Quantitative evaluation of left ventricular function by radiographic techniques.

Abstract

since these initial contributions to quantitative angiocardiography, the principles and techniques have remained generally unchanged and are testimony to the clear understanding of ventricular dynamics shown by these investigators. Biplane radiographic equipment and filming devices, direct manual measurements from the ventriculogram, geometric assumptions, and extensive mathematical calculations were basic to these methods for estimation of left ventricular volume. The studies of Arvidsson and Dodge were performed using large cut-films which had filming speeds of six biplane film pairs per second. Chapman and colleagues photographed the anteroposterior and lateral fluoroscopic screens in early experimental and clinical studies. The duration of filming was 3 to 5 sec. TechniqueCurrently utilized radiographic equipment for quantitative angiocardiography includes biplane large film changers with 6 to 12 film pairs per second, biplane cinefluorographic units with filming speeds of 30 to 60 frames per second, and single plane cinefluorographic units. The large film ventriculograms allow a limited number of sequential observations but produce superior clarity of the opacified ventricle. The left ventricle and left atrium can be demonstrated. Cineangiograms may not provide the sharpness of the margins of the opacified chamber that can be obtained with large films but provide more sequential volume observations per unit of time. Moderately dilated left ventricles may not be completely contained within the cine frame.Not only is the radiographic technique important for delineation of the opacified left ventricular chamber, but the site of injection of contrast material influences the quality of the image of the opacified ventricle that is used for tracing

The law of Laplace. Its limitations as a relation for diastolic pressure, volume, or wall stress of the left ventricle.

“…The differences between the Valanis-Landel and Rivlin-Saunders predictions also illustrate the limitations of the common practice (Glantz, 1976;Rackley, 1976;Fester and Samet, 1974;Mirsky and Parmley, 1973;Lafferty et al, 1972;Diamond et al, 1971) of attempting to deduce myocardial stressstretch behavior from observed LV P-V behavior. Just as two (or more) stress-stretch relations can have virtually the same uniaxial stress-stretch behavior but lead to very different P-V and P-S relations, so too can many stress-stretch relations lead to the same P-V behavior but have very dissimilar uniaxial stress-stretch behavior and lead to different P-S relations.…”

“…This interrelationship is a mathematical model which is used to predict wall stress from observed pressure and geometry (Ford, 1976;Rackley, 1976;Mirsky, 1974;Spotnitz and Sonnenblick, 1973;Streeter andHanna, 1973a, Gould et al, 1972;Falsetti, et al, 1970Falsetti, et al, ,1971Burns et al, 1971) and stressstrain relations for myocardial tissue from either LV pressure-volume behavior (Glantz, 1976;Rackley, 1976;Fester and Samet, 1974;Mirsky and Parmley, 1973;Lafferty et al, 1972;Diamond et al, 1971), or stress-strain relations of papillary muscle. It also is used to assess myocardial contractility (Falsetti et al, 1971;Hugenholtz et al, 1970) and predict LV volume from pressure (Burns et al, 1971) or vice versa (Sonnenblick and Strobeck, 1977).…”

Left ventricular performance and regional blood flows before and after ductus arteriosus occlusion in premature lambs treated with surfactant.

“…Other investigators using Doppler methods have suggested reduced diastolic cerebral blood flow velocity in premature infants with patent ductus arteriosus.37 These observations are consistent with our finding of significantly decreased cerebral blood flow in the lambs before occlusion of the ductus arteriosus. The association of cerebral ischemia and cerebral hemorrhage has been well documented in the premature infant.38 19 The contribution of cerebral hypoperfusion or ischemia secondary to left-to-right ductal shunting in the pathogenesis of cerebral hemorrhage remains to be evaluated. 39 The mechanical and autoregulatory factors that influence the quantity and distribution of coronary blood flow are complex.40-3 The increased myocardial blood flow after occlusion of the ductus arteriosus was most likely associated with a diminished coronary vascular "resistance," for transcoronary perfusion pressure changed minimally.42 43 Furthermore, the rate-pressure product, which correlates well with instantaneous myocardial oxygen consumption (MVO2) in sheep and newborn lambs, did not change after occlusion (table 1, fig.…”

Acute hemodynamic responses to sublingual nifedipine: dependence on left ventricular function.

“…Nineteen patients received nifedipine and 13 received placebo. No change occurred in any variable after placebo.…”