Harold Sandler

Bio: Harold Sandler is an academic researcher from University of Washington. The author has contributed to research in topics: Stroke volume & Ventricle. The author has an hindex of 11, co-authored 11 publications receiving 4142 citations. Previous affiliations of Harold Sandler include United States Department of Veterans Affairs.

Usefulness and limitations of radiographic methods for determining left ventricular volume.

Abstract: The various methods currently being used to determine left ventricular chamber volumes from biplane angiocardiograms are described and discussed. The spatial direction and change of direction and length of the long axis of the left ventricle over the heart cycle is described. The long axis of the left ventricle is in most subjects directed approximately 20 degrees from being parallel with the frontal plane of the body and results in only slight foreshortening of the long axis of the left ventricle on films taken in the anteroposterior projection. A method is described and evaluated for determining left ventricular chamber volume from angiocardiograms taken in a single anteroposterior projection. Values for normal end-diastolic volume and systolic ejection fraction obtained by various investigators using the radiographic methods are given. The application of these radiographic methods to estimate aortic and mitral valve regurgitant flow is reviewed. Pressure-volu ne relations of the diastolic left ventricle have been determined in 176 patients and demonstrate large patient-to-patient differences of ventricular distensibility in patients with different types and durations of heart disease. Measurement of compliance of the diastolic left ventricle from the pressure-volume curves is discussed. By relating pressure and volume curves over the entire heart cycle, left ventricular pressure-volume curves can be constructed and from these the various components of pressure-volume work determined: systolic work, work done in distending the ventricle during diastole, and net work. Values obtained for these various components of ventricular work in patients with heart and valvular disease are discussed. A method for calculating wall tension and stress from measurement of chamber pressure and chamber dimensions is reviewed. Left ventricular mass can be calculated from chamber dimensions and wall thickness determined from angiocardiograms. A value of 92 ± 16 gm. has been obtained by this method in patients without left ventricular disease, and this is similar to values obtained in earlier postmortem studies. Measurement of left ventricular oxygen consumption and mechanical efficiency in patients with heart disease is discussed.

Left Ventricular Tension and Stress in Man

Abstract: A method is described for calculating tension and stress acting within the wall of the left ventricle during the cardiac cycle. This method is based upon ventricular pressure observations and measurements of left ventricular dimensions and wall thickness made from biplane angiocardiograms. To calculate wall tension and stress, it is assumed that the left ventricle can be represented as an ellipsoid of revolution with a relatively thin wall. The relative importance of ventricular pressure, volume, shape and wall thickness in determining the magnitude of wall tension and stress is illustrated and discussed.

Recommendations regarding quantitation in M-mode echocardiography: results of a survey of echocardiographic measurements.

Abstract: Four hundred M-mode echocardiographic surveys were distributed to determine interobserver variability in M-mode echocardiographic measurements. This was done with a view toward examining the need and determining the criteria for standardization of measurement. Each survey consisted of five M-mode echocardiograms with a calibration marker, measured by the survey participants anonymously. The echoes were judged of adequate quality for measurement of structures. Seventy-six of the 400 (19%) were returned, allowing comparison of interobserver variability as well as examination of the measurement criteria which were used. Mean measurements and percent uncertainty were derived for each structure for each criterion of measurement. For example, for the aorta, 33% of examiners measured the aorta as an outer/inner or leading edge dimension, and 20% measured it as an outer/outer dimension. The percent uncertainty for the measurement (1.97 SD divided by the mean) showed a mean of 13.8% for the 25 packets of five echoes measured using the former criteria and 24.2% using the latter criteria. For ventricular chamber and cavity measurements, almost one-half of the examiners used the peak of the QRS and one-half of the examiners used the onset of the QRS for determining end-diastole. Estimates of the percent of measurement uncertainty for the septum, posterior wall and left ventricular cavity dimension in this study were 10--25%. They were much higher (40--70%) for the right ventricular cavity and right ventricular anterior wall. The survey shows significant interobserver and interlaboratory variation in measurement when examining the same echoes and indicates a need for ongoing education, quality control and standardization of measurement criteria. Recommendations for new criteria for measurement of M-mode echocardiograms are offered.

Echocardiographic assessment of left ventricular hypertrophy: Comparison to necropsy findings

Abstract: To determine the accuracy of echocardiographic left ventricular (LV) dimension and mass measurements for detection and quantification of LV hypertrophy, results of blindly read antemortem echocardiograms were compared with LV mass measurements made at necropsy in 55 patients. LV mass was calculated using M-mode LV measurements by Penn and American Society of Echocardiography (ASE) conventions and cube function and volume correction formulas in 52 patients. Penn-cube LV mass correlated closely with necropsy LV mass (r = 0.92, p

Problems in echocardiographic volume determinations: Echocardiographic-angiographic correlations in the presence or absence of asynergy

Abstract: The relation of minor and major axes of the left ventricle was determined in 100 left ventriculograms performed in the right anterior oblique projection. This relation taken over a wide range of volumes was used to derive a theoretically correct equation for determination of ventricular volume by echocardiography. The final equation was: V =[7.0/2.4 +d] (D3), where V = volume and D = the echocardiographically measured internal dimension. In 12 patients without asynergy, this equation accurately and directly calculated end-systolic and end-diastolic volumes whether the left ventricle was small or large. However, in 12 patients exhibiting left ventricular asynergy the correlation between angiographically and echocardiographically determined volumes was poor. Thus, caution is recommended in the use of time-motion echocardiography to calculate ventricular volumes in patients with coronary artery disease and possible left ventricular asynergy.

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

Abstract: It is generally recognized that chronic left ventricular (LV) pressure overload results primarily in wall thickening and concentric hypertrophy, while chronic LV volume overload is characterized by chamber enlargement and an eccentric pattern of hypertrophy. To assess the potential role of the hemodynamic factors which might account for these different patterns of hypertrophy, we measured LV wall stresses throughout the cardiac cycle in 30 patients studied at the time of cardiac catheterization. The study group consisted of 6 subjects with LV pressure overload, 18 with LV volume overload, and 6 with no evidence of heart disease (control). LV pressure, meridional wall stress (sigman), wall thickness (h), and radius (R) were measured in each patient throughout the cardiac cycle. For patients with pressure overload, LV peak systolic and end diastolic pressures were significantly increased (220 plus or minus 6/23 plus or minus 3 mm Hg) compared to control (117 plus or minus 7/10 plus or minus 1 mm Hg, P less than 0.01 for each). However, peak systolic and end diastolic (sigman) were normal (161 plus or minus 24/23 plus or minus 3 times 10-3 dyn/cm-2) compared to control (151 plus or minus 14/17 plus or minus 2 times 10-3 dyn/cm-2, NS), reflecting the fact that the pressure overload was exactly counterbalanced by increased wall thickness (1.5 plus or minus 0.1 cm for pressure overload vs. 0.8 plus or minus 0.1 cm for control, P less than 0.01). For patients with volume overload, peak systolic (sigman) was not significantly different from control, but end diastolic (sigmam) was consistently higher than normal (41 plus or minus 3 times 10-3 dyn/cm-2 for volume overload, 17 plus or minus 2 times 10-3 dyn/cm-2 for control, P less than 0.01). LV pressure overload was associated with concentric hypertrophy, and an increased value for the ratio of wall thickness to radius (h/R ratio). In contrast, LV volume overload was associated with eccentric hypertrophy, and a normal h/R ratio. These data suggest the hypothesis that hypertrophy develops to normalize systolic but not diastolic wall stress. We propose that increased systolic tension development by myocardial fibers results in fiber thickening just sufficient to return the systolic stress (force per unit cross-sectional area) to normal. In contrast, increased resting or diastolic tension appears to result in gradual fiber elongation or lengthening which improves efficiency of the ventricular chamber but cannot normalize the diastolic wall stress.