2 diseases.