Impact of Essential Hypertension and Diabetes Mellitus on Left Ventricular Systolic and Diastolic Performance

Impact of oxidative stress on myocardial performance in patients with diabetes: a focus on subclinical left ventricular dysfunction

INTRODUCTION

Oxidative stress is known to affect left ventricular functions negatively. There is a strong bidirectional connection between diabetes mellitus (DM) and oxidative stress. In parallel, left ventricular dysfunction is observed more frequently, even in patients with DM without other risk factors. In this context, the objective of this study is to comparatively investigate the potential relationship between oxidative stress and subclinical left ventricular dysfunction (SCLVD) assessed by Myocardial Performance Index (MPI) in patients with and without DM.

RESEARCH DESIGN AND METHODS

The sample of this observational cross-sectional single-center study consisted of 151 patients who were evaluated for oxidative stress and SCLVD by tissue Doppler echocardiography. Patients' total oxidant status (TOS), total antioxidant status (TAS), and Oxidative Stress Index (OSI) values were calculated. The effects of oxidative stress and DM on MPI were analyzed.

RESULTS

There were 81 patients with DM (mean age: 46.17±10.33 years) and 70 healthy individuals (mean age: 45.72±9.04 years). Mean TOS and OSI values of the DM group were higher than healthy individuals (5.72±0.55 vs 5.31±0.50, p = <0.001; and 4.92±1.93 vs 1.79±0.39, p = <0.001; respectively). The mean TAS value of the DM group was significantly lower than the healthy group (1.21±0.40 vs 3.23±0.51, p = <0.001). There was a significant correlation between OSI and MPI mitral in the DM group (R 0.554, p = <0.001) but not in the healthy group (R -0.069, p=0.249).

CONCLUSIONS

Both oxidative stress and myocardial dysfunction were found to be more common in patients with DM. The study's findings indicated the negative effect of oxidative stress on myocardial functions. Accordingly, increased oxidative stress caused more significant deterioration in MPI in patients with DM compared with healthy individuals.

Determinants of improvement of left ventricular mechano-energetic efficiency in hypertensive patients

Background

Arterial hypertension, especially when coexisting with other cardiovascular risk factors, could determine an imbalance between myocardial energetic demand and altered efficiency, leading to an early left ventricular (LV) systolic dysfunction, even in terms of echo-derived mechano-energetic efficiency indexed for myocardial mass (MEEi). We aim to analyse an improvement in LV MEEi, if any, in a population of hypertensive patients with a long-term follow-up and to identify clinical, metabolic and therapeutic determinants of LV MEEi amelioration.

Materials and methods

In total, 7,052 hypertensive patients, followed-up for 5.3 ± 4.5 years, enrolled in the Campania Salute Network, underwent echocardiographic and clinical evaluation. LV MEEi was obtained as the ratio between stroke volume and heart rate and normalized per grams of LV mass and ΔMEEi was calculated as difference between follow-up and baseline MEEi. Patients in the highest ΔMEEi quartile (≥0.0454 mL/s/g) (group 1) were compared to the merged first, second and third quartiles (<0.0454 mL/s/g) (group 2). METS-IR (Metabolic Score for Insulin Resistance), an established index of insulin sensitivity, was also derived.

Results

Patients with MEEi improvement experienced a lower rate of major cardiovascular events (p = 0.02). After excluding patients experiencing cardiovascular events, patients in group 1 were younger (p < 0.0001), less often diabetic (p = 0.001) and obese (p = 0.035). Group 1 experienced more frequently LV mass index reduction, lower occurrence of LV ejection fraction reduction, and had a better metabolic control in terms of mean METS-IR during the follow-up (all p < 0.0001). Beta-blockers were more often used in group 1 (p < 0.0001) than group 2. A logistic regression analysis showed that younger age, lower mean METS-IR values, more frequent LV mass index reduction and therapy with beta-blockers were significantly associated with LV MEEi improvement, independently of presence of diabetes and obesity.

Conclusion

Metabolic control and therapy with beta-blockers could act in a synergic way, determining an improvement in LV MEEi in hypertensive patients over time, possibly confining cardiac damage and hampering progression toward heart failure.

Assessment of Left Ventricular Function and Mitral Regurgitation Severity Early After Percutaneous Device Closure of the Atrial Septal Defect

BACKGROUND

Atrial septal defect (ASD) is one the most prevalent forms of congenital heart disease in adults. Closure of ASDs eliminates left-to-right shunt and reduces right heart volumes, but the effects of ASD closure, on the left ventricle (LV) and mitral valve competence are somewhat inconsistent. Therefore, we designed this study to evaluate the early effect of percutaneous closure of ASD on LV function and mitral regurgitation (MR) severity.

METHODS

In this prospective study, we enrolled 32 patients with ASD secundum who underwent percutaneous device closure in Tehran Heart Center. We used transthoracic and transesophageal echocardiography (TEE) before the procedure and TTE 24 hours after the procedure, then compared obtained LV parameters before and after the procedure.

RESULTS

LV end-diastolic diameter (LVEDD) increased significantly from 44.8 ± 2.4 to 45.8 ± 2.8 (P < 0.001). LV end-systolic diameter (LVESD) also increased but was statistically insignificant (P = 0.063) and LV ejection fraction (LVEF) remained nearly unchanged. Highest alteration was in right ventricular systolic pressure (12.4% decrease; P < 0.001) and mitral early Doppler/tissue Doppler velocity ratio (E/E') (9.7% increase; P = 0.010). The change in MR severity was insignificant using Wilcoxon signed-rank test (P = 0.157).

CONCLUSIONS

We concluded that systolic functions do not change immediately. However, LVEDD and E/E' will increase immediately, resulting from the passage of all blood from the LA into the LV in the early diastole just after closure. We also observed the positive effect of device closure on reducing right ventricular systolic pressure, and at least it does not worsen MR early after the procedure.

Joint influences of obesity, diabetes, and hypertension on indices of ventricular remodeling: Findings from the community-based Framingham Heart Study

Introduction

Obesity, hypertension, and diabetes are independently associated with cardiac remodeling and frequently co-cluster. The conjoint and separate influences of these conditions on cardiac remodeling have not been investigated.

Materials and methods

We evaluated 5,741 Framingham Study participants (mean age 50 years, 55% women) who underwent echocardiographic measurements of left ventricular (LV) mass (LVM), LV ejection fraction (LVEF), global longitudinal strain (GLS), mitral E/e’, left atrial end-systolic (peak) dimension (LASD) and emptying fraction (LAEF). We used multivariable generalized linear models to estimate the adjusted-least square means of these measures according to cross-classified categories of body mass index (BMI; normal, overweight and obese), hypertension (yes/no), and diabetes (yes/no).

Results

We observed statistically significant interactions of BMI category, hypertension, and diabetes with LVM, LVEF, GLS, and LAEF (p for all 3-way interactions <0.01). Overweight and obesity (compared to normal BMI), hypertension, and diabetes status were individually and conjointly associated with higher LVM and worse GLS (p<0.01 for all). We observed an increase of 34% for LVM and of 9% for GLS between individuals with a normal BMI and without hypertension or diabetes compared to obese individuals with hypertension and diabetes. Presence of hypertension was associated with higher LVEF, whereas people with diabetes had lower LVEF.

Conclusions

Obesity, hypertension, and diabetes interact synergistically to influence cardiac remodeling. These findings may explain the markedly heightened risk of heart failure and cardiovascular disease when these factors co-cluster.

Alterations in plasma triglycerides and ceramides: links with cardiac function in humans with type 2 diabetes

Cardiac dysfunction in T2D is associated with excessive FA uptake, oxidation, and generation of toxic lipid species by the heart. It is not known whether decreasing lipid delivery to the heart can effect improvement in cardiac function in humans with T2D. Thus, our objective was to test the hypothesis that lowering lipid delivery to the heart would result in evidence of decreased "lipotoxicity," improved cardiac function, and salutary effects on plasma biomarkers of cardiovascular risk. Thus, we performed a double-blind randomized placebo-controlled parallel design study of the effects of 12 weeks of fenofibrate-induced lipid lowering on cardiac function, inflammation, and oxidation biomarkers, and on the ratio of two plasma ceramides, Cer d18:1 (4E) (1OH, 3OH)/24:0 and Cer d18:1 (4E) (1OH, 3OH)/16:0 (i.e., "C24:0/C16:0"), which is associated with decreased risk of cardiac dysfunction and heart failure. Fenofibrate lowered plasma TG and cholesterol but did not improve heart systolic or diastolic function. Fenofibrate treatment lowered the plasma C24:0/C16:0 ceramide ratio and minimally altered oxidative stress markers but did not alter measures of inflammation. Overall, plasma TG lowering correlated with improvement of cardiac relaxation (diastolic function) as measured by tissue Doppler-derived parameter e'. Moreover, lowering the plasma C24:0/C16:0 ceramide ratio was correlated with worse diastolic function. These findings indicate that fenofibrate treatment per se is not sufficient to effect changes in cardiac function; however, decreases in plasma TG may be linked to improved diastolic function. In contrast, decreases in plasma C24:0/C16:0 are linked with worsening cardiac function.

Cardiac function in survivors of childhood acute myeloid leukemia treated with chemotherapy only: a NOPHO-AML study

OBJECTIVES

We report cardiac function of patients treated for Childhood acute myeloid leukemia with chemotherapy only according to three consecutive Nordic protocols.

METHODS

Ninety-eight of 138 eligible patients accepted examination with standardized echocardiography. Results were compared with age- and sex-matched controls.

RESULTS

The median age was 3 yr at diagnosis (range 0-15), and the median time from diagnosis to study was 11 yr (4-25). All but one patient had received doxorubicin and 90% had received mitoxantrone. The median cumulative dose of daunorubicin equivalents was 300 mg/m(2) (210-525). Left ventricular fractional shortening (LVFS) and ejection fraction (LVEF) were lower in patients than in controls (32.6% (SD 4.0) vs. 35.2% (SD 3.4), P = 0.002 and 59.9% (SD 5.5) vs. 64.2% (SD 4.4), P = 0.001). The myocardial performance index (MPI) was higher in patients than in controls (0.32 (SD 0.081) vs. 0.26 (SD 0.074), P < 0.0001). Cumulative dose of doxorubicin but not mitoxantrone was related to lower LVFS (P = 0.037) and LVEF (P = 0.016). Longer follow-up was associated with lower LVFS (P = 0.034). Higher MPI was associated with young age at diagnosis (P = 0.04) and longer follow-up (P = 0.031).

CONCLUSIONS

In this study, most patients had cardiac function within normal limits and reported very few cardiac symptoms. However, compared with healthy controls, they had significantly reduced left ventricular function.

Effect of Weight Loss Induced by Intragastric Balloon Therapy on Cardiac Function in Morbidly Obese Individuals: A Pilot Study

OBJECTIVE

The aim of the study was to investigate the effect of intragastric balloon therapy on left ventricular function and left ventricular mass in a cohort of morbidly obese patients.

SUBJECTS AND METHODS

A prospective trial was performed in a cohort of 17 class II and class III morbidly obese individuals. The intragastric balloon was retained in the stomach for an average of 6 months. Conventional and tissue Doppler echocardiography were performed in all patients before and after the procedure.

RESULTS

The mean age of the study participants was 36 ± 10 years (range: 18-55). The mean body mass index was significantly decreased following the intragastric balloon insertion procedure (44 ± 8 vs. 38 ± 5, p < 0.001). The left ventricular mass index and left atrial volume index were significantly decreased following the procedure (112 ± 21 vs. 93 ± 17, p = 0.001 and 20 ± 6 vs. 14 ± 5, p = 0.02, respectfully). In addition, the ratio of mitral peak early diastolic velocity to tissue Doppler-derived peak diastolic velocity and tissue Doppler echocardiography-derived left ventricular myocardial performance index were decreased significantly following the procedure (9.5 ± 1.9 vs. 7.7 ± 1.5, p = 0.002 and 0.57 ± 0.11 vs. 0.46 ± 0.06, p = 0.001, respectively).

CONCLUSIONS

Intragastric balloon therapy resulted in significant weight reduction in morbidly obese patients. This weight reduction was associated with improved left ventricular function.

Early subclinical left-ventricular dysfunction in obese nonhypertensive children: a tissue Doppler imaging study

A direct effect of obesity on myocardial function has not been not well established. Our aim was to investigate the effect of body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR) on left-ventricular (LV) myocardial function in normotensive overweight and obese children by tissue Doppler imaging (TDI). We calculated the mitral annular displacement index (DI) and myocardial performance index (MPI) using TDI indices of systolic and diastolic LV function. In this hospital-based, prospective cross-sectional study, we studied 60 obese (mean age 13.2 ± 2.0 years) and 50 normal children. Subjects were divided into three groups: group 1 (BMI < 25, n = 50, control), group 2 (BMI 25-29.9 kg/m(2), n = 30, overweight), and group 3 (BMI ≥ 30 kg/m(2), n = 30, morbidly obese). Standard echocardiography showed increased LV diameters and LV mass/index and preserved ejection fraction in obese children. By TDI, LV systolic and diastolic function showed that peak late myocardial velocity (Em = 15.4 ± 2 cm/s), peak early myocardial velocity (Am = 8.7 ± 1.3 cm/s), Em/Am ratio (1.8 ± 0.3), isovolumetric relaxation time (IVRT = 59.2 ± 8.2 ms), MPI (0.39 ± 0.03), and DI (25.5 ± 3.2 %) of the lateral mitral annulus in the obese subgroups were significantly different from those of control subjects (18.2 ± 1.2 cm/sn, 6.9 ± 0.6 cm/sn, 2.6 ± 0.2, 51.2 ± 9.6 ms, 0.34 ± 0.03, and 33.13 ± 5.0 %, respectively; p < 0.001). These structural and functional abnormalities were significantly related to BMI. There were positive correlations between HOMA-IR, septal MPI, and LV mass. DI and MPI data indicated impaired subclinical LV function in all grades of isolated obesity at a preclinical stage. Insulin resistance and BMI correlated significantly with indices of LV function.

Metabolic syndrome and left ventricular function: is the number of criteria actually important?

BACKGROUND

Metabolic syndrome (MS) is a clustering of cardiovascular risk factors responsible for the development of target organ damage. The aim of this study was to determine the effect of the increasing number of MS risk factors on left ventricular function assessed by noninvasive methods.

MATERIAL/METHODS

The study included 204 subjects with MS and 76 controls with no MS risk factors. MS was defined by the presence of 3 or more of ATP-NCEP III criteria. MS subjects were grouped according to the number of criteria they fulfilled: 3 criteria (n=91), 4 criteria (n=65) and 5 criteria (n=48). All subjects underwent laboratory blood tests, complete 2-dimensional, pulse and tissue Doppler echocardiography. Echocardiography was used to assess systolic (LVEF, sseptal), diastolic function, by pulse-wave Doppler (E/A ratio) and tissue Doppler imaging (E/e'average), and global left ventricular function (Tei index). Appropriate time intervals for the estimation of the Tei index were obtained by tissue Doppler.

RESULTS

Transmitral E/A ratio decreased significantly and progressively from the 3 criteria to the 5 criteria group (0.82 ± 0.25 vs. 0.79 ± 0.24 vs. 0.67 ± 0.14, p<0.001). The transmitral E/E'average ratio was significantly and gradually increased from the 3 criteria to the 5 criteria group (7.76 ± 1.81 vs. 9.44 ± 2.35 vs. 10.82 ± 2.56, p<0.001). The left ventricle Tei index progressively increased from the 3 criteria to the 5 criteria group (0.43 ± 0.11 vs. 0.48 ± 0.10 vs. 0.54 ± 0.12, p<0.001).

CONCLUSIONS

The increasing number of MS criteria is associated with cardiac diastolic dysfunction.

Doppler-derived myocardial performance index in patients with impaired left ventricular relaxation and preserved systolic function

BACKGROUND

The Doppler-derived myocardial performance index (MPI) has been used in the evaluation of left ventricular (LV) function in several diseases. In patients with isolated diastolic dysfunction, the diagnostic utility of this index remains unclear. The aim of this study was to determine the diagnostic utility of MPI in patients with systemic hypertension, impaired LV relaxation, and normal ejection fraction.

METHODS

Thirty hypertensive patients with impaired LV relaxation were compared to 30 control subjects. MPI and its components, isovolumetric relaxation time (IRT), isovolumetric contraction time (ICT), and the ejection time (ET), were measured from LV outflow and mitral inflow Doppler velocity profiles.

RESULTS

MPI was higher in patients than in control subjects (0.45 +/- 0.13 vs 0.37 +/- 0.07 P < 0.0029). The increase in MPI was due to the prolongation of IRT without significant change of ICT and ET. MPI cutoff value of > or =0.40 identified impaired LV relaxation with a sensitivity of 63% and specificity of 70% while an IRT >94 ms had a sensitivity of 67% and specificity of 80%. Multivariate analysis identified relative wall thickness, mitral early filling wave velocity (E), and systolic myocardial velocity (Sm) as independent predictors of MPI in patients with hypertension.

CONCLUSIONS

MPI was increase in patients with hypertension, diastolic dysfunction, and normal ejection fraction but was not superior to IRT to detect impaired LV relaxation.

Index of myocardial performance in patients with type 2 diabetes without hypertension and its relationship with clinical and echocardiographic parameters

BACKGROUND

Diabetes mellitus affects the systolic and diastolic function of the left ventricle (LV). The aim of the present study was to evaluate the index of myocardial performance (IMP), a new Doppler index, in asymptomatic, normotensive patients with type 2 diabetes mellitus (T2DM).

METHODS

The study population consisted of 40 asymptomatic normotensive patients with T2DM (22 women, 18 men; mean [±SD] age 49 ± 7 years) and 20 healthy controls (13 women, seven men; mean age 45 ± 4 years). M-Mode and two-dimensional Doppler echocardiography was performed in all subjects to calculate IMP. Venous blood samples were collected for analysis and body mass index (BMI) was calculated.

RESULTS

In normotensive T2DM patients, the mitral E wave was decreased, whereas mitral A wave, mitral E/A ratio, and septal wall thickening were increased compared with values obtained for the control group. The IMP was higher in normotensive T2DM patients than in the control group (P = 0.004). There was a significant correlation between IMP and triglyceride (TG) levels (P < 0.001), mitral E wave (P < 0.001), mitral E/A ratio (P < 0.001), ejection fraction (P = 0.001), fasting blood glucose (P =0.007), LV systolic dimension (P < 0.001), duration of diabetes (P = 0.017), and BMI (P = 0.029). Stepwise multiple regression analysis demonstrated that only TG levels (β = 0.355, t = 2.487, P = 0.017) and the mitral E/A ratio (β = -0.384, t = -2.690, P = 0.011) had an independent effect on IMP.

CONCLUSION

The results of the present study indicate that IMP is increased in normotensive T2DM patients. The findings suggest that increased IMP may be an early sign of diabetic cardiomyopathy in normotensive diabetic patients with preserved LV function.

Maternal cardiac function in normotensive and pre-eclamptic intrauterine growth restriction

OBJECTIVES

To compare maternal cardiac function between pregnancies complicated by normotensive and pre-eclamptic intrauterine growth restriction (IUGR).

METHODS

Two-dimensional Doppler echocardiography and Doppler tissue imaging (DTI) were used to examine 19 pregnant women with IUGR and 17 with pre-eclampsia complicated by IUGR at 20-38 weeks of gestation. Indices were converted into differences in SDs from the expected normal mean for gestation (Z-scores) and compared.

RESULTS

With respect to normal pregnancy, in the normotensive IUGR compared with the pre-eclamptic IUGR group, there were similar reductions in maternal cardiac output (Z-score, - 1.71 vs. - 1.37, P = 0.26) and heart rate (Z-score, - 3.67 vs. - 9.43, P = 0.1) and a similar increase in total vascular resistance (Z-score, 2.91 vs. 3.93, P = 0.05). There was also a greater decrease in stroke volume (Z-score, - 1.72 vs. - 0.69, P = 0.01), a smaller increase in mean arterial pressure (Z-score, 0.73 vs. 2.94, P < 0.01) and a smaller decrease in DTI systolic velocity at the lateral mitral margin (Z-score, - 0.4 vs. - 1.42, P = 0.02). In terms of diastolic function, there was a smaller transmitral late diastolic velocity (Z-score, 0.04 vs. 0.93, P = 0.03) and a greater DTI early diastolic velocity at the lateral mitral margin (Z-score, - 0.17 vs. - 1.6, P < 0.01).

CONCLUSIONS

In normotensive IUGR and pre-eclamptic IUGR there is a similar alteration in maternal left ventricular systolic function, but there is greater impairment in maternal diastolic function in pre-eclamptic IUGR.

Myocardial involvement during the early course of type 2 diabetes mellitus: usefulness of myocardial performance index

To evaluate whether myocardial performance index detects a subclinical impairment of left ventricular systolic and diastolic function in patients with early stage of type 2 diabetes, without coronary artery disease, with or without hypertension. Furthermore, to evaluate whether some echocardiographic parameters relate to the metabolic control. Fourty-five consecutive male patients (mean age 52.5 years) with type 2 diabetes mellitus of recent onset (23 hypertensives and 22 normotensives) and 22 age matched healthy controls males were analysed. All participants had normal exercise ECG. All subjects underwent standard and Doppler echocardiography for the assessment of the isovolumic Doppler time interval and Doppler-derived myocardial performance index. In all diabetic patients a glycated haemoglobin test was also performed.

No differences were observed in blood pressure, heart rate, and conventional echocardiographic parameters comparing the 2 subgroups of diabetic patients and the controls. Myocardial performance index was significantly higher in diabetic patients independently of the hypertension occurrence, compared to the controls (0.49 and 0.49 diabetic normotensives and hypertensives respectively vs. 0.39, p < 0.01). Myocardial performance index correlated to glycated haemoglobin significantly (r = 0.37, p < 0.01) in both diabetic subgroups. Thus, an early involvement of left ventricular performance was shown by myocardial performance index in patients with type 2 diabetes of recent onset without coronary artery disease, independently of the hypertension presence. These abnormalities can provide a feasible approach to detect a pre-clinical diabetic cardiomyopathy and could be useful for an indirect assessment of the metabolic control.

Is chronic diabetic foot ulcer an indicator of cardiac disease?

OBJECTIVE

To evaluate presence and severity of cardiac disease in individuals with chronic diabetic foot ulcers using echocardiography.

METHOD

Eighty consecutive patients with chronic foot ulcers attending the multidisciplinary diabetes foot clinic at Helsingborg Hospital underwent clinical examination, toe blood pressure measurement and a standard echocardiographic examination.

RESULTS

Sixty-nine percent of the patients had a history of myocardial infarction and/or hypertension and/or heart failure; 78% had signs of left ventricular dysfunction and/or left ventricular hypertrophy and/or diastolic dysfunction; 76% of the patients without a history of cardiovascular disease had signs of cardiac dysfunction on echocardiography.

CONCLUSION

Cardiac dysfunction is a common occurrence present in patients with chronic diabetic foot ulcers, even in those without known cardiac disease or hypertension. Echocardiography may be recommended as a screening procedure in the management of diabetic patients with chronic foot ulcers. The present study supports the view that diabetic chronic foot ulcers ought to be seen as a sign of cardiac disease, although further research is needed to elucidate this issue.

Diastolic Dysfunction After an Acute Myocardial Infarction in Patients with Antecedent Hypertension

OBJECTIVE

We sought to assess changes in the left ventricular systolic and diastolic function in patients with antecedent hypertension and an acute myocardial infarction.

METHODS

A group of 38 patients with antecedent hypertension and acute myocardial infarction were compared with an age-matched nonhypertensive control group. There was a 30-day follow-up. Outcome measures were left ventricular volumes and ejection fraction, systolic velocities, and strain. Diastolic function was assessed by mitral inflow combined with tissue velocities of the mitral ring.

RESULTS

Patients with antecedent hypertension did not experience any regression in the E/E' ratio (16.5 +/- 7.5 vs 17.1 +/- 9.0, P = not significant) or increase in the E'/A' ratio (0.76 +/- 0.5 vs 0.84 +/- 0.6, P = not significant) compared with significant improvements in E/E' ratio (18.9 +/- 8.7 vs 12.8 +/- 7.4, P < .01) and E'/A' ratio (0.76 +/- 0.5 vs 1.1 +/- 0.7, P < .01) in the control group. This was found despite similar changes ejection fraction, volumes, and systolic strain.

CONCLUSIONS

Patients with antecedent hypertension have incomplete improvement of the diastolic function compared with control subjects despite comparable left ventricular volumes and ejection fraction after an acute myocardial infarction.

Left ventricle diastolic dysfunction in obese patients with newly diagnosed arterial hypertension

BACKGROUND

The frequent coexistence of obesity and arterial hypertension is well known. Although both conditions have been identified as independent risk factors for impaired left ventricular diastolic function, there is a paucity of data on the dysfunction among obese patients with newly diagnosed arterial hypertension. The study was performed to determine the prevalence of diastolic dysfunction in obese individuals with newly diagnosed arterial hypertension and to compare it with the prevalence in normotensive obese persons.

METHODS

We enrolled 125 obese patients: 65 with newly diagnosed hypertension and 60 normotensive patients matched for age, sex and body mass index. Left ventricular diastolic function was assessed from the following Doppler-echocardiographic measurements: mitral inflow velocities (E and A wave), E wave deceleration time, isovolumetric relaxation time, left atrial and left ventricular diameters, left ventricular wall thickness and left ventricular heart mass index. Diastolic dysfunction was considered when the E/A ratio was <1.

RESULTS

We found significantly higher A wave, lower E/A ratio, longer E deceleration time and a bigger left atrium in obese patients with newly diagnosed arterial hypertension. We did not find significant differences in E wave peak velocities between the two groups. Although there was no difference in left ventricle heart mass or the prevalence of left ventricle hypertrophy, the prevalence of diastolic dysfunction was higher in the group with newly diagnosed arterial hypertension.

CONCLUSION

This study suggests that newly diagnosed arterial hypertension significantly contributes to impairment of left ventricular diastolic function in obese patients before development of structural aberrations detectable on echocardiography.

Cardiac Manifestations of Exhaustive Exercise in Nonathletic Adults: Does Cardiac Fatigue Occur?

The aim of the study was to examine the impact of prolonged exercise leading to physical exhaustion on left ventricular (LV) systolic and diastolic function in untrained healthy subjects, and to examine cardiovascular determinants of exercise performance. Twenty-four nonathletic healthy adults (14 males, 10 females; mean age 42 +/- 11 years) were exercised on a treadmill at 70% of maximal oxygen consumption until physical exhaustion occurred after an average of 84 +/- 39 minutes. Two-dimensional and Doppler echocardiography was performed before and 15 minutes after exercise to assess LV function and geometry, and right ventricular (RV) systolic function. After prolonged exercise, LV ejection fraction and geometry were unchanged, but LV end-diastolic volume, end-systolic volume, and stroke volume decreased. However, due to a higher heart rate (HR), cardiac output increased at 15 minutes post exercise. RV fractional shortening was unchanged. LV peak early to atrial filling velocity ratio decreased post exercise, with an increase in percent atrial contribution. However, less preload-dependent variables of LV diastolic function such as deceleration time, LV inflow propagation rate, mitral annular tissue Doppler and myocardial performance index were unchanged. Preexercise stroke volume and HR were the only predictors (r = 0.86, P < 0.01) of exercise duration. However, age, resting blood pressure, indices of systolic and diastolic function, and LV geometry were not predictors. Prolonged exercise leading to physical exhaustion is not associated with systolic or diastolic dysfunction. Reduced early LV diastolic filling and the relative increase in left atrial contribution seen with prolonged exercise are likely due to preload reduction rather than true diastolic dysfunction.

Role of Exercise and Metabolism in Heart Failure with Normal Ejection fraction

Left ventricular dysfunction associated with metabolic disorders has a number of features that might shed light on the integrity of heart failure with normal ejection fraction. First, although these patients may be dyspneic and have a normal ejection fraction, their diastolic dysfunction is not isolated. Both experimental models and sensitive new parameters in humans have shown abnormal systolic function, even though the less sensitive parameters (such as ejection fraction) become abnormal only with stress. Moreover, the mechanistic contributors to myocardial dysfunction, including structural changes and metabolic influences on the cardiac myocyte, interstitial fibrosis, vascular disease, and altered loading, are likely to influence systolic as much as diastolic function. The responses of systolic and diastolic heart failure to exercise training show analogies, particularly with respect to the importance of peripheral adaptation, as well as a similar training response. Together, these features are more supportive of a continuum of pathophysiology between systolic and diastolic heart failure, rather than the 2 representing discreet phenomena.

Diabetes and diastolic function: stiffness and relaxation from transmitral flow

To characterize the mechanism by which diabetes affects the heart in diabetic (n = 15) and age-matched control subjects (n = 15), we quantified and compared diastolic function (DF) in terms of chamber stiffness and viscosity/relaxation by analyzing Doppler E- and E'-waves and simultaneous (high-fidelity) hemodynamic data. We compared tau, standard Doppler indexes and indexes of stiffness and viscosity/relaxation computed via the parameterized diastolic filling (PDF) formalism. Three PDF parameters uniquely characterize each E-wave in terms of load (x(o)), viscoelasticity or viscosity/relaxation (c) and stiffness (k). Significant differences for c (p = 0.00004), the peak atrioventricular pressure gradient (kx(o)) (p = 0.02) and the stored elastic energy available for early filling (1/2kx(o)2) (p = 0.04) were found. The only conventional index attaining significance was E-wave acceleration time (p = 0.007). Neither time constant of isovolumic relaxation (tau) nor E-wave deceleration time, E', k or x(o) differentiated between groups. We conclude that PDF based DF assessment differentiates between diabetic and nondiabetic controls better than conventional echo- or cath-based indexes. Our results in humans agree with published results from animal studies. We conclude that diabetes affects the heart via a quantifiable increase in chamber viscoelasticity (c) rather than an increase in chamber stiffness (k) and that phenotypic characterization of diabetic cardiomyopathy is facilitated by DF assessment via the PDF formalism.

Measurement of Cardiac Time Intervals by Doppler Tissue M-Mode Imaging of the Anterior Mitral Leaflet

OBJECTIVE

We sought to evaluate a new method of measuring cardiac time intervals from Doppler tissue imaging (DTI) of the anterior leaflet of the mitral valve.

BACKGROUND

For a reliable analysis of the regional cardiac performance by DTI, a reference of time intervals of global cardiac events in the same cardiac cycle and based on the same imaging modality is required to reduce measurement error.

METHODS

We conducted a comparison of the measurements of isovolumic contraction and relaxation time and left ventricular (LV) ejection time by DTI M-mode analysis of the anterior mitral leaflet and the traditional approach based on spectral Doppler recordings. The measurements were done in 20 control subjects and 40 patients with cardiac diseases known to affect cardiac time intervals: heart failure, aortic stenosis, and essential hypertension with LV hypertrophy.

RESULTS

Mean difference in milliseconds (95% limits of agreement) of measurements were not different overall (-0.20 [-10.58; 10.18], -1.95 [-16.66; 12.76], 1.48 [-8.34; 11.34], and 0 [-0.06; 0.07] for isovolumic contraction time, LV ejection time, isovolumic relaxation time, and calculated index of myocardial performance, respectively). Intraobserver variability was low. Analysis of patients with different categories of cardiac diseases confirmed the expected values for time intervals and index of myocardial performance.

CONCLUSIONS

Measurement of isovolumic periods and LV ejection time was feasible and reliable by DTI M-mode analysis of the anterior mitral valve leaflet. The DTI method can, therefore, be used for obtaining information of global events in the cardiac cycle from the same heart beat as used for analysis of regional cardiac performance.

Quantitation of mitral annular oscillations and longitudinal "ringing" of the left ventricle: a new window into longitudinal diastolic function

For diastolic function (DF) quantification, transmitral flow velocity has been characterized in terms of the geometric features of a triangle (heights, widths, areas, durations) approximating the E-wave contour, whereas mitral annular velocity has only been characterized by E'-wave peak amplitude. The fact that E-waves convey global DF information, whereas annular E'-waves provide longitudinal DF information, has not been fully characterized, nor has the physiological legitimacy of combining fluid motion (E)- and tissue motion (E')-derived measurements into routinely used indexes (E/E') been fully elucidated. To place these Doppler echo measurements on a firmer causal, physiological, and clinical basis, we examined features of the E'-wave (and annular motion in general), including timing, amplitude, duration, and contour (shape), in kinematic terms. We derive longitudinal rather than global indexes of stiffness and relaxation of the left ventricle and explain the observed difference between E- and E'-wave durations. On the basis of the close agreement between model prediction and E'-wave contour for subjects having normal physiology, we propose damped harmonic oscillation as the proper paradigm in which to view and analyze the motion of the mitral annulus during early filling. Novel, longitudinal indexes of left ventricular stiffness, relaxation, viscosity, and stored (end-systolic) elastic strain can be determined from the E'-wave (and any subsequent waves) by modeling annular motion during early filling as damped harmonic oscillation. A subgroup exploratory analysis conducted in diabetic subjects (n = 9) and nondiabetic controls (n = 12) indicates that longitudinal DF indexes differentiate between these groups on the basis of longitudinal damping (P < 0.025) and longitudinal stored elastic strain (P < 0.005).

Diastolic dysfunction and mortality in diabetic patients on hemodialysis: a 4.25-year controlled prospective study

Among patients on hemodialysis, the mortality rate is higher in individuals with diabetes than in nondiabetic individuals, especially due to cardiovascular causes. The objective of the present study was to evaluate the role of echocardiographic abnormalities to predict mortality in diabetic patients starting hemodialysis. A 4.25-year prospective study was carried out with 40 diabetic and 28 nondiabetic patients starting hemodialysis in five dialysis centers in the metropolitan area of Porto Alegre, Brazil, between August 1996 and June 1999. Cardiovascular status was evaluated based on World Health Organization criteria, resting electrocardiogram (ECG), myocardial scintigraphy (at rest and after dipyridamole administration), and M-mode and Doppler echocardiography. Left ventricular diastolic function was classified into the following filling patterns: normal, impaired relaxation, pseudonormal, or restrictive. The survival rate was analyzed by Kaplan-Meier curves and predictors of death by Cox's proportional-hazards model. At the end of the study, the overall mortality rate was higher in patients with diabetes [19/40 (47.5%)] than in those without diabetes [2/28 (7.1%), P=.0013, log rank test]. Pseudonormal and restrictive filling patterns (HR: 3.2; 95% CI: 1.2-8.8; P=.02) and presence of diabetes (HR: 4.7; 95% CI: 1.03-21.4; P=.04) were associated with mortality. In conclusion, left ventricular diastolic dysfunction (LVDD) was the main predictor of mortality in this cohort of diabetic and nondiabetic patients starting dialysis. Intensive treatment of cardiovascular risk factors before the start of dialysis and during the treatment might reduce the mortality rate in diabetic patients.

Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases: Results of the Myocardial Doppler in Diabetes (MYDID) Study 1

AIMS

Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension (HTN).

SUBJECTS AND METHODS

Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n = 23), patients with HTN (n = 20), CAD (n = 35), uncomplicated DM (n = 59), DM+HTN (n = 27), DM+CAD (n = 16) and DM+CAD+HTN (n = 20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables.

RESULTS

Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls.

CONCLUSION

The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

Role of impaired myocardial relaxation in the production of elevated left ventricular filling pressure

Although present in many patients with heart failure and a normal ejection fraction, the role of isolated impairments in active myocardial relaxation in the genesis of elevated filling pressures is not well characterized. Because of difficulties in determining the effect of prolonged myocardial relaxation in vivo, we used a cardiovascular simulated computer model. The effect of myocardial relaxation, as assessed by tau (exponential time constant of relaxation), on pulmonary vein pressure (PVP) and left ventricular end-diastolic pressure (LVEDP) was investigated over a wide range of tau values (20-100 ms) and heart rate (60-140 beats/min) while keeping end-diastolic volume constant. Cardiac output was recorded over a wide range of tau and heart rate while keeping PVP constant. The effect of systolic intervals was investigated by changing time to end systole at the same heart rate. At a heart rate of 60 beats/min, increases in tau from a baseline to extreme value of 100 ms cause only a minor increase in PVP of 3 mmHg. In contrast, at 120 beats/min, the same increase in tau increases PVP by 23 mmHg. An increase in filling pressures at high heart rates was attributable to incomplete relaxation. The PVP-LVEDP gradient was not constant and increased with increasing tau and heart rate. Prolonged systolic intervals augmented the effects of tau on PVP. Impaired myocardial relaxation is an important determinant of PVP and cardiac output only during rapid heart rate and especially when combined with prolonged systolic intervals. These findings clarify the role of myocardial relaxation in the pathogenesis of elevated filling pressures characteristic of heart failure.