Study on Left Ventricular Contractility in Chronic Valvular Heart Disease of Various Volume Load(With Reference to End Systolic Pressure-Volume, Stress-Volume Relations)

摘要

Authors analysed systolic pressure-volume-stress relations by combined echo-pressure-cineangiographic measurement in 10 normal subjects(Group I) and 37 patients with chronic valvular heart diseases. Patients with chronic valvular heart diseases were divided into 3 groups : Group II ; mitral stenosis(n=9), Group III ; mitral stenosis with aortic regurgitation(n=19). The aims of this study are to find useful left ventricular(LV) contractility indices and evaluate left ventricular contractility at various volume loading states. Studied LV contractility indices were maximal elastance of isovolumic contraction(Eiso), endsystolic pressure-volume ratio(Ees) and slope of regression line in late systolic stress-volume loop(A). Eiso was estimated using an isovolumic contraction model of Sunagawa and A was analysed in a single ejecting beat. Endsystolic volume index(ESVI), end diastolic volume index(EDVI), stress at peak pressure(Speak), cardiac index, Vmax, mean Vcf and ejection fraction were determined also. The obtained results were as follows. 1) Significant correlations were found in whole group(n=47) between Eiso and Ees(r=0.88, P 2) Significant correlation between A and cardiac index was noted in Group I+II+III(n=28, r=0.48, p 3) In Group II(patients with mitral stenosis), cardiac index* and EDVI* and stress at peak pressure** were decreased significantly(*:p**:p 4) In Group IV(patients with amitral regurgitation with or without aortic regurgitation), **EDVI and ESVI** were increased while Eiso**, Ees, Vmax*, mean Vcf* and cardiac index** were decreased significantly. But ejection fraction and A were not decrease. These findings suggested that ejection fraction and A may not be decreased at volume overload, despite of impaired left ventricular contractility. In summary; Eiso or Ees was evaluated as an useful contractility index which appeared not to be influenced by various volume loading state, while eiection fraction and A to be influenced. Patients with mitral stenosis as a group have reduced cardiac performance which is not due to impairment of left ventricular contractility(muscle function) but to reduced preload.