Size dependence of the end-systolic stress/volume ratio in humans: implications for the evaluation of myocardial contractile performance in pressure and volume overload.
The end-systolic stress/volume ratio is currently recognized as a relatively load-independent index of myocardial contractile performance, but its dependence on ventricular size may limit its value for interpatient comparisons. In this study, the relation between the end-systolic stress/volume ratio and left ventricular end-diastolic volume was angiographically analyzed in 104 patients with normal coronary angiograms. Eighteen patients had a normal ventricle, 24 had aortic stenosis, 18 had aortic regurgitation, 9 had mitral regurgitation and 35 had cardiomyopathy. An inverse relation between the end-systolic stress/volume ratio and left ventricular end-diastolic volume was demonstrated in the normal group (r = 0.72, p less than 0.001); subjects with a larger left ventricle had a reduced index but, presumably, the same degree of contractility as that of subjects with a smaller ventricle. Attempts to normalize values by using end-diastolic volume or body surface area were unsuccessful. A similar inverse relation was demonstrated in the aortic stenosis group (r = 0.48, p less than 0.05), probably because hypertrophy helps to keep wall stress normal or low despite progressive ventricular enlargement in these patients. The end-systolic stress/volume ratio was also inversely related to left ventricular chamber size in patients with volume overload due to aortic regurgitation (r = 0.80, p less than 0.001) and in those with cardiomyopathy (r = 0.84, p less than 0.001). However, at a given left ventricular end-diastolic volume, the end-systolic stress/volume ratio was higher in patients with aortic regurgitation than in those with cardiomyopathy, suggesting better contractile performance for a comparable degree of ventricular dilation.(ABSTRACT TRUNCATED AT 250 WORDS)
Foult
J M
JM
Service d'Explorations Fonctionnelles, Centre Hospitalier Universitaire Xavier Bichat, Paris, France.
Loiseau
A
A
Nitenberg
A
A
D000328:Adult; D001022:Aortic Valve Insufficiency / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000503:physiopathology; D009202:Cardiomyopathies / Q000503:physiopathology; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000503:physiopathology; D009200:Myocardial Contraction / Q000502:physiology*; D012016:Reference Values; D013314:Stress, Mechanical; D013318:Stroke Volume / Q000502:physiology*