Effects of diabetes mellitus on left atrial volume and functions in normotensive patients without symptomatic cardiovascular disease

Association of diabetes and glycemic control with left atrial function: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Although glycemic status is associated with impaired cardiac structure and function, less is known on left atrial (LA) function across the glycemic spectrum. We evaluated the association of diabetes and glycemic control with LA function in a community-based cohort of older adults.

METHODS AND RESULTS

This cross-sectional analysis included 5075 participants from the Atherosclerosis Risk in Communities Study (mean age 75.5 years, 58 % women, and 20 % Black adults) with echocardiographic strain data for LA reservoir, conduit, and contractile function. Multivariable linear regression was used to assess associations of diabetes status and glycemic control with LA function. In participants without diabetes, we used ordinal linear regression to evaluate associations of fasting glucose and HbA1c with LA function. Compared to individuals with a normal fasting glucose, prevalent diabetes was associated with 0.68 % lower LA conduit function (95 % confidence interval (CI): 1.11 to -0.25) and prediabetes a 0.47 % reduction (95 % CI: 0.85 to -0.09) in fully adjusted analyses. Persons with diabetes and high HbA1c (HgbA1c ≥ 7 % vs <7 %) had 1.05 % lower LA conduit function (95 % CI: 1.63, -0.48). Among individuals without diagnosed diabetes, higher fasting glucose, but not HbA1c, was significantly associated with worse LA conduit function. No significant associations were observed for LA reservoir and contractile function.

CONCLUSIONS

A history of diabetes, prediabetes, and higher fasting glucose levels in persons without diabetes were associated with worse LA conduit function. Corroborative research is needed in prospective cohorts as well as studies that explore underlying mechanisms.

Echocardiographic Changes in Saudi Patients with Type 2 Diabetes Mellitus

Background and Objectives: Cardiovascular disease is one of the leading causes of morbidity and mortality among the diabetic population. Given the high prevalence of diabetes mellitus (DM) in Saudi Arabia and the high prevalence of heart failure in the diabetic population, this study assesses the echocardiographic changes in Saudi patients with type 2 DM (T2DM) compared with healthy controls. Materials and Methods: In this retrospective case-control study, 80 patients with diabetes (45 males, age: 58.78 ± 10.2 years) were compared with 80 controls (45 males, age: 58.6 ± 10 years) who underwent an echocardiographic study in the King Saud University Medical City, Riyadh, Saudi Arabia. Results: There were no significant differences between the patients with diabetes and controls in terms of aortic root diameter, left atrium diameter, posterior wall, interventricular wall thickness, left ventricular diameters and ejection fraction. However, diastolic dysfunction was statistically significantly higher in the diabetic group than in the control group (p < 0.05). Conclusions: This is the first case-control study in Saudi Arabia that assesses echocardiographic parameters in T2DM patients. DM is an independent risk factor for diastolic dysfunction regardless of its association with hypertension and dyslipidemia.

Specific inflammatory profile of acute ischemic stroke patients with left atrial enlargement

Background

The inflammatory process underlying atrial myopathy may affect the inflammatory response activated in acute ischemic stroke (AIS).

Objectives

We aimed to assess whether left atrial enlargement (LAE) as a marker of atrial myopathy is associated with a different profile of circulating inflammatory markers in AIS patients.

Methods

HIBISCUS-STROKE is a cohort study including anterior circulation AIS patients treated with mechanical thrombectomy following MRI. Ten circulating inflammatory markers were measured at admission and 6, 24, and 48 h after admission. LAE was defined as a left atrial volume index (LAVi) ≥34 ml/m2. A multiple logistic regression model was performed to detect an independent association between the area under the curve (AUC) of these markers and LAE.

Results

We included 143 patients. Of them, 85 (59.4%) had LAE. On univariable analysis, we found that patients with LAE had higher soluble form suppression of tumorigenicity 2 (sST2), soluble tumor necrosis factor receptor I (sTNFR1), and vascular cellular adhesion molecule-1 (VCAM-1) AUC, were older, mostly female, had a higher National Institutes of Health Stroke Scale (NIHSS) score and blood glucose level at admission, had more often hypertension, and a cardioembolic source of AIS, such as atrial fibrillation, while they were less frequently current smokers and had a lower rate of tandem occlusion than patients without LAE. On multivariable analysis, we found that among circulating inflammatory markers, only high VCAM-1 (OR: 9.13, 95% CI: 3.21-25.9) and sST2 (OR: 3.40, 95% CI: 1.68-6.86) AUC remained associated with LAE.

Conclusions

High VCAM-1 and sST2 levels within the first 48 h are associated with LAE in AIS patients.

Impact of empagliflozin on left atrial mechanical and conduction functions in patients with type 2 diabetes mellitus

OBJECTIVE

Empagliflozin, an oral anti-diabetic drug that inhibits the sodium-dependent glucose co-transporter 2 (SGLT2), has pleiotropic effects on the myocardium. The aim of the study is to investigate the effect of empagliflozin on atrial electromechanical delay (AEMD) and the left atrial (LA) mechanical functions in patients with type 2 diabetes mellitus (DM).

METHOD

In total 62 patients (40.3% female, mean age 50.5 ± 8.6 years old) with type 2 DM were enrolled to the study. Participants were used a SGLT2 inhibitor (empagliflozin 10-25 mg/daily) for 6 months. Patients were examined initially and after 6 months with echocardiography. LA volume was recorded, atrial conduction times were measured using tissue Doppler imaging (TDI).

RESULTS

No significant change was observed in LA volumes (maximal, minimal, and presystolic), total emptying and passive emptying volume at the end of 6 months; however, there was a significant decrease in active emptying volume (8.3 ± 2.9 ml/m² vs. 7.9 ± 2.9 ml/m² , p = 0.04). The posteroanterior lateral, septal, and tricuspid conduction times significantly decreased after the empagliflozin treatment. The decrease in right inter-AEMD was statistically significant (13.25 ± 10.21 ms vs. 10.85 ± 9.14 ms, p = 0.011). The changes in inter-AEMD were found to be correlated with the changes in LA active emptying volume (r = 0.408).

CONCLUSION

Empagliflozin may enhance the structure and electrical conductions of the atrium and may prevent DM patients from DM-2-related functional disorder and arrhythmia.

Diabetic microvascular complications are associated with left atrial structural alterations in asymptomatic type 2 diabetes patients: A cross-sectional study

AIMS

We used 4D-Auto LAQ to quantitatively evaluate the morphological and functional changes of left atrium in patients with asymptomatic type 2 diabetes mellitus (T2DM), and explored its correlations with diabetic microvascular complications (MICRO).

METHODS

This study included 319 patients with asymptomatic T2DM. According to the occurrence of MICRO, these patients were divided into 3 groups: patients with no complication, 1 complication, and 2-3 complications. 4D-Auto LAQ was used to evaluate left atrial volume (LAVImin, LAVImax, LAVIpre) and calculate the left atrial function (DEI, PEI, AEI) in different phases. Multiple linear regression was used to analyze the correlation between changes in left atrial volume and function and the number of MICROs in DM patients.

RESULTS

A total of 279 patients with asymptomatic T2DM were included in this study. (1) The ultrasound data of the three T2DM groups showed that there was no significant difference in left ventricular size and function among the three groups; (2) with the increase of MICRO number, the left atrial volume (LAVImin, LAVImax, LAVIpre) progressively increased, the left atrial storage function index (DEI) gradually decreased, and the differences were significant (P < 0.05). (3) Multiple linear regression analysis showed that: with the increase of MICRO number (no complication→1 complication→2-3 complications), the left atrial volume (LAVImin, LAVIpre) showed an increasing trend (both P < 0.05).

CONCLUSION

In asymptomatic T2DM patients, MICRO number showed a significant positive correlation with LAVImin and LAVIpre (P < 0.05). Therefore, the increase in left atrial volume can dynamically reflect the severity of microvascular lesions in patients with asymptomatic T2DM.

Prognostic relevance of left atrial function and stiffness in heart failure with preserved ejection fraction patients with and without diabetes mellitus

Background

Although the left atrium (LA) plays a key role in the pathophysiology and disease progression of heart failure with preserved ejection fraction (HFpEF), the impact of type 2 diabetes mellitus (T2DM) on LA function and stiffness in HFpEF patients remains unclear. Furthermore, the prognostic value of different phases of LA function and stiffness is less well-established in HFpEF patients.

Methods

This study prospectively enrolled 164 HFpEF patients who were in sinus rhythm at the time of echocardiography, including 61 (37%) HFpEF patients with T2DM. LA reservoir, conduit, and pump function were assessed using two-dimensional volume indices and speckle tracking echocardiography. The LA stiffness was calculated as the ratio of early mitral inflow velocity-to-early annular tissue velocity (E/e’) and LA reservoir function. The primary end point was a combined outcome of heart failure hospitalization or death.

Results

Left atrium reservoir function [measured by peak LA strain (LAS-peak)] and LA pump function (measured by LAS-active) remained significantly lower in the HFpEF patients with T2DM compared with those without T2DM, even after adjustment for potential confounders. In addition, the LA stiffness of HFpEF patients with T2DM was higher than those without T2DM. After a median follow-up of 13.7 months, 46 patients (28.1%) reached the composite end point. LAS-peak (hazard ratios: 0.88; 95% confidence interval: 0.81–0.95; P = 0.001) was significantly associated with the risk of heart failure hospitalization or death after adjusting for demographic and clinical characteristics, LV global longitudinal strain, E/e’, and LA volume index. In contrast, other LA function and stiffness parameters did not independently predict the risk of adverse events. Kaplan-Meier analysis showed that HFpEF patients with T2DM and low LAS-peak (<27.2%) had a significantly increased risk of heart failure-related hospitalization or death (log-rank P < 0.001).

Conclusion

Left atrium reservoir and pump function are impaired, whereas LA stiffness is increased in HFpEF patients with T2DM compared with those without T2DM. LAS-peak is a powerful predictor of adverse clinical outcomes and may be crucial for risk stratification in HFpEF patients with and without T2DM.

The impact of lifestyle intervention on left atrial function in type 2 diabetes: results from the DIASTOLIC study

Aerobic exercise training and low energy diets have been shown to improve left ventricular remodelling and diastolic function in adults with type 2 diabetes (T2D), albeit with differential effects. The impact of these lifestyle interventions on left atrial (LA) function, however, has not previously been reported. The DIASTOLIC study was a prospective, randomised, open-label, blind endpoint trial, in which 90 people with obesity and T2D and no prevalent cardiovascular disease were randomised to a 12-week intervention of: (i) routine care, (ii) aerobic exercise training, or (iii) low energy (≈ 810 kcal/day) meal replacement plan (MRP). Cardiac magnetic resonance (CMR) imaging was performed pre- and post-intervention. Image analysis included LA volumes (LAV), emptying fraction (LAEF), and LA strain (LAS) corresponding to LA reservoir (LAS-r), conduit (LAS-cd), and booster pump (LAS-bp) function. 73 participants with T2D (mean age 50 ± 6 years, 62% male, body mass index (BMI) 36.1 ± 5.3 kg/m2) completed the trial and had analysable LA images. There was no significant change in CMR measured LA volumetric function (LAV/LAEF) in any group. The routine care group showed no significant change in BMI or LAS. In the MRP group, there were significant reductions in BMI (4.5 kg/m2) and a significant increase in LAS-r and LAS-bp (29.9 ± 7.0 to 32.3 ± 7.0%, p = 0.036 and 14.6 ± 5.3 to 17.2 ± 3.7%, p = 0.034). The exercise group showed a small reduction in BMI (0.49 kg/m2), with no significant change in LAS. Compared to routine care, weight loss via a 12-week MRP, led to improvements in LA filling and contractile function in adults with T2D and obesity. However, these within-group changes were not statistically significant on between-group comparison. ClinicalTrials.gov Identifier: NCT02590822.

Association of Left Atrial Size Measured by Non-Contrast Computed Tomography with Cardiovascular Risk Factors—The Danish Cardiovascular Screening Trial (DANCAVAS)

Left atrium (LA) size is associated with adverse cardiovascular events. The purpose of this study was to investigate the association of LA enlargement measured by non-contrast CT (NCCT) with traditional cardiovascular risk factors. Individuals aged 60–75 years from the population-based multicentre Danish Cardiovascular Screening (DANCAVAS) trial were included in this cross-sectional study. The LA was manually traced on the NCCT scans, and the largest cross-section area was indexed to body surface area. All traditional risk factors were recorded, and a subgroup received an echocardiographic examination. We enrolled 14,987 individuals. Participants with known cardiovascular disease or lacking measurements of LA size or body surface area were excluded, resulting in 10,902 men for the main analysis and 616 women for a sensitivity analysis. Adjusted multivariable analysis showed a significantly increased indexed LA size by increasing age and pulse pressure, while smoking, HbA1c, and total cholesterol were associated with decreased indexed LA size. The findings were confirmed in a supplementary analysis including left ventricle ejection fraction and mass. In this population-based cohort of elderly men, an association was found between age and pulse pressure and increasing LA size. Surprisingly, smoking, HbA1c, and total cholesterol were associated with a decrease in LA size. This indicates that the pathophysiology behind atrial cardiomyopathy is not only reflected by enlargement, but also shrinking.

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 prediabetes with impaired left atrial contractility in patients with never-treated hypertension

AIM

Prediabetes defined by HbA1c 5.7-6.4 has been shown to be associated with left ventricular (LV) hypertrophy and diastolic dysfunction in hypertensive patients. We hypothesized HbA1c prediabetes may be related to the alterations of LA contractility or volume in nondiabetic hypertension.

METHODS

Nondiabetic individuals on sinus rhythm were enrolled; 107 patients with never-treated hypertension, 134 patients with treated hypertension, and 71 normotensive subjects. Participants were classified as normal glucose tolerance (NGT, HbA1c<5.7), prediabetes (HbA1c 5.7-6.4) according to the ADA criteria. They underwent echocardiography to measure left atrial (LA) phasic volumes and functions, as well as mitral E/e' and mitral e'.

RESULTS

In nondiabetic patients with never-treated hypertension, prediabetes saw lower LA total emptying fraction (53.7 ± 8.2 vs. 48.3 ± 9.9*) and mitral e' (7.38 ± 2.18 vs. 6.17 ± 1.50*) than NGT, implicating that the association of prediabetes with reduced LA contractility and LV stiffness. On the other hand, in nondiabetic patients with treated hypertension, prediabetes saw higher maximum LA volume/BSA (29.7 ± 7.1 vs. 32.9 ± 6.2* ml/mm²) and mitral E/e' (10.72 ± 3.08 vs. 12.37 ± 3.35*) than NGT, suggesting the relationship of prediabetes with increased LA preload.

CONCLUSION

Prediabetes may be involved in the progression of LA structural and functional alterations in nondiabetic hypertensive patients.

Left atrial function in diabetes: does it help?

Left atrial (LA) structural, functional and mechanical changes have important role in development of diabetic cardiomyopathy and it was discovered that LA remodeling has important prognostic role in the patients with diabetes (DM). Previously the focus of echocardiographic studies in DM population was on the left ventricular structure and function, but the atrioventricular coupling was proved to be one of the main predictors of cardiovascular morbidity and mortality in DM patients. Each phase of LA cycle has determinant role in the atrioventricular coupling and therefore the accurate assessment of LA phasic function gained importance over last decade. The failure of any of the three LA phasic functions (reservoir, conduit or contractile) leads potentially to LA dilatation, left ventricular diastolic dysfunction, atrial fibrillation and ultimately development of heart failure with preserved (or even reduced) ejection fraction. Even though LA phasic function has not been extensively studied in DM population, it is reasonable to hypothesize that LA dysfunction is very frequent in these patients, considering the high prevalence of atrial fibrillation and heart failure in these individuals. In research and clinical purposes two techniques have been used for determination of LA phasic function: volumetric and strain. Although these methods fundamentally differ, with their own advantages and limitations, they also provide comparable results that can direct our therapeutic approach in DM patients. Namely, not only that LA function represents an independent predictor of cardiovascular outcome in DM patients, but also it has been also associated with parameters of glycemic control. This review summarized the current knowledge regarding LA phasic function in DM patients.

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.

The E/e' ratio difference between subjects with type 2 diabetes and controls. A meta-analysis of clinical studies

Type 2 diabetes is associated with an increased risk of heart failure. Left ventricular diastolic dysfunction and type 2 diabetes are frequently associated. Using echocardiography, we know that tissue Doppler imaging E/e’ ratio is a reliable predictor of left ventricular filling pressure. We performed a systematic review and meta-analysis to investigate the averaged E/e’ ratio value in patients with type 2 diabetes compared to non-diabetic controls. In the analysis we included cross-sectional studies providing the averaged E/e’ ratio. Subgroup/sensitivity analyses were conducted according to variables known to influence E/e’ ratio measurements. The analysis included 15 cross sectional studies with 877 type 2 diabetes patients and 1193 controls. The weighted mean difference showed higher values in diabetes (WMD 2.02; 95% CI 1.35, 2.70; p<0.001). The result was consistent in the subgroup/sensitivity analyses. Visual inspection of the funnel plot did not identify substantial asymmetry and the Egger test for funnel plot asymmetry showed a p value of 0.36. In conclusion, our assessment suggests that averaged E/e’ ratio is consistently increased in patients with type 2 diabetes compared to non-diabetic controls in the absence of cardiovascular diseases and complicated hypertension. This alteration may be a precocious diastolic alteration in the diabetic cardiomyopathy.

Left atrial size and function in a South Asian population and their potential influence on the risk of atrial fibrillation

BACKGROUND

South Asians have a low prevalence of atrial fibrillation (AF) compared with Caucasians despite having a higher prevalence of conventional risk factors for the arrhythmia. The reason for this disparity is uncertain but may be due to ethnic differences in atrial morphology. This study examines the association between ethnicity and left atrial (LA) size and function in South Asian and Caucasian subjects using the reference technique of cardiovascular magnetic resonance imaging (MRI).

HYPOTHESIS

South Asians have smaller LA size and therefore increased LA function.

METHODS

Retrospective case-control study of 60 South Asian and 60 Caucasian patients who had undergone a clinically indicated MRI between April 2010 and October 2017 and had been found to have a structurally normal heart. LA and left ventricular (LV) volume and function were assessed and compared between the ethnicities.

RESULTS

In comparison with Caucasians, South Asians had significantly lower minimum (27.7 ± 11.1 mL vs 34.9 ± 12.3 mL, P = 0.002) and maximum LA volumes (64.7 ± 21.1 mL vs 80.9 ± 22.5 mL, P < 0.001), lower LV end-diastolic volume (P < 0.001), lower LV stroke volume (P < 0.001), and lower LV mass (P = 0.022) and these values remained significant after correcting for body surface area. Further analysis revealed that LA volume was independently associated with South Asian ethnicity. There was no difference in LA function between the ethnic groups.

CONCLUSIONS

South Asians have reduced LA volumes and a proportionally smaller heart size in comparison to Caucasians. Smaller LA size may protect against the development of AF by reducing the risk of reentrant circuit formation and atrial fibrosis development.

Assessment of left atrial function in patients with type 2 diabetes mellitus with a disease duration of six months

INTRODUCTION

Changes in left atrial (LA) size and function are associated with adverse clinical events. Recently, duration of diabetes mellitus (DM2) has been found to be positively associated with increased LA volume and impaired LA function. This study was performed, using two-dimensional echocardiograpy, to evaluate the changes in LA volume and function in patients with DM2 with a disease duration of six months, and to assess the parameters that affect LA volume and function.

METHODS

Fifty-six patients (28 male, age: 52.6 ± 6.5 years) with DM2 and 56 controls (24 male; age: 50.1 ± 7.0 years) were enrolled in the study. Each subject underwent conventional two-dimensional echocardiography to assess LA volume (indexed maximal LA volume: Vmax, pre-atrial contraction volume: Volp, minimal LA volume: Vmin) and LA function [passive emptying volume - passive emptying fraction (PEV - PEF), active emptying volume - active emptying fraction (AEV - AEF), total emptying volume - total emptying fraction (TEV - TEF) ].

RESULTS

LA diameter, indexed Vmax, Volp, Vmin, AEV and TEV were found to be significantly higher in the DM2 group compared with the controls (p < 0.05). Indexed Vmax, Volp and Vmin were significantly correlated with HbA1c level, body mass index (BMI), high-sensitivity C-reactive protein and uric acid levels, mitral A wave, E/E' ratio and A' wave. According to multivariate analysis, age and BMI had a statistically significant effect on LA volume.

CONCLUSION

Impaired LA function may be present in patients with newly diagnosed DM2. BMI and increasing age caused LA enlargement and LA volumes that were independent of the effects of hypertension and DM2.

Left atrium passive ejection fraction is the most sensitive index of type 2 diabetes mellitus-related cardiac changes

The aims of this study were to use cardiovascular magnetic resonance (CMR) cine to assess left atrium (LA) and left ventricle (LV) function and structure in normotensive type 2 diabetes mellitus (T2DM) patients and to identify the most sensitive index of those T2DM-related cardiac changes. Fifty T2DM patients with normotension (25 males, age 54.7 ± 8.7 years, duration of diabetes: 7.5 ± 5.1 years) and 35 controls (16 males, age: 52.2 ± 13.2 years) were prospectively enrolled. All patients were scanned using CMR four- and two-chamber long-axis cine to assess LA and LV structure and function. Normotensive T2DM patients were associated with decreased LA total ejection fraction (EF), passive EF and LV end diastolic volume, normal LA active EF and LV myocardial mass and increased LV mass/volume (M/V). LA total EF and passive EF correlated with body mass index, duration of diabetes and M/V. To differentiate between diabetic patients and healthy controls, area under the receiver operating characteristic (ROC) curve (AUC) values were calculated to be 0.763, 0.706, 0.647 and 0.649 for LA passive EF, total EF, LVEDV and M/V, respectively. The addition of LA total EF, LVEDV, M/V and the combination thereof did not significantly improve AUC values in a model containing LA passive EF. Normotensive T2DM patients were associated with LA decreased total ejection fraction, decreased passive EF and LV concentric remodeling. Among these indices, LA passive EF was the most sensitive to T2DM-related LA function changes.

Left atrial remodeling, hypertrophy, and fibrosis in mouse models of heart failure

Left ventricular dysfunction increases left atrial pressures and causes atrial remodeling. In human subjects, increased left atrial size is a powerful predictor of mortality and adverse events in a broad range of cardiac pathologic conditions. Moreover, structural remodeling of the atrium plays an important role in the pathogenesis of atrial tachyarrhythmias. Despite the potential value of the atrium in assessment of functional endpoints in myocardial disease, atrial pathologic alterations in mouse models of left ventricular disease have not been systematically investigated. Our study describes the geometric, morphologic, and structural changes in experimental mouse models of cardiac pressure overload (induced through transverse aortic constriction), myocardial infarction, and diabetes. Morphometric and histological analysis showed that pressure overload was associated with left atrial dilation, increased left atrial mass, loss of myofibrillar content in a subset of atrial cardiomyocytes, atrial cardiomyocyte hypertrophy, and atrial fibrosis. In mice undergoing nonreperfused myocardial infarction protocols, marked left ventricular systolic dysfunction was associated with left atrial enlargement, atrial cardiomyocyte hypertrophy, and atrial fibrosis. Both infarcted animals and pressure overloaded mice exhibited attenuation and perturbed localization of atrial connexin-43 immunoreactivity, suggesting gap junctional remodeling. In the absence of injury, obese diabetic db/db mice had diastolic dysfunction associated with atrial dilation, atrial cardiomyocyte hypertrophy, and mild atrial fibrosis. Considering the challenges in assessment of clinically relevant functional endpoints in mouse models of heart disease, study of atrial geometry and morphology may serve as an important new tool for evaluation of ventricular function.

Impaired Left Atrial Conduit Function in Coronary Artery Disease Patients With Poorly Controlled Diabetes: Two-Dimensional Speckle-Tracking Echocardiographic Study

OBJECTIVES

The myocardium can be affected by diabetes mellitus. The effects of blood glucose control on some organs such as the kidney and eye have been previously reported. The aim of our study was to evaluate left atrial function via 2-dimensional (2D) speckle-tracking echocardiography in a group of coronary artery disease (CAD) patients with well-controlled diabetes (hemoglobin A1c [HbA1c] < 7%) and to compare it with that in a group of CAD patients with poorly controlled diabetes.

METHODS

This cross-sectional study included 110 CAD patients, comprising 44 euglycemic control patients, 33 patients with well-controlled diabetes (HbA1c < 7%), and 33 patients with poorly controlled diabetes. The study population thereafter underwent 2D speckle-tracking echocardiography for an evaluation of their left atrial function.

RESULTS

Our findings showed that the absolute values of early diastolic strain and early diastolic strain rate were lower in the CAD patients with poorly controlled diabetes than in the euglycemic control patients with CAD. Moreover, early diastolic strain in the CAD patients with poorly controlled diabetes was lower than that in the CAD patients with well-controlled diabetes. Multivariable analysis revealed that poorly controlled diabetes was an independent determinant of early diastolic strain and strain rate.

CONCLUSIONS

The conduit function of the left atrium was impaired in the CAD patients with poorly controlled diabetes compared with that in the euglycemic control patients with CAD and the CAD patients with well-controlled diabetes.

Silent diabetic cardiomyopathy in everyday practice: a clinical and echocardiographic study

BACKGROUND

Whether type 2 diabetes mellitus (DM) in the absence of hypertension (HTA) and coronary artery disease (CAD) affects left ventricular (LV) phenotype and function among asymptomatic DM patients that can be easily discovered in everyday practice, what is the clinical risk profile for diabetic cardiomyopathy and how HTA and CAD modulate LV structure and function above diabetic cardiomyopathy, are still incompletely answered questions.

METHODS

In 210 DM patients (group I: 70 asymptomatic DM patients without HTA and CAD; group II: 70 DM patients with HTA and no CAD; group III: 70 DM patients with CAD and no HTA) and 80 healthy individuals, comprehensive echocardiography including speckle tracking strain and strain rate analysis, was done.

RESULTS

Compared to control DM patients without HTA and CAD had increased LV mass, more frequently concentric remodeling, impaired LV relaxation and lower LV ejection fraction (EF), fraction of shortening (FS) and mitral annular plane excursion (MAPSE). Addition of HTA further impaired EF, FS and MAPSE and aggravated diastolic dysfunction, whereas concomitant CAD further impaired FS and MAPSE. Peak global longitudinal strain (Slong) and early diastolic longitudinal strain rate (SRlong E) were impaired in group I compared to control, even when EF was preserved. Peak circumferential strain (Scirc) was impaired only when DM was associated with HTA or CAD. In multivariate analysis DM was significantly and independently from HTA, CAD, age, gender and body mass index associated with: increased LV mass, concentric LV remodeling, lower EF, FS, MAPSE, Slong, SRlongE and distorted diastolic parameters. DM duration, glycosylated hemoglobin, microalbuminuria and retinopathy, were not independent predictors of LV geometry and function.

CONCLUSION

DM per se has strong and independent influence on LV phenotype and function that can be detected by conventional and speckle tracking echocardiography in everyday clinical practice, even in asymptomatic patients. We could not confirm that these changes were independently related to duration of DM, quality of metabolic control and presence of microvascular complications. Concomitant HTA or CAD furthermore distorted LV systolic and diastolic function.

Association between atrial function assessed by 2D-speckle tracking echocardiography and albuminuria in patients with type 2 diabetes and coronary artery disease

PURPOSE

We compared left atrial function as assessed by two-dimensional speckle-tracking echocardiography (2DSTE) between patients with type 2 diabetes and coronary artery disease (CAD) with or without albuminuria, nondiabetic patients without CAD, and CAD patients without type 2 diabetes.

METHODS

This cross-sectional study was performed on 112 consecutive patients with CAD (28 nonalbuminuric patients without diabetes, 40 nonalbuminuric patients with type 2 diabetes, and 44 albuminuric patients with type 2 diabetes) and 30 consecutive patients with no CAD, no diabetes, and no albuminuria. Spot urine analysis was performed to measure the urine level of creatinine and albumin. Atrial mechanical variables were measured by 2DSTE.

RESULTS

Although systolic strain and the absolute value of early diastolic strain rate were lower in the CAD groups than in the non-CAD group, there were no significant differences between the CAD groups. Early diastolic strain was lower in the diabetic patients with CAD than in the nondiabetic non-CAD group. There were, however, no significant differences between the CAD groups.

CONCLUSIONS

In our CAD patients, there was no significant association between the presence of type 2 diabetes mellitus and albuminuria and left atrial function, but the reservoir and conduit function of the left atrium were lower in the CAD patients. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:561-570, 2016.

Evidence of left atrial remodeling and left ventricular diastolic dysfunction in type 2 diabetes mellitus with preserved systolic function

BACKGROUND AND AIMS

Prognosis of type 2 diabetes is associated with the occurrence of cardiovascular diseases. Left atrial (LA) size is a predictor of outcome in several diseases, including diabetes. Long duration of diabetes is an established risk factor of poor prognosis. No data are available on the relationship between LA size and duration of diabetes. The present study was aimed to investigate the relationship between LA volume index (LAVI) and the duration of diabetes to test the hypothesis that LA volume will increase as a function of diabetes duration.

METHODS AND RESULTS

Forty-four male patients with newly diagnosed and 172 male patients with established type 2 diabetes were recruited for this cross-sectional study. All patients were evaluated with a transthoracic echocardiographic Doppler. About 28.2% of patients had increased LAVI. Indices of both diastolic and systolic function were significantly lower in patients with larger left atrium. The values of LAVI increased across classes of duration of diabetes. In multivariable analysis, longer duration was a predictor of LAVI ≥34 ml/m² (odds ratio 1.65, 95% CI 1.11-2.46, p = 0.014) after adjusting for age, hemoglobin A1c, hypertension, microvascular complication status, and relevant echocardiographic parameters of systolic and diastolic function.

CONCLUSIONS

These results indicate that duration of diabetes is strongly and positively associated with larger LAVI in type 2 diabetic men with preserved systolic function. Future studies are needed to better elucidate the biological mechanisms underlying linking type 2 diabetes with abnormally increased LAVI in subjects with type 2 diabetes.