Left ventricular diastolic function is related to glucose in a middle-aged population

Left ventricular diastolic dysfunction in diabetes mellitus and the therapeutic role of exercise training

Abstract Left ventricular diastolic dysfunction (LVDD) with normal ejection fraction is considered common among people with diabetes mellitus (DM). LVDD is a progressive condition and an independent predictor of mortality in diabetic patients. The etiopathogenesis of LVDD is multifactorial, including diabetes associated comorbidities, such as hypertension, coronary atherosclerosis and obesity, as well as myocardial vascular and metabolic disturbances which lead to diabetic cardiomyopathy. Early stages of LVDD may be detected using echocardiographic techniques. Treatment strategies evolve, based on a better understanding of pathogenic mechanisms, although it is still difficult to efficiently control LVDD evolution. This review synthesizes the main pathophysiological processes and clinical features that characterize DM associated LVDD. Among treatment options, the therapeutic relevance of exercise training programs is underlined. Key words: diabetes mellitus, left ventricular diastolic dysfunction, physical training,

The effects of type 1 diabetes mellitus on cardiac functions in children: evaluation by conventional and tissue Doppler echocardiography

BACKGROUND

Several studies have pointed out the existence of cardiac dysfunction in patients with type 1 diabetes mellitus (DM) even in the absence of ischemic, valvular, or hypertensive heart disease. The present study evaluated cardiac dysfunction and the relationship between severity of disease and degree of cardiac dysfunction in children with type 1 DM.

METHODS

In this prospective study, 31 patients with type 1 DM and 33 sex- and age-matched healthy children were evaluated with conventional echocardiography and tissue Doppler echocardiography (TDE). A correlation between cardiac functions and glycated hemoglobin (HbA1C) was examined.

RESULTS

TDE results indicated that mitral valve early diastolic annular peak flow rate (E'), mitral valve systolic flow rate (S'), ratio of mitral valve early diastolic peak flow rate to mitral valve early diastolic annular peak flow rate (E/E'), and left ventricular (LV) myocardial performance index (MPI) were higher, and LV ejection time (ET) was shorter in patients with type 1 DM (p<0.05). In addition, tricuspid valve E' and right ventricular (RV) MPI were higher, while RV ET and tricuspid E/E' were lower in patients with type 1 DM compared to healthy children (p<0.05).

CONCLUSIONS

Although conventional echocardiography revealed no difference between patients with type 1 DM and healthy children, TDE showed dysfunctions of both ventricles. This state is closely related to degree of blood glucose level control. These findings signify diagnostic value of TDE in the early detection of cardiac effects among patients with type 1 DM.

Study on Diastolic Dysfunction in Newly Diagnosed Type 2 Diabetes Mellitus and its Correlation with Glycosylated Haemoglobin (HbA1C)

INTRODUCTION

Left ventricular diastolic dysfunction (LVDD) represents the first stage of diabetic cardiomyopathy preceding changes in systolic function, reinforcing the importance of early examination of ventricular function in individuals with diabetes mellitus (DM). This cross-sectional study was conducted to determine the incidence of asymptomatic LVDD in newly diagnosed normotensive cases of type 2 diabetes subjects, and its relation to glycosylated haemoglobin (HbA1C), age at the time of diagnosis, body mass index (BMI) and serum total cholesterol.

AIM AND OBJECTIVE

To study the incidence of left ventricular diastolic dysfunction (LVDD) and its correlation with HbA1C in normotensive, newly diagnosed type 2 diabetic patients.

MATERIALS AND METHODS

This cross-sectional study was done in western U.P. on 100 patients of newly diagnosed (within 1 month) type 2 DM between patients 30 and 60 years of age, visiting the Medicine and Endocrinology outpatient Department of LLRM Medical College, Meerut. Patients with established type 2 diabetes and already taking antidiabetic treatment, cardiac diseases like valvular heart disease, ischemic and hypertensive heart disease, congestive heart failure, cardiomyopathy, renal failure, chronic pulmonary disease, severe anaemia and haemoglobinopathies were excluded from the study. These patients were informed about the study and informed consent was obtained before proceeding with the investigations. Patients selected were evaluated with relevant investigations like fasting and post prandial blood sugar, HbA1C level, lipid profile and 2D echocardiography to assess LVDD. These selected patients were divided in 2 groups; one with left ventricular diastolic dysfunction (LVDD) and second group of subjects without LVDD. Various parameters like HbA1C, age, body mass index and serum cholesterol were evaluated between these 2 groups. Statistical analysis was performed using Student t-test, Chi-square and Fisher Exact-test.

RESULTS

Out of 100 patients 65 were males and 35 females. Mean age of the population was 50.08 ± 6.32 years. Overall incidence of LVDD was 41%. Grade 1 LVDD was most common. Mean HbA1C level of LVDD group was found higher as compared to those without LVDD.

CONCLUSION

LVDD is very common at the time of diagnosis of type 2 DM even in normotensive patients independent of confounding effect of hypertension, ischemia and BMI. HbA1C and age, were found to be strong indicators of LVDD in newly diagnosed cases of Type 2 DM.

Hyperglycemia has a greater impact on left ventricle function in South Asians than in Europeans

OBJECTIVE Diabetes is associated with left ventricular (LV) diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction owing to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycemia in LV dysfunction in a community-based cohort of older South Asians and white Europeans. RESEARCH DESIGN AND METHODS Conventional and Doppler echocardiography was performed in 999 participants (542 Europeans and 457 South Asians aged 58-86 years) in a population-based study. Anthropometry, fasting bloods, coronary artery calcification scoring, blood pressure, and renal function were measured. RESULTS Diabetes and hyperglycemia across the spectrum of HbA1c had a greater adverse effect on LV function in South Asians than Europeans (N-terminal-probrain natriuretic peptide β ± SE 0.09 ± 0.04, P = 0.01, vs. -0.04 ± 0.05, P = 0.4, P for HbA1c/ethnicity interaction 0.02), diastolic function (E/e' 0.69 ± 0.12, P < 0.0001, vs. 0.09 ± 0.2, P = 0.6, P for interaction 0.005), and systolic function (s' -0.11 ± 0.06, P = 0.04, vs. 0.14 ± 0.09, P = 0.1, P for interaction 0.2). Multivariable adjustment for hypertension, microvascular disease, LV mass, coronary disease, and dyslipidemia only partially accounted for the ethnic differences. Adverse LV function in diabetic South Asians could not be accounted for by poorer glycemic control or longer diabetes duration. CONCLUSIONS Diabetes and hyperglycemia have a greater adverse effect on LV function in South Asians than Europeans, incompletely explained by adverse risk factors. South Asians may require earlier and more aggressive treatment of their cardiometabolic risk factors to reduce risks of LV dysfunction.

Plasma glucose levels and left ventricular diastolic function in nondiabetic hypertensive patients

BACKGROUND

Changes in left ventricular (LV) diastolic filling anticipate diastolic heart failure and are frequently detected in patients with hypertension or diabetes. We tested the hypothesis that increased fasting and postload glucose levels are associated with diastolic dysfunction as assessed by tissue Doppler imaging (TDI) in hypertensive patients.

METHODS

In 104 untreated, nondiabetic, hypertensive patients free of cardiovascular complications, we measured glucose and insulin at fast and after an oral glucose load, calculated the Homeostatic Model Assessment (HOMA) index, and performed electrocardiogram (ECG), conventional echocardiography, and TDI.

RESULTS

Thirty-one patients who had impaired fasting glucose/impaired glucose tolerance had more frequent LV strain at ECG and worse TDI markers of diastolic function than patients with normal plasma glucose but no differences in variables LV mass, LV geometry, systolic function, and early-/late-wave transmitral diastolic velocity. TDI detected diastolic dysfunction in 46 patients who were older and had greater body mass index, blood pressure, fasting and postload glucose, insulin, HOMA index, LV mass, and left atrial diameter than patients with preserved diastolic function. Variables of diastolic function measured at TDI were significantly related with age, body mass index, LV mass, and fasting and postload plasma glucose. Stepwise regression analysis showed that the relationship of markers of diastolic dysfunction with both fasting and postload glucose levels was independent of possible confounders.

CONCLUSIONS

Initially abnormal fasting and postload glucose levels are associated with more prominent diastolic impairment in uncomplicated hypertensive patients, suggesting that hyperglycemia might increase the risk of diastolic heart failure even in the absence of diabetes.

Serum adiponectin and hsCRP levels and non-invasive radiological methods in the early diagnosis of cardiovascular system complications in children and adolescents with type 1 diabetes mellitus

OBJECTIVE

Adiponectin and high-sensitivity C-reactive protein (hsCRP) can be used as early biochemical markers of cardiovascular diseases (CVDs). Radiologically, non-invasive flow-mediated dilation (FMD) of the brachial artery and carotid intima-media thickness (CIMT) measurements may be used as indicators in the early diagnosis of CVDs. To compare the biochemical markers of atherosclerosis with radiological markers of CVDs (CIMT, FMD, ventricular systolic and diastolic functions) and to assess the relationship of these parameters with metabolic control in diabetic children and adolescents.

METHODS

A total of 55 patients with type 1 diabetes mellitus (T1DM) of at least 5-year duration and 30 healthy subjects were included in the study. Serum adiponectin, hsCRP, hemoglobin A1c (HbA1c), and lipid levels were evaluated in the patients and in the controls. CIMT, FMD, ventricular systolic and diastolic functions were assessed by echocardiography.

RESULTS

Mean age of the patients with diabetes was 17.6 years; mean diabetes duration was 10.4 years. Mean serum hsCRP was elevated in children with diabetes (0.21±0.31 vs. 0.10±0.16 μg/mL, p=0.00), while no significant difference from the controls was found in adiponectin levels. Mean CIMT was significantly higher in diabetic children compared to the control group (0.53±0.11 vs. 0.34±0.46 mm, p=0.00). Mean FMD of the diabetic children was significantly lower than that of the controls (6.86±2.85% vs. 12.13±1.99%, p=0.00). Diabetes duration was positively correlated with CIMT and negatively correlated with FMD. Right ventricular (RV) and left ventricular (LV) myocardial performance index (MPI) were higher in the patient group (p=0.00).

CONCLUSIONS

Our data suggest that in addition to standard echocardiography, tissue Doppler echocardiography, FMD, and CIMT can be used as early-stage radiological markers and hsCRP as an early-stage biochemical marker of atherosclerosis in the routine follow-up of T1DM patients.

Diastolic function is reduced in adolescents with type 1 diabetes in response to exercise

OBJECTIVE

To determine whether adolescents with type 1 diabetes have left ventricular functional changes at rest and during acute exercise and whether these changes are affected by metabolic control and diabetes duration.

RESEARCH DESIGN AND METHODS

The study evaluated 53 adolescents with type 1 diabetes and 22 control adolescents. Baseline data included peak exercise capacity and body composition by dual-energy X-ray absorptiometry. Left ventricular functional parameters were obtained at rest and during acute exercise using magnetic resonance imaging.

RESULTS

Compared with nondiabetic control subjects, adolescents with type 1 diabetes had lower exercise capacity (44.7 ± 09 vs. 48.5 ± 1.4 mL/kg fat-free mass [FFM]/min; P < 0.05). Stroke volume was reduced in the diabetes group at rest (1.86 ± 0.04 vs. 2.05 ± 0.07 mL/kg FFM; P = 0.02) and during acute exercise (1.89 ± 0.04 vs. 2.17 ± 0.06 mL/kg FFM; P = 0.01). Diabetic adolescents also had reduced end-diastolic volume at rest (2.94 ± 0.06 vs. 3.26 ± 0.09 mL/kg FFM; P = 0.01) and during acute exercise (2.78 ± 0.05 vs. 3.09 ± 0.08 mL/kg FFM; P = 0.01). End-systolic volume was lower in the diabetic group at rest (1.08 ± 0.03 vs. 1.21 ± 0.04 mL/kg FFM; P = 0.01) but not during acute exercise. Exercise capacity and resting and exercise stroke volumes were correlated with glycemic control but not with diabetes duration.

CONCLUSIONS

Adolescents with type 1 diabetes have reduced exercise capacity and display alterations in cardiac function compared with nondiabetic control subjects, associated with reduced stroke volume during exercise.

Age and gender differences in the association between Nt-proBNP and glucometabolic disturbances

OBJECTIVES

Glucometabolic disturbances are associated with myocardial dysfunction. Brain natriuretic peptides (BNP) are used for detecting myocardial dysfunction in clinical practice. However, studies on elderly subjects and gender-specific analyses are sparse.

DESIGN

We examined cross-sectional associations between Nt-proBNP and 1) fasting plasma glucose (FPG), and 2) categories of glucometabolic disturbances, in middle-aged and older subjects (1266 men, 526 women), applying multivariate linear regression analysis.

RESULTS

FPG was positively correlated with Nt-proBNP among middle-aged men (p = 0.04) and negatively albeit non-significantly (p = 0.1) among middle-aged women. Weaker non-significant correlations were seen among older subjects. Middle-aged men with new-onset and prevalent diabetes had higher Nt-proBNP than the reference group (FPG ≤5.0 mmol/L): 9.53 (p = 0.002) and 8.23 (p = 0.02) vs. 5.71 pmol/L. No differences in Nt-proBNP between categories of glucometabolic disturbance were observed among older men or women.

CONCLUSIONS

The results indicate an age- and gender difference in the ability of Nt-proBNP to identify myocardial dysfunction in relation to glucometabolic disturbances. Therefore, Nt-proBNP should be used with caution as a general surrogate marker for myocardial dysfunction in this setting.

Myocardial structure and function by echocardiography in relation to glucometabolic status in elderly subjects from 2 population-based cohorts: a cross-sectional study

BACKGROUND

Left ventricular (LV) diastolic dysfunction has been associated with impaired glucometabolic status. However, studies of older subjects are lacking. We examined associations between echocardiographic indices of LV diastolic function and LV mass index (LVMI) and glucometabolic status among middle-aged and elderly subjects free from heart disease, hypothesizing that the associations would be comparative to younger cohorts.

METHODS

We examined the Age Gene/Environment Susceptibility Reykjavik Study (Iceland; n = 607, 76 +/- 6 years) and the Malmö Preventive Project Re-Examination Study (MPP-RES) cohorts (Sweden; n = 1,519, 67 +/- 6 years), evaluating associations with multivariable regression analysis.

RESULTS

In the Age Gene/Environment Susceptibility Reykjavik Study, LVMI was positively correlated with glycosylated hemoglobin (HbA1c) (P = .001). Otherwise, echocardiographic variables were not associated with glucometabolic status. In the MPP-RES, LVMI increased with increasing glucometabolic disturbance among both older (70-80 years) and middle-aged (57-69 years) subjects. Among older subjects, HbA1c was positively correlated with 2 variables reflecting LV diastolic function: late transmitral peak flow velocity (A) (P = .001) and early transmitral peak flow velocity (E)/early diastolic peak tissue velocity (Em) (P = .046). In middle-aged MPP-RES subjects, increasing glucometabolic disturbance was correlated with increasing late diastolic peak tissue velocity (Am) (P = .002) and, after age adjustment, with increasing A (P = .001) and decreasing Em/Am (P = .009). With age adjustment, Am and A were positively correlated with fasting glucose and HbA1c.

CONCLUSIONS

Contrary to our hypothesis, in 2 independent cohorts of older individuals, associations between glucometabolic status and LV diastolic function were generally weak. These contrast with previous reports, as well as with observations among middle-aged subjects in the present study. Changes in LV diastolic function may be more age-related than associated with glucose metabolism in older subjects.

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.

Cardiovascular impairment in children, adolescents, and young adults with type 1 diabetes mellitus (T1DM)

Left ventricular (LV) function was assessed in 42 patients (mean age +/- SD, 18.45 +/- 3.76 years; 17 males) with type I diabetes mellitus (T1DM; mean duration 9.89 years) and in 43 healthy controls (mean age +/- SD, 18.27 +/- 3.36 years; 18 males). Systolic, diastolic cardiac function and LV dimensions were assessed using M-mode and Doppler echocardiography. Neural autonomic function was assessed by measuring RR variation during deep breathing, Valsava maneuver, 30/15 ratio, and blood pressure response to standing. Fractional shortening, peak velocity of early ventricular filling (E wave), peak velocity of LV filling (A wave), E/A ratio, deceleration time, isovolumic relaxation time, LV dimensions (interventricular septum, posterior wall thickness, end diastolic diameter [EDD] and systolic diameter [ESD]) were all comparable between patients with T1DM and controls. However, in 11 T1DM patients with microalbuminuria and/or retinopathy, EDD, ESD, E/A ratio, and E wave were all lower (p = 0.0011, p = 0.019, p = 0.0011, and p = 0.030, respectively) while, A wave, heart rate, and diastolic blood pressure were all higher (p = 0.008, p = 0.0024 and p = 0.004, respectively) compared to matched for age and sex controls. Furthermore, in six of the 11 T1DM patients with microangiopathy who had E/A <1.12 (<2 SD of the control mean), significant and marginally significant correlations were found between E/A ratio and the duration of the disease as well as the mean HbA1c of the last year (r = -0.38, p = 0.011 and r = -0.287, p = 0.064, respectively). In conclusion, it has been found that impairment of diastolic, but not systolic, LV function can be detected early in young patients with T1DM and microangiopathy.

Early signs of left ventricular dysfunction in adolescents with type 1 diabetes mellitus: the importance of impaired circadian modulation of blood pressure and heart rate

Diabetic cardiomyopathy is a well-defined complication of diabetes that occurs in the absence of ischemic heart disease or hypertension. Moreover impaired circadian blood pressure (BP) variation has been associated with autonomic dysfunction. The aim of our study was to evaluate diurnal BP fluctuations and autonomic function and their association with left ventricular function in adolescents with Type 1 diabetes mellitus (T1DM). In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/-SD) age of 17.3 (+/-4.1) yr and a mean (+/-SD) diabetes duration of 8.5 (+/-3.3) yr, 24-h ambulatory BP was recorded. Moreover 24-h heart rate (HR) monitoring was performed. Myocardial structural parameters were studied by echocardiogram. Left ventricular end-diastolic (EDDLV) and end-systolic diameters (ESDLV) were estimated and left ventricular mass index (LVMI) was calculated using the Devereux formula. The patients were divided into 2 groups according to the absence of decrease (non-dippers) or the decrease (dippers) of nocturnal diastolic BP (DBP). The non-dippers showed, in comparison with the dippers, reduced mean 24-h HR (79.6 vs 84.0 beats/min, p=0.05) and reduced mean day-time HR (81.3 vs 86.0 beats/min, p=0.05). The nondippers also presented greater ESDLV (28.7 vs 25.9 mm, p=0.001) and EDDLV (47.8 vs 45.1 mm, p=0.040), and LVMI (90.2 vs 78.3 g/m2, p=0.044), in comparison with the dippers. During stepwise multiple regression, the most important variables affecting LVMI were mean HR (day): (b=-0.40, p=0.001), high frequency domain variable of HR variability (b=0.38, p=0.016) and glycosylated hemoglobin (b=0.67, p=0.001). In conclusion, we found that a group of normotensive diabetic adolescents with impaired nocturnal BP reduction, also had autonomic dysfunction, together with impaired left ventricular function. These findings suggest that there is a close relationship between autonomic function and left ventricular remodeling in patients with T1DM, which may be attributed to altered diurnal BP profile, autonomic neuropathy and poor glycemic control.

Left ventricle diastolic dysfunction in diabetes: an update

Diabetes mellitus, a disease that has been reaching epidemic proportions, is an important risk factor to the development of cardiovascular complication. Diabetes causes changes within the cardiac structure and function, even in the absence of atherosclerotic disease. The left ventricular diastolic dysfunction (VE) represents the earliest pre-clinical manifestation of diabetic cardiomyopathy, preceding the systolic dysfunction and being able to evolve to symptomatic heart failure. The doppler echocardiography has emerged as an important noninvasive diagnostic tool, providing reliable data in the stages of diastolic function, as well as for systolic function. With the advent of recent echocardiographic techniques, such as tissue Doppler and color M-mode, the accuracy in identifying the moderate diastolic dysfunction, the pseudonormal pattern, has significantly improved. Due to cardiometabolic repercussions of DM, a detailed evaluation of cardiovascular function in diabetic patients is important, and some alterations may be seen even in patients with gestational diabetes.

Is glycated haemoglobin a sensitive index to identify left ventricular dysfunction two months after acute myocardial infarction in normotensive subjects?

BACKGROUND

Glycated haemoglobin concentration (HbA1c) is a marker of glucose metabolism. Glucose intolerance is associated with a high incidence of left ventricular (LV) dysfunction after acute myocardial infarction (AMI). This study was carried out in order to relate HbA1c to LV function two months following AMI in 171 normotensive patients who were not previously known to have had diabetes mellitus.

METHODS

Oral glucose tolerance test (GTT) and HbA1c. Echo and Doppler-cardiography were used to measure the E/A (peak velocity of the early filling/atrial contraction waves) at rest and at peak isometric exercise (IME), deceleration time (DT) of E wave, LV ejection fraction (LVEF), LV mass index and diastolic LV function.

RESULTS

GTT was diabetic in 20, impaired in 35 and normal in 116 subjects. HbA1c was >6.0% (cut off level for high risk subjects) in 76 patients (67%) with impaired relaxation (E/A<1) during IME and in 30 patients (27%) with restrictive LV filling (identified by E/A=1-2, DT<140 ms). The sensitivity and specificity of HbA1c to predict underlying impaired LV relaxation were 68% and 37%, respectively, and to predict restrictive LV filling were 27% and 98%, respectively. Whereas in univariate analysis, DT.3 was linearly related to HbA1c only (p=0.0002), multiple regression analysis showed that HbA1c was related to LVEF, DT and E/A but not to LVH, LVMI, smoking habit, age, gender and creatinine kinase level during admission for AMI.

CONCLUSION

At 2 months after admission for AMI, HbA1c is related to systolic and diastolic LV function but not to LVMI or LVH. HbA1c is a sensitive predictor of impaired relaxation but highly specific to rule out underlying non-restrictive LV filling.

Determinants of exercise capacity in patients with type 2 diabetes

OBJECTIVE

Type 2 diabetes is associated with reduced exercise capacity, but the cause of this association is unclear. We sought the associations of impaired exercise capacity in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Subclinical left ventricular (LV) dysfunction was sought from myocardial strain rate and the basal segmental diastolic velocity (Em) of each wall in 170 patients with type 2 diabetes (aged 56 +/- 10 years, 91 men), good quality echocardiographic images, and negative exercise echocardiograms. The same measurements were made in 56 control subjects (aged 53 +/- 10 years, 29 men). Exercise capacity was calculated in metabolic equivalents, and heart rate recovery (HRR) was measured as the heart rate difference between peak and 1 min after exercise. In subjects with type 2 diabetes, exercise capacity was correlated with clinical, therapeutic, biochemical, and echocardiographic variables, and significant independent associations were sought using a multiple linear regression model.

RESULTS

Exercise capacity, strain rate, Em, and HRR were significantly reduced in type 2 diabetes. Exercise capacity was associated with age (r = -0.37, P < 0.001), male sex (r = 0.26, P = 0.001), BMI (r = -0.19, P = 0.012), HbA(1c) (A1C; r = -0.22, P = 0.009), Em (r = 0.43, P < 0.001), HRR (r = 0.42, P < 0.001), diabetes duration (r = -0.18, P = 0.021), and hypertension history (r = -0.28, P < 0.001). Age (P < 0.001), male sex (P = 0.007), BMI (P = 0.001), Em (P = 0.032), HRR (P = 0.013), and A1C (P = 0.0007) were independent predictors of exercise capacity.

CONCLUSIONS

Reduced exercise capacity in patients with type 2 diabetes is associated with diabetes control, subclinical LV dysfunction, and impaired HRR.

Tissue Doppler imaging for the detection and quantitation of myocardial dysfunction in patients with type 2 diabetes mellitus

The prevalence of type 2 diabetes mellitus is rapidly increasing. Myocardial dysfunction may be a consequence of diabetic cardiomyopathy and it contributes to the poor prognosis of diabetic patients.

AIMS

This study was designed to test whether tissue Doppler imaging might be a suitable tool for early detection of myocardial dysfunction in diabetic patients.

METHODS

Forty-three diabetic patients and 33 non-diabetic controls, including age-matched subgroups without evidence of coronary artery disease (n=12), were recruited if they had normal LV-function by standard 2-D echocardiography and no clinical signs of heart failure. They were investigated with tissue Doppler imaging at rest and during pharmacological stress with dipyridamole and/or dobutamine. Myocardial function was calculated as the mean value from six basal myocardial segments for peak velocity at systole (Vs), early diastole (Ve) and atrial contraction (Va).

RESULTS

Compared to controls, diabetic patients had compromised Ve at rest (8.5 +/- 1.7 vs. 9.6 +/- 1.9 cm/sec, p < 0.02), as did the subgroups without coronary artery disease (9.3 +/- 1.7 vs. 10.7 +/- 1.5 cm/sec, p < 0.05). Dobutamine stress resulted in lower Vs (10.7 +/- 2.7 vs. 13.6 +/- 3.4 cm/sec, p < 0.05) and Ve (10.0 +/- 2.1 vs. 13.1 +/- 3.8 cm/sec, p < 0.05) in the diabetic patients, demonstrating an impaired increase of Vs, Vd and Va (p < 0.05, p < 0.0003 and p < 0.03, respectively). An inverse correlation was observed between Ve and age in both control and diabetic individuals. Thus, abnormal values were defined in relation to age.

CONCLUSIONS

Diastolic and systolic myocardial dysfunction in patients with type 2 diabetes may be identified by quantitative tissue Doppler imaging before the onset of clinical signs of heart failure and before the appearance of traditional echocardiographic indices of systolic myocardial dysfunction.

Left ventricular diastolic dysfunction: an early sign of diabetic cardiomyopathy?

The existence of a diabetic cardiomyopathy has been proposed as evidence has accumulated for the presence of myocardial dysfunction in diabetic patients in the absence of ischemic, valvular or hypertensive heart disease. Diastolic dysfunction has been described as an early sign of this diabetic heart muscle disease preceding the systolic damage. Abnormalities in diastolic performance have been first demonstrated by cardiac catheterisation and subsequently by mainly using echocardiography. The pathogenesis of this left ventricular dysfunction is not clearly understood. Microangiopathy, increased extracellular collagen deposition, or abnormalities in calcium transport alone or in combination are considered to be associated with this dysfunction. The relationship between diastolic dysfunction and glycemic control is still a matter of debate. Some epidemiological and clinical arguments suggest that diastolic abnormalities may contribute to the high morbidity and mortality among diabetic patients. However, the prognostic importance of subclinical diastolic dysfunction and the possibilities for intervention are not fully known. Eventually, despite numerous studies, evidence of an intrinsic diastolic dysfunction in diabetes mellitus remains questionable. Indeed, quite contradictory results have been reported. They have been obtained in small, inhomogeneous populations, with sometimes confounding factors, using various echocardiographic indices with known limitations. Also, further studies using more refined techniques for the evaluation of diastolic function are needed, as a prerequisite, to unequivocally relate diabetes mellitus to a specific cardiomyopathy.

Female children and adolescents with type 1 diabetes have more pronounced early echocardiographic signs of diabetic cardiomyopathy

OBJECTIVE

This study was designed to assess whether children and adolescents with type 1 diabetes have early echocardiographic signs of subclinical cardiac dysfunction and whether sex, state of metabolic control, and diabetes duration are of influence.

RESEARCH DESIGN AND METHODS

Systolic and diastolic blood pressure in supine and upright positions and echocardiographic parameters, including tissue Doppler measurements of the septal mitral annulus, were evaluated in 80 children and adolescents with stable type 1 diabetes and 52 age- and sex-matched control subjects. A possible correlation was examined for age, sex, HbA(1c), and diabetes duration with univariate and multivariate regression analysis.

RESULTS

Female diabetic patients showed significantly larger left ventricular wall dimensions (left ventricular posterior wall in diastole 0.54 +/- 0.08 vs. 0.48 +/- 0.11 cm) and signs of significant diastolic filling abnormalities on conventional and tissue Doppler echocardiography (mitral valve-atrial contraction velocity 0.47 +/- 0.12 vs. 0.40 +/- 0.09 m/s; tricuspid valve-atrial contraction velocity 0.35 +/- 0.09 vs. 0.30 +/- 0.07 m/s; early filling velocity/myocardial velocity during early filling 7.15 +/- 1.47 vs. 6.17 +/- 1.07; isovolumetric relaxation time [IVRT] 66 +/- 8 vs. 58 +/- 8 ms) compared with female control subjects, suggesting delayed myocardial relaxation. Male diabetic patients only differed significantly from their control subjects for IVRT (66 +/- 9 vs. 59 +/- 8 ms). The measured parameters showed an expected correlation with age and BMI standard deviation scores in the control group. This correlation was significantly weaker in the diabetic population; only a weak influence was found for diabetes duration and glycosylated hemoglobin levels.

CONCLUSIONS

Young diabetic patients already have significant changes in left ventricular dimensions and myocardial relaxation, with the girls clearly being more affected. Tissue Doppler proved to have additional value in the evaluation of ventricular filling in this population. Almost no correlation was found for diabetes duration and HbA(1c) with the cardiovascular changes.