Ability of left ventricular stress-shortening relations, end-systolic stress/volume ratio and indirect indexes to detect severe contractile failure in ischemic or idiopathic dilated cardiomyopathy

Association of depressed cardiac gp130-mediated antiapoptotic pathways with stimulated cardiomyocyte apoptosis in hypertensive patients with heart failure

OBJECTIVE

To investigate whether the glycoprotein (gp130)-mediated survival pathway, which protects cardiomyocytes from apoptosis, is depressed in left ventricular hypertrophy hypertensive patients with chronic heart failure.

METHODS

Transvenous endomyocardial biopsies were obtained in 52 hypertensive patients with left ventricular hypertrophy: 28 without heart failure and 24 with heart failure. gp130 and gp130-dependent antiapoptotic pathways p42/44 mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) as well as gp130 agonist cardiotrophin-1 were analyzed by reverse transcriptase-polymerase chain reaction and western blot. Apoptosis was assessed by DNA end-labeling (TUNEL), caspase-3 immunostaining and caspase substrate poly(ADP-ribose) polymerase cleavage.

RESULTS

gp130 protein expression (P < 0.05) and p42/44 MAPK and PI3K/Akt activation (P < 0.01) were decreased in heart-failure hypertensive patients compared with nonheart-failure hypertensive individuals. No changes in gp130 mRNA expression were found between the two groups. Cardiotrophin-1 was increased (P < 0.05) at both the mRNA and protein levels in heart-failure hypertensive individuals compared with nonheart-failure hypertensive individuals. Cardiomyocyte apoptosis was increased (P < 0.01) in heart-failure hypertensive individuals compared with nonheart-failure hypertensive individuals. Inverse correlations (P < 0.01) occurred between cardiomyocyte apoptosis and p42/44 MAPK and PI3K/Akt activation in all hypertensive patients. Cardiotrophin-1 correlated inversely (r = -0.554, P < 0.05) with gp130 in all hypertensive individuals. In cultured HL-1 cardiomyocytes, cardiotrophin-1 decreased (P < 0.05) the gp130:phosphorylated gp130 (at Ser782) ratio and increased (P < 0.05) gp130ubiquitination.

CONCLUSIONS

An association exists between depression of the gp130 cytoprotective pathway and stimulation of cardiomyocyte apoptosis in hypertensive patients that develop heart failure. Whether the excess of cardiotrophin-1 induces ligand-induced receptor down-regulation in these patients requires further study.

Gender differences in left ventricular systolic function in American Indians (from the Strong Heart Study)

Data from population-based studies indicate that men have a higher incidence and worse prognoses of congestive heart failure than women. Echocardiography was used to compare left ventricular (LV) myocardial and chamber contractility between 490 male and 861 female American Indian participants in the second Strong Heart Study examination. After adjusting for fat-free mass, baseline hypertension, diabetes mellitus, coronary heart disease, and alcohol consumption, LV ejection fractions were higher in women than men (66 +/- 8% vs 63 +/- 9%, p = 0.002), as were stress-corrected mid-wall shortening (106 +/- 13% vs 104+/-15%, p = 0.006) and the circumferential end-systolic stress/end-systolic volume index (7.1 x 10(4) +/- 1.9 x 10(4) vs 6.5 x 10(4) +/- 2.1 x 10(4) kdyne/cm3, all p values <0.001). LV ejection fractions were less than the predefined partition value in 4.7% of women and in 16.7% of men (odds ratio 0.25, 95% confidence interval 0.18 to 0.34, p <0.001). Stress-corrected mid-wall shortening was less than the predetermined lower limit of normal in 2.9% of women and in 6.2% of men (odds ratio 0.45, 95% confidence interval 0.29 to 0.70, p <0.001). There was no significant gender difference in supranormal function by either measure of LV systolic function. Estimated mean independent effects of female gender were a 3% greater ejection fraction, 2.7% greater stress-corrected mid-wall shortening, and a 0.4 x 10(4) kdyne/cm3 greater circumferential end-systolic stress/end-systolic volume index. In conclusion, in a population-based sample aged 45 to 74 years, women had greater LV myocardial and chamber function than men. Gender-specific partition values for measures of LV systolic function may be necessary to detect abnormal contractility in clinical and epidemiologic studies.

Usefulness of the assessment of the appropriateness of left ventricular mass to detect left ventricular systolic and diastolic abnormalities in absence of echocardiographic left ventricular hypertrophy: the LIFE study

Conventional definitions of left ventricular (LV) hypertrophy do not account for interindividual differences in loading conditions. We may define LV mass as inappropriately high when exceeding 128% of theoretical values predicted by gender, height(2.7), and stroke work, which explain up to 82% of the variability of LV mass in normal reference subjects. In 652 participants in the Losartan Intervention For Endpoint reduction in hypertension study without clinically overt cardiovascular disease or diabetes, we investigated whether inappropriately high LV mass is associated with relevant LV abnormalities independent of traditional definition of LV hypertrophy (ie, LV mass index >116 g/m(2) in men and >104 g/m(2) in women). The study sample was divided into three groups: patients with inappropriately high LV mass but without LV hypertrophy were compared to patients with LV hypertrophy and to patients with appropriate LV mass and without LV hypertrophy. Patients with inappropriately high but nonhypertrophic LV mass had higher body mass index and relative wall thickness, and lower LV myocardial systolic function, than patients with appropriate LV mass or patients with LV hypertrophy. In multivariate analyses, inappropriately high LV mass was independently associated with lower myocardial systolic function independent of LV hypertrophy and other covariates. Inappropriately high LV mass was also associated with prolonged isovolumic relaxation time and lower mitral E/A ratio independent of covariates. In conclusion, inappropriately high LV mass was associated with relevant, often preclinical, manifestations of cardiac disease in the absence of traditionally defined echocardiographic LV hypertrophy and concentric geometry.

An assessment of two different methods of left ventricular ejection time measurement by transesophageal echocardiography

Left ventricular ejection time (LVET) is an important component in evaluating left ventricular performance. This measurement is usually made by measuring the timing of the transaortic valve flow velocity by continuous-wave Doppler. Although M-mode has also been used for measuring LVET, it has not been compared with the Doppler method. We tested the hypothesis that the M-mode-measured duration of aortic valve opening is comparable to Doppler-derived measurement of LVET by transesophageal echocardiography (TEE). Measurements were made in 31 patients undergoing nonaortic valve cardiac surgery. The timing of transaortic flow by continuous-wave Doppler was compared with the M-mode-derived timing of aortic valve opening. There was close correlation (Pearson correlation coefficient, r = 0.86; P < 0.0001) between M-mode and Doppler measurements. There was no significant difference between the two techniques by linearity tests (P > 0.1). Bland-Altman analysis showed no significant bias. We confirmed the hypothesis that M-mode-derived measurement of LVET is comparable to Doppler-derived measurement of LVET. M-mode may be an acceptable alternative to the Doppler method, especially when transvalvular velocity gradients cannot be readily obtained. M-mode is a simple, yet often underused, method of evaluating LVET during TEE.

Relationship between left ventricular diastolic relaxation and systolic function in hypertension: The Hypertension Genetic Epidemiology Network (HyperGEN) Study

The relation of impaired left ventricular relaxation, as measured by prolonged isovolumic relaxation time, to ventricular systolic function in hypertension remains uncertain in population-based samples. In the Hypertension Genetic Epidemiology Network (HyperGEN) Study, echocardiograms were analyzed in 1457 hypertensive participants without diabetes, >/=2+ valvular regurgitation, or coronary disease. Impaired relaxation (isovolumic relaxation time >100 ms) was present in 219 (15%) of the participants; they were older and had higher arterial pressure than did those with normal relaxation. Ventricular chamber size, wall thicknesses, mass, and relative wall thickness were greater, and stress-corrected midwall shortening and end-systolic stress/end-systolic volume index were lower with impaired relaxation than with normal relaxation time. Fractional shortening and ejection fraction did not differ between the groups. In logistic regression, the likelihood of prolonged isovolumic relaxation time decreased with higher stress-corrected midwall shortening (odds ratio, 0.97%; 95% confidence interval, 0.96 to 0.99), independently of age, heart rate, and ventricular mass. Neither ejection fraction nor the end-systolic stress/end-systolic volume index was independently related to isovolumic relaxation time. In hypertension, impaired left ventricular relaxation parallels ventricular midwall dysfunction but not systolic chamber function. Whether combined diastolic and systolic dysfunction identifies hypertensive patients at especially high risk of cardiovascular events requires further study.

Noninvasive assessment of left ventricular systolic function by stress-shortening relation, rate of change of power, preload-adjusted maximal power, and ejection force in idiopathic dilated cardiomyopathy: prognostic implications

Indexes of left ventricular systolic function that are considered relatively load-insensitive were assessed to determine their relation to the severity of heart failure symptoms and their ability to predict the outcome of idiopathic dilated cardiomyopathy. Stress, flow, power, and ejection force were calculated throughout ejection by echocardiography at rest in 35 patients with idiopathic dilated cardiomyopathy and in 20 control subjects. Patients were evaluated prospectively every 6 months for 2 years. Asymptomatic patients were separated most clearly from New York Heart Association (NYHA) class II by end-systolic stress; NYHA class II patients were separated from NYHA class III and the latter from NYHA class IV by peak rate of change of flow. Ten patients showed improvement in symptoms as well as in systolic indexes; none of them died during the follow-up. Improvement was unpredictable with the evaluated variables. One- and 2-year cardiovascular mortality rates were 17% and 26%, respectively. Patients whose condition did not improve after the first year had a 17% second-year mortality rate. Peak rate of change of power predicted death with 100% sensitivity, 56% specificity, and 64% positive predictive value in NYHA III and IV patients.

Evaluation of extent of shortening versus velocity of shortening at the endocardium and midwall in hypertensive heart disease

To assess the incremental value of velocity of shortening velocity parameters compared with simpler, more widely used, extent of shortening parameters in compensated left ventricular hypertrophy, we studied 52 patients with left ventricular hypertrophy and 63 age-matched controls. Velocity parameters did not provide incremental information beyond that obtained by extent of shortening parameters.

Peak systolic stress-rate-corrected mean velocity of fiber shortening in preterm and fullterm infants

The relation of rate-corrected mean velocity of fiber shortening (mVcfc)-end-systolic wall stress (ESS) is a load-independent index of left ventricular contractility, but involves simultaneous M-mode echocardiography, carotid or axillary pulse tracing and blood pressure determination, which may be impractical in younger infants. We examined whether the relation of the peak systolic wall stress (PSS)-mVcfc could be used as a simpler method of assessing left ventricular contractility in preterm and fullterm infants. In 45 preterm and fullterm infants, mVcfc, ESS, and PSS were determined using echocardiography, axillary pulse tracing and blood pressure measurement. Five patients with left ventricular dysfunction or low cardiac output state were also studied. The relation of PSS and ESS was PSS=5.19+1.04 ESS (r=0.98, p<0.01). The slope of mVcfc=1.58-0.012 ESS (r=-0.78, p<0.01) was nearly identical to that of mVcfc=1.60-0.011 PSS (r=-0.75, p<0.01), with no difference in the regression coefficients. The relationship of PSS and ESS in 5 patients was very close and the slope of the regression line was nearly identical to that of 45 infants. The relation of mVcfc PSS correlates well with the relation using ESS and can be used as a simple method of assessing left ventricular contractility.

Relations of left ventricular mass to demographic and hemodynamic variables in American Indians: the Strong Heart Study

BACKGROUND

Previous studies have identified associations of left ventricular (LV) mass with demographic (body habitus and sex) and hemodynamic variables (blood pressure, stroke volume [SV], and myocardial contractility), but the relative strength and independence of these associations remain unknown.

METHODS AND RESULTS

We examined the relations of echocardiographically determined LV mass to demographic variables, blood pressure, Doppler SV, and measures of contractility (end-systolic stress [ESS]/end-systolic volume index and midwall fractional shortening [MFS] as a percentage of predicted for circumferential end-systolic stress [stress-independent shortening]) in 1935 American Indian participants in the Strong Heart Study phase 2 examination without mitral regurgitation or segmental wall motion abnormalities. Weak positive relations of LV mass with systolic and diastolic pressures (r=.22 and r=.20) were exceeded by positive relations with height (r=.30), weight (r=.47), body mass index (r=.31), body surface area (r=.49), and Doppler SV (r=.50) and negative relations with ESS/volume index ratios (r= -.33 and -.29) and stress-independent MFS (r= -.26, all P<.0001). In multivariate analyses that included blood pressure, SV, and a different contractility measure in each model, systolic pressure, stroke volume, and the contractility measure were independent correlates of LV mass (multiple R=.60 to .66, all P<.0001). When demographic variables were added, LV mass was more strongly predicted by higher SV and lower afterload-independent MFS than by greater systolic pressure, height, and body mass index (each P<.00001, multiple R=.71).

CONCLUSIONS

Additional characterization of volume load and contractile efficiency improves hemodynamic prediction of LV mass (R(2)=.30 to .44) over the use of systolic blood pressure alone (R(2)=.05), with a further increase in R(2) to .51 when demographic variables are also considered. However, nearly half of the ventricular mass variability remains unexplained.

Estimation of regional end-systolic wall stress during exercise in coronary artery disease

Estimating left ventricular wall stress has recognized applications, but formulae for global stress cannot be applied to ischemic ventricles. A mathematic method for estimating regional stress in infarcted ventricles has been described. The hypothesis tested was that exercise-induced ischemia increases end-systolic wall stress. Subcostal four-chamber echocardiograms were recorded at rest and during peak symptom-limited exercise in 19 controls and 41 patients with chest pain undergoing coronary arteriography. Centerline regional wall motion and regional end-systolic wall stress were measured at rest and at peak exercise. The normal controls had increased wall motion with exercise, but wall stress remained low. All 32 of the patients with coronary artery disease (> or = 50% diameter narrowing) had wall motion abnormalities with exercise, but the sensitivity of identifying right coronary artery obstructions was poor. Patients with coronary disease had higher regional stress at peak exercise than did the controls. The sensitivity of identifying lesions in all three coronary arteries (0.95 to 1.0) was better than that for wall motion (p < 0.04). The specificity of wall stress needs to be tested in a larger population. Exercise-induced ischemia causes increased regional end-systolic wall stress that reflects its distribution in patients with coronary artery disease. These changes can be measured non-invasively during exercise echocardiography.

Assessment of left ventricular function by meridional and circumferential end-systolic stress/minor-axis shortening relations in dilated cardiomyopathy

Echocardiographic meridional wall stress-endocardial shortening relations provide estimates of left ventricular (LV) contractility that do not uniformly detect myocardial dysfunction despite severe symptoms in dilated cardiomyopathy. To improve detection of myocardial dysfunction in patients with congestive heart failure (CHF) due to dilated cardiomyopathy, echocardiographic meridional and circumferential end-systolic stress were related to endocardial and midwall shortening in 42 patients (95% dead within a mean of 22 months) with dilated cardiomyopathy and 140 normal subjects. A method to estimate LV long-axis dimension from M-mode minor-axis epicardial measurements was developed in a separate series of 115 subjects. Endocardial shortening to meridional wall stress relation identified 31 of 42 CHF patients falling below the 95% normal confidence interval of the reference population; use of midwall shortening decreased this number to 26 (p = NS). The use of circumferential wall stress identified 39 of 42 patients with subnormal endocardial LV shortening and 41 of 42 patients with depressed midwall performance (p < 0.01 vs use of meridional stress). The circumferential/meridional wall stress ratio was 2.6 +/- 0.5 in normal subjects and 1.3 +/- 0.2 in CHF patients (p < 0.0001). Thus, use of circumferential end-systolic stress as the measure of afterload improves the detection of myocardial dysfunction by stress/shortening relations in patients with CHF. The ratio between the 2 stresses decreases with more spherical LV shape. Midwall and endocardial shortening measurements are equivalent in the setting of thin LV walls as occurs in dilated cardiomyopathy.

Short- and long-term variability of echocardiographic stress-velocity indexes of cardiac function in a pediatric population

This study determined the short- and long-term variability of stress-velocity relationships at end systole and peak systole. A prospective study during the short term (0 to 15 and 0 to 30 minutes) and long term (0 to 1 and 0 to 12 months) was performed calculating variability by the limits of agreement method. The study was performed in a tertiary-care pediatric echocardiographic laboratory. Twenty-five normal children underwent repeat testing as described. Standard blood pressure, carotid pulse tracing, and M-echocardiography of the left ventricle was performed at the intervals described. The rate-corrected mean velocity of fiber shortening (MVCFC), echocardiographic stress at end systole (SES), and echocardiographic stress at peak systole (SPS) were calculated for all recordings. The slopes of MVCFC-SES and MVCFC-SPS were determined by regression and plotted. With these slopes, the second and third stress values were normalized to the first stress value for the short and long term. The differences in normalized MVCFC and MVCFC (delta MVCFC) for 15 to 0 minutes, 30 to 0 months, 1 to 0 month, and 12 to 1 month were obtained for both SES and SPS, and 95% limits of agreement were estimated. The mean delta MVCFC for SES and SPS for the short and long term were not different from 0 or each other, indicating no bias. The 95% limits of agreement of delta MVCFCs (i.e., variability for SES at 15 to 0 minutes, 30 to 0 minutes, 1 to 0 month, and 12 to 0 month) were +/- 0.18, +/- 0.24, +/- 0.34, and +/- 0.27, respectively, and for SPS +/- 0.18, +/- 0.24, +/- 0.33, and +/- 0.28. Variability showed an increasing trend with time but was significant only from 15 to 0 minutes and 1 to 0 month (p = 0.006). This study has established short- and long-term variability in the stress-velocity relationship that is essential for monitoring acute and chronic changes in ventricular contractility in an individual patient.

The effect of midazolam on left ventricular pump performance and contractility in anesthetized patients with coronary artery disease: effect of preoperative ejection fraction

Forty patients undergoing coronary artery bypass grafting were studied, of whom 24 had depressed global left ventricular (LV) function at preoperative catheterization, to evaluate the effects of midazolam on LV pump performance and contractility. Transesophageal echocardiography and simultaneous hemodynamic measurements were used to assess LV preload, afterload, and systolic performance during inhalation of 100% O2 and after 0.1 mg/kg of midazolam. Systolic function indices were expressed as a percent of the predicted value for observed end-systolic stress to estimate LV contractility. In the entire study population, midazolam did not affect cardiac index. Heart rate and mean arterial pressure were reduced (63 +/- 13 to 59 +/- 12 bm; P < 0.0006 and 89 +/- 15 to 76 +/- 16 mm Hg; P < 0.0001) as were pulmonary capillary wedge pressure, central venous pressure, and systemic and pulmonary vascular resistance. Afterload, as measured by end-systolic stress, was reduced (55 +/- 33 to 48 +/- 26 kdyne/cm2; P = 0.007) with no change in fractional shortening or percent area change. As a result, systolic function decreased in relation to observed end-systolic stress, providing evidence of reduced LV contractility. Thus, midazolam administration (0.1 mg/kg) caused no change in cardiac pump performance but decreased LV contractility in the entire population. Myocardial contractility was lower at baseline and after the administration of midazolam in the depressed ejection fraction group, but the decrease in contractility was not exaggerated in the depressed ejection fraction group.(ABSTRACT TRUNCATED AT 250 WORDS)

Evolution of cardiac changes in young insulin-dependent (type 1) diabetic patients--one more piece of the puzzle of diabetic cardiopathy

Based on our recent reports that increased myocardial contractility has been found in newly diagnosed diabetic patients, and that diastolic (D) dysfunction precedes systolic (S) dysfunction, we suggested that the development of diabetic cardiopathy passes through the following stages: (I) increased myocardial contractility, (II) intact S and D function, (III) intact S function and D dysfunction, and (IV) S and D dysfunction. The aim of this pilot study was to test this hypothesis. One hundred fifty-seven young (26.2 +/- 7.4 years) cardiac-asymptomatic patients with type I diabetes and 54 healthy subjects were studied using M-mode echocardiography. The presence of at least one of the variables for systolic function (ejection fraction, mean velocity of circumference, fiber shortening, and stroke index) or diastolic function [left atrium emptying index (LAEI), EFo slope of anterior mitral leaflet, and isovolumetric relaxation time (IRT)] outside the control mean +/- 2 SD was interpreted as an increased or depressed myocardial contractility, and diastolic dysfunction, respectively. The severity of diabetic complications (retinopathy, nephropathy, and cardiac autonomic neuropathy) was evaluated by the diabetic complication index (DCI = 0 divided by 6 scores). Our hypothesis was confirmed significantly (p < 0.001) in 148 (94%) patients with diabetes. Duration of diabetes and DCI progressed significantly (ANOVA: F = 36.6, p < 0.001; F = 70.8, p < 0.001) with hypothetical stages. Diastolic dysfunction was more pronounced in stage IV than in stage III: IRT (80.5 +/- 18.6 ms vs. 62.5 +/- 16.4, p < 0.001), EFo (63 +/- 15 mm/s vs. 72 +/- 21, p < 0.05), LAEI (0.58 +/- 0.13 vs. 0.8 +/- 0.15, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Rate-corrected mean velocity of fiber shortening-stress at peak systole as a load-independent measure of contractility

The relation of mean velocity of fiber shortening-stress at end-systole is a good load-independent index of left ventricular contractility, but involves simultaneous M-mode echocardiography, carotid tracing and blood pressure determination, which may be impractical in children. As stress at peak systole and end-systole are closely related, this study examined whether the relation of mean velocity of fiber shortening-stress at peak systole could be used as a simpler method of assessing left ventricular contractility in a normal population of children. In addition, the cross-sectional normal range for a pediatric population was obtained. In 25 normal children aged 4 to 17 years (mean age 11), rate-corrected mean velocity of fiber shortening (MVCFc), stress at peak systole (sigma PS), and end-systolic stress (sigma ES) were determined using echocardiography, carotid pulse tracing and blood pressure measurement. Six patients with cardiomyopathy (mean age 8 years) were also studied. The relation of stress at peak systole and end-systolic stress was sigma PS = 1.004 sigma ES + 12.0 (r = 0.91, SEE = 4.98; p less than 0.001) for the normal group, and sigma PS = 1.083 sigma ES + 7.7 (r = 0.99, SEE = 4.07; p less than .001) for the cardiomyopathic group. This slope of the regression line was slightly higher and the difference was statistically significant. The slope of MVCFc = 0.0066 sigma PS + 1.55 (SEE = 0.131, r = -0.52) was nearly identical to that of MVCFc = 0.0065 sigma ES + 1.46, (SEE = 0.135, r = -0.46), with no difference in the regression coefficients.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular mass in childhood dilated cardiomyopathy: a possible predictor for selection of patients for cardiac transplantation

To determine the relationship of left ventricular hypertrophy (as assessed by mass) to symptoms and cardiac function in chronic childhood dilated cardiomyopathy, 17 long-term survivors (12 asymptomatic, 5 symptomatic) were studied at a median follow-up of 6.25 years (1.25 to 16.8 years). Left ventricular mass, dimension, wall stress, and contractility (relationship between velocity of circumferential fiber shortening and end-systolic wall stress) were assessed by echocardiography. These data were compared to measurements at the onset of disease. At follow-up, mass decreased significantly from the onset in the asymptomatic patients but remained elevated in the symptomatic patients (101 +/- 35 gm/m2 to 54 +/- 12 gm/m2, p = 0.001; 122 +/- 55 gm/m2 to 198 +/- 115 gm/m2, p = 0.23, respectively). Shortening fraction and contractility were both significantly lower in the symptomatic group compared with the asymptomatic group at follow-up (shortening fraction = 21 +/- 7% vs 29 +/- 5%, p = 0.02; contractility = -0.24 +/- 0.14 circ/sec vs -0.05 +/- 0.11 circ/sec, p = 0.01). Follow-up wall stress was slightly higher in symptomatic patients compared with asymptomatic patients. Three symptomatic patients had progressive hypertrophy and either died or required transplantation. Higher left ventricular mass is associated with the presence of symptoms, depressed contractility, and slightly higher wall stress. Persistence or progression of hypertrophy may be a poor prognostic sign in survivors of childhood dilated cardiomyopathy. Measurement of mass may be useful to indicate the necessity for closer follow-up to select patients for cardiac transplantation before hemodynamic decompensation.

Comparison of noninvasive measures of contractility in dilated cardiomyopathy

Left ventricular performance is usually quantified by ejection phase indices such as ejection fraction, cardiac output, and fractional shortening. The load-dependence of these measures may result in inaccurate estimation of intrinsic myocardial contractility in states of chronic pressure or volume overload. End-systolic and stress-shortening relations have been proposed as measures of contractile state insofar as they are theoretically independent of preload and incorporate afterload. This article examines the behavior of these relations in response to changes in loading conditions and contractile state and reviews their application utilizing noninvasive methodology, particularly in the setting of dilated cardiomyopathy.

Relation of obesity, high sodium intake, and eccentric left ventricular hypertrophy to left ventricular exercise dysfunction in essential hypertension

PURPOSE

To elucidate determinants of abnormal left ventricular functional responses to exercise in hypertensive patients.

PATIENTS AND METHODS

One hundred twenty-seven patients with uncomplicated essential hypertension were studied by rest and exercise radionuclide angiography and by echocardiography at rest.

RESULTS

The 24 patients with subnormal left ventricular ejection fraction at peak exercise (less than 54%) were similar in age and rest and exercise blood pressures to the 103 with normal exercise ejection fraction, but were more obese (p less than 0.005) and had greater left ventricular mass (p less than 0.03) and internal dimensions (p less than 0.001). The parallel increase in left ventricular chamber size and mass (eccentric hypertrophy) in the group of patients with exercise dysfunction was associated with higher resting end-systolic wall stress (p less than 0.001) and abnormal increases of end-systolic left ventricular volume from rest to peak exercise (p less than 0.001). Multivariate analysis revealed that exercise left ventricular dysfunction was independently associated with higher left ventricular mass (p less than 0.0005), end-systolic wall stress (p less than 0.001), dietary sodium intake (p less than 0.01), and body mass index (p less than 0.03).

CONCLUSION

Among patients with uncomplicated essential hypertension, abnormal functional responses to exercise are strongly associated with eccentric ventricular hypertrophy, obesity, and high sodium intake.