An Overview of Deep Learning Methods for Left Ventricle Segmentation

Cardiac health diseases are one of the key causes of death around the globe. The number of heart patients has considerably increased during the pandemic. Therefore, it is crucial to assess and analyze the medical and cardiac images. Deep learning architectures, specifically convolutional neural networks have profoundly become the primary choice for the assessment of cardiac medical images. The left ventricle is a vital part of the cardiovascular system where the boundary and size perform a significant role in the evaluation of cardiac function. Due to automatic segmentation and good promising results, the left ventricle segmentation using deep learning has attracted a lot of attention. This article presents a critical review of deep learning methods used for the left ventricle segmentation from frequently used imaging modalities including magnetic resonance images, ultrasound, and computer tomography. This study also demonstrates the details of the network architecture, software, and hardware used for training along with publicly available cardiac image datasets and self-prepared dataset details incorporated. The summary of the evaluation matrices with results used by different researchers is also presented in this study. Finally, all this information is summarized and comprehended in order to assist the readers to understand the motivation and methodology of various deep learning models, as well as exploring potential solutions to future challenges in LV segmentation.

Cathelicidin as a marker for subclinical cardiac changes and microvascular complications in children and adolescents with type 1 diabetes

OBJECTIVES

To detect cathelicidin levels in pediatric patients with type 1 diabetes (T1D) as a potential marker for diabetic vascular complications and to assess its relation to diastolic dysfunction as an index for subclinical macrovasculopathy.

METHODS

Totally, 84 patients with T1D were categorized into three groups; newly diagnosed diabetes group (28 patients with a mean age of 12.38 ± 1.99) years, T1D without microvascular complications group (28 patients with a mean age of 13.04 ± 2.27), and T1D with microvascular complications group (28 patients with a mean age of 13.96 ± 2.30). Patients were evaluated using serum cathelicidin levels and echocardiography.

RESULTS

Total cholesterol, microalbuminuria, and cathelicidin levels were significantly higher in patients with microvascular complications when compared to the other two groups (p<0.001). Additionally, carotid intima-media thickness (CIMT) echocardiography values and diastolic functions were significantly higher in patients with complications (p<0.001). Cathelicidin was positively correlated to the duration of diabetes (r=0.542, p<0.001), total cholesterol (r=0.346, p=0.001), recurrence of hypoglycemia (r=0.351, p=0.001), recurrence of diabetes ketoacidosis (r=0.365, p=0.001), CIMT (r=0.544, p<0.001), and E/A values (r=0.405, p<0.001).

CONCLUSIONS

Serum cathelicidin levels can be used as an early marker for the occurrence and progression of vascular complications in patients with T1D.

Quality of glycemic control has significant impact on myocardial mechanics in type 1 diabetes mellitus

The potential associations between disease duration, glycemic control, and the echocardiographic markers of the myocardial mechanics were investigated in asymptomatic T1DM patients. Seventy T1DM patients (38.2 ± 11.7 years, 46 female) and 30 healthy volunteers were investigated. Besides the conventional and tissue Doppler measurements, left ventricular global longitudinal (GLS) and circumferential (GCS) strain as well as left and right atrial strain parameters were measured with 2D speckle tracking technique. Median HbA_1c level was 7.4 (1.8)%. Even when added age and hypertension to the model, current HbA1c level remained independent predictor of left ventricular GLS (p = 0.002), GCS (p < 0.001), mitral e' (p = 0.018), tricuspid e' (p = 0.018) and left (p = 0.039) and right atrial conduit strain (p = 0.047) in multiple linear regression models. Correlations between disease duration and the echocardiographic variables lost their significance in multiple models. In patients with a combination of HbA_1c ≤ 7.4% and no hypertension, echocardiographic findings did not differ from those in healthy volunteers. Patients with HbA_1c > 7.4% and no hypertension and especially patients with coexisting hypertension and HbA_1c > 7.4%, exhibited significantly impaired myocardial mechanics. Quality of glycemic control has a significant impact on myocardial mechanics in T1DM patients. Regarding disease duration this relationship was not proved.

Use of strain, strain rate, tissue velocity imaging, and endothelial function for early detection of cardiovascular involvement in young diabetics

Background:

Subtle structural and functional changes may precede the onset of overt global left ventricular (LV) dysfunction. Data pertaining to tissue velocity imaging (TVI)and strain imaging to assess regional myocardial function and flow mediated vasodilatation are limited in young patients with diabetes.

Materials:

Conventional echocardiography, TVI parameters along with strain (S), and strain rate (SR) were measured in 50 young diabetics (15.16 ± 2.95 years, mean HBA1c 8.15 ± 1.37 g %) and 25 controls (15.60 ± 2.51 years). Flow-mediated dilation (FMD), nitrate--mediated dilatation (NMD), and carotid intima–media thickness were also assessed.

Results:

Conventional echocardiography parameters were similar in patients and controls; however, deceleration time of the mitral inflow velocity (early deceleration time) was significantly shorter in patients when compared with controls (149.06 ± 31.66 vs. 184.56 ± 19.27 ms, P =0.001). Patients had lower strain values at the basal lateral LV (21.39 ± 4.12 vs. 23.78 ± 2.02; P =0.001), mid-lateral LV (21.43 ± 4.27 vs. 23.17 ± 1.92 P =0.02), basal septum (20.59 ± 5.28 vs. 22.91 ± 2.00; P = 0.01), and midseptum (22.06 ± 4.75 vs. 24.10 ± 1.99; P = 0.01) as compared to controls. SR at the basal and midsegments of the lateral LV wall and at the basal septum was also significantly lower in diabetic patients. Diabetic children also had endothelial dysfunction with significantly lower FMD (8.36 ± 4.27 vs. 10.57 ± 4.12, P = 0.04).

Conclusions:

LV strain indices and flow--mediated dilatation are impaired in asymptomatic children and adolescents with type 1 diabetes mellitus despite absence of overt heart failure and normal ejection fraction. Early detection of subclinical regional myocardial dysfunction by deformation analysis including strain and strain rate may be useful in the asymptomatic diabetic population.

Cardiovascular disease in young People with Type 1 Diabetes: Search for Cardiovascular Biomarkers

Premature onset of cardiovascular disease is common in people with type 1 diabetes and is relatively understudied in youth. Several reports in adolescents and young adults with diabetes demonstrate evidence of arterial stiffness and cardiac dysfunction, yet critical gaps exist in our current understanding of the temporal progression of cardiac and vascular dysfunction in these youth, and mechanistic investigations with robust pathophysiologic assessment are lacking. This review attempts to summarize relevant cardiovascular studies concerning children, adolescents, and young adults with type 1 diabetes. We focus on imaging-based biomarkers routinely applied to youth and adults that are well-established in their ability to predict adjudicated cardiovascular outcomes, and their relevant physiologic interpretation. Particularly, we focus the attention to 1) cardiac ventricular strain imaging techniques which are known to be predictive of clinical outcomes in patients with heterogenous causes of heart failure, and 2) stiffness in large arteries, a well-established prognostic marker of cardiovascular events. We conclude that there remains an urgent need for sensitive and quantitative biomarkers to define the natural history of cardiac and vascular disease origination and progression in type 1 diabetes, and set the stage for interpreting interventional studies focused on preventing, reversing or slowing disease progression.

Three-Dimensional Echocardiography in Evaluating LA Volumes and Functions in Diabetic Normotensive Patients without Symptomatic Cardiovascular Disease

Background

Cardiovascular complications are the most serious threat to diabetic patients. Associated metabolic and microvascular changes are the main cause of cardiac function affection, and the earliest cardiac change is diastolic dysfunction. Assessment of LA function changes is a key to determine early heart damage of diabetic patients.

Objectives

To evaluate the effect of diabetes mellitus on left atrial volumes and functions by using real-time 3-dimensional echocardiography in normotensive patients free from cardiovascular disease.

Methods

The study included 110 individuals, 50 controls and 60 patients with diabetes mellitus, 30 patients with type 1 diabetes mellitus and 30 patients with type 2 diabetes mellitus. 2-dimensional echocardiography was used to assess the LA maximum volume and LA phasic volumes, and LA maximum volume indexed to body surface area were measured by 3D echocardiography. LA functions (LA total stroke volume, LA active stroke volume, and LA active emptying fraction) were obtained from RT3D volumetric analysis.

Results

The results of the analysis revealed that type 2 diabetes mellitus showed enlarged V _max, V _min, and LAVi with an increased LA total stroke volume and decreased active emptying fraction, while type 1 diabetics showed only decreased in active emptying fraction. The LA maximum volume indexed to body surface area (LAVi) was significantly higher in type 2 diabetic patients as compared to normal controls which was 23.55 ± 3.37 ml/m² versus 20.30.

Conclusion

Patients with type 2 diabetes mellitus have an increased LA volume with impaired compliance and contractility, while patients with type 1 diabetes mellitus have only impaired contractility compared to nondiabetic subjects.

Echocardiography improves prediction of major adverse cardiovascular events in a population with type 1 diabetes and without known heart disease: the Thousand & 1 Study

AIMS/HYPOTHESIS

Cardiovascular disease is the most common comorbidity in type 1 diabetes. However, current guidelines do not include routine assessment of myocardial function. We investigated whether echocardiography provides incremental prognostic information in individuals with type 1 diabetes without known heart disease.

METHODS

A prospective cohort of individuals with type 1 diabetes without known heart disease was recruited from the outpatient clinic. Follow-up was performed through Danish national registers. The association of echocardiography with major adverse cardiovascular events (MACE) and the incremental prognostic value when added to the clinical Steno T1D Risk Engine were examined.

RESULTS

A total of 1093 individuals were included: median (interquartile range) age 50.2 (39.2-60.3) years and HbA_1c 65 (56-74) mmol/mol; 53% men; and mean (SD) BMI 25.5 (3.9) kg/m² and diabetes duration 25.8 (14.6) years. During 7.5 years of follow-up, 145 (13.3%) experienced MACE. Echocardiography significantly and independently predicted MACE: left ventricular ejection fraction (LVEF) <45% (n = 18) vs ≥45% (n = 1075), HR (95% CI) 3.93 (1.91, 8.08), p < 0.001; impaired global longitudinal strain (GLS), 1.65 (1.17, 2.34) (n = 263), p = 0.005; diastolic mitral early velocity (E)/early diastolic tissue Doppler velocity (e') <8 (n = 723) vs E/e' 8-12 (n = 285), 1.59 (1.04, 2.42), p = 0.031; and E/e' <8 vs E/e' ≥12 (n = 85), 2.30 (1.33, 3.97), p = 0.003. In individuals with preserved LVEF (n = 1075), estimates for impaired GLS were 1.49 (1.04, 2.15), p = 0.032; E/e' <8 vs E/e' 8-12, 1.61 (1.04, 2.49), p = 0.033; and E/e' <8 vs E/e' ≥12, 2.49 (1.41, 4.37), p = 0.001. Adding echocardiographic variables to the Steno T1D Risk Engine significantly improved risk prediction: Harrell's C statistic, 0.791 (0.757, 0.824) vs 0.780 (0.746, 0.815), p = 0.027; and net reclassification index, 52%, p < 0.001.

CONCLUSIONS/INTERPRETATION

In individuals with type 1 diabetes without known heart disease, echocardiography significantly improves risk prediction over and above guideline-recommended clinical risk factors alone and could have a role in clinical care.

Predictors of early cardiac changes in patients with type 1 diabetes mellitus: An echocardiography-based study

In patients with type 1 diabetes mellitus (T1DM) imaging studies have demonstrated an increased prevalence of left ventricular diastolic dysfunction and increased left ventricular mass (LVM) unrelated to arterial hypertension and ischemic heart disease. The aim of our study was to identify potential predictors of early subclinical changes in cardiac chamber size and function in such patients. Sixty-one middle-aged asymptomatic normotensive patients with T1DM were included in the study. Conventional and tissue Doppler echocardiography was performed and fasting serum levels of glucose, glycated hemoglobin (HbA1c), lipids, and creatinine were measured. We found moderate bivariate correlations of body mass index (BMI) with left atrial volume (r = 0.47, p < 0.01), LVM (r = 0.42, p < 0.01), left ventricular relative wall thickness (r = 0.32, p = 0.01), and all observed parameters of diastolic function of both ventricles. The five-year average value of HbA1c weakly correlated with the Doppler index of left ventricular filling pressure E/e´sept (r = 0.27, p = 0.04). We found no significant association of diabetes duration, five-year trend of HbA1c, serum lipids, and glomerular filtration rate with cardiac structure and function. After adjusting for other parameters, BMI remained significantly associated with left atrial volume, LVM as well as with the transmitral Doppler ratio E/A. In our study, BMI was the only observed parameter significantly associated with subclinical structural and functional cardiac changes in the asymptomatic middle-aged patients with T1DM.

Evaluation of tissue Doppler ultrasonographic and strain imaging for assessment of myocardial dysfunction in dogs with type 1 diabetes mellitus

OBJECTIVE To investigate cardiac structural and functional changes by tissue Doppler imaging (TDI) and strain imaging in dogs with spontaneous type 1 diabetes mellitus. ANIMALS 30 client-owned dogs, of which 10 had normotensive type 1 diabetes mellitus and 20 were healthy. PROCEDURES All dogs underwent physical examination, laboratory analyses, standard echocardiography, and TDI. RESULTS On TDI and strain imaging, transmitral peak early diastolic velocity (E)-to-tissue Doppler-derived peak early diastolic velocity at basal segment (E') of septum ratio, E:lateral E' ratio, and septal tissue Doppler-derived peak late diastolic velocity at basal segment (A') were significantly higher and the septal E':A' ratio and lateral longitudinal strain were significantly lower for diabetic dogs than for control dogs. Furthermore, in diabetic dogs, serum glucose and fructosamine concentrations after a 12-hour period of food withholding were positively correlated with regional systolic functional variables (septal and lateral longitudinal strain) and left ventricular filling pressure indices (E:septal E' and E:lateral E' ratios) but were negatively correlated with diastolic functional variables (E:transmitral peak late diastolic velocity and septal and lateral E':A' ratios). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that myocardial function in diabetic dogs may be altered before the development of clinical heart-associated signs and that the change may be more readily detected by TDI and strain imaging than by conventional echocardiography. In addition, findings indicated that hyperglycemia could have detrimental effects on myocardial function, independent of hypertension, other cardiac diseases, and left ventricular hypertrophy, in dogs with type 1 diabetes.

Subclinical left ventricular systolic and diastolic dysfunction in type 1 diabetic children and adolescents with good metabolic control

OBJECTIVE

Cardiac dysfunction is a well-known consequence of diabetes mellitus. This study was designed to assess whether type 1 diabetic children and adolescents with good metabolic control have early echocardiographic signs of subclinical left ventricular dysfunction and whether diabetes duration has any influence, using conventional and nonconventional echocardiographic tools.

METHODS

A total of 100 patients with type 1 diabetes mellitus and 80 gender- and age-matched healthy controls were included. The cases underwent standard conventional transthoracic echocardiography, tissue Doppler imaging, and two-dimensional speckle tracking echocardiography. None of the diabetic patients had signs of renal, retinal, or neurological complications of the disease, and all were good metabolic control (mean HbA_1c <7.5%).

RESULTS

There was no difference among groups in relation to age, sex, body mass index, and blood pressure. Conventional echocardiographic parameters were similar between diabetic and nondiabetic subjects except increased mitral valve peak A-wave and significantly lower mitral E/A ratio in diabetics. Diabetic patients had more advanced diastolic dysfunction with TDI analysis. In the diabetic group, left ventricular global longitudinal, circumferential, and radial strain and strain rate were significantly lower compared with the controls. There was a positive correlation between diabetes duration and cardiac dysfunction.

CONCLUSION

The results of this study showed that the diabetic children and adolescents with good metabolic control had diastolic dysfunction when assessed with either conventional or tissue Doppler echocardiography. Also diabetic patients had subclinical LV systolic dysfunction with a normal LVEF which can be detected with 2D speckle tracking echocardiography.

Advanced glycation end products in children with type 1 diabetes and early reduced diastolic heart function

BACKGROUND

Reduced diastolic function is an early sign of diabetes cardiomyopathy in adults and is associated with elevated levels of HbA1c and advanced glycation end products (AGEs).

OBJECTIVE

To assess the associations between early reduced diastolic function and elevated levels of HbA1c and AGEs in children and adolescents with type 1 diabetes (T1D).

METHODS

One hundred fourty six T1D patients (age 8-18 years) without known diabetic complications were examined with tissue Doppler imaging and stratified into two groups according to diastolic function. A clinical examination and ultrasound of the common carotid arteries were performed. Methylglyoxal-derived hydroimidazolone-1 (MG-H1) was measured by immunoassay.

RESULTS

At inclusion, 36 (25%) participants were stratified into a low diastolic function group (E'/A'-ratio < 2.0). Compared to the rest of the T1D children, these participants had higher body mass index (BMI), 22.8 (SD = 4.0) vs. 20.1 (SD = 3.4) kg/m², p < 0.001, higher systolic blood pressure 104.2 (SD = 8.7) vs. 99.7 (SD = 9.3) mmHg, p = 0.010, and higher diastolic blood pressure, 63.6 (SD = 8.3) vs. 59.9 (SD = 7.9) mmHg, p = 0.016. The distensibility coefficient was lower, 0.035 (SD = 0.010) vs. 0.042 (SD = 0.02) kPa^-1, p = 0.013, Young's modulus higher, 429 (SD = 106) vs. 365 (SD = 143), p = 0.009, and MG-H1 higher, 163.9 (SD = 39.2) vs. 150.3 (SD = 33.4) U/ml, p = 0.046. There was no difference in carotid intima-media thickness between the groups. There were no associations between reduced diastolic function and years from diagnosis, HBA1c, mean HBA1c, CRP or calculated glycemic burden. Logistic regression analysis showed that BMI was an independent risk factor for E'/A'-ratio as well as a non-significant, but relatively large effect size for MG-H1, indicating a possible role for AGEs.

CONCLUSIONS

Early signs of reduced diastolic function in children and adolescents with T1D had higher BMI, but not higher HbA1c. They also had elevated serum levels of the advanced glycation end product MG-H1, higher blood pressure and increased stiffness of the common carotid artery, but these associations did not reach statistical significance when tested in a logistic regression model.

Evaluation of Cardiac Functions in Children and Adolescents with Type 1 Diabetes

Background

Cardiac dysfunction in patients with type 1 diabetes (T1D) represents one of the serious complications. To evaluate the cardiac function in children with T1D by conventional echocardiography and tissue Doppler imaging (TDI).

Methods

The study included 40 T1D patients (age between 6 and 16 years) with > 5 years duration of diabetes and 42 healthy control children. The patients were subjected to clinical evaluation and laboratory investigations [glycosylated hemoglobin A1c (HbA1c), serum lipids and lipoproteins]. Conventional echocardiography and TDI were performed to patients and controls.

Results

The patients had lower early diastolic filling velocity (E wave) of the tricuspid valve and mitral valves with a p value of (0.000 and 0.006, respectively). TDI revealed that patients had lower S′velocity of the T1D, shorter isovolumic contraction time, longer isovolumic relaxation time and lower E/E′ of the right ventricle than controls (p value 0.002, 0.001, 0.004, 0.003, and 0.016, respectively). The left ventricle (LV)-T1D of the patients was significantly higher (p value 0.02). Twenty eight patients had poor glycemic control without significant differences between them and those with good glycemic control regarding echocardiographic data. Patients with dyslipidemia (13 patients) had higher late diastolic filling velocity of the mitral valve (A) and the lower LV late tissue velocity (A′) (p wave 0.047 and 0.015). No correlation existed between the duration of illness or the level of HbA1c and the echocardiographic parameters.

Conclusion

Diabetic children have evidence of echocardiographic diastolic dysfunctions. Periodic cardiac evaluation with both conventional and tissue Doppler echocardiography is recommended for early detection of this dysfunction.

Decreased regional left ventricular myocardial strain in type 1 diabetic children: a first sign of diabetic cardiomyopathy?

BACKGROUND AND OBJECTIVES

Type 1 diabetes is a major cardiovascular risk factor associated with an excess of mortality in young adults due to premature cardiovascular events, which includes heart failure. The relation between type 1 diabetes and cardiac structure and function in children was poorly documented. Our study investigates (1) whether type 1 diabetic children have echocardiographic signs of subclinical cardiac dysfunction assessed by tissue Doppler strain and (2) whether state of metabolic control and diabetes duration have any influence on the cardiac event.

METHODS

Standard echocardiography and tissue Doppler imaging were prospectively performed in type 1 diabetic children. Left ventricular dimensions, standard indices of systolic and diastolic function, and septal longitudinal strain were investigated.

RESULTS

Thirty consecutive asymptomatic diabetic children (age: 12.4 [5-17] years; males: 53%) were compared to 30 age and sex-matched healthy control subjects. Left ventricular mass index and diastolic septal thickness were significantly increased in diabetic children. There was no difference between two groups as regards the left ventricular ejection fraction and conventional mitral Doppler parameters (E, A, Ea). The global longitudinal systolic strain and strain rate were found to be decreased in children with diabetes. The global longitudinal early diastolic strain rate (Esr) was negatively correlated with metabolic control. Longitudinal strain was not correlated with diabetes duration.

CONCLUSION

Children with Type 1 diabetes had subclinical alterations in left ventricular size and longitudinal myocardial deformation.

Non-ischemic diabetic cardiomyopathy may initially exhibit a transient subclinical phase of hyperdynamic myocardial performance

Cardiovascular complications are the key cause for mortality in diabetes mellitus. Besides ischemia-related cardiac malfunction there is growing evidence for non-ischemic diabetes-associated heart failure in both type 1 and type 2 diabetes mellitus. The underlying pathophysiology of non-ischemic diabetic cardiomyopathy (NIDC) is poorly understood and data on myocardial mechanics in early stages of the disease are rare. However, several studies in both human and experimental animal settings have reported prima facie unexplained features indicating myocardial hyperdynamics early in the course of the disease. The new hypothesis is that - other than previously thought - NIDC may be non-linear and initially feature an asymptomatic subclinical phase of myocardial hypercontractility that precedes the long-term development of diabetes-associated cardiac dysfunction and ultimately heart failure. Diabetes-induced metabolic imbalances may lead to a paradoxic inotropic increase and inefficient myocardial mechanics that finally result in a gradual deterioration of myocardial performance. In conclusion, diabetic patients should be screened regularly and early in the course of the disease utilizing ultra-sensitive myocardial deformation imaging in order to identify patients at risk for diabetes-associated heart failure. Moreover, hyperdynamic myocardial deformation might help distinguish non-ischemic from ischemic diabetic cardiomyopathy. Further studies are needed to illuminate the underlying pathophysiological mechanisms, the exact spatiotemporal evolvement of diabetic cardiomyopathy and its long-term relation to clinical outcome parameters.

Early reduced myocardial diastolic function in children and adolescents with type 1 diabetes mellitus a population-based study

BACKGROUND

Reduced diastolic myocardial function is an early sign of diabetic cardiomyopathy. The aim of this study was to test the hypothesis that children and adolescents with type 1 diabetes mellitus (T1D), but without other known complications, have early reduced diastolic myocardial function diagnosed with echocardiographic color tissue Doppler imaging (cTDI).

METHODS

cTDI examination was carried out in 173 T1D patients and 62 age-matched controls. The T1D-patients were 8-18 years old with (mean (SD)) diabetes duration of 5.6 (3.4) years and HbA1c of 8.4 (1.3). All were treated with either insulin pumps or 4-6 daily insulin injections. cTDI early (E') and late (A') peak diastolic velocities and systolic peak velocity were measured from the lateral, septal, anterior and posterior mitral annulus and from the lateral tricuspidal annulus.

RESULTS

Myocardial diastolic function was reduced in the T1D-patients with higher peak A'-velocity and lower E'/A'-ratio in all registrations. Overall mean (SD) mitral E'/A'-ratio was 2.3 (0.5) in T1D and 2.7 (0.6) in the controls (p < 0001). The overall mitral E'/A'-ratio was negative associated with blood pressure (BP) and body mass index (BMI). Stratifying all participants into three groups according to BMI (<25, 25-75, >75 centile, respectively), the T1D had lower E'/A'-values in all stratified groups, except for in the highest BMI-group where both T1D and controls had the lowest E'/A'-ratio. Systolic function did not differ in any of the measurements. There were no associations with sex, diabetes duration, carotid artery intima-media-thickness, vessel elasticity or HbA1c.

CONCLUSION

Diabetic children and adolescents using modern intensive insulin treatment had echocardiographic signs of reduced diastolic myocardial function despite short duration of disease. The reduced function was associated with higher BP and higher BMI.

Tissue Doppler imaging is a sensitive echocardiographic technique to detect subclinical systolic and diastolic dysfunction of both ventricles in type 1 diabetes mellitus

Background

Subclinical left (LV) and right ventricular (RV) dysfunction has been demonstrated in type 2 diabetes mellitus and evidence indicates impaired LV diastolic function in type 1 diabetes mellitus (T1DM) as well. The aim of our study was to evaluate the role of tissue Doppler imaging (TDI) in assessment of global LV and RV function in T1DM patients.

Methods

A detailed two-dimensional, pulsed wave Doppler and pulsed wave TDI analysis was performed in 53 normotensive middle-aged T1DM patients and compared to healthy controls.

Results

In T1DM patients TDI analysis revealed reduced mean mitral septal and lateral E’ velocities as well as reduced mean tricuspid E˙t velocity compared to healthy controls (E’sept 8.89 ± 1.89 cm/s vs. 11.50 ± 2.41 cm/s, p < 0.001; E’lat 12.29 ± 2.58 cm/s vs.15.30 ± 2.95 cm/s, p < 0,001; E’t 13.56 ± 2.91 cm/s vs. 15.60 ± 2.99 cm/s, p = 0.001). Mean ratios E/E’sept, E/E’lat and E/E’t were significantly higher in diabetics with cutoff value of 7.4 for E/E’sept and 3.4 for E/E’t, differentiating diabetics with LV and RV diastolic impairement from matched healthy controls (sensitivity 76.5 %, specificity 73.8 % for E/E’sept and sensitivity 72.1 %, specificity 66.7 % for E/E’t). Myocardial acceleration during isovolumetric contraction (IVA) measured at the septal mitral (LV IVA) and lateral tricuspid annulus (RV IVA) was the only parameter indicating reduced contractility of both ventricles in diabetics compared to controls (LV IVA 230.70 ± 61.26 cm/s² vs. 283.32 ± 59.74 cm/s², p < 0,001; RV IVA 275.48 ± 68.08 cm/s² vs. 316.86 ± 80.95 cm/s², p = 0.011). LV IVA had better diagnostic accuracy than RV IVA to predict early contractile impairement in T1DM patients (area under the curve 0.758, p < 0.001 for LV IVA and 0.648, p = 0.017 for RV IVA).

Conclusions

TDI is essential to detect subclinical diastolic deterioration of both ventricles in T1DM patients. TDI-derived IVA might be useful to assess early systolic alterations of both ventricles in T1DM patients.

Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study

Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV) myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM). 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5 ± 3.1 years and mean disease duration 4.3 ± 3.5 years) and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate) during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p = 0.019) and circumferential (p = 0.016) strain rate both at rest and during exercise (p = 0.021). This was more pronounced in T1DM patients with a longer disease duration (p = 0.038). T1DM patients with serum HbA1c > 9% showed impaired longitudinal (p = 0.008) and circumferential strain (p = 0.005) and a reduced E/A-ratio (p = 0.018). In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment.

Left and right ventricular systolic function impairment in type 1 diabetic young adults assessed by 2D speckle tracking echocardiography

AIMS

Subclinical left ventricular (LV) and right ventricular (RV) systolic dysfunction has been proved in type 2 diabetes mellitus (DM). There is lack of uniform data on systolic myocardial function in type 1 DM. The aim of this study was to evaluate LV and RV function with 2D speckle tracking echocardiography (2D STE) in adult type 1 diabetic patients.

METHODS AND RESULTS

Totally, 50 patients with type 1 DM and 50 control subjects in the same range of age were prospectively evaluated. The 2D STE assessment of LV longitudinal, radial, circumferential strain and RV free-wall longitudinal strain was performed. In diabetic group, left ventricular global longitudinal strain (LVGLS), left ventricular global circumferential strain (LVGCS), left ventricular radial strain at basal level (LVRS-basal), and right ventricular free-wall global longitudinal strain (RVGLS) were significantly lower compared with the controls: LVGLS (-20.3 ± 2.0% vs. -22.2 ± 1.8%, P < 0.001), LVGCS (-21.1 ± 2.5% vs. -22.2 ± 2.4%, P < 0.05), LVRS-basal (50.5% ± 11.5 vs. 57.1% ±17.0, P < 0.05), and RVGLS (-30.1% ± 3.5 vs. -32.7% ± 3.9, P < 0.01). Multivariable logistic regression analysis showed that the only independent predictor of reduced LVGLS was low-density lipoprotein cholesterol [odds ratio 3.65 (95% confidence interval: 1.27-10.5), P = 0.014].

CONCLUSION

Type 1 DM is associated with subclinical LV systolic dysfunction and worse RV systolic function, which can be detected with 2D STE.

Biventricular function and glycemic load in type 1 diabetic children: Doppler tissue-imaging study

To assess right- and left-ventricular function in children with type 1 diabetes mellitus (DM) as well as correlate cardiac function with diabetes duration and state of metabolic control. The present study included 30 patients with type 1 DM (group 1) and 20 apparently normal children with comparable age and sex as controls (group 2). All children were subjected to detailed history, clinical examination, and routine laboratory investigations, including glycated hemoglobin, as well as conventional echocardiographic and tissue Doppler examination. Children with type 1 DM have impaired diastolic function in both left and right ventricles before the development of systolic dysfunction when assessed with either conventional or tissue Doppler echocardiography. Resting heart rate in diabetic patients showed a significant positive correlation with mitral A flow velocity and a significant negative correlation with mitral and tricuspid E/A ratio. Regarding morphological parameters of the left ventricle, all dimensions and volumes were comparable between diabetic patients and controls; however, a significant positive correlation was found between interventricular septal thickness at diastole (IVSd), interventricular septal thickness at systole (IVSs), and left ventricular posterior wall at systole (LVPWs) and the duration of diabetes. Children with type 1 DM have impaired diastolic function in both left and right ventricles with normal systolic function when assessed with either conventional or tissue Doppler echocardiography.

Assessment of left ventricular myocardial systolic acceleration in diabetic rats using velocity vector imaging

OBJECTIVES

The purpose of this study was to investigate how the myocardial acceleration during isovolumic contraction changed in rats with diabetic cardiomyopathy and a normal left ventricular ejection fraction (LVEF) by using velocity vector imaging.

METHODS

Velocity vector imaging was performed in 12 control rats and 15 rats with streptozotocin-induced diabetic cardiomyopathy 12 weeks after streptozotocin injection. The segmental radial displacement, velocity, acceleration, and percent wall thickening were measured at the mid-left ventricular (LV) level.

RESULTS

Compared to control rats, rats with cardiomyopathy had a significant decrease in the peak radial acceleration during isovolumic contraction in most segments of the LV wall (including the anterior, anterolateral, inferolateral, and inferior segments; P < .05) but a similar LVEF, fractional shortening, and segmental displacement. Rats with cardiomyopathy also had a significant increase in LV end-diastolic and end-systolic diameters when corrected for body mass (P < .001; P = .003, respectively) and a significant decrease in the radial peak systolic velocities of the inferolateral and inferior wall segments (P < .05). In addition, rats with cardiomyopathy had a significant decrease in the peak radial diastolic acceleration in most segments of the LV wall (except for the anterolateral one; P< .05) but similar peak radial diastolic velocities in all LV wall segments compared to controls. Pathologic examination in rats with cardiomyopathy revealed ultrastructural impairment of the capillary and cardiocyte without any atherosclerotic lesion in the coronary artery compared to control rats.

CONCLUSIONS

Myocardial acceleration during isovolumic contraction decreases in rats with diabetic cardiomyopathy and a preserved LVEF, suggesting the presence of regional LV systolic dysfunction.

Prevalence of systolic and diastolic dysfunction in patients with type 1 diabetes without known heart disease: the Thousand & 1 Study

AIMS/HYPOTHESIS

Heart failure is one of the leading causes of mortality in type 1 diabetes. Early identification is vitally important. We sought to determine the prevalence and clinical characteristics associated with subclinical impaired systolic and diastolic function in type 1 diabetes patients without known heart disease.

METHODS

In this cross-sectional examination of 1,093 type 1 diabetes patients without known heart disease, randomly selected from the Steno Diabetes Center, complete clinical and echocardiographic examinations were performed and analysed in uni- and multivariable regression models.

RESULTS

The mean (SD) age was 49.6 (15) years, 53% of participants were men, and the mean duration of diabetes was 25.5 (15) years. Overall, 15.5% (n = 169) of participants had grossly abnormal systolic or diastolic function, including 1.7% with left ventricular ejection fraction (LVEF) < 45% and 14.4% with evidence of long-standing diastolic dysfunction. In univariable models, clinical characteristics associated with abnormal myocardial function were: age (per 10 years), OR (95% CI) 2.1 (1.8, 2.4); diabetes duration (per 10 years), 1.7 (1.4, 1.9); systolic BP ≥ 140 mmHg, 2.7 (1.9, 3.8); diastolic BP ≥ 90 mmHg, 1.8 (1.0, 3.1); estimated (e)GFR < 60 ml min(-1) 1.73 m(-2), 3.8 (2.5, 5.9); microalbuminuria, 2.0 (1.3, 3.0); macroalbuminuria, 5.9 (3.8, 9.3); proliferative retinopathy, 3.6 (2.3, 5.8); blindness, 10.1 (3.2, 31.6); and peripheral neuropathy, 3.8 (2.7, 5.3). In multivariable models only age (2.1 [1.7, 2.5]), female sex, (1.9 [1.2, 2.8]) and macroalbuminuria (5.2 [2.9, 10.3]) remained significantly associated with subclinical grossly abnormal myocardial function.

CONCLUSIONS/INTERPRETATION

Subclinical myocardial dysfunction is a common finding in type 1 diabetes patients without known heart disease. Type 1 diabetes patients with albuminuria are at greatly increased risk of having subclinical abnormal myocardial function compared with patients without albuminuria. Echocardiography may be particularly warranted in patients with albuminuria.

Prevalence, predictors and evolution of echocardiographically defined cardiac abnormalities in adults with type 1 diabetes: an observational cohort study

AIMS/HYPOTHESIS

The aims of this observational study were to determine the prevalence and predictors of an abnormal echocardiogram in adults with type 1 diabetes, and to assess the evolution of changes in a subset of subjects.

METHODS

Cardiac function and structure were prospectively investigated by comprehensive transthoracic echocardiographic techniques in asymptomatic adults with type 1 diabetes seen in the ambulatory care setting.

RESULTS

We recruited 136 subjects (mean age 39 years, SD 14 years) with a median diabetes duration of 21 years [25(th), 75(th) interquartile range; 11, 29]. An abnormal echocardiogram was present in 29% of subjects; diastolic dysfunction in 69%, left ventricular hypertrophy in 38% and systolic dysfunction in 10%. The independent predictors of an abnormal echocardiogram were age, with a 9-fold increase in those ≥40 years (OR 9.40 [95% CI 2.68-33.04], P <0.0001), and increased body mass index (BMI), with a 17% increase in risk (P=0.04). A second echocardiogram was available in 65 subjects (3.8±1.7 years later). The results showed that one in five with a normal first study had developed an abnormal second study, mainly diastolic dysfunction, with age being the only independent predictor of progression (P=0.006).

CONCLUSIONS/INTERPRETATION

Subclinical echocardiographic abnormalities are common in asymptomatic type 1 diabetes adults, and changes are progressive. The addition of an echocardiogram to complication surveillance programs in those with type 1 diabetes aged ≥40 years may represent a cost-effective way to screen for, and aggressively treat, occult cardiac disease.

Diabetic cardiomyopathy: pathophysiology and clinical features

Since diabetic cardiomyopathy was first reported four decades ago, substantial information on its pathogenesis and clinical features has accumulated. In the heart, diabetes enhances fatty acid metabolism, suppresses glucose oxidation, and modifies intracellular signaling, leading to impairments in multiple steps of excitation–contraction coupling, inefficient energy production, and increased susceptibility to ischemia/reperfusion injury. Loss of normal microvessels and remodeling of the extracellular matrix are also involved in contractile dysfunction of diabetic hearts. Use of sensitive echocardiographic techniques (tissue Doppler imaging and strain rate imaging) and magnetic resonance spectroscopy enables detection of diabetic cardiomyopathy at an early stage, and a combination of the modalities allows differentiation of this type of cardiomyopathy from other organic heart diseases. Circumstantial evidence to date indicates that diabetic cardiomyopathy is a common but frequently unrecognized pathological process in asymptomatic diabetic patients. However, a strategy for prevention or treatment of diabetic cardiomyopathy to improve its prognosis has not yet been established. Here, we review both basic and clinical studies on diabetic cardiomyopathy and summarize problems remaining to be solved for improving management of this type of cardiomyopathy.

Impaired diastolic function and elevated Nt-proBNP levels in type 1 diabetic patients without overt cardiovascular disease

Diabetic cardiomyopathy is an important complication of type 1 diabetes mellitus. Diastolic heart failure is an early manifestation of diabetic cardiac disease. Nt-proBNP is a valuable marker of ventricular dysfunction. The aim of this study was to determine Nt-proBNP concentrations in type 1 diabetic patients and determine their relationship with ventricular diastolic dysfunction (DD) and carotid artery intima media thickness (CIMT) measurements. Sixty-seven type 1 diabetic patients (30.2 ± 8.0 years; W/M: 24/43) without known cardiovascular disease and 48 healthy controls (30.5 ± 6.4 years; W/M: 19/29) were recruited. Nt-proBNP levels were measured. Conventional and tissue Doppler echocardiography were used to evaluate left ventricular diastolic function and CIMT. Nt-proBNP in diabetic patients was significantly higher than in controls (38 ± 34.8 vs. 15.1 ± 12.7 pg/ml) (P = 0.004). Ea level was higher (12.3 ± 3 vs. 10.3 ± 4 cm/s, P = 0.003) and E/Ea ratio was lower in patients (6.6 ± 2.5 vs. 9.7 ± 5.9, P = 0.001) compared with controls. Ratio of DD was higher in patients than controls (11.1 vs. 2.1%, P = 0.01). CIMT measurements in diabetic patients were higher than controls (0.54 ± 0.11 vs. 0.48 ± 0.05 mm, P = 0.02). Logistic regression revealed age and HbA1c to be independently associated with the presence of DD. Nt-proBNP levels are elevated in type 1 diabetic patients without overt cardiovascular disease and the presence of DD is increased in diabetic patients in comparison with controls. Nt-proBNP levels do not seem to be related to the presence of DD and subclinical atherosclerosis in this group of patients.

Left atrial volume index as a marker of left ventricular diastolic dysfunction in asymptomatic Tanzanian diabetic patients

AIM

To determine the prevalence of left atrial (LA) enlargement and its relation to left ventricular (LV) diastolic dysfunction among asymptomatic diabetic outpatients attending Muhimbili National Hospital in Dar es Salaam, Tanzania.

METHODS

Echocardiography was performed in 122 type 2 and 58 type 1 diabetic patients. Diastolic dysfunction was defined as peak transmitral blood velocity to medial mitral annulus velocity (E/E') ratio ≥ 15. LA volume indexed to body surface area (LAVI) was considered enlarged if ≥ 29 ml/m(2).

RESULTS

Enlarged LAVI and LV diastolic dysfunction were more common in type 2 than in type 1 diabetic patients (44.3 vs 25.9% and 20.5 vs 3.5%, respectively, both p < 0.05). In multivariate linear regression analysis, larger LAVI was associated with LV diastolic dysfunction independent of significant associations with LV mass index and presence of mitral regurgitation in type 2 diabetic patients, while LV mass index, lower ejection fraction and longer duration of diabetes were the main covariates of larger LAVI in type 1 diabetic patients (all p < 0.05).

CONCLUSION

Enlarged LA is common among asymptomatic Tanzanian diabetic patients, and particularly associated with LV diastolic dysfunction in type 2, and with cardiomyopathy and lower systolic function in type 1 diabetic patients.

Left ventricular radial systolic dysfunction in diabetic patients assessed by myocardial acceleration derived from velocity vector imaging

OBJECTIVES

The purpose of this study was to determine whether left ventricular (LV) radial systolic dysfunction occurred in diabetic patients with a normal left ventricular ejection fraction (LVEF) and impaired longitudinal contraction.

METHODS

Velocity vector imaging was performed in 22 patients with type 2 diabetes without microangiopathy (12 men and 10 women; mean age ± SD, 49 ± 7 years), 21 patients with microangiopathy (12 men and 9 women; mean age, 50 ± 6 years), and 21 healthy control participants (11 men and 10 women; mean age, 49 ± 8 years). The groups were matched for age and sex. All had no clinical symptoms of heart disease, coronary artery disease, or hypertension.

RESULTS

The LVEF, fractional shortening, and end-diastolic diameter were statistically comparable in all groups. The left ventricular wall thickness was significantly greater in diabetic patients than controls (P < .05). Average peak early diastolic accelerations at all LV levels were significantly lower in diabetic patients than controls in the long-and short-axis directions (all P < .05). In the long-axis direction, a significantly lower average peak isovolumic contraction acceleration was found at the mid and apical levels in patients without microangiopathy and at all LV levels in patients with microangiopathy than controls (all P < .05). In the short-axis direction, a significantly lower average isovolumic contraction acceleration was found at the apical level in patients without microangiopathy and at the basal and apical levels in patients with microangiopathy (all P < .05).

CONCLUSIONS

In diabetic patients with a normal LVEF, myocardial systolic dysfunction occurs not only in the long-axis direction but also in the short-axis direction.

Glycaemic control and incidence of heart failure in 20,985 patients with type 1 diabetes: an observational study

BACKGROUND

Poor glycaemic control is associated with microvascular and macrovascular complications in type 1 diabetes, but whether glycaemic control is associated with heart failure in such patients is not known. We aimed to assess this association in a large cohort of patients with type 1 diabetes identified from the Swedish national diabetes registry.

METHODS

We identified all patients (aged ≥18 years) with type 1 diabetes and no known heart failure who were registered in the national diabetes registry between January, 1998, and December, 2003. These patients were followed up until hospital admission for heart failure, death, or end of follow-up on Dec 31, 2009. We calculated incidence categorised by glycated haemoglobin A(1c) (HbA(1c)) values, and we assessed the association between patients' characteristics, including HbA(1c), and heart failure.

FINDINGS

In a cohort of 20,985 patients with mean age of 38·6 years (SD 13·3) at baseline, 635 patients (3%) were admitted to hospital with a primary or secondary diagnosis of heart failure during a median follow-up of 9·0 years (IQR 7·3-11·0), with an incidence of 3·38 events per 1000 patient-years (95% CI 3·12-3·65). Incidence increased monotonically with HbA(1c), with a range of 1·42-5·20 per 1000 patient-years between patients in the lowest (<6·5%) and highest (≥10·5%) categories of HbA(1c). In a Cox regression analysis, with adjustment for age, sex, duration of diabetes, cardiovascular risk factors, and baseline or intervening acute myocardial infarction and other comorbidities, the hazard ratio for development of heart failure was 3·98 (95% CI 2·23-7·14) in patients with HbA(1c) of 10·5% or higher compared with a reference group of patients with HbA(1c) of less than 6·5%. Risk of heart failure increased with age and duration of diabetes. Other modifiable factors associated with increased risk of heart failure were smoking, high systolic blood pressure, and raised body-mass index. In a subgroup of 18,281 patients (87%) with data for blood lipids, higher HDL cholesterol was associated with lower risk of heart failure, but there was no association with LDL cholesterol.

INTERPRETATION

The positive association between HbA(1c) and risk of heart failure in fairly young patients with type 1 diabetes indicates a potential for prevention of heart failure with improved glycaemic control.

FUNDING

AstraZeneca, Novo Nordisk Scandinavia, Swedish Heart and Lung Foundation, and Swedish Research Council.

The relationship between early left ventricular myocardial alterations and reduced coronary flow reserve in non-insulin-dependent diabetic patients with microvascular angina

AIMS

To evaluate left ventricular (LV) systolic and diastolic myocardial function, and their relation to coronary flow reserve in patients with non-insulin-dependent diabetes mellitus (DM) and microvascular angina.

METHODS AND RESULTS

We selected a population of 45 normotensive patients with DM (56.3 ± 8.2 years; 25 males) with LV ejection fraction >50% and microvascular angina (anginal pain, positive imaging stress test and normal coronary angiography). Thirty-five age- and sex-matched healthy controls were also enrolled. All the patients underwent standard echocardiography, Tissue Doppler (TDI), two-dimensional strain (2DSE) imaging, and coronary flow reserve (CFR) measurement. LV myocardial early diastolic peak velocities (E(m)) and peak systolic 2DSE were reduced in both interventricular septum (IVS) and LV lateral wall (p<0.01) in DM, as well as CFR (1.89 ± 0.7 vs 2.55 ± 0.56, p<0.0001) compared with controls. By multivariate analysis, the independent determinants of E(m) were glycated haemoglobin (β coefficient=-0.36; p<0.01) and age (β=-0.46, p<0.001), while global longitudinal strain was predicted by glycated haemoglobin (β=0.48, P<0.001) and by the duration of the disease (β=0.38, P<0.005). An independent association between LV global longitudinal strain and CFR (β coefficient=-0.47, p<0.001) in DM patients was also evidenced.

CONCLUSIONS

TDI, 2DSE and CFR are valuable non-invasive and easy-repeatable tools for detecting LV myocardial and coronary function in DM patients with microvascular angina.

Current cardiac imaging techniques for detection of left ventricular mass

Estimation of left ventricular (LV) mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE) is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR) and cardiovascular computed tomography (CCT) are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test.