Changes in left atrial volume in diabetes mellitus: more than diastolic dysfunction?

Left atrial cardiomyopathy: Pathophysiological insights, assessment methods and clinical implications

Atrial cardiomyopathy is defined as any complex of structural, architectural, contractile or electrophysiological changes affecting atria, with the potential to produce clinically relevant manifestations. Most of our knowledge about the mechanistic aspects of atrial cardiomyopathy is derived from studies investigating animal models of atrial fibrillation and atrial tissue samples obtained from individuals who have a history of atrial fibrillation. Several noninvasive tools have been reported to characterize atrial cardiomyopathy in patients, which may be relevant for predicting the risk of incident atrial fibrillation and its related outcomes, such as stroke. Here, we provide an overview of the pathophysiological mechanisms involved in atrial cardiomyopathy, and discuss the complex interplay of these mechanisms, including aging, left atrial pressure overload, metabolic disorders and genetic factors. We discuss clinical tools currently available to characterize atrial cardiomyopathy, including electrocardiograms, cardiac imaging and serum biomarkers. Finally, we discuss the clinical impact of atrial cardiomyopathy, and its potential role for predicting atrial fibrillation, stroke, heart failure and dementia. Overall, this review aims to highlight the critical need for a clinically relevant definition of atrial cardiomyopathy to improve treatment strategies.

Comorbidities in heart failure patients that predict cardiovascular readmissions within 100 days-An observational study

BACKGROUND

Heart failure (HF) commonly arises as a complication to cardiovascular diseases and is closely associated with various comorbidities. The impacts of these comorbidities in patients with HF are diverse. We aimed to analyze the increased risk for cardiovascular-related readmission within 100 days after discharge in patients with HF depending on their different comorbidities.

METHODS

A population-based retrospective study was conducted in Region Halland with 5029 patients admitted to hospital with a diagnosis of HF during 2017-2019. The occurrence and number of comorbidities were recorded. Competing risk regression was employed to analyze the hazard ratio (HR) of 10 comorbidities for cardiovascular-related readmission within 100 days after discharge. A composite measure of the 10 common comorbidities was constructed with the comorbidities as dichotomous indicator variables and Rasch analysis. Receiver operating characteristic (ROC) and area under curve (AUC) after logistic regression were used to estimate how well the model explained the probability of death or readmission within 100 days after discharge according to their individual comorbidity level.

RESULTS

HF patients with atrial fibrillation, chronic obstructive pulmonary disease, chronic kidney disease, peripheral artery disease or diabetes mellitus as comorbidities had an increased HR for readmission within 100 days after discharge. When these comorbidities were adjusted together, only atrial fibrillation, chronic kidney disease and chronic obstructive pulmonary disease had an increased HR for readmission. ROC analysis after the most complete models using logistic regression with the comorbidities as dichotomous indicator variables or Rasch analysis had a low AUC.

CONCLUSIONS

Atrial fibrillation, chronic kidney disease or chronic obstructive pulmonary disease were significantly associated with increased risk for readmission in HF patients, but ROC analysis showed a low AUC, which indicates that other factors are more important for predicting the increased risk of readmission.

Modifications of long-term heart rate variability produced in an experimental model of diet-induced metabolic syndrome

Metabolic syndrome (MetS) has been linked to a higher prevalence of cardiac arrhythmias, the most frequent being atrial fibrillation, but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic nervous system activity, which can be quantified by analysing heart rate variability (HRV). Our aim was to investigate the modifications of long-term HRV in an experimental model of diet-induced MetS to identify the early changes in HRV and the link between autonomic dysregulation and MetS components. NZW rabbits were randomly assigned to control (n = 10) or MetS (n = 10) groups, fed 28 weeks with high-fat, high-sucrose diet. 24-hour recordings were used to analyse HRV at week 28 using time-domain, frequency-domain and nonlinear analyses. Time-domain analysis showed a decrease in RR interval and triangular index (Ti). In the frequency domain, we found a decrease in the low frequency band. Nonlinear analyses showed a decrease in DFA-α1 and DFA-α2 (detrended fluctuations analysis) and maximum multiscale entropy. The strongest association between HRV parameters and markers of MetS was found between Ti and mean arterial pressure, and Ti and left atrial diameter, which could point towards the initial changes induced by the autonomic imbalance in MetS.

Left atrial phasic function: physiology, clinical assessment and prognostic value

Left atrial (LA) phasic function provides significant insights into the pathophysiology of cardiovascular disease. LA function is described in three phases: reservoir (atrial filling, during systole), conduit (passive emptying, during early diastole) and contractile (active emptying, during late diastole). LA phasic function can be evaluated by different imaging modalities, and a variety of techniques including volumetric analysis, deformation (strain) and Doppler methods. LA phasic function (particularly LA reservoir strain) is more sensitive and provides earlier detection of LA dysfunction than alterations in LA volume. LA function parameters have also demonstrated significant diagnostic and prognostic value, particularly in heart failure, atrial fibrillation and stroke. However, there remain barriers to implementation of phasic function parameters in clinical practice and guidelines. This review outlines the physiology of LA phasic function, methods of assessment, and its diagnostic and prognostic utility in varying pathologies.

Subclinical systolic dysfunction detected by 2D speckle tracking echocardiography in adults with diabetes mellitus: systematic review and meta-analysis of 6668 individuals with diabetes mellitus and 7218 controls

PURPOSE

Speckle tracking echocardiography (STE) can help to identify subclinical features of diabetic cardiomyopathy (DCM). There is, however, significant heterogeneity in the reported strain values in literature. We performed a systematic review and meta-analysis to compare cardiac systolic strain values assessed by 2D-STE in asymptomatic adults with diabetes mellitus (DM) and healthy controls.

METHODS

Five databases were searched, and a total of 41 valid studies (6668 individuals with DM and 7218 controls) were included for analysis. Pooled mean in each group and mean difference (MD) for left ventricular global longitudinal strain (LVGLS), LV global circumferential strain (LVGCS), LV global radial strain (LVGRS), LV longitudinal systolic strain rate (LVSR), left atrial reservoir strain (LARS) and right ventricular GLS (RVGLS) were assessed.

RESULTS

Patients with DM had overall 2 units lower LVGLS than healthy subjects 17.5% [16.8, 18.3], vs 19.5 [18.7, 20.4], MD = - 1.96 [- 2.27, - 1.64]. Other strain values were also lower in patients with DM: LVGCS (MD = - 0.89 [- 1.26, - 0.51]); LVGRS (MD = - 5.03 [- 7.18, - 2.87]); LVSR (MD = - 0.06 [- 0.10, - 0.03]); LARS (MD = - 8.41 [- 11.5, - 5.33]); and RVGLS (MD = - 2.41 [- 3.60, - 1.22]). Meta-regression identified higher body mass index (BMI) as the single contributor to worse LVGLS, LVGCS and LVSR. Those with higher Hemoglobulin A1c had worse RVGLS.

CONCLUSION

Myocardial strains were reduced in whole heart in patients with DM. The largest reduction was observed in LA reservoir strain, followed by RVGLS and LVGLS. Higher BMI in patients with DM is associated with worse LV strain values.

Role of Echocardiography in Diabetic Cardiomyopathy: From Mechanisms to Clinical Practice

It has been well established that diabetes mellitus (DM) is considered as a core risk factor for the development of cardiovascular diseases. However, what is less appreciated is the fact that DM may affect cardiac function irrespective of cardiac pathologies to which it contributes, such as coronary artery disease and hypertension. Although echocardiography provides accurate and reproducible diagnostic and prognostic data in patients with DM, its use in these patients is still underappreciated, resulting in progression of DM-related heart failure in many patients. Hence, in the present review, we aimed to discuss the role of echocardiography in the contemporary management of diabetic cardiomyopathy (DCM), as well as the role of emerging echocardiographic techniques, which may contribute to earlier diagnosis and more appropriate management of this complication of DM. In order to improve outcomes, focus must be placed on early diagnosis of this condition using a combination of echocardiography and emerging biomarkers, but perhaps the more important thing is to change perspective when it comes to the clinical importance of DCM.

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.

Burden of Microvascular Disease and Risk of Atrial Fibrillation in Adults with Type 2 Diabetes

BACKGROUND

Epidemiological data on the associations of microvascular disease with atrial fibrillation are scarce. We evaluated the associations of diabetes-related microvascular disease in multiple vascular beds and its burden with incident atrial fibrillation among adults with type 2 diabetes.

METHODS

A total of 7603 participants with type 2 diabetes and without atrial fibrillation were assessed for diabetic kidney disease, retinopathy, or neuropathy at baseline in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study. Incident atrial fibrillation events were adjudicated using follow-up electrocardiograms. Modified Poisson regression was used to generate risk ratios (RRs) and 95% confidence intervals (CIs) for atrial fibrillation.

RESULTS

Of the 7603 participants (mean age 62.5 years, 38.0% women, 63.4% white), 63.3% (n = 4816) had microvascular disease-defined as the presence of ≥1 of: diabetic kidney disease, retinopathy, or neuropathy at baseline. Over a median of 7 years, there were 137 atrial fibrillation events (1.8%). Participants with microvascular disease had a 1.9-fold higher risk of incident atrial fibrillation compared with those without microvascular disease (RR 1.88; 95% CI, 1.20-2.95). Compared with no microvascular disease, the RRs for atrial fibrillation were 1.62 (95% CI, 1.01-2.61) and 2.47 (95% CI, 1.46-4.16) for those with 1 and ≥2 microvascular territories affected, respectively. The RRs for atrial fibrillation by type of microvascular disease were 1.57 (95% CI, 1.09-2.26), 0.95 (95% CI, 0.53-1.70), and 1.67 (95% CI, 1.15-2.44) for neuropathy, retinopathy, and diabetic kidney disease, respectively.

CONCLUSIONS

In a large cohort of adults with type 2 diabetes, the presence of microvascular disease and its burden were independently associated with higher risk of incident atrial fibrillation.

Clinical and echocardiographic characteristics in patients with heart failure and type 2 diabetes

Objective: The coexistence of type 2 diabetes (T2D) and heart failure (HF) has obvious consequences during cardiovascular diagnosis. This study evaluated the relationship between T2D and clinical and echocardiographic features of patients with HF. Methods & results: 121 patients with HF were clinically evaluated by echocardiography in this case-control study. They were divided into two groups based on the presence of T2D. Patients with diabetes were subdivided and compared via an HbA1c control. Significant differences between T2D and non-T2D groups were detected by comparing the left atrial diameter, E/E' and left ventricular end-diastolic diameter. When comparing patients with diabetes, differences in acute heart failure episodes, left ventricular ejection fraction, left atrial diameter and E/E' were evaluated. Conclusion: T2D was associated with important cardiac alterations and more severe HF. Poor control of diabetes resulted in worse cardiovascular outcomes.

Diabetes Mellitus Is an Independent Risk Factor for a Stiff Left Atrial Physiology After Catheter Ablation for Atrial Fibrillation

Background

Scar tissue formation after catheter ablation for atrial fibrillation (AF) may adversely affect the diastolic properties of the left atrium (LA), which can result in a stiff LA physiology in a small proportion of patients. In this study, we aimed to explore the relationship between diabetes mellitus and a stiff LA physiology after AF catheter ablation (AFCA).

Methods

A total of 1,326 patients who underwent de novo AFCA, and baseline and 1-year follow-up echocardiographies were enrolled. After 1:3 propensity score (PS) matching for age, sex, and AF type, we compared 211 patients with DM with 633 patients without DM. A stiff LA physiology was defined as estimated pulmonary arterial pressure increase of >10 mmHg and a right ventricular systolic pressure of >35 mmHg at 1-year follow-up echocardiography. Pulmonary vascular resistance (PVR) was estimated using echocardiographic parameters.

Results

Among the 844 PS-matched patients, a stiff LA physiology was observed in 32 patients (4.1%). The patients with DM showed a higher peak LA pressure (p < 0.001) and greater LA wall stress (p = 0.001) than did those without. A stiff LA physiology was independently associated with DM [Odds ratio (OR) = 2.39, 95% confidence interval (CI) 1.02-5.59, p = 0.045], empirical extra-pulmonary vein LA ablation (OR = 3.14, 95% CI 1.07–9.3, p = 0.038) and the ΔPVR (OR = 1.78, 95% CI 1.37–2.31, p < 0.001). The ΔPVR was independently associated with DM (β = 0.37, 95% CI 0.06-0.67, p = 0.020) and a stiff LA physiology (β = 1.40, 95% CI 0.70–2.10, p < 0.001). During the 38.8 ± 29.3months follow-up, the incidence of the clinical recurrence of AF was significantly higher in the patients with a stiff LA physiology than in those without (log rank p = 0.032).

Conclusion

A stiff LA physiology was independently associated with DM because of the relatively small decrease in the PVR after AFCA in this population. The patients with a stiff LA physiology had worse rhythm outcomes after AFCA than those without.

Cardiac Structure and Function and Diabetes-Related Risk of Death or Heart Failure in Older Adults

Background Whether cardiac structure and function abnormalities associated with dysglycemia are sufficient to explain the increased risk of death or heart failure (HF) remains unclear. Methods and Results We analyzed 6059 participants (mean age, 75±5 years; 58% women; and 22% Black individuals) who attended the ARIC (Atherosclerosis Risk in Communities) study visit 5 examination (2011-2013). Participants were categorized as no diabetes, pre-diabetes, and diabetes (on the basis of medical history and glycated hemoglobin values). We assessed whether diabetes modified the association between echocardiographic measures of cardiac structure and function and the composite of all-cause death or HF hospitalization and then estimated the extent to which the increased risk of the composite outcome associated with diabetes was explained by cardiac structure and function. Diabetes was prevalent in 33.5% of the subjects. Death or HF occurred in 1111 (18%) at a rate of 3.6 per 100 person-years. Both measures of cardiac structure and function and diabetes status were significantly associated with worse prognosis after accounting for clinical confounders. While diabetes was consistently associated with a higher risk of events, it did not significantly modify the association between cardiac abnormalities and the risk of death or HF, except for subjects with higher left atrial volume who showed higher relative risk of events (P for interaction <0.001). Measures of cardiac structure and function accounted for ≈16% of the increased risk of death or HF associated with diabetes. Similar results were observed analyzing subjects without prevalent heart disease. Conclusions In a biracial cohort of older adults, the increased risk of events associated with diabetes was partially explained by cardiac structure and function abnormalities.

Multimodality imaging approach to left ventricular dysfunction in diabetes: an expert consensus document from the European Association of Cardiovascular Imaging

Heart failure (HF) is among the most important and frequent complications of diabetes mellitus (DM). The detection of subclinical dysfunction is a marker of HF risk and presents a potential target for reducing incident HF in DM. Left ventricular (LV) dysfunction secondary to DM is heterogeneous, with phenotypes including predominantly systolic, predominantly diastolic, and mixed dysfunction. Indeed, the pathogenesis of HF in this setting is heterogeneous. Effective management of this problem will require detailed phenotyping of the contributions of fibrosis, microcirculatory disturbance, abnormal metabolism, and sympathetic innervation, among other mechanisms. For this reason, an imaging strategy for the detection of HF risk needs to not only detect subclinical LV dysfunction (LVD) but also characterize its pathogenesis. At present, it is possible to identify individuals with DM at increased risk HF, and there is evidence that cardioprotection may be of benefit. However, there is insufficient justification for HF screening, because we need stronger evidence of the links between the detection of LVD, treatment, and improved outcome. This review discusses the options for screening for LVD, the potential means of identifying the underlying mechanisms, and the pathways to treatment.

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber.

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 Diabetes With Atrial Fibrillation Phenotype and Cardiac and Neurological Comorbidities: Insights From the Swiss-AF Study

Background

Diabetes is a major risk factor for atrial fibrillation (AF). However, it remains unclear whether individual AF phenotype and related comorbidities differ between patients who have AF with and without diabetes. This study investigated the association of diabetes with AF phenotype and cardiac and neurological comorbidities in patients with documented AF.

Methods and Results

Participants in the multicenter Swiss‐AF (Swiss Atrial Fibrillation) study with data on diabetes and AF phenotype were eligible. Primary outcomes were parameters of AF phenotype, including AF type, AF symptoms, and quality of life (assessed by the European Quality of Life‐5 Dimensions Questionnaire [EQ‐5D]). Secondary outcomes were cardiac (ie, history of hypertension, myocardial infarction, and heart failure) and neurological (ie, history of stroke and cognitive impairment) comorbidities. The cross‐sectional association of diabetes with these outcomes was assessed using logistic and linear regression, adjusted for age, sex, and cardiovascular risk factors. We included 2411 patients with AF (27.4% women; median age, 73.6 years). Diabetes was not associated with nonparoxysmal AF (odds ratio [OR], 1.01; 95% CI, 0.81–1.27). Patients with diabetes less often perceived AF symptoms (OR, 0.74; 95% CI, 0.59–0.92) but had worse quality of life (β=−4.54; 95% CI, −6.40 to −2.68) than those without diabetes. Patients with diabetes were more likely to have cardiac (hypertension [OR, 3.04; 95% CI, 2.19–4.22], myocardial infarction [OR, 1.55; 95% CI, 1.18–2.03], heart failure [OR, 1.99; 95% CI, 1.57–2.51]) and neurological (stroke [OR, 1.39, 95% CI, 1.03–1.87], cognitive impairment [OR, 1.75, 95% CI, 1.39–2.21]) comorbidities.

Conclusions

Patients who have AF with diabetes less often perceive AF symptoms but have worse quality of life and more cardiac and neurological comorbidities than those without diabetes. This raises the question of whether patients with diabetes should be systematically screened for silent AF.

Registration

URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02105844.

Impact of BMI on Left Atrial Strain and Abnormal Atrioventricular Interaction in Patients With Type 2 Diabetes Mellitus: A Cardiac Magnetic Resonance Feature Tracking Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obesity often coexist and together contribute to left atrial (LA) functional abnormalities. However, little is known about the impact of body mass index (BMI) on LA strains measured using cardiac magnetic resonance feature tracking (MR-FT).

PURPOSE

To investigate the additive effect of BMI on LA functional remodeling using MR-FT as well as to explore abnormal atrioventricular interaction in T2DM patients.

STUDY TYPE

Retrospective.

POPULATION

One hundred and fifty-nine T2DM patients (53, 34, and 72 normal-weight, overweight, and obese individuals) and 105 non-diabetic controls (46, 32, and 27 normal-weight, overweight, and obese individuals).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession.

ASSESSMENT

LA reservoir strain (ε_s ), conduit strain (ε_e ), and active strain (ε_a ) and their corresponding strain rates (SRs, SRe, SRa) were measured together with left ventricular (LV) radial, circumferential, and longitudinal peak strain, peak systolic strain rate, and peak diastolic strain rate.

STATISTICAL TESTS

Student's t-test or Mann-Whitney U test, one-way ANOVA, univariate and multivariate linear regression. A P value <0.05 was considered statistically significant.

RESULTS

Compared to controls in the same BMI category, T2DM patients had significantly decreased reservoir and conduit function, while pump function was not significantly different (ε_a and SRa: P = 0.757 and 0.583 for normal-weight, P = 0.171 and 0.426 for overweight, P = 0.067 and 0.330 for obese). LA strains were significantly correlated with BMI (r = -0.346 for ε_s , -0.345 for ε_e ) in T2DM patients. Multivariable linear regression analysis indicated that BMI was independently associated with LA ε_s and ε_e , LV global longitudinal strain was independently associated with LA ε_s and ε_a , and LV circumferential peak diastolic strain rate was independently associated with LA ε_e .

DATA CONCLUSION

These findings suggest that the coexistence of increased body weight and T2DM patients can exacerbate the impairment of LA strains and indicate abnormal atrioventricular interactions.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3.

Contemporary narrative review on left atrial strain mechanics in echocardiography: cardiomyopathy, valvular heart disease and beyond

Left atrial (LA) strain mechanics refer to the measurement of LA myocardial deformation expressed as a percentage, and have been gathering interest over the last decade with expanding research supporting their utility in multiple cardiovascular disorders. Measured through advanced dynamic imaging techniques which include tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking echocardiography (STE), LA strain mechanics are affected by left ventricular diastolic dysfunction prior to the onset of functional and structural changes in the left ventricle (LV). There is a need for practising cardiologists to become more familiar with the clinical utility of LA strain mechanics. In this article, we begin by reviewing the physiologic function of the LA, using this as a basis for understanding LA strain mechanics. The focus of this review article is to provide a contemporary update on the utility of LA strain mechanics in a range of cardiovascular disorders, including atrial fibrillation (AF), hypertrophic cardiomyopathy (HCM), valvular pathologies, coronary artery disease (CAD) as well as systemic diseases, such as hypertension (HTN), obesity and diabetes mellitus (DM). This article also highlights the current limitations in more widespread clinical applications of LA strain mechanics, as well as outlining the future perspectives on the clinical applications of LA strain mechanics.

Meta-analysis of metabolic syndrome and its individual components with risk of atrial fibrillation in different populations

Background

Recent studies have reported the effects of metabolic syndrome (MetS) and its components on atrial fibrillation (AF), but the results remain controversial. Therefore, we performed a meta-analysis to evaluate the relationship between MetS and AF risk.

Methods

Studies were searched from the Cochrane library, PubMed, and Embase databases through May 2020. Adjusted hazard ratios (HRs) and its corresponding 95% confidence intervals (CIs) were extracted and then pooled by using a random effects model.

Results

A total of 6 observational cohort studies were finally included. In the pooled analysis, MetS was associated with an increased risk of AF (HR 1.57; 95% CI 1.40–1.77; P < 0.01). And the components of MetS including abdominal obesity (HR 1.37; 95% CI 1.36–1.38; P < 0.01), elevated blood pressure (HR 1.56; 95% CI 1.46–1.66; P < 0.01), elevated fasting glucose (HR 1.18; 95% CI 1.15–1.21; P < 0.01) and low high density cholesterol (HDL) (HR 1.18; 95% CI 1.06–1.32; P < 0.01) was also associated with an increased risk of AF, while high triglyceride (HR 0.99; 95% CI 0.87–1.11, P = 0.82) was not.

Conclusions

Our present meta-analysis suggested that MetS, as well as its components including abdominal obesity, elevated blood pressure, elevated fasting glucose and low HDL cholesterol were associated with an increase in the risk of AF.

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.

Cardiovascular and systemic determinants of exercise capacity in people with type 2 diabetes mellitus

The global burden of heart failure (HF) is on the rise owing to an increasing incidence of lifestyle related diseases, predominantly type 2 diabetes mellitus (T2D). Diabetes is an independent risk factor for cardiovascular disease, and up to 75% of those with T2D develop HF in their lifetime. T2D leads to pathological alterations within the cardiovascular system, which can progress insidiously and asymptomatically in the absence of conventional risk factors. Reduced exercise tolerance is consistently reported, even in otherwise asymptomatic individuals with T2D, and is the first sign of a failing heart. Because aggressive modification of cardiovascular risk factors does not eliminate the risk of HF in T2D, it is likely that other factors play a role in the pathogenesis of HF. Early identification of individuals at risk of HF is advantageous, as it allows for modification of the reversible risk factors and early initiation of treatment with the aim of improving clinical outcomes. In this review, cardiac and extra-cardiac contributors to reduced exercise tolerance in people with T2D are explored.

Echocardiography, an Indispensable Tool for the Management of Diabetics, with or without Coronary Artery Disease, in Clinical Practice

Diabetes mellitus is a major factor contributing to the development of cardiovascular disease. As morbidity and mortality rates rise dramatically, when target organ damage develops pre-symptomatic assessment is critical for the management of diabetic patients. Echocardiography is a noninvasive and reproducible method that may aid in risk stratification and in evaluation of treatment effects. The aim of this review is to analyze the echocardiographic techniques which can detect early alteration in cardiac function in patients with diabetes.

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.

Impact of Type-2 Diabetes Mellitus on the Outcomes of Catheter Ablation of Atrial Fibrillation (European Observational Multicentre Study)

Type-2 diabetes mellitus (DM) is associated with an increased risk of atrial fibrillation (AF). It is unclear whether DM is a risk factor for arrhythmia recurrence following catheter ablation of AF. We performed a nonrandomised, observational study in 7 high-volume European centres. A total of 2,504 patients who underwent catheter ablation of AF were included, and procedural outcomes were compared among patients with or without DM. Patients with DM (234) accounted for 9.3% of the sample, and were significantly older, had a higher BMI and suffered more frequently from persistent AF. Arrhythmia relapses at 12 months after AF ablation occurred more frequently in the DM group (32.0% vs 25.3%, p = 0.031). After adjusting for type of AF (i.e., paroxysmal vs persistent), during a median follow-up of 17 ± 16 months, atrial arrhythmia free-survival was lower in the diabetics with persistent AF (log-rank p = 0.003), and comparable for paroxysmal AF (log-rank p = 0.554). These results were confirmed in a propensity-matched analysis, and DM was also an independent predictor of AF recurrence on the multivariate analysis (hazard ratio 1.39; 95% confidence interval _95%1.07 to 1.88; p = 0.016). There was no significant difference in the rate of periprocedural complications among DM and non-DM patients (3.8% vs 6.3%, p = 0.128). Efficacy and safety of cryoballoon ablation were comparable to radiofrequency ablation in both DM and no-DM groups. In conclusion, catheter ablation of AF appears to be safe in patients with DM. However, DM is associated with higher rate of atrial arrhythmia relapse, particularly for patients with persistent AF.

Atrial Cardiomyopathy: An Unexplored Limb of Virchow's Triad for AF Stroke Prophylaxis

The most dreaded complication of atrial fibrillation is stroke, and 70–80% of patients with AF-related stroke die or become disabled. The mechanisms of thromboembolism in AF are multifactorial, with evidence demonstrating that all three criteria of Virchow's triad are satisfied in AF: abnormal stasis of blood, endothelial damage, and hypercoagulability. Mechanistic insights into the latter two limbs have resulted in effective stroke prophylactic therapies (left atrial appendage occlusion and oral anticoagulants); however, despite these advances, there remains an excess of stroke in the AF population that may be due, in part, to a lack of mechanistic understanding of atrial hypocontractility resulting in abnormal stasis of blood within the atrium. These observations support the emerging concept of atrial cardiomyopathy as a cause of stroke. In this Review, we evaluate molecular, translational, and clinical evidence for atrial cardiomyopathy as a cause for stroke from AF, and present a rationale for further investigation of this largely unaddressed limb of Virchow's triad in AF.

Glycemic control is associated with atrial structural remodeling in patients with type 2 diabetes

Background

Diabetes mellitus (DM) has been demonstrated to be a strong risk factor for development and perpetuation of atrial fibrillation (AF). However, how DM and glycemic control affect the pathogenesis of AF has not been sufficiently investigated, especially for the atrial structural remodeling.

Methods

A total of 86 patients undergoing coronary artery bypass graft surgery were enrolled in this study, with atrium sample collected in the operation. The patients were divided into the DM group (n = 40) and the control group (n = 46) accordingly. Demographics, clinical data were collected and compared. Echocardiography, Masson staining and Western blotting were conducted to evaluate atrial structural remodeling.

Results

There was no significant difference between the two groups in baseline characteristics (all P > 0.05). Fast blood glucose and HbA1c of DM group were significantly higher than the control group (P < 0.001). Echocardiography results demonstrated that the left atrium diameter (LAD) and left atrium volume index (LAVI) of DM group was significantly higher than the control group (P < 0.001). Masson staining showed that the collagen volume fraction (CVF), a quantitative indicator of fibrosis, was significantly higher in DM patients (P = 0.03). Western blot results indicated that the Collagen I of DM group was more expressed in the DM group than the control group (P < 0.001). Univariate linear regression revealed that the HbA1c level was significantly associated with both LAD (Y = 1.139X + 25.575, P < 0.001, R² = 0.291) and CVF (Y = 0.444X + 29.648, P = 0.009, R² = 0.078).

Conclusions

DM was associated with atrial structural remodeling, including atrium enlargement and atrial fibrosis, which might be attributed to poor glycemic control.

Non-Invasive Imaging in Diabetic Cardiomyopathy

There is increasing recognition of a specific diabetic cardiomyopathy beyond ischemic cardiomyopathy, which leads to structural and functional myocardial abnormalities. The aim of this review is to summarize the recent literature on diagnostic findings and prognostic significance of non-invasive imaging including echocardiography, nuclear imaging, computed tomography and cardiovascular magnetic resonance in diabetic cardiomyopathy.

Rationale, design and study protocol of the randomised controlled trial: Diabetes Interventional Assessment of Slimming or Training tO Lessen Inconspicuous Cardiovascular Dysfunction (the DIASTOLIC study)

INTRODUCTION

Despite their young age and relatively short duration of disease, younger adults with type 2 diabetes (T2D) already have diastolic dysfunction and may be at risk of incipient heart failure. Whether weight loss or exercise training improve cardiac dysfunction in people with T2D remains to be established.

METHODS AND ANALYSIS

Prospective, randomised, open-label, blind endpoint trial. The primary aim of the study is to determine if diastolic function can be improved by either a meal replacement plan or a supervised exercise programme, compared with guideline-directed care. A total of 90 obese participants with T2D (aged 18-65 years), diabetes duration <12 years and not on insulin treatment will be randomised to either guideline-directed clinical care with lifestyle coaching, a low-energy meal replacement diet (average ≈810 kcal/day) or a supervised exercise programme for 12 weeks. Participants undergo glycometabolic profiling, cardiopulmonary exercise testing, echocardiography and MRI scanning to assesses cardiac structure and function and dual-energy X-ray absorptiometry scanning for body composition. Key secondary aims are to assess the effects of the interventions on glycaemic control and insulin resistance, exercise capacity, blood pressure, changes in body composition and association of favourable cardiac remodelling with improvements in weight loss, exercise capacity and glycometabolic control.

ETHICS AND DISSEMINATION

The study has full ethical approval, and data collection was completed in August 2018. The study results will be submitted for publication within 6 months of completion.

TRIAL REGISTRATION NUMBER

NCT02590822; Pre-results.

Diabetic cardiomyopathy: prevalence, determinants and potential treatments

The prevalence of type 2 diabetes (T2D) has reached a pandemic scale. These patients are at a substantially elevated risk of developing cardiovascular disease, with heart failure (HF) being a leading cause of morbidity and mortality. Even in the absence of traditional risk factors, diabetes still confers up to a twofold increased risk of developing HF. This has led to identifying diabetes as an independent risk factor for HF and recognition of the distinct clinical entity, diabetic cardiomyopathy. Despite a wealth of research interest, the prevalence and determinants of diabetic cardiomyopathy remain uncertain. This limited understanding of the pathophysiology of diabetic heart disease has also hindered development of effective treatments. Tight blood-glucose and blood-pressure control have not convincingly been shown to reduce macrovascular outcomes in T2D. There is, however, emerging evidence that T2D is reversible and that the metabolic abnormalities can be reversed with weight loss. Increased aerobic exercise capacity is associated with significantly lower cardiovascular and overall mortality in diabetes. Whether such lifestyle modifications as weight loss and exercise may ameliorate the structural and functional derangements of the diabetic heart has yet to be established. In this review, the link between T2D and myocardial dysfunction is explored. Insights into the structural and functional perturbations that typify the diabetic heart are first described. This is followed by an examination of the pathophysiological mechanisms that contribute to the development of cardiovascular disease in T2D. Lastly, the current and emerging therapeutic strategies to prevent or ameliorate cardiac dysfunction in T2D are evaluated.

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.

Data Linking Diabetes Mellitus and Atrial Fibrillation-How Strong Is the Evidence? From Epidemiology and Pathophysiology to Therapeutic Implications

According to estimates, around 5% of the world population has hazel eyes. And there are about as many people with diabetes mellitus (DM). Red hair occurs naturally in up to 2% of the human population. And about as many people are estimated to have atrial fibrillation (AF). If a hazel eyed person with red hair does not surprise us, should a diabetic patient with AF? Accumulating epidemiologic data suggest, however, that the DM-AF association may be more than a simple coincidence. But, how strong is this evidence? Experimental studies bring evidence for a DM-induced atrial proarrhythmic remodelling. But how relevant are these data for the clinical setting? In this review, we aim to provide a critical analysis of the existing clinical and experimental, epidemiologic, and mechanistic data that bridge DM and AF, we emphasize a number of questions that remain to be answered, and we identify hotspots for future research. The therapeutic implications of the DM-AF coexistence are also discussed, with a focus on rhythm control and on conventional and DM-specific upstream therapies for AF management.

Left atrial appendage morphology and relative contrast agent concentration in patients undergoing coronary artery CTA

AIM

To evaluate whether certain morphological features of the left atrial appendage (LAA) would influence the LAA/ascending aorta (AA) radiodensity ratio, as a reflection of the blood flow conditions in the LAA.

MATERIALS AND METHODS

Eight-hundred and eight consecutive patients undergoing computed tomography angiography (CCTA) were evaluated. Of these, 749 had no history of atrial fibrillation and none had suffered acute stroke. The LAA/AA radiodensity ratio, and the length, lobe number, and morphological classification of LAAs were assessed.

RESULTS

The distribution of morphological classes for LAAs were: windsock 62.3%, cactus 18.6%, chicken wing 10.0%, and cauliflower 9.2%. The mean LAA/AA radiodensity ratio was 0.87±0.14 (range 0.22-1.44). Female gender (p=0.001), elevated body mass index (BMI; r=-0.129; p=0.003), and diabetes (p=0.03) were associated with lower LAA/AA radiodensity ratios, while heart failure (p=0.017), significant coronary artery stenosis (p=0.010), and LAAs with multiple lobes (p=0.018), exhibited higher LAA/AA radiodensity ratios. Multiple regression analysis revealed that a short one-lobed cauliflower morphology was an independent predictor (p=0.007) of a decreased LAA/AA radiodensity ratio.

CONCLUSION

A decline in the LAA/AA radiodensity ratio may reflect decreased blood flow in the LAA, paralleling spontaneous echo contrast in transoesophageal echocardiography. Thus, CCTA might be of value in recognising LAA structures that predispose to decreased blood flow.

Thiazolidinediones and Risk of Atrial Fibrillation Among Patients with Diabetes and Coronary Disease

BACKGROUND

We sought to determine whether insulin-sensitizing therapy (thiazolidinediones or metformin) decreased the risk of developing atrial fibrillation compared with insulin-providing therapy (insulin, sulfonylurea, or a meglitinide). Thiazolidinediones are insulin sensitizers that also decrease the inflammatory response. Because inflammation is a risk factor for atrial fibrillation, we hypothesized that treating diabetes with thiazolidinediones might decrease the risk of developing atrial fibrillation.

METHODS

The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial enrolled patients with type 2 diabetes and documented coronary artery disease. All patients were randomized to insulin-sensitizing therapy or insulin-providing therapy.

RESULTS

A total of 2319 patients entered the study, with 1160 assigned to the insulin-sensitization strategy and 1159 assigned to the insulin-provision strategy. Over a median follow-up of 4.2 years, 90 patients (3.9%) developed new-onset atrial fibrillation. In the intention-to-treat analysis, the incidence of atrial fibrillation was 8.7 per 1000 person-years in patients assigned to insulin sensitization compared with 9.5 in patients assigned to insulin provision with a hazard ratio (HR) of 0.91 (95% confidence interval [CI], 0.60-1.38, P = .66). In a time-varying exposure analysis, the incidence rate per 1000 person-years was 7.2 while exposed to thiazolidinediones and 9.7 while not exposed to thiazolidinediones with an adjusted HR of 0.80 (95% CI, 0.33-1.94, P = .62). In a subset of patients matched on propensity to receive a thiazolidinediones, the HR was 0.75 (95% CI, 0.43-1.30, P = .30).

CONCLUSIONS

We did not find a significant reduction of atrial fibrillation incidence with use of thiazolidinediones.

Variations in subclinical left ventricular dysfunction, functional capacity, and clinical outcomes in different heart failure aetiologies

Aims

Patients with heart failure (HF) risk factors are described as being in Stage A of this condition (SAHF). Management is directed towards prevention of HF progression, but to date, no evidence has been described to align the intensity of this intervention to HF risk. We sought to what extent SAHF of Type 2 diabetes mellitus (T2DM) and other HF risks showed differences in subclinical left ventricular function, exercise capacity, and prognosis.

Methods and results

We recruited 551 elder asymptomatic SAHF patients (age 71 ± 5 years, 49% men, 290 T2DM) with at least one risk factor from a community‐based population with preserved ejection fraction. All underwent a comprehensive echocardiogram including global longitudinal strain (GLS) and a 6 min walk test and were followed for 2 years. The primary endpoints were new‐onset HF and all‐cause mortality. The T2DM group was associated with reduced 6 min walk test distance (451 ± 111 vs. 493 ± 87 m, P < 0.001), worse diastolic function (E/e′ 9.2 ± 2.7 vs. 8.7 ± 2.4, P = 0.028), and impaired GLS (−17.7 ± 2.6% vs. −19.0 ± 2.6%, P < 0.001). Over a median follow‐up of 1.6 years, 49 T2DM‐SAHF and 27 other‐SAHF met the primary endpoint. T2DM‐SAHF had significantly worse outcome than other‐SAHF (P = 0.021). In Cox models, obesity [hazard ratio (HR) = 2.46; P = 0.007], atrial fibrillation (HR = 2.39; P = 0.028), 6 min walk distance (HR = 0.99; P = 0.034), and GLS (HR = 1.14; P = 0.033) were independently associated with the primary endpoint in T2DM‐SAHF, independent of age and glycaemic control.

Conclusions

The T2DM‐SAHF has worse subclinical left ventricular function, exercise capacity, and prognosis than other‐SAHF. Impaired GLS, atrial fibrillation, exercise capacity, and obesity are associated with a worse prognosis in T2DM‐SAHF but not in other‐SAHF.

Left atrial function: evaluation by strain analysis

The left atrium has an important role in modulating left ventricular filling and is an important biomarker of cardiovascular disease and adverse cardiovascular outcomes. While previously left atrial (LA) size was utilised, the role of LA function as a biomarker is increasingly being evaluated, both independently and also in combination with LA size. Strain analysis has been utilised for evaluation of LA function and can be measured throughout the cardiac cycle, thereby enabling the evaluation of LA reservoir, conduit and contractile function. Strain evaluates myocardial deformation while strain rate examines the rate of change in strain. This review will focus on the various types of strain analysis for evaluation of LA function, alterations in LA strain in physiological and pathologic states that alter LA function and finally evaluate its utility as a prognostic marker.

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.

Early detection of cardiac alterations by left atrial strain in patients with risk for cardiac abnormalities with preserved left ventricular systolic and diastolic function

This study sought to examine whether early cardiac alterations could be detected by left atrial (LA) strain in patients with risk for cardiac abnormalities. In this cross-sectional and retrospective study, we included patients with (n = 234) and without (n = 48) risk for cardiac abnormalities (i.e. those with arterial hypertension, diabetes mellitus and/or a history of coronary artery disease) of similar age and with preserved left ventricular (LV) systolic and diastolic function according to standard criteria. LA strain was significantly altered in patients with risk for cardiac abnormalities in comparison to those without risk (29.2 ± 8.6 vs. 38.5 ± 12.6%; rate of impaired LA strain: 18.8% vs. 0%; all p < 0.01) and was the most sensitive parameter to detect early LA alterations in comparison with other LA functional parameters (rate of impaired LA strain rate, LA total emptying fraction, and LA expansion index 3.8%, 7.3%, and 3.8%, respectively). Moreover, in patients with risk for cardiac abnormalities LA strain was altered even in the absence of subtle LV systolic and diastolic alterations (rates 13.9% and 6.8%), albeit to a lesser extent than in patients with an abnormal LV longitudinal systolic strain or abnormal mitral annular e' velocities (rates 48.5% and 24.4%). Regarding the clinical relevance of these findings, an impaired LA strain (i.e. < 23%) was significantly linked to exertional dyspnea (OR 3.5 [1.7-7.0]) even adjusting the analyses by age, gender and subtle LV abnormalities. In conclusion, the findings from this study suggest that LA strain measurements could be useful to detect early cardiac alterations in patients with risk for cardiac abnormalities with preserved LV systolic and diastolic function and that these early LA strain alterations could be linked to exertional dyspnea.

Two-dimensional speckle-tracking echocardiography evaluation of left atrial function according to glycemic state in patients with coronary artery disease

Prediabetes and diabetes are dysglycemic conditions associated with increased cardiovascular risks and subtle myocardial injuries. The aim of our study was to evaluate left atrial (LA) function by two-dimensional speckle-tracking echocardiography in prediabetic and diabetic patients with coronary artery disease (CAD) and compare the results with those in euglycemic patients with CAD.

METHODS

The study population comprised 205 consecutive patients with CAD: 104 diabetic, 51 prediabetic, and 50 euglycemic patients. LA function was evaluated with two-dimensional speckle-tracking echocardiography and the longitudinal deformation indices of the LA were measured.

RESULTS

Our results showed that early diastolic strain was lower in the diabetic patients than in the prediabetic and euglycemic patients. The absolute value of early diastolic strain rate was reduced in the diabetic patients compared with the euglycemic patients. Late diastolic strain was increased in the diabetic patients compared with the prediabetic and euglycemic patients. The multivariate analysis showed that diabetes was a determinant of early diastolic strain and strain rate, but not late diastolic strain.

CONCLUSION

LA conduit function, as evaluated in terms of early diastolic strain and strain rate, was impaired in the diabetic CAD patients compared with the prediabetic and euglycemic CAD patients.

Diabetes Mellitus and Heart Failure

Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure.

Diabetes Mellitus and Heart Failure

Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure.

Left atrial phasic function and heart rate variability in asymptomatic diabetic patients

AIMS

We evaluated left atrial (LA) phasic function and heart rate variability (HRV) in asymptomatic diabetic patients, and the relationship between HRV indices and LA phasic function assessed by volumes and speckle tracking imaging.

METHOD

This cross-sectional study included 55 asymptomatic patients with type 2 diabetes and 50 healthy controls without cardiovascular risk factors. All study subjects underwent laboratory analyses, complete two-dimensional echocardiography examination (2DE) and 24-h Holter monitoring.

RESULTS

Maximum, minimum LA and pre-A LA volumes and volume indexes are significantly higher in diabetic patients. Total and passive LA emptying fractions (EF), representing the LA reservoir and conduit function, are significantly lower in diabetic subjects. Active LA EF, the parameter of the LA booster pump function, is compensatory increased in diabetic patients. Similar results were obtained by 2DE strain analysis. Cardiac autonomic function, assessed by HRV, is significantly deteriorated in diabetic patients. Time and frequency-domain HRV measures are significantly lower in diabetic subjects than in controls. HbA1c, LV mass index and HRV are associated with total LA EF and longitudinal LA strain independently of age, body mass index and LV diastolic function in the whole study population.

CONCLUSIONS

LA phasic function and cardiac autonomic nervous system assessed by HRV are impacted by diabetes. HbA1c and HRV are independently associated with LA reservoir function evaluated by volumetric and strain methods in the whole study population. This study emphasizes the importance of determination of LA function and HRV as important markers of preclinical cardiac damage and autonomic function impairment in diabetic patients.

Early impairment in left ventricular longitudinal systolic function is associated with an increased risk of incident atrial fibrillation in patients with type 2 diabetes

AIMS

It is known that type 2 diabetic patients are at high risk of atrial fibrillation (AF). However, the early echocardiographic determinants of AF vulnerability in this patient population remain poorly known.

METHODS

We followed-up for 2years a sample of 180 consecutive outpatients with type 2 diabetes, who were free from AF and ischemic heart disease at baseline. All patients underwent a baseline echocardiographic-Doppler evaluation with tissue Doppler and 2-D strain analysis. Standard electrocardiograms were performed twice per year, and a diagnosis of incident AF was confirmed in affected patients by a single cardiologist.

RESULTS

Over the 2-year follow-up period, 14 (7.8%) patients developed incident AF. In univariate analyses, echocardiographic predictors of new-onset AF were greater indexed cardiac mass, larger indexed left atrial volume (LAVI), lower global longitudinal strain (LS_SYS), lower global diastolic strain rate during early phase of diastole (SR_E), lower global diastolic strain rate during late phase of diastole (SR_L), and higher E/SR_E ratio. Multivariate logistic regression analysis showed that lower LS_SYS remained the only significant predictor of new-onset AF (adjusted-odds ratio 1.63, 95%CI 1.17-2.27; p<0.005) after adjustment for age, sex, diabetes duration, indexed cardiac mass and LAVI. Results were unchanged even after adjustment for body mass index, hypertension and glycemic control.

CONCLUSIONS

This is the first prospective study to show that early LS_SYS impairment independently predicts the risk of new-onset AF in type 2 diabetic patients with preserved ejection fraction and without ischemic heart disease. Future larger prospective studies are needed to confirm these findings.

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.

Impact of obesity and epicardial fat on early left atrial dysfunction assessed by cardiac MRI strain analysis

BACKGROUND

Diastolic dysfunction is a major cause of morbidity in obese individuals. We aimed to assess the ability of magnetic resonance imaging (MRI) derived left atrial (LA) strain to detect early diastolic dysfunction in individuals with obesity and type 2 diabetes, and to explore the association between cardiac adipose tissue and LA function.

METHODS

Twenty patients with obesity and T2D (55 ± 8 years) and nineteen healthy controls (48 ± 13 years) were imaged using cine steady state free precession and 2-point Dixon cardiovascular magnetic resonance. LA function was quantified using a feature tracking technique with definition of phasic longitudinal strain and strain rates, as well as radial motion fraction and radial velocities.

RESULTS

Systolic left ventricular size and function were similar between the obesity and type 2 diabetes and control groups by MRI. All patients except four had normal diastolic assessment by echocardiography. In contrast, measures of LA function using magnetic resonance feature tracking were uniformly altered in the obesity and type 2 diabetes group only. Although there was no significant difference in intra-myocardial fat fraction, Dixon 3D epicardial fat volume(EFV) was significantly elevated in the obesity and type 2 diabetes versus control group (135 ± 31 vs. 90 ± 30 mL/m², p < 0.001). There were significant correlations between LA functional indices and both BMI and EFV (p ≤ 0.007).

CONCLUSIONS

LA MRI-strain may be a sensitive tool for the detection of early diastolic dysfunction in individuals with obesity and type 2 diabetes and correlated with BMI and epicardial fat supporting a possible association between adiposity and LA strain. Trials Registration Australian New Zealand Clinical Trials Registry No. ACTRN12613001069741.

Effects of Bisphenol A Metabolite 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene on Lung Function and Type 2 Pulmonary Alveolar Epithelial Cell Growth

Bisphenol A (BPA) is recognized as a major pollutant worldwide. 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is a major active metabolite of BPA. The epidemiological and animal studies have reported that BPA is harmful to lung function. The role of MBP in lung dysfunction after BPA exposure still remains unclear. This study investigated whether MBP would induce lung alveolar cell damage and evaluated the role of MBP in the BPA exposure-induced lung dysfunction. An in vitro type 2 alveolar epithelial cell (L2) model and an ex vivo isolated reperfused rat lung model were used to determine the effects of BPA or MBP on cell growth and lung function. MBP, but not BPA, dose-dependently increased the mean artery pressure (Pa), pulmonary capillary pressure (Pc), pulmonary capillary filtration coefficient (K_fc), and wet/dry weight ratio in isolated reperfused rat lungs. MBP significantly reduced cell viability and induced caspases-3/7 cleavage and apoptosis and increased AMP-activated protein kinas (AMPK) phosphorylation and endoplasmic reticulum (ER) stress-related molecules expression in L2 cells, which could be reversed by AMPK-siRNA transfection. These findings demonstrated for the first time that MBP exposure induced type 2 alveolar cell apoptosis and lung dysfunction through an AMPK-regulated ER stress signaling pathway.