Right ventricular involvement in diabetic cardiomyopathy

Right ventricular dysfunction in preclinical models of type I and type II diabetes

Diabetic cardiomyopathy (DCM) is a growing clinical entity and major health burden characterized by comorbid diabetes mellitus and heart failure. DCM has been commonly associated with impaired function of the left ventricle (LV); however, DCM likely also occurs in the right ventricle (RV) which has distinct physiology and pathophysiology from the LV. RV dysfunction is the strongest determinant of mortality in several clinical contexts yet remains poorly studied in diabetes. We investigated RV-specific pathophysiology using two models of diabetes-a well-characterized type 2 diabetes (T2DM) model of high-fat diet and low-dose streptozotocin (STZ) in the mouse and a large animal model of type I diabetes in domestic pigs rendered diabetic with STZ. RV global and systolic function deteriorated with diabetes, alongside hypertrophic and fibrotic remodeling. We report evidence of impaired RV insulin sensitivity, dysregulated RV metabolic gene expression, and impaired mitochondrial dynamics. Importantly, while some of these outcomes were similar to those widely reported in the LV, others were not, such as unchanged antioxidant gene expression and regulators of fatty acid uptake. Importantly, these RV-specific changes occurred in both male and female T2DM mice, together emphasizing the importance of distinguishing the RV from the LV when studying DCM and begging the consideration of RV-specific therapies.

Clinical parameters of death and heart failure hospitalization in biventricular systolic dysfunction assessed via cardiac magnetic resonance

AIMS

While factors associated with adverse events are well elucidated in setting of isolated left ventricular dysfunction, clinical and imaging-based prognosticators of adverse outcomes are lacking in context of biventricular dysfunction. The purpose of this study was to establish role of clinical variables in prognosis of biventricular heart failure (HF), as assessed by cardiac magnetic resonance imaging.

METHODS

Study cohort consisted of 840 patients enrolled in DERIVATE registry with coexisting CMR-derived right ventricular (RV) and left ventricular (LV) dysfunction, as defined by RV and LV ejection fractions ≤45 % and ≤ 50 %, respectively. The primary objective was to identify factors associated with adverse long-term outcomes, defined as composite of all-cause death and HF hospitalizations (DHFH). Kaplan-Meir curves were plotted for survival analysis. Cox proportional hazard models were constructed to estimate adjusted hazard ratios (aHRs) and associated 95 % confidence intervals for clinical variables and their correlation with adverse events.

RESULTS

Mean age was 61.0 years; 83.1 % were male, 26.6 % had diabetes mellitus (DM), and 45.9 % had non-ischemic cardiomyopathy. At median follow-up of 2 years, DHFH occurred in 32.5 % of the cohort. Kaplan-Meir analysis showed higher rate of DHFH in patients with DM (35.2 % vs. 22.6 %, p < 0.001). Multivariate Cox regression analysis showed that DM was independently associated with DHFH (aHR 1.61 [95 % CI: 1.15-2.25]; p = 0.003). Importantly, ACE-inhibitor/ARB usage in patients with DM was associated with significant reduction in DHFH (aHR 0.53 [95 % CI: 0.31-0.90]; p = 0.02).

CONCLUSION

In patients with biventricular HF, DM was a strong predictor of DHFH, with ACE-inhibitor/ARB usage having cardioprotective effect.

Association of Glycemic Control With Right Ventricular Function Assessed by Two-Dimensional Speckle-Tracking and Three-Dimensional Echocardiography in Type 2 Diabetes Mellitus

BACKGROUND

Right ventricular (RV) involvement has been reported in type 2 diabetes mellitus (T2DM). The relationship between glycemic control and RV function remains unknown. We aimed to investigate the association between glycemic control and RV function assessed by two-dimensional speckle-tracking echocardiography and three-dimensional echocardiography in T2DM individuals.

METHODS

This study prospectively enrolled 207 patients with T2DM and 84 individuals with normal glucose metabolism. The T2DM patients were divided into 2 subgroups according to glycated hemoglobin (HbA1c) level: controlled (HbA1c < 7.0%, n = 91) and uncontrolled subgroup (HbA1c ≥ 7.0%, n = 116). Right venticular free wall longitudinal strain (RVFWLS) was acquired by two-dimensional speckle-tracking echocardiography, and RV volumes and RV ejection fraction (RVEF) were assessed using three-dimensional echocardiography . Right ventricular coupling to pulmonary circulation was defined as the ratio of RVFWLS/pulmonary artery systolic pressure (PASP).

RESULTS

Controlled and uncontrolled T2DM subgroups had impaired RV function as reflected by reduced RVFWLS and RVEF compared to the normal glucose metabolism group. The reduction in RVFWLS was more pronounced in the uncontrolled subgroup than in the controlled subgroup (P < .001), whereas no significant difference was found in RVEF between these 2 T2DM subgroups. Higher PASP and lower RVFWLS/PASP ratio were also noted in uncontrolled T2DM patients. Additionally, the incidence of RV dysfunction was significantly higher in the uncontrolled T2DM patients than in the controlled subgroup (43.1% vs 17.6%, P < .001). After adjustment for potential clinical confounders, PASP, and left ventricular parameters, HbA1c level was independently associated with RVFWLS (β = 0.290, P = .003) and RVFWLS/PASP ratio (β = 0.028, P = .006).

CONCLUSIONS

Subclinical RV myocardial dysfunction is present in T2DM patients and is more pronounced in patients with uncontrolled blood glucose. HbA1c level is independently associated with subclinical RV myocardial dysfunction, providing further insight into a possible link between poor glycemic control and diabetic cardiomyopathy.

Association between subclinical right ventricular alterations and aerobic exercise capacity in type 2 diabetes

BACKGROUND

Type 2 diabetes (T2D) leads to cardiovascular remodeling, and heart failure has emerged as a major complication of T2D. There is a limited understanding of the impact of T2D on the right heart. This study aimed to assess subclinical right heart alterations and their contribution to aerobic exercise capacity (peak oxygen consumption; peak VO2) in adults with T2D.

METHODS

Single center, prospective, case-control comparison of adults with and without T2D, and no prevalent cardiac disease. Comprehensive evaluation of the left and right heart was performed using transthoracic echocardiography and stress cardiovascular magnetic resonance. Cardiopulmonary exercise testing on a bicycle ergometer with expired gas analysis was performed to determine peak VO2. Between group comparison was adjusted for age, sex, race, and body mass index using analysis of covariance (ANCOVA). Multivariable linear regression, including key clinical and left heart variables, was undertaken in people with T2D to identify independent associations between measures of right ventricular (RV) structure and function with peak VO2.

RESULTS

Three hundred and forty people with T2D (median age 64years, 62% (211) male, mean glycated hemoglobin (HbA1c) 7.3%) and 66 controls (median age 58years, 58% (38) male, mean HbA1c 5.5%) were included. T2D participants had markedly lower peak VO2 (adjusted mean 20.3 (95% confidence interval (CI): 19.8-20.9) vs 23.3(22.2-24.5)mL/kg/min, P < 0.001) than controls and had smaller left ventricular (LV) volumes and LV concentric remodeling. Those with T2D had smaller RV volumes (indexed RV end-diastolic volume: 84 (82-86) vs 100 (96-104)mL/m, P < 0.001) with evidence of hyperdynamic RV systolic function (global longitudinal strain (GLS): 26.3 (25.8-26.8) vs 23.5 (22.5-24.5)%, P < 0.001) and impaired RV relaxation (longitudinal peak early diastolic strain rate (PEDSR): 0.77 (0.74-0.80) vs 0.92 (0.85-1.00) s-1, P < 0.001). Multivariable linear regression demonstrated that RV end-diastolic volume (β =-0.342, P = 0.004) and RV cardiac output (β = 0.296, P = 0.001), but not LV parameters, were independent determinants of peak VO2.

CONCLUSION

In T2D, markers of RV remodeling are associated with aerobic exercise capacity, independent of left heart alterations.

Influence of gestational diabetes mellitus on subclinical myocardial dysfunction during pregnancy: A systematic review and meta-analysis

OBJECTIVE

The correlation between gestational diabetes mellitus (GDM) and subclinical myocardial dysfunction has been poorly investigated. Accordingly, we performed a meta-analysis to examine the influence of GDM on left ventricular (LV) global longitudinal strain (GLS), assessed by speckle tracking echocardiography (STE), during pregnancy.

STUDY DESIGN

All echocardiographic studies assessing conventional echoDoppler parameters and LV-GLS in GDM women vs. healthy controls, selected from PubMed and EMBASE databases, were included. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment of Case-Control Studies. The subtotal and overall standardized mean differences (SMDs) of LV-GLS were calculated using the random-effect model.

RESULTS

The full-texts of 10 studies with 1147 women with GDM and 7706 pregnant women without diabetes were analyzed. GDM women enrolled in the included studies were diagnosed with a small reduction in LV-GLS in comparison to controls (average value -19.4 ± 2.5 vs -21.8 ± 2.5 %, P < 0.001) and to the accepted reference values (more negative than -20 %). Substantial heterogeneity was detected for the included studies, with an overall statistic value I2 of 94.4 % (P < 0.001). Large SMDs were obtained for the included studies, with an overall SMD of -0.97 (95 %CI -1.32, -0.63, P < 0.001). Egger's test for a regression intercept gave a P-value of 0.99, indicating no publication bias. On meta-regression analysis, all moderators and/or potential confounders (age at pregnancy, BMI, systolic blood pressure and ethnicity) were not significantly associated with effect modification (all P < 0.05).

CONCLUSIONS

GDM is independently associated with subclinical myocardial dysfunction in pregnancy. STE analysis allows to identify, among GDM women, those who might benefit of targeted non-pharmacological and/or pharmacological interventions, aimed at reducing the risk of developing type 2 diabetes and cardiovascular complications later in life.

Progress in Cardiac Magnetic Resonance Feature Tracking for Evaluating Myocardial Strain in Type-2 Diabetes Mellitus

The global prevalence of type-2 diabetes mellitus (T2DM) has caused harm to human health and economies. Cardiovascular disease is one main cause of T2DM mortality. Increased prevalence of diabetes and associated heart failure (HF) is common in older populations, so accurately evaluating heart-related injury and T2DM risk factors and conducting early intervention are important. Quantitative cardiovascular system imaging assessments, including functional imaging during cardiovascular disease treatment, are also important. The left-ventricular ejection fraction (LVEF) has been traditionally used to monitor cardiac function; it is often preserved or increased in early T2DM, but subclinical heart deformation and dysfunction can occur. Myocardial strains are sensitive to global and regional heart dysfunction in subclinical T2DM. Cardiac magnetic resonance feature-tracking technology (CMR-FT) can visualize and quantify strain and identify subclinical myocardial injury for early management, especially with preserved LVEF. Meanwhile, CMR-FT can be used to evaluate the multiple cardiac chambers involvement mediated by T2DM and the coexistence of complications. This review discusses CMR-FT principles, clinical applications, and research progress in the evaluation of myocardial strain in T2DM.

[Pulmonary heart: A review]

The review on the problem of the pulmonary heart pursues two goals: firstly, to restore historical justice and to show the priority studies of doctor Dmitry D. Pletnev on such problems as diagnosis of right ventricular myocardial infarction, clinical characteristics of congestive heart failure of the right ventricle; secondly, to outline the modern concept of the pulmonary heart. The review provides an analysis of the pathogenetic mechanisms of the development of heart failure in the pulmonary heart. Much attention is paid to echo cardiography data and biological markers are emphasized in assessing the function of the right atrium, right ventricle, tricuspid valve regurgitation, pulmonary artery pressure. Prognostically unfavorable signs of the course of the pulmonary heart have been identified, which include a high degree of tricuspid valve regurgitation, the amplitude of movement of the fibrous valve ring (TAPSE) and atrial fibrillation developing with dilation of the right atrium.

The current state of preclinical modeling of human diabetic cardiomyopathy using rodents

The prevalence of diabetic cardiomyopathy (DCM), a specific cardiovascular complication of diabetes mellitus, has recently increased. Its pathogenesis is not fully understood, and no consensus regarding therapeutic options has been reached. Experimental studies on rodents are expected to yield further data at the preclinical stage. The present paper describes and quantitatively compares the experimental protocols intended to mimic human DCM. Experimental articles (conducted between 1990 and 2022) were identified from online electronic databases according to the PRISMA Protocol. The Cochrane Q-test was used to estimate study heterogeneity; the quality of each individual study was assessed using SYRCLE's risk of bias tool for animal studies. Sensitivity analysis was performed according to the leave-one-out method. Publication bias across studies was assessed using Egger's weighted regression and Duval and Tweedie 'trim and fill' method. A wide spectrum of protocols - from 651 papers, was examined (type 1 or 2 diabetes mellitus, as well as obesity models). They were found to vary in their presentation of DCM according to a variety of hemodynamic, echocardiographic, histopathologic and metabolic parameters. Particular attention was paid to comorbid conditions, and cardiac performance featured as systolic, diastolic dysfunction, or refractory heart failure. The majority of models displayed diastolic dysfunction, as well as myocardial fibrosis and left ventricle hypertrophy, which mimics early stage DCM. Unlike in humans, animal DCM rarely progressed to the symptomatic heart failure with reduced ejection fraction (HFrEF). The ability of individual procedures to reflect refractory heart failure or biventricular dysfunction - in the end-stage DCM has remained unclear.

Subclinical right ventricular dysfunction in patients with asymptomatic type 2 diabetes mellitus: A cross-sectional study

BACKGROUND

Diabetic cardiomyopathy, which involves both the right and left ventricles, progresses from a preclinical stage to overt heart failure. Detection of this entity at a preclinical stage could be crucial in intervening to halt its progression to overt heart failure. There is a paucity of literature on subclinical RV dysfunction in diabetic patients, and it is even rarer in the Indian literature. Our study intended to study this clinical entity through an echocardiographic assessment of asymptomatic patients.

OBJECTIVES

This was a cross-sectional observational analytic study, comparing subclinical RV dysfunction in diabetic and non-diabetic subjects by using echocardiography as a primary objective, while the secondary objective of the study was to find out the correlation between RV dysfunction and the duration of diabetes mellitus and HbA1C levels.

METHODS

Conventional echocardiography with tissue Doppler imaging (TDI) was used to measure nine different echocardiographic parameters in the diabetic and non-diabetic groups. All probable causes of RV dysfunction were excluded before enrolling the patients in the study. Unpaired t-test was used to compare the parameters between the two groups, and multivariate regression analysis was done taking into consideration age, duration of diabetes, and HbA1C levels as the independent variables, and echocardiographic parameters as the dependent variables.

RESULTS

Out of the nine different echocardiographic parameters, Tricuspid annular plane systolic excursion (TAPSE), RV end diastolic diameter (RVEDD), Tricuspid peak late diastolic velocity (A), E/A ratio, RV basal segment peak myocardial systolic velocity (Sm), RV basal segment peak early diastolic velocity (Em), RV basal segment peak late diastolic velocity (Am), and E/Em ratio showed statistically significant differences between the two groups. These results show the presence of subclinical RV dysfunction in diabetic patients. TAPSE and E/A ratio showed a significant correlation with the duration of diabetes, while Em showed a significant correlation with HbA1C.

CONCLUSION

Diabetes mellitus is associated with subclinical systolic as well as diastolic RV dysfunction. In addition to helping identify people at high risk, the early recognition of RV dysfunction gives us a window of opportunity to take action and slow down the disease's course. This study emphasizes that the early identification of RV diastolic as well as systolic dysfunction in asymptomatic Type 2 diabetic patients can be a helpful tool in halting the progression of disease from subclinical to frank clinical cases, thereby preventing the morbidity and mortality associated with heart failure. Hence, it adds value to the pre-existing literature.

Cardiac MRI to guide heart failure and atrial fibrillation drug discovery: a Mendelian randomization analysis

Background

drug development and disease prevention of heart failure (HF) and atrial fibrillation (AF) are impeded by a lack of robust early-stage surrogates. We determined to what extent cardiac magnetic resonance (CMR) measurements act as surrogates for the development of HF or AF in healthy individuals.

Methods

Genetic data was sourced on the association with 22 atrial and ventricular CMR measurements. Mendelian randomization was used to determine CMR associations with atrial fibrillation (AF), heart failure (HF), non-ischemic cardiomyopathy (CMP), and dilated cardiomyopathy (DCM). Additionally, for the CMR surrogates of AF and HF, we explored their association with non-cardiac traits.

Results

In total we found that 9 CMR measures were associated with the development of HF, 7 with development of non-ischemic CMR, 6 with DCM, and 12 with AF. biventricular ejection fraction (EF), biventricular or end-systolic volumes (ESV) and left-ventricular (LV) end diastolic volume (EDV) were associated with all 4 cardiac outcomes. Increased LV-MVR (mass to volume ratio) affected HF (odds ratio (OR) 0.83, 95%CI 0.79; 0.88), and DCM (OR 0.26, 95%CI 0.20; 0.34. We were able to identify 9 CMR surrogates for HF and/or AF (including LV-MVR, biventricular EDV, ESV, and right-ventricular EF) which associated with non-cardiac traits such as blood pressure, lung function traits, BMI, cardioembolic stroke, and late-onset Alzheimer's disease.

Conclusion

CMR measurements may act as surrogate endpoints for the development of HF (including non-ischemic CMP and DCM) or AF. Additionally, we show that changes in cardiac function and structure measured through CMR, may affect diseases of other organs leading to lung disease or late-onset Alzheimer's disease.

Diabetic cardiomyopathy: Clinical phenotype and practice

Diabetic cardiomyopathy (DCM) is a pathophysiological condition of cardiac structure and function changes in diabetic patients without coronary artery disease, hypertension, and other types of heart diseases. DCM is not uncommon in people with diabetes, which increases the risk of heart failure. However, the treatment is scarce, and the prognosis is poor. Since 1972, one clinical study after another on DCM has been conducted. However, the complex phenotype of DCM still has not been fully revealed. This dilemma hinders the pace of understanding the essence of DCM and makes it difficult to carry out penetrating clinical or basic research. This review summarizes the literature on DCM over the last 40 years and discusses the overall perspective of DCM, phase of progression, potential clinical indicators, diagnostic and screening criteria, and related randomized controlled trials to understand DCM better.

Association of left ventricular longitudinal myocardial function with subclinical right ventricular dysfunction in type 2 diabetes mellitus

Background

Left ventricular (LV) involvement in diabetic cardiomyopathy has been reported; however, only limited data exist on right ventricular (RV) involvement. Therefore, our purpose was to investigate RV systolic dysfunction and its association with LV longitudinal myocardial dysfunction in patients with type 2 diabetes mellitus (T2DM) and preserved LV ejection fraction (LVEF).

Methods

We studied 177 T2DM patients with preserved LVEF and 79 age-, sex-, and LVEF-matched healthy volunteers. LV longitudinal myocardial function was assessed as global longitudinal strain (GLS), and RV systolic function was assessed as RV free-wall strain, and predefined cutoff values for subclinical dysfunction were set at GLS < 18% and RV free-wall strain < 20%, respectively.

Results

RV free-wall strain in T2DM patients was significantly lower than that in normal controls (19.3% ± 4.8% vs. 24.4% ± 5.1%; P < 0.0001). RV free-wall strain in T2DM patients and LV longitudinal dysfunction was similar compared to that in T2DM patients without (19.0 ± 4.5% vs. 19.6 ± 5.0%, P = 0.40). Furthermore, multivariate logistic regression analyses showed that GLS was independently associated with RV systolic dysfunction as well as mitral inflow E and mitral e′ annular velocities ratio (odds ratio, 1.16; 95% confidence interval: 1.03–1.31; P < 0.05). Sequential logistic models evaluating the association of RV systolic dysfunction in T2DM patients showed an improvement in clinical variables (χ² = 6.2) with the addition of conventional echocardiographic parameters (χ² = 13.4, P < 0.001) and a further improvement with the addition of GLS (χ² = 20.8, P < 0.001).

Conclusion

RV subclinical systolic dysfunction was observed in T2DM patients with preserved LVEF and was associated with LV longitudinal myocardial dysfunction. Our findings may provide additional findings for the management of T2DM patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01404-5.

Echocardiographic follow-up to right ventricular modifications in secondary pulmonary hypertension to diabetes in rats

Clinical studies suggest that diabetes is a risk factor in the development of pulmonary arterial hypertension. The increase in blood pressure in the pulmonary area is characterized by the increase in the afterload and hypertrophy of the right ventricle. The objective of this study was to conduct a longitudinal follow-up of the morphological and functional changes in the right ventricle in a rat model with pulmonary arterial hypertension secondary to diabetes. Male Sprague Dawley rats were randomly divided into a control group (saline solution) and a diabetic group (60 mg/kg with streptozotocin). For 12 weeks, an echocardiography for longitudinal (in vivo) image analysis of the pulmonary pressure was performed at the same time as the evaluation of myocardial remodeling and right ventricular. After this period, the pulmonary pressure was measured by means of a pulmonary artery catheterization, and the presence of hypertrophy was determined by means of the Fulton index. The plasma concentration of brain natriuretic peptide was measured by means of the ELISA technique. It was found that the diabetic rats showed an increase in pressure in the pulmonary arteries, an increase in the Fulton index, and an increase in brain natriuretic peptide. The echocardiographic follow-up showed that the diabetic rats presented an increase in the pulmonary artery from the fourth week, while hypertrophy and right ventricular systolic dysfunction occurred until the twelfth week. In conclusion, pulmonary arterial hypertension induced by experimental diabetes generated hypertrophy and systolic dysfunction of the right ventricle.

Cardiac MRI for Patients with Increased Cardiometabolic Risk

Cardiac MRI (CMR) has rich potential for future cardiovascular screening even though not approved clinically for routine screening for cardiovascular disease among patients with increased cardiometabolic risk. Patients with increased cardiometabolic risk include those with abnormal blood pressure, body mass, cholesterol level, or fasting glucose level, which may be related to dietary and exercise habits. However, CMR does accurately evaluate cardiac structure and function. CMR allows for effective tissue characterization with a variety of sequences that provide unique insights as to fibrosis, infiltration, inflammation, edema, presence of fat, strain, and other potential pathologic features that influence future cardiovascular risk. Ongoing epidemiologic and clinical research may demonstrate clinical benefit leading to increased future use. © RSNA, 2021.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.

Associations of (pre)diabetes with right ventricular and atrial structure and function: the Maastricht Study

Backgrounds

The role of right ventricular (RV) and atrial (RA) structure and function, in the increased heart failure risk in (pre)diabetes is incompletely understood. The purpose of this study is to investigate the associations between (pre)diabetes and RV and RA structure and function, and whether these are mediated by left ventricular (LV) alterations or pulmonary pressure.

Methods

Participants of the Maastricht Study; a population-based cohort study (426 normal glucose metabolism (NGM), 142 prediabetes, 224 diabetes), underwent two-dimensional and tissue Doppler echocardiography. Multiple linear regression analyses with pairwise comparisons of (pre)diabetes versus NGM, adjusted for cardiovascular risk factors, and mediation analyses were used.

Results

In general, differences were small. Nevertheless, in individuals with prediabetes and diabetes compared to NGM; RA volume index was lower (both p < 0.01, p_trend < 0.01), RV diameter was lower (both p < 0.01, p_trend < 0.01) and RV length was significantly smaller in diabetes (p = 0.67 and p = 0.03 respectively, p_trend = 0.04), TDI S′RV was lower (p = 0.08 and p < 0.01 respectively, p_trend < 0.01), TDI E′RV was lower (p = 0.01 and p = 0.02 respectively, p_trend = 0.01) and TDI A′RV was lower (p < 0.01 and p = 0.07 respectively, p_trend = 0.04). Only the differences in RA volume index (7.8%) and RV diameter (6.2%) were mediated by the maximum tricuspid gradient, but no other LV structure and function measurements.

Conclusions

(Pre)diabetes is associated with structural RA and RV changes, and impaired RV systolic and diastolic function, independent of cardiovascular risk factors. These associations were largely not mediated by indices of LV structure, LV function or pulmonary pressure. This suggests that (pre)diabetes affects RA and RV structure and function due to direct myocardial involvement.

Early detection of left atrial and bi-ventricular myocardial strain abnormalities by MRI feature tracking in normotensive or hypertensive T2DM patients with preserved LV function

BACKGROUND

Previous studies have found that impaired global myocardial systolic strain is associated with cardiovascular events in T2DM patients. However, the effect of hypertension (HT) on left atrial (LA), right ventricular (RV) and left ventricular (LV) myocardial deformation in hypertensive T2DM patients has not been fully studied by cardiac magnetic resonance feature tracking (CMR-FT). Our aim was to assess LA, RV and LV strain in T2DM patients with T2DM-HT and without hypertension using CMR-FT and to determine the underlying relationships with clinical parameters.

METHODS

A total of 27 T2DM patients, 23 T2DM-HT patients and 31 controls were studied. LA, LV and RV strain was evaluated using CMR-FT. The clinical and biochemical parameters of the patients were collected.

RESULTS

The T2DM patients had reduced LA global circumferential strain (LAGCS), radial strain (LAGRS), longitudinal strain (LAGLS) and right ventricular longitudinal strain (RVGLS) compared with the controls (LAGCS: 27.2 ± 2.1% vs 33.5 ± 2.4%; LAGRS: - 28.6 ± 1.1% vs - 31.9 ± 1.3%; LAGLS: 24.3 ± 1.3% vs 31.4 ± 1.5; RVGLS: - 21.4 ± 1.2% vs - 26.3 ± 1.1%, p < 0.05 for all). The T2DM-HT patients had greater LAGCS, LAGRS and LAGLS than the T2DM patients (LAGCS: 40.4 ± 3.8% vs 27.2 ± 2.1%; LAGRS: - 36.8 ± 2.0% vs - 28.6 ± 1.1%; LAGLS: 32.3 ± 2.4% vs 24.3 ± 1.3%, p < 0.05 for all). In the diabetic patients, LAGCS was associated with microalbuminuria levels (standardized ß = - 0.289, p = 0.021), and LAGCS, LAGRS and LAGLS were correlated with diuretic treatment (standardized ß =0.440, - 0.442, and 0.643, p < 0.05 for all).

CONCLUSIONS

CMR-FT may be considered a promising tool for the early detection of abnormal LA and RV myocardial strain. LA and RV strain values are impaired in T2DM patients. The amelioration of LA strain might be associated with hypertensive compensation or antihypertensive treatment, which requires to be confirmed in larger trials.

Cardiorespiratory fitness and right ventricular mechanics in uncomplicated diabetic patients: Is there any relationship?

AIMS

This study investigated the association between cardiorespiratory fitness and right ventricular (RV) strain in uncomplicated diabetic patients.

METHODS

This cross-sectional study involved 70 controls and 61 uncomplicated patients with type 2 diabetes, who underwent laboratory analysis, comprehensive echocardiographic study and cardiopulmonary exercise testing.

RESULTS

RV endocardial and mid-myocardial longitudinal strains were significantly reduced in diabetic subjects (- 27.5 ± 4.2% vs. - 25.3 ± 4.3%, p = 0.004 for endocardial strain; - 25.6 ± 3.5% vs. - 24.1 ± 3.2%, p = 0.012 for mid-myocardial strain). The same was revealed for endocardial and mid-myocardial of RV free wall. There was no difference in RV epicardial strain. VO₂ was significantly lower in the diabetic group (27.8 ± 4.5 ml/kg/min vs. 21.5 ± 4.2 ml/kg/min, p < 0.001), whereas ventilation/carbon dioxide slope was significantly higher in diabetic subjects (25.4 ± 2.9 vs. 28.6 ± 3.3). Heart rate recovery was significantly lower in diabetic patients. HbA1c and global RV endocardial longitudinal strain were independently associated with peak VO₂ and oxygen pulse in the whole study population.

CONCLUSION

Diabetes impacts RV mechanics, but endocardial and mid-myocardial layers are more affected than epicardial layer. RV endocardial strain and HbA1c were independently associated with cardiorespiratory fitness in the whole study population. Our findings show that impairment in RV strain and cardiorespiratory fitness may be useful indicators in early type 2 diabetes, prior to the development of further complications.

Changes in Cardiac Morphology and Function in Individuals With Diabetes Mellitus: The UK Biobank Cardiovascular Magnetic Resonance Substudy

BACKGROUND

Diabetes mellitus (DM) is associated with increased risk of cardiovascular disease. Detection of early cardiac changes before manifest disease develops is important. We investigated early alterations in cardiac structure and function associated with DM using cardiovascular magnetic resonance imaging.

METHODS

Participants from the UK Biobank Cardiovascular Magnetic Resonance Substudy, a community cohort study, without known cardiovascular disease and left ventricular ejection fraction ≥50% were included. Multivariable linear regression models were performed. The investigators were blinded to DM status.

RESULTS

A total of 3984 individuals, 45% men, (mean [SD]) age 61.3 (7.5) years, hereof 143 individuals (3.6%) with DM. There was no difference in left ventricular (LV) ejection fraction (DM versus no DM; coefficient [95% CI]: -0.86% [-1.8 to 0.5]; P=0.065), LV mass (-0.13 g/m2 [-1.6 to 1.3], P=0.86), or right ventricular ejection fraction (-0.23% [-1.2 to 0.8], P=0.65). However, both LV and right ventricular volumes were significantly smaller in DM, (LV end-diastolic volume/m2: -3.46 mL/m2 [-5.8 to -1.2], P=0.003, right ventricular end-diastolic volume/m2: -4.2 mL/m2 [-6.8 to -1.7], P=0.001, LV stroke volume/m2: -3.0 mL/m2 [-4.5 to -1.5], P<0.001; right ventricular stroke volume/m2: -3.8 mL/m2 [-6.5 to -1.1], P=0.005), LV mass/volume: 0.026 (0.01 to 0.04) g/mL, P=0.006. Both left atrial and right atrial emptying fraction were lower in DM (right atrial emptying fraction: -6.2% [-10.2 to -2.1], P=0.003; left atrial emptying fraction:-3.5% [-6.9 to -0.1], P=0.043). LV global circumferential strain was impaired in DM (coefficient [95% CI]: 0.38% [0.01 to 0.7], P=0.045).

CONCLUSIONS

In a low-risk general population without known cardiovascular disease and with preserved LV ejection fraction, DM is associated with early changes in all 4 cardiac chambers. These findings suggest that diabetic cardiomyopathy is not a regional condition of the LV but affects the heart globally.

Diabetic lung disease: fact or fiction?

Diabetes mellitus is a chronic, progressive, incompletely understood metabolic disorder whose prevalence has been increasing steadily worldwide. Even though little attention has been paid to lung disorders in the context of diabetes, its prevalence has recently been challenged by newer studies of disease development. In this review, we summarize and discuss the role of diabetes mellitus involved in the progression of pulmonary diseases, with the main focus on pulmonary fibrosis, which represents a chronic and progressive disease with high mortality and limited therapeutic options.

Elevated 1-h post-load plasma glucose is associated with right ventricular morphofunctional parameters in hypertensive patients

PURPOSE

Emerging data demonstrate that type 2 diabetes mellitus (T2DM) is associated with right ventricular (RV) dysfunction. A cutoff point of 155 mg/dL for the 1-hour (h) post-load plasma glucose, during oral glucose tolerance test (OGTT), identifies patients with normal glucose tolerance (NGT) at high risk to develop T2DM and cardiovascular (CV) disease. We investigated if 1-h post-load glucose may affect RV geometry and function in a group of never-treated hypertensive individuals.

METHODS

We enrolled 446 Caucasian newly diagnosed hypertensive outpatients. All patients underwent an OGTT and a standard echocardiography. The tricuspid annular plane systolic excursion (TAPSE) and the RV fractional area change (RVFAC) were measured together with systolic pulmonary arterial pressure (s-PAP) and pulmonary vascular resistances (PVR). Insulin sensitivity was evaluated using the Matsuda index.

RESULTS

Among all partecipants, 296 had NGT, 100 impaired glucose tolerance (IGT), and 50 T2DM. Considering the cutoff point of 155 mg/dl for 1-h glucose, NGT subjects were stratified into two groups: NGT < 155 (n = 207), NGT ≥ 155 (n = 89). Subjects NGT ≥ 155 presented a worse metabolic and inflammatory profile than NGT < 155. RV functional parameters (TAPSE, RVFAC, TAPSE/s-PAP, and TAPSE/PVR) were significantly reduced in NGT ≥ 155 subjects compared with NGT < 155 patients. On the contrary, s-PAP and PVR were significantly higher. At multiple regression analysis, 1-h glucose was the strongest predictor of TAPSE in NGT ≥ 155, IGT, and T2DM.

CONCLUSIONS

The presence of RV impairment in hypertensive NGT ≥ 155 subjects further complicates their CV burden and it may, at least in part, justify the worse clinical outcome in this setting of patients.

Impairment of left and right ventricular longitudinal strain in asymptomatic children with type 1 diabetes

Aim

The relationship between type 1 diabetes (T1DM) and cardiac function in children is not well established. The purpose of this study was to investigate whether children and adolescents with T1DM present early asymptomatic abnormalities of left ventricular (LV) and right ventricular (RV) function. In addition, we evaluated the relationship of any such abnormalities with glycemic control and diabetes duration.

Methods

This was a prospective study. Standard echocardiography, tissue Doppler imaging, and two-dimensional strain analysis were performed prospectively in 52 children with T1DM. The results were compared with those from 52 healthy children matched for age and sex.

Results

There were no significant differences between the two groups in LV ejection fraction or RV systolic function. There was a difference between the two study groups in transtricuspid flow: the E-wave and A-wave velocities were significantly higher in the diabetic group. Left ventricular global longitudinal strain (LV GLS) was significantly lower in children with T1DM (−20.01 ± 1.86% vs. −22.99 ± 0.98%, respectively; P < .001), as was RV free-wall longitudinal strain (RV FWLS) (−29.13 ± 1.85% vs. −30.22 ± 1.53%, respectively; P = .002). LV GLS was correlated with diabetes duration (r = 0.444, P < .001) and glycated hemoglobin (HbA1c) (r = 0.683, P < .001); however, no correlation was found between RV FWLS and HbA1c or diabetes duration.

Conclusions

Our findings suggest that LV GLS and RV FWLS are impaired in children with T1DM and that the decrease in LV GLS is correlated with diabetes duration and HbA1c levels.

Effective Treatment of Diabetic Cardiomyopathy and Heart Failure with Reconstituted HDL (Milano) in Mice

The risk of heart failure (HF) is prominently increased in patients with type 2 diabetes mellitus. The objectives of this study were to establish a murine model of diabetic cardiomyopathy induced by feeding a high-sugar/high-fat (HSHF) diet and to evaluate the effect of reconstituted HDL_Milano administration on established HF in this model. The HSHF diet was initiated at the age of 12 weeks and continued for 16 weeks. To investigate the effect of reconstituted HDL_Milano on HF, eight intraperitoneal administrations of MDCO-216 (100 mg/kg protein concentration) or of an identical volume of control buffer were executed with a 48-h interval starting at the age of 28 weeks. The HSHF diet-induced obesity, hyperinsulinemia, and type 2 diabetes mellitus. Diabetic cardiomyopathy was present in HSHF diet mice as evidenced by cardiac hypertrophy, increased interstitial and perivascular fibrosis, and decreased myocardial capillary density. Pressure-volume loop analysis indicated the presence of both systolic and diastolic dysfunction and of decreased cardiac output in HSHF diet mice. Treatment with MDCO-216 reversed pathological remodelling and cardiac dysfunction and normalized wet lung weight, indicating effective treatment of HF. No effect of control buffer injection was observed. In conclusion, reconstituted HDL_Milano reverses HF in type 2 diabetic mice.

Left and right ventricular function by echocardiography, tissue Doppler imaging, carotid intima-media thickness, and asymmetric dimethyl arginine levels in obese adolescents with metabolic syndrome

PurposeThe aim of our study was to assess left ventricle and right ventricle systolic and diastolic functions in obese adolescents with metabolic syndrome using conventional echocardiography and pulsed-wave tissue Doppler imaging and to investigate carotis intima-media thickness, and asymmetric dimethyl arginine levels.

METHODS

A total of 198 obese adolescents were enrolled in the study. The obese patients were divided into metabolic syndrome group and non-metabolic syndrome group. All subjects underwent laboratory blood tests, including asymmetric dimethyl arginine, complete two-dimensional, pulsed, and tissue Doppler echocardiography, and measurement of the carotid intima-media thickness.

RESULTS

Obese adolescents were characterised by enlarged left end-diastolic, end-systolic and left atrial diameters, thicker left and right ventricular walls compared with non-obese adolescents. The metabolic syndrome group had normal left ventricle systolic function, impaired diastolic function, and altered global systolic and diastolic myocardial performance. In the metabolic syndrome obese group patients, left ventricle mass was found positively correlated with body mass index, waist and hip circumferences, diastolic blood pressure, age, and waist-to-hip circumference ratio. The carotid intima-media thickness was found positively correlated with waist and hip circumferences and total cholesterol levels. Asymmetric dimethyl arginine levels were found positively correlated with systolic blood pressure, waist-to-hip circumference ratio, and diastolic blood pressure.

CONCLUSIONS

The results of this study demonstrate that metabolic syndrome in adolescence is associated with significant changes in myocardial geometry and function. In addition, it has been associated with a high level of asymmetric dimethyl arginine concentration and thicker carotid intima-media thickness reflecting endothelial dysfunction.

Right ventricular dysfunction and remodeling in diabetic cardiomyopathy

The increasing prevalence of diabetic cardiomyopathy (DCM) is an important threat to health worldwide. While left ventricular (LV) dysfunction in DCM is well recognized, the accurate detection, diagnosis, and treatment of changes in right ventricular (RV) structure and function have not been well characterized. The pathophysiology of RV dysfunction in DCM may share features with LV diastolic and systolic dysfunction, including pathways related to insulin resistance and oxidant injury, although the RV has a unique cellular origin and composition and unique biomechanical properties and is coupled to the lower-impedance pulmonary vascular bed. In this review, we discuss potential mechanisms responsible for RV dysfunction in DCM and review the imaging approaches useful for early detection, protection, and intervention strategies. Additional data are required from animal models and clinical trials to better identify the onset and features of altered RV and pulmonary vascular structure and function during the onset and progression of DCM and to determine the efficacy of early detection and treatment of RV dysfunction on clinical symptoms and outcomes.

Metabolic Effects of Metformin in the Failing Heart

Accumulating evidence shows that metformin is an insulin-sensitizing antidiabetic drug widely used in the treatment of type 2 diabetes mellitus (T2DM), which can exert favorable effects on cardiovascular risk and may be safely used in patients with heart failure (HF), and even able to reduce the incidence of HF and to reduce HF mortality. In failing hearts, metformin improves myocardial energy metabolic status through the activation of AMP (adenosine monophosphate)-activated protein kinase (AMPK) and the regulation of lipid and glucose metabolism. By increasing nitric oxide (NO) bioavailability, limiting interstitial fibrosis, reducing the deposition of advanced glycation end-products (AGEs), and inhibiting myocardial cell apoptosis metformin reduces cardiac remodeling and hypertrophy, and thereby preserves left ventricular systolic and diastolic functions. While a lot of preclinical and clinical studies showed the cardiovascular safety of metformin therapy in diabetic patients and HF, to confirm observed benefits, the specific large-scale trials configured for HF development in diabetic patients as a primary endpoints are necessary.

A Pediatric Case of Graves' Hyperthyroidism with Associated Glucose Intolerance Detected by a Urine Glucose Screening Program at School

We report here a 13-year-old female with Graves' disease, whose diagnostic clue was glycosuria, which was detected by a urine glucose screening program at school. She had had mild general malaise, and a physical examination revealed a slightly enlarged thyroid gland. Hyperthyroidism (thyroid-stimulating hormone (TSH) < 0.01 μU/ml, free triiodothyronine (fT3) 23.57 pg/ml, free thyroxine (fT4) 3.38 ng/dl) and anti-thyroid autoantibodies (TRAb 43.6%) were detected in laboratory tests, and her plasma glucose at 120 minutes was 142 mg/dl in a 75 g oral glucose tolerance test. She was diagnosed as having borderline diabetes. These findings revealed a diagnosis of Graves' hyperthyroidism with associated impaired glucose tolerance. Although it is reported that many adults with hyperthyroidism develop disorders of glucose metabolism, pediatric patients rarely have complications of glucose intolerance or diabetes mellitus, and there are no previous reports of Graves' disease diagnosed by a urine glucose screening program at school. This case suggests a possibility of abnormalities in glucose metabolism even in pediatric cases of Graves' disease. To avoid overlooking the diagnosis of glucose intolerance associated with hyperthyroidism, a careful medical interview and examination should be performed even if the clinical features are mild.

Diagnosis and Significance of Pulmonary Microvascular Disease in Diabetes

OBJECTIVE

To determine whether pulmonary microvascular disease is detectable in subjects with diabetes and associated with diminished exercise capacity using a novel echocardiographic marker quantifying the pulmonary transit of agitated contrast bubbles (PTAC).

RESEARCH DESIGN AND METHODS

Sixty participants (40 with diabetes and 20 control subjects) performed cardiopulmonary (maximal oxygen consumption [VO₂peak]) and semisupine bicycle echocardiography exercise tests within a 1-week period. Pulmonary microvascular disease was assessed using PTAC (the number of bubbles traversing the pulmonary circulation to reach the left ventricle, categorized as low PTAC or high PTAC). Echocardiographic measures of cardiac output, pulmonary artery pressures, and biventricular function were obtained during exercise.

RESULTS

Subjects with diabetes and control subjects were of similar age (44 ± 13 vs. 43 ± 13 years, P = 0.87) and sex composition (70% vs. 65% male, P = 0.7). At peak exercise, low PTAC was present in more participants with diabetes than control subjects (41% vs. 12.5%, χ²P = 0.041) and, in particular, in more subjects with diabetes with microvascular complications compared with both those without complications and control subjects (55% vs. 26% vs. 13%, χ²P = 0.02). When compared with high PTAC, low PTAC was associated with a 24% lower VO₂peak (P = 0.006), reduced right ventricular function (P = 0.015), and greater pulmonary artery pressures during exercise (P = 0.02).

CONCLUSIONS

PTAC is reduced in diabetes, particularly in the presence of microvascular pathology in other vascular beds, suggesting that it may be a meaningful indicator of pulmonary microvascular disease with important consequences for cardiovascular function and exercise capacity.

Exercise capacity in diabetes mellitus is predicted by activity status and cardiac size rather than cardiac function: a case control study

Background

The reasons for reduced exercise capacity in diabetes mellitus (DM) remains incompletely understood, although diastolic dysfunction and diabetic cardiomyopathy are often favored explanations. However, there is a paucity of literature detailing cardiac function and reserve during incremental exercise to evaluate its significance and contribution. We sought to determine associations between comprehensive measures of cardiac function during exercise and maximal oxygen consumption (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2}$$\end{document}V˙O2peak), with the hypothesis that the reduction in exercise capacity and cardiac function would be associated with co-morbidities and sedentary behavior rather than diabetes itself.

Methods

This case–control study involved 60 subjects [20 with type 1 DM (T1DM), 20 T2DM, and 10 healthy controls age/sex-matched to each diabetes subtype] performing cardiopulmonary exercise testing and bicycle ergometer echocardiography studies. Measures of biventricular function were assessed during incremental exercise to maximal intensity.

Results

T2DM subjects were middle-aged (52 ± 11 years) with a mean T2DM diagnosis of 12 ± 7 years and modest glycemic control (HbA_1c 57 ± 12 mmol/mol). T1DM participants were younger (35 ± 8 years), with a 19 ± 10 year history of T1DM and suboptimal glycemic control (HbA_1c 65 ± 16 mmol/mol). Participants with T2DM were heavier than their controls (body mass index 29.3 ± 3.4 kg/m² vs. 24.7 ± 2.9, P = 0.001), performed less exercise (10 ± 12 vs. 28 ± 30 MET hours/week, P = 0.031) and had lower exercise capacity (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2}$$\end{document}V˙O2peak = 26 ± 6 vs. 38 ± 8 ml/min/kg, P < 0.0001). These differences were not associated with biventricular systolic or left ventricular (LV) diastolic dysfunction at rest or during exercise. There was no difference in weight, exercise participation or \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2}$$\end{document}V˙O2peak in T1DM subjects as compared to their controls. After accounting for age, sex and body surface area in a multivariate analysis, significant positive predictors of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2}$$\end{document}V˙O2peak were cardiac size (LV end-diastolic volume, LVEDV) and estimated MET-hours, while T2DM was a negative predictor. These combined factors accounted for 80% of the variance in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2}$$\end{document}V˙O2peak (P < 0.0001).

Conclusions

Exercise capacity is reduced in T2DM subjects relative to matched controls, whereas exercise capacity is preserved in T1DM. There was no evidence of sub-clinical cardiac dysfunction but, rather, there was an association between impaired exercise capacity, small LV volumes and sedentary behavior.

Prevalence of arrhythmias in patients with type 2 diabetes and the role of structural changes in myocardium in their development

OBJECTIVE

The aim of the study was to evaluate the prevalence of arrhythmias in patients with type 2 diabetes and their relationships with the structural parameters of the heart.

METHODS

A retrospective case-control study was conducted using clinical and biochemical profiles of patients with diabetes at the Endocrinology Centre and City Clinical Hospital No. 40, Ekaterinburg, Russia.

RESULTS

The total study sample included 75 subjects. The average age (SD) was 48.2 (5.6) years, and the mean duration of diabetes (SD) was 6.2 (2.4) years. The most common type of extrasystoles were the single supraventricular extrasystoles, observed in 72.29% of cases (vs 38.89% in the control group) and paired supraventricular extrasystoles, which were identified in 30% of cases (vs 19.44% in the control group). Ventricular cardiac arrhythmias in the form of ventricular extrasystoles (VE) were identified in 25.71% of cases (13.89% in the control group).

CONCLUSIONS

This study revealed the signs of the morphological restructuring of the right chambers of the heart and a relatively high prevalence of supraventricular arrhythmias in the early stages of type 2 diabetes. Moreover, according to the results, the incidence of some types of supraventricular arrhythmias and the occurrence of tachycardia episodes in patients with type 2 diabetes mostly depends on the restructuring of the right chambers of the heart, which may be caused by the peculiarities of the cardiac innervation, with the higher density of choline and adrenergic plexuses in the right chambers.

Sprint interval training decreases left-ventricular glucose uptake compared to moderate-intensity continuous training in subjects with type 2 diabetes or prediabetes

Type 2 diabetes mellitus (T2DM) is associated with reduced myocardial glucose uptake (GU) and increased free fatty acid uptake (FFAU). Sprint interval training (SIT) improves physical exercise capacity and metabolic biomarkers, but effects of SIT on cardiac function and energy substrate metabolism in diabetic subjects are unknown. We tested the hypothesis that SIT is more effective than moderate-intensity continuous training (MICT) on adaptations in left and right ventricle (LV and RV) glucose and fatty acid metabolism in diabetic subjects. Twenty-six untrained men and women with T2DM or prediabetes were randomized into two-week-long SIT (n = 13) and MICT (n = 13) interventions. Insulin-stimulated myocardial GU and fasted state FFAU were measured by positron emission tomography and changes in LV and RV structure and function by cardiac magnetic resonance. In contrast to our hypothesis, SIT significantly decreased GU compared to MICT in LV. FFAU of both ventricles remained unchanged by training. RV end-diastolic volume (EDV) and RV mass increased only after MICT, whereas LV EDV, LV mass, and RV and LV end-systolic volumes increased similarly after both training modes. As SIT decreases myocardial insulin-stimulated GU compared to MICT which may already be reduced in T2DM, SIT may be metabolically less beneficial than MICT for a diabetic heart.

The relationship between right ventricular deformation and heart rate variability in asymptomatic diabetic patients

OBJECTIVE

To investigate heart rate variability (HRV) and right ventricular (RV) remodeling in asymptomatic diabetic patients, as well as the relationship between HRV indices and RV structure, function and deformation.

METHOD

This cross-sectional study included 59 asymptomatic patients with type 2 diabetes and 45 healthy controls without cardiovascular risk factors. All study subjects underwent 24-h Holter monitoring, laboratory analyses and complete two-dimensional echocardiography examination (2DE).

RESULTS

RV diastolic function and longitudinal deformation were significantly impaired in diabetic individuals comparing with controls. RV global longitudinal strain and layer-specific longitudinal strains were significantly decreased in diabetic group. The same trend of changes in RV deformation was observed for global RV and lateral wall. All parameters of time and frequency domain of HRV were reduced in diabetic subjects. RV endocardial longitudinal strain together with LV mass index, mitral E/e' ratio and HbA1c correlated with HRV parameters. However, multivariate linear regression analysis showed that only RV endocardial longitudinal strain and LV mass index are associated with HRV parameters independently of age, BMI, HbA1c, RV free wall thickness and pulmonary artery pressure.

CONCLUSIONS

RV subendocardial strain is independently associated with HRV parameters in the whole study population. This reveals potentially important role of determination of layer-specific RV longitudinal function as important marker of preclinical cardiac damage, but also indirectly show the impairment of cardiac autonomic function in diabetic patients.

Diagnostic approaches for diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a cardiac dysfunction which affects approximately 12% of diabetic patients, leading to overt heart failure and death. However, there is not an efficient and specific methodology for DCM diagnosis, possibly because molecular mechanisms are not fully elucidated, and it remains asymptomatic for many years. Also, DCM frequently coexists with other comorbidities such as hypertension, obesity, dyslipidemia, and vasculopathies. Thus, human DCM is not specifically identified after heart failure is established. In this sense, echocardiography has been traditionally considered the gold standard imaging test to evaluate the presence of cardiac dysfunction, although other techniques may cover earlier DCM detection by quantification of altered myocardial metabolism and strain. In this sense, Phase-Magnetic Resonance Imaging and 2D/3D-Speckle Tracking Echocardiography may potentially diagnose and stratify diabetic patients. Additionally, this information could be completed with a quantification of specific plasma biomarkers related to related to initial stages of the disease. Cardiotrophin-1, activin A, insulin-like growth factor binding protein-7 (IGFBP-7) and Heart fatty-acid binding protein have demonstrated a stable positive correlation with cardiac hypertrophy, contractibility and steatosis responses. Thus, we suggest a combination of minimally-invasive diagnosis tools for human DCM recognition based on imaging techniques and measurements of related plasma biomarkers.

The Clinical Significance of HbA1c in Operable Chronic Thromboembolic Pulmonary Hypertension

Background

Glycosylated hemoglobin A1c (HbA1c) has been proposed as an independent predictor of long-term prognosis in pulmonary arterial hypertension. However, the clinical relevance of HbA1c in patients with operable chronic thromboembolic pulmonary hypertension (CTEPH) remains unknown. The aim of the present study was to investigate the clinical significance of HbA1c as a biomarker in CTEPH.

Methods

Prospectively, 102 patients underwent pulmonary endarterectomy (PEA) in our national referral center between March 2013 and March 2014, of which after exclusion 45 patients were analyzed. HbA1c- levels, hemodynamic and exercise parameters were analyzed prior and one-year post-PEA.

Results

45 patients (BMI: 27.3 ± 6.0 kg/m²; age: 62.7 ± 12.3 years) with a mean pulmonary arterial pressure (mPAP) of 43.6 ± 9.4 mmHg, a pulmonary vascular resistance (PVR) of 712.1 ± 520.4 dyn*s/cm⁵, a cardiac index (CI) of 2.4 ± 0.5 l/min/m² and a mean HbA1c-level of 39.8 ± 5.6 mmol/mol were included. One-year post-PEA pulmonary hemodynamic and functional status significantly improved in our cohort. Baseline HbA1c-levels were significantly associated with CI, right atrial pressure, peak oxygen uptake and the change of 6-minute walking distance using linear regression analysis. However, using logistic regression analysis baseline HbA1c-levels were not significantly associated with residual post-PEA PH.

Conclusions

This is the first prospective study to describe an association of HbA1c-levels with pulmonary hemodynamics and exercise capacity in operable CTEPH patients. Our preliminary results indicate that in these patients impaired glucose metabolism as assessed by HbA1c is of clinical significance. However, HbA1c failed as a predictor of the hemodynamic outcome one-year post-PEA.

The Role of Hyperglycemia and Insulin Resistance in the Development and Progression of Pulmonary Arterial Hypertension

Pulmonary hypertension is a progressive disorder which often leads to right ventricular failure and death. While the existing classification system for pulmonary hypertension does not account for the impact of diabetes mellitus, evidence is emerging that suggests that diabetes is associated with pulmonary hypertension and that diabetes modifies the course of pulmonary hypertension. There is also growing radiographic, hemodynamic, biochemical, and pathologic data supporting an association between diabetes and pulmonary hypertension. More robust epidemiologic studies are needed to confirm an association between diabetes and pulmonary hypertension and to show that diabetes is a disease modifier in pulmonary hypertension. In addition, evaluating the effects of glucose control in animals with pulmonary hypertension and diabetes (as well as in humans) is warranted.

Impact of diabetes in patients with pulmonary hypertension

Diabetes complicates management in a number of disease states and adversely impacts survival; how diabetes affects patients with pulmonary hypertension (PH) has not been well characterized. With insulin resistance having recently been demonstrated in PH, we sought to examine the impact of diabetes in these patients. Demographic characteristics, echo data, and invasive hemodynamic data were prospectively collected for 261 patients with PH referred for initial hemodynamic assessment. Diabetes was defined as documented insulin resistance or treatment with antidiabetic medications. Fifty-five patients (21%) had diabetes, and compared with nondiabetic patients, they were older (mean years ± SD, 61 ± 13 vs. 56 ± 16; [Formula: see text]), more likely to be black (29% vs. 14%; [Formula: see text]) and hypertensive (71% vs. 30%; [Formula: see text]), and had higher mean (±SD) serum creatinine levels (1.1 ± 0.5 vs. 1.0 ± 0.4; [Formula: see text]). Diabetic patients had similar World Health Organization functional class at presentation but were more likely to have pulmonary venous etiology of PH (24% vs. 10%; [Formula: see text]). Echo findings, including biventricular function, tricuspid regurgitation, and pressure estimates were similar. Invasive pulmonary pressures and cardiac output were similar, but right atrial pressure was appreciably higher (14 ± 8 mmHg vs. 10 ± 5 mmHg; [Formula: see text]). Despite similar management, survival was markedly worse and remained so after statistical adjustment. In summary, diabetic patients referred for assessment of PH were more likely to have pulmonary venous disease than nondiabetic patients with PH, with hemodynamics suggesting greater right-sided diastolic dysfunction. The markedly worse survival in these patients merits further study.

Cardiac structure and function across the glycemic spectrum in elderly men and women free of prevalent heart disease: the Atherosclerosis Risk In the Community study

BACKGROUND

Individuals with diabetes mellitus and pre-diabetes mellitus are at particularly high risk of incident heart failure or death, even after accounting for known confounders. Nevertheless, the extent of impairments in cardiac structure and function in elderly individuals with diabetes mellitus and pre-diabetes mellitus is not well known. We aimed to assess the relationship between echocardiographic measures of cardiac structure and function and dysglycemia.

METHODS AND RESULTS

We assessed measures of cardiac structure and function in 4419 participants without prevalent coronary heart disease or heart failure who attended the Atherosclerosis Risk In the Community (ARIC) visit 5 examination (2011-2013) and underwent transthoracic echocardiography (age, 75±6 years; 61% women, 23% black). Subjects were grouped across the dysglycemia spectrum as normal (39%), pre-diabetes mellitus (31%), or diabetes mellitus (30%) based on medical history, antidiabetic medication use, and glycated hemoglobin levels. Glycemic status was related to measures of cardiac structure and function. Worsening dysglycemia was associated with increased left ventricular mass, worse diastolic function, and subtle reduction in left ventricular systolic function (P≤0.01 for all). For every 1% higher glycated hemoglobin, left ventricular mass was higher by 3.0 g (95% confidence interval, 1.5-4.6 g), E/E' by 0.5 (95% confidence interval, 0.4-0.7), and global longitudinal strain by 0.3% (95% confidence interval, 0.2-0.4) in multivariable analyses.

CONCLUSIONS

In a large contemporary biracial cohort of elderly subjects without prevalent cardiovascular disease or heart failure, dysglycemia was associated with subtle and subclinical alterations of cardiac structure, and left ventricular systolic and diastolic function. It remains unclear whether these are sufficient to explain the heightened risk of heart failure in individuals with diabetes mellitus.

Right heart mechanics in untreated normotensive patients with prediabetes and type 2 diabetes mellitus: a two- and three-dimensional echocardiographic study

BACKGROUND

The aim of this study was to determine right ventricular (RV) and right atrial (RA) deformation assessed by two-dimensional echocardiographic and three-dimensional echocardiographic (3DE) imaging in patients with prediabetes and type 2 diabetes mellitus.

METHODS

This cross-sectional study included 47 untreated normotensive subjects with prediabetes, 57 recently diagnosed normotensive patients with diabetes, and 54 healthy controls of similar sex and age distributions. All subjects underwent laboratory analyses and complete two-dimensional echocardiographic and 3DE examinations.

RESULTS

Three-dimensional echocardiographic RV end-diastolic volume index gradually decreased from controls across patients with diabetes to those with diabetes (69 ± 10 vs 63 ± 8 vs 58 ± 8 mL/m(2), P < .001), whereas 3DE RV end-systolic volume index was higher in controls compared with patients with diabetes and those with diabetes (25 ± 4 vs 23 ± 4 vs 22 ± 4 mL/m(2), P < .001). However, there was no difference in 3DE RV ejection fraction among the three groups (63 ± 4% vs 62 ± 4% vs 61 ± 5%, P = .063). RV and RA global strain and systolic and early diastolic strain rates were decreased in patients with prediabetes and in those with diabetes compared with controls, whereas RV and RA late diastolic strain rates were increased in these patients. Multivariate regression analysis showed that RV global strain was associated with glycated hemoglobin, independent of left ventricular parameters.

CONCLUSIONS

RV and RA myocardial deformation and function obtained by 3DE and two-dimensional echocardiographic strain, even in normal ranges, were decreased in patients with prediabetes and in those with diabetes compared with controls. The long-term parameter of glucose control was correlated with the right heart mechanics.

Vascular imaging in diabetes

Diabetes is a global epidemic affecting individuals of all socioeconomic backgrounds. Despite intensive efforts, morbidity and mortality secondary to the micro- and macrovascular complications remain unacceptably high. As a result, the use of imaging modalities to determine the underlying pathophysiology, early onset of complications, and disease progression has become an integral component of the management of such individuals. Echocardiography, stress echocardiography, and nuclear imaging have been the mainstay of noninvasive cardiovascular imaging tools to detect myocardial ischemia, but newer modalities such as cardiac MRI, cardiac CT, and PET imaging provide incremental information not available with standard imaging. While vascular imaging to detect cerebrovascular and peripheral arterial disease non-invasively has traditionally used ultrasound, CT- and MRI-based techniques are increasingly being employed. In this review, we will provide an outline of recent studies utilizing non-invasive imaging techniques to assist in disease diagnosis as well as monitoring disease progression. In addition, we will review the evidence for newer modalities such as MR spectroscopy, 3D intravascular ultrasound, and optical coherence tomography that provide exquisite detail of metabolic function and coronary anatomy not available with standard imaging, but that have not yet become mainstream.

Effects of short-term nutritional interventions on right ventricular function in healthy men

BACKGROUND

A physiological model of increased plasma nonesterified fatty acid (NEFA) levels result in myocardial triglyceride (TG) accumulation, which is related to cardiac dysfunction. A pathophysiological model of increased plasma NEFA levels result in hepatic steatosis, which has been linked to abnormal myocardial energy metabolism. Hepatic steatosis is accompanied by hepatic inflammation, reflected by plasma cholesteryl ester transfer protein (CETP) levels. The current study aimed to investigate effects of these models via different nutritional interventions on right ventricular (RV) function.

METHODS

Fifteen men (age 25.0±6.6 years) were included and underwent magnetic resonance imaging and spectroscopy in this prospective crossover intervention study. RV function, myocardial and hepatic TG content, and CETP levels were assessed on three occasions: after normal diet, very low-calorie diet (VLCD, physiological model) and high-fat high-energy (HFHE, pathophysiological model) diet (all 3-days diets, randomly ordered, washout phase at least 14 days).

RESULTS

VLCD induced a decrease in mean E deceleration by 27%. Myocardial TG content increased by 55%, whereas hepatic TG content decreased by 32%. Plasma CETP levels decreased by 14% (all P<0.05). HFHE diet induced a decrease in E/A by 19% (P<0.05). Myocardial TG content did not change, whereas hepatic TG content increased by 112% (P<0.01). Plasma CETP levels increased by 14% (P<0.05).

CONCLUSIONS

These findings show that RV diastolic function is impaired after short-term VLCD and HFHE diet in healthy men, respectively a physiological and a pathophysiological model of increased plasma NEFA levels. After short-term VLCD, myocardial lipotoxicity may be of importance in decreased RV diastolic function. RV diastolic dysfunction is accompanied by increased hepatic TG content and plasma CETP levels after short-term HFHE diet, suggesting that systemic inflammation reflecting local macrophage infiltration in the heart may be involved in RV dysfunction.

HbA1c in the diagnosis of diabetes and abnormal glucose tolerance in patients with Graves' hyperthyroidism

OBJECTIVE

To assess the suitability of HbA1c as a criterion for the diagnosis of diabetes in patients with Graves' disease.

METHODS

This study enrolled 310 patients with untreated newly diagnosed Graves' disease, 208 patients with euthyroid goiter and 329 age-matched (control) subjects without thyroid disease from Fuzhou, China. The performance of HbA1c against the OGTT for diagnosing diabetes was determined. The Framingham risk score was used to assess general cardiovascular disease (CVD) risk.

RESULTS

The percentage of patients with abnormal glucose metabolism as classified by HbA1c levels was lower than by OGTT criteria in patients with Graves' disease-33.2% vs. 41.3% for pre-diabetes and 4.5% vs. 11.3% for diabetes, respectively. The sensitivity of HbA1c for diagnosing diabetes in patients with Graves' disease was lower than in patients with euthyroid goiter and subjects without thyroid disease (34.9%, 63.2% and 60.6% respectively), while the specificity was similar (99.3%, 98.6%, 97.4%). Approximately 7.4% of patients with Graves' disease diagnosed with diabetes according to OGTT criteria were misdiagnosed as not having the disease by HbA1c, much higher than that for the other two groups. Patients with Graves' disease with diabetes not diagnosed with the disease by HbA1c showed a high risk for CVD.

CONCLUSIONS

The low sensitivity of the HbA1c criterion underestimated the percentage of diabetes in patients with Graves' disease. Patients with diabetes who were misdiagnosed as not having the disease by HbA1c were at high risk for CVD.