Left Ventricular Wall Stress Calculated from One-Plane Cineangiography

Abstract

Left ventricular dimensions from routine clinical one-plane cineangiograms were combined with left ventricular pressure measurements to permit calculation of left ventricular wall stresses. The 25 patients included 12 with normal left ventricular dynamics, 6 with volume overload, 3 with outflow obstruction, and 4 with cardiomyopathy. Average stresses calculated on the basis of an ellipsoid model agreed with average values obtained from the exact solution of a thick-walled elastic ellipsoidal shell. Peak values were 150 to 625 g/cm 2 in the circular direction and 75 to 365 g/cm 2 in the longitudinal direction. A fiber-corrected stress was defined which represents a force per muscle fiber. The variation in fiber-corrected stress during the cardiac cycle may be considerably different from the variation in simple stress.The force-velocity characteristics of circular fibers for the 25 patients are presented. The data on peak wall stress overlap in the four groups of patients. Peak velocity of circumferential fiber shortening varied from 0.44 to 0.63 lengths/sec in patients with myocardial weakness and varied from 0.74 to 2.56 lengths/sec in the other patients. Contractile element velocity was determined during ventricular ejection when the rate of force change equaled zero. Contractile element velocity of shortening was 0.22 to 0.32 lengths/sec in the cardiomyopathy group and 0.50 to 1.32 lengths/sec in the other patients. ADDITIONAL KEY WORDScontractile element velocity of shortening left ventricular wall thickness cardiac muscle mechanics B The force developed by a contracting muscle is a function of the velocity of contraction. The force-velocity relation was first determined for skeletal muscle (1, 2) and more recently has also been determined in isolated cardiac muscle (3-5). The mechanical behavior of the intact heart is a complicated function of its geometry as well as of the contractile behavior of individual muscle fibers. The performance of the heart may be determined by cineangiography

Wall stress and patterns of hypertrophy in the human left ventricle.

“…One important shortcoming, however, is that we have examined an average wall stress across the entire thickness of the LV wall. More appropriate to the study of mechanisms of hypertrophy would be assessment of a "fiber-corrected stress," such as has been recently described by Falsetti, Mates, Grant, Greene, and Bunnell (32).…”

Evidence for Cardiomyopathy in Familial Diabetes Mellitus

“…Samples were taken from the free wall of the left ventricle, 1 cm above the apex at the anticipated site of venting; these were 6-8 mm long and 1-2 mm in diameter. This was limited to patients with pure mitral stenosis because the left ventricle does not enlarge and frequently exhibits normal function in adults with this disease (33,34 To assess whether the lipid composition of the ventricle was altered in a manner similar to the diabetic animal model (4), 1-g samples of grossly normal ventricle were taken from the same sites as the tissue for morphological examination. After trimming, these were analyzed for triglyceride (35), phospholipid (36), and cholesterol (37).…”

Quantitative comparison of the force-interval relationships of the canine right and left ventricles.

“…Several investigators have developed quantitative models which relate the pressure generated in a ventricular chamber to the force generated by its constituent muscle fibers (Falsetti et al, 1970;Anderson et al, 1974; also see Yin, 1981, for a recent review). Most of them can be expressed in the following form:…”