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Biomedical subjects

W L Henry

Publications and source records attributed to W L Henry.

At least 91 records · Page 5Linked to original sources
PubMed1983

Evaluation of dilated cardiomyopathy by pulsed Doppler echocardiography.

The ability of pulsed Doppler echocardiography to identify patients with left ventricular systolic dysfunction was evaluated in 12 patients with dilated (congestive) cardiomyopathy. A range-gated, spectrum analyzer-based Doppler velocimeter was used to record blood flow velocity in the ascending aorta and main pulmonary artery. The following blood flow velocity parameters were measured or derived: peak flow velocity, acceleration time, average acceleration, deceleration time, average deceleration, ejection time, and aortic flow velocity integral. Doppler blood flow velocity data in the cardiomyopathy patients were compared to data from 20 normal subjects. Measurements from the ascending aorta revealed that peak aortic flow velocity discriminated between cardiomyopathy patients (mean 47 cm/sec, range 35 to 62) and normal subjects (mean 92 cm/sec, range 72 to 120) with no overlap in data (p less than 0.001). Aortic flow velocity integral was also able to separate the patients with dilated cardiomyopathy (mean 6.7 cm, range 3.5 to 9.1) from normal subjects (mean 15.7 cm, range 12.6 to 22.5) with no overlap in data (p less than 0.001). Although mean values for average aortic acceleration and aortic ejection time were also significantly different (both p less than 0.005), there was some overlap between the two groups. Pulmonary artery blood flow studies demonstrated significantly increased average acceleration, as well as decreased ejection time (both p less than 0.05), but no difference in average deceleration or peak flow velocity in cardiomyopathy patients compared to normals. Compared to pulmonary flow measurements, aortic Doppler flow velocity measurements allowed better separation of cardiomyopathy and normal groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

The use of Doppler flow velocity measurement to assess the hemodynamic response to vasodilators in patients with heart failure.

To determine if the hemodynamic response to vasodilator therapy can be assessed noninvasively by pulsed Doppler velocimetry, we compared the hemodynamic changes after treatment to changes in Doppler aortic blood flow measurements. The relationship between the absolute values and percent changes of invasively measured systemic vascular resistance (SVR) and stroke volume (SV) and Doppler-measured peak flow velocity (PFV), left ventricular ejection time (ET) and flow velocity integral (FVI) were evaluated. Measurements were made during 18 drug interventions in 13 patients treated with vasodilator agents for congestive heart failure (CHF). A poor correlation was found between the absolute values of either SVR or SV and the absolute values of each of the three Doppler aortic blood flow indexes studied. In contrast, a good correlation was found between percent changes in aortic PFV and in SVR (r = -0.89), and between percent changes in Doppler aortic FVI and in SV (r = 0.88). The correlation between percent changes in SVR and FVI revealed an r value of -0.65, while the correlation between percent changes in SVR and in ET showed an r value of -0.15. Percent changes in SV and either PFV or ET correlated with r values of 0.75 and 0.70, respectively. We conclude that Doppler aortic blood flow measurement can be used to assess quantitative changes in SVR and SV after vasodilator therapy. These findings suggest that it may be useful for evaluating vasodilator drug therapy in patients with CHF.

Adult↗
PubMed1983

Cardiac output by thermodilution technique. Effect of injectate's volume and temperature on accuracy and reproducibility in the critically Ill patient.

We compared determinations of cardiac output using various combinations of injectate volumes and temperatures to results obtained with 10 ml of iced (0 degrees C) injectate (standard technique) in 33 critically ill patients. The use of a 10-ml injectate at room temperature resulted in comparable reproducibility (12.7 vs 10.8 percent; not significant) and a small and nonsignificant error (-0.013 +/- 0.543 L/min). Five milliliters at room temperature resulted in markedly decreased reproducibility (17.9 vs 8.9 percent; p less than 0.05); however, the error associated with the technique was still not significant (0.136 +/- 0.829 L/min). When a 5-ml injectate at 0 degrees C was used, a reproducibility comparable to that of 10 ml at 0 degrees C was obtained (12.3 vs 7.5 percent; not significant). The results underestimated values obtained with 10 ml at 0 degrees C (-0.360 +/- 0.857 L/minute); however, the difference did not reach statistical significance. The use of 3 ml at 0 degrees C was associated with a substantial increase in variability, with a coefficient of variation of 32.0 percent (10.4 percent for 10 ml of iced injectate; p less than 0.01); however, the differences between the average value of cardiac output obtained with this technique and the standard technique were only minimal (error, -0.063 +/- 0.455; not significant). We reached the following conclusions: (1) the use of 10 ml at room temperature and 5 ml at 0 degrees C as the indicator for thermodilution determinations of cardiac output results in small and insignificant differences in reproducibility and accuracy from the standard technique; (2) five milliliters at room temperature and 3 ml at 0 degrees C are associated with markedly decreased reproducibility; however, the error in values for cardiac output obtained with these techniques is not statistically significant; and (3) the ability to use injectate at room temperature and in small volume should substantially simplify the technique, lowering its cost, and should prevent volume overloading.

Adult↗
PubMed1982

Diabetic gangrene in black patients.

We reviewed diabetic gangrene in 104 American blacks and found that the clinical features were similar to those reported for the general diabetic population. We observed, however, that there was a significant association of hypertension with above-knee and bilateral amputations in our patients (P less than .001 and .01, respectively), and that the mean blood pressure of the bilateral amputees (124.5 +/- 3.8 mm Hg) (SEM) was significantly higher (P less than .005) than that of the unilateral amputees (114.4 +/- 1.7 mm Hg). There results suggest a strong association of hypertension with far-advanced occlusive vascular disease of the lower limbs. Moderately severe anemia (hematocrit 20% to 30%) was associated significantly with primary above-knee amputation and mortality (P less than .02 and .05, respectively). Mortality resulted mostly from mixed causes (cardiopulmonary failure, uremia, sepsis, diabetic coma). The dead patients had significantly increased prevalence of cardiac disease (P less than .02), higher frequency of above-knee amputation (P less than .01), and a duration of diabetes (17.4 +/- 2.8 years) significantly longer (P less than .025) than that of the surviving patients (12.0 +/- 1.0 years).

Adult↗
PubMed1981

Echocardiographic abnormalities in chronic alcoholics with and without overt congestive heart failure.

To assess the type and prevalence of cardiac abnormalities in heavy drinkers with and without overt congestive heart failure, M mode echocardiography was performed in 11 symptomatic chronic alcoholics with dilated (congestive) cardiomyopathy and in 22 asymptomatic chronic alcoholics. Echocardiographic data in both groups were adjusted for age and body surface area using previously derived regression equations. All 11 symptomatic patients had a significantly decreased left ventricular percent fractional shortening (mean 14 percent, normal range 28 to 44) along with significant increases in left ventricular systolic and diastolic dimensions (mean increases of 105 and 48 percent above normal, respectively), left atrial dimension (mean increase 21 percent) and estimated left ventricular mass (mean increase 105 percent). Among the 22 asymptomatic patients, 15 (68 percent) demonstrated significant increases in at least one of the following echocardiographic variables: left ventricular mass, left ventricular dimensions, septal and left ventricular wall thicknesses, and left atrial dimension. Asymptomatic patients could be classified into two subgroups: (1) those with a left ventricular diastolic dimension less than 10 percent above the normal predicted value and an increased left ventricular wall thickness to radius ratio (mean increase 16 percent above normal) and upper normal percent fractional shortening, and (2) those with a left ventricular diastolic dimension 10 to 24 percent above normal and a slightly subnormal thickness to radius ratio and lower normal percent fractional shortening. Echocardiographic abnormalities in asymptomatic chronic alcoholics did not correlate with the presence or absence of auscultatory abnormalities on physical examination and appear to reflect an earlier stage in the spectrum of alcoholic disease before the development of dilated cardiomyopathy.

Adult↗
PubMed1981

Insulin binding and degradation by human erythrocytes at physiological temperature.

When evaluated at 15 C, insulin binding to human erythrocytes is similar to that of human adipocytes fibroblasts, monocytes and placental membranes. At 37 C, however, both insulin binding and degradation by human erythrocytes have a unique character. At this temperature, by the end of the first 30 minutes, erythrocyte specific insulin binding is 3 to 4% of the total available insulin. This percentage of binding remains until the end of the first hour, then for the next four hours, increases linearly to 24%. Intact erythrocytes had negligible degradation of the free 125I-insulin but 56% of the 125I-insulin associated with the erythrocytes was degraded after five hours of incubation at 37 C. The degradation of the bound insulin was determined to be an intracellular property of erythrocytes. This degradation may be the mass action driving force responsible for the increased association of 125I-insulin observed after one hour of incubation. On the other hand, erythrocyte ghosts reached a steady state with 2% of the 125I-insulin bound after 1.5 hours of incubation at 37 C. More than 94% of the bound and free insulins were intact after 5 hours of incubation. These observations indicate, for the first time, that erythrocyte insulin degrading activity is localized inside the cells, not in their membranes, and that the human erythrocyte with its insulin receptors may be one of the important cell types in the metabolism of insulin.

Erythrocyte Membrane↗
PubMed1980

Observations on the optimum time for operative intervention for aortic regurgitation. I. Evaluation of the results of aortic valve replacement in symptomatic patients.

Fifty consecutive patients undergoing aortic valve replacement for isolated aortic regurgitation were studied prospectively by echocardiography, electrocardiography and cardiac catheterization. Good quality echocardiograms were obtained in 49 of the 50 patients. Left ventricular (LV) dilatation was present in all 49 patients. LV systolic function, as assessed by echocardiographic percent fractional shortening, was normal in many patients but was moderately to severely reduced (less than 25%) in 14 patients (29%). Echocardiographic studies 6 months postoperatively revealed significant reductions in LV end-diastolic dimension (73.8 mm vs 58.7 mm; p less than 0.01), and serial echocardiographic studies early and late after operation revealed that the decrease in LV size had occurred by the time of the early study (8-22 days postoperatively), with little additional change thereafter. Operative deaths occurred in three of the 49 patients (6%). Eight of the 49 patients (16%) died of congestive heart failure (CHF) after hospital discharge at times ranging from 5-43 months after operation. Preoperative echocardiographic measurements of the LV end-systolic dimension and percent fractional shortening were strongly associated (p less than 0.01) with these late CHF deaths. Preoperative LV end-systolic dimension greater than 55 mm and fractional shortening less than 25% identified the high-risk group: nine of 13 patients (69%) in this group died either at operation or subsequently from CHF. In contrast, of 32 patients with LV end-systolic dimension less than 55 mm, only one died at operation and one died late from CHF. Thus, the population at high risk of late death from CHF was identified before operation by echocardiography.

Adult↗
PubMed1980

Evaluation of aortic valve replacement in patients with valvular aortic stenosis.

Echocardiographic and hemodynamic studies were obtained in 42 consecutive patients undergoing aortic valve replacement for isolated aortic stenosis. Concentric left ventricular (LV) wall thickening, the most common preoperative abnormality, occurred in 95% of patients. LV dilation with reduced fractional shortening was noted in approximately 25% of patients but was severe in only one patient. Six months after operation, LV wall thickness had decreased on average but had not returned to normal and fractional shortening was unchanged. Repeat measurements in 13 patients an average of 37 months after operation were unchanged compared with measurements made 6 months after operation. When patients were subdivided into those with LV dilatation and those without, we found that patients with dilated ventricles preoperatively had a greater decrease in LV internal dimension and mass than those without preoperative dilatation. The patient data also were examined for possible association with mortality. One operative (2%) and five late cardiac (13%) deaths occurred. No preoperative or 6-month postoperative echocardiographic or hemodynamic measurement was strongly associated with these deaths, nor were any late deaths due to congestive heart failure. Compared with preoperative measurements in symptomatic patients who were operated for isolated aortic regurgitation, patients with aortic stenosis had smaller left ventricles with less depression of systolic function, as well as less aortic root and left atrial dilatation. Our data do not support the concept that the aortic valve should be replaced before the onset of symptoms to prevent irreversible LV damage in patients with isolated aortic stenosis.

Adult↗
PubMed1980

Echocardiographic measurements in normal subjects from infancy to old age.

Echocardiographic data from 92 younger normal subjects (1 month to 23 years of age) and 136 older normal subjects (20-97 years of age) were pooled and analyzed to obtain prediction equations for normal echocardiographic values. Using a bivariate regression model with the assumption that variability is constant as a percentage of the expected value, we developed regression equation and graphs that allow calculation of a 95% prediction interval for several echocardiographic measurements as a function of the subject's age and either body weight or body surface area. Body weight could be substituted for body surface area with no loss of precision. Further, examination of residuals showed that the linear prediction model fit well for all ages and all echocardiographic measurements studied. The measurements were obtained using the recently published standards recommended by the American Society of Echocardiography.

Adolescent↗
PubMed1980

Preoperative exercise capacity in symptomatic patients with aortic regurgitation as a predictor of postoperative left ventricular function and long-term prognosis.

Forty-five symptomatic patients with aortic regurgitation underwent graded treadmill exercise testing before operation. Twenty-seven patients (group A) could not complete stage I of the National Institutes of Health exercise protocol because of limiting symptoms (exercise duration less than or equal to 22.5 minutes); 18 patients (group B) completed this stage without limiting symptoms (exercise duration > 22.5 minutes). Patients in group A had higher resting pulmonary capillary wedge pressures (mean 19 vs 13 mm Hg, p < 0.05) and left ventricular (LV) end-diastolic pressures (mean 24 vs 16 mm Hg, p < 0.05) than those in group B, but did not differ with respect to LV systolic dimension or fractional shortening by echocardiography or LV ejection fraction at rest or during exercise by radionuclide cineangiography. Among 32 patients with subnormal preoperative LV fractional shortening on echo, nine of 17 in group A and 0 of 15 in group B have died (p < 0.01); seven of the nine deaths were from late congestive heart failure. Group A patients also had less decrease postoperatively in LV diastolic size by echocardiography (mean decrease 8 vs 23 mm, p < 0.001) and less increase postoperatively in LV ejection fraction during exercise by radionuclide cineangiography (mean increase 11% vs 23%, p 0.05) than group B patients. No group A patient and 60% of group B patients had normal exercise ejection fractions postoperatively (p < 0.01). The differences in postoperative mortality and function were not predicted by the differences in preoperative hemodynamics between the two groups. Thus, exercise capacity is imprecise in assessing preoperative LV function in symptomatic patients with aortic regurgitation, but is useful in predicting long-term survival after operation and reversibility of LV dilatation and systolic dysfunction.

Adult↗
PubMed1979

Echocardiographic measurements in normal subjects: evaluation of an adult population without clinically apparent heart disease.

In order to determine normal echocardiographic values for older subjects, we studied 136 adults (78 men and 58 women, 20 to 97 years of age) without evidence of cardiovascular disease. When patients were subdivided into six age groups, progressive changes were found in mean normal values for various parameters. Specifically, when the oldest group (over 70 years) was compared with the youngest group (21-30 years), significant (p less than 0.01) increases in aortic root (22 percent) and left atrial (16 percent) dimensions, in ventricular septal (20 percent) and left ventricular free-wall (18 percent) thicknesses, and in estimated left ventricular mass (15 percent) were noted. In addition, a significant (p less than 0.01) decrease in mean mitral E-F slope (43 percent) and slight decreases in mean left ventricular systolic and diastolic internal dimensions (5 and 6 percent, respectively; p less than 0.05) were noted. Left ventricular ejection fraction and percentage fractional shortening were found to be independent of age. These data have been used to derive regression equations that are related to both age and body surface area. The regression equations can be used to calculate mean normal values and 95 percent prediction intervals for echocardiographic measurements in adults.

Adult↗