Increased Left Atrial Stiffness is Significantly Associated with Paroxysmal Atrial Fibrillation in Diabetic Patients

Renal denervation ameliorates atrial remodeling in type 2 diabetic rats by regulating mitochondrial dynamics

There is no effective treatment for diabetes-related atrial remodeling currently. This study aimed to investigate the effects of renal denervation (RDN) on diabetes-related atrial remodeling and explore the related mechanisms. A type 2 diabetes mellitus model was established by high-fat diet feeding and low-dose streptozotocin injection in Sprague‒Dawley rats. After successful modeling, the diabetic rats were randomly assigned to two groups according to whether they were subjected to RDN or sham RDN surgery. At the end of the experiment, cardiac function and structure were evaluated by echocardiography and histology, respectively. Mitochondrial morphology, function and mitochondrial dynamics were assessed by multiple methods. Mdivi1 was used to verify the mechanism by which RDN improves atrial remodeling. In the 10th week, diabetic rats exhibited obvious atrial remodeling, including atrial enlargement and diastolic dysfunction. Pathological staining showed that diabetic rats had cardiomyocyte hypertrophy and interstitial fibrosis in atrial tissues. In terms of mitochondrial morphology and function, diabetic rats exhibited fragmented mitochondria, reduced adenosine triphosphate production and decreased mitochondrial membrane potential levels. Abnormal mitochondrial dynamics in diabetic rats were characterized by the inhibition of mitochondrial fusion, excessive mitochondrial fission, and the suppression of mitophagy. However, RDN effectively ameliorated diabetes-induced pathological atrial remodeling. In addition, RDN significantly improved mitochondrial morphological and functional abnormalities and corrected the disorders of mitochondrial dynamics. Furthermore, the protective effects of RDN against atrial remodeling were related to the regulation of mitochondrial dynamics. RDN prevented diabetes-induced atrial remodeling. These protective effects might be related to improvements in mitochondrial dynamics.

Beyond Blood Sugar: How Left Atrium Strain Predicts Cardiac Outcomes in Type 2 Diabetes

Speckle tracking echocardiography is an innovative imaging technique that evaluates myocardial motion, including the function of the left atrium (LA). The assessment of the left atrium's function across its dimensions can have diagnostic and prognostic roles in various cardiovascular conditions. Left atrial strain has been recognized as a valuable predictor of mortality and cardiovascular incidents in the general population across various conditions. For individuals with type 2 diabetes mellitus (T2DM), left atrial dysfunction, as gauged by speckle tracking echocardiography, appears particularly prognostic. Parameters such as peak atrial longitudinal strain (PALS) and left atrial stiffness have been linked with heightened risks of severe cardiovascular events, including atrial fibrillation (AF), heart failure (HF) hospitalizations, or mortality. Consequently, recognizing left atrial dysfunction early is crucial for accurate diagnosis, guiding treatment choices, comprehensive patient management, and prognosis evaluation. Using two-dimensional (2D) speckle tracking echocardiography, results from recent studies report that treatment with empagliflozin significantly enhanced LA function in patients with type 2 diabetes mellitus, improving left atrial strain (LAS) contraction and reservoir values. Furthermore, treatments with glucagon-like peptide-1 (GLP)-1 receptor agonists and sodium-glucose cotransporter-2 (SGLT-2) inhibitors were shown to improve LA reservoir strain more effectively than insulin alone, suggesting their potential in reducing cardiovascular complications in T2DM patients. This narrative review further addresses ongoing challenges and potential enhancements needed to boost the clinical value of left atrium strain, emphasizing its significance in managing and improving outcomes for diabetic patients.

Evaluation of the relationship between left atrial stiffness, left ventricular stiffness, and left atrioventricular coupling index in type 2 diabetes patients: a speckle tracking echocardiography study

Background

Cardiovascular complications are a leading cause of mortality and disability in individuals with diabetes mellitus (DM). Moreover, DM can directly impact the structure and function of cardiac muscle. We conducted a study to evaluate cardiac stiffness in DM patients in both the left atrium (LA) and left ventricle (LV), as well as to assess the impact of DM on the synchronization of the LA and LV, particularly within the Vietnamese population, utilizing speckle tracking echocardiography (STE).

Methods

We studied 111 research subjects divided into two groups comprising 52 patients with DM and 59 healthy individuals. All the subjects provided relevant clinical information, and echocardiography was performed to assess the indices of LA stiffness, LV stiffness, and left atrioventricular coupling index (LACI).

Results

Our study indicated that DM patients exhibited greater LA and LV stiffness than control patients. The LACI (%) in the DM group was also greater than that in the control group (17.12% ± 6.72% vs. 12.28% ± 3.96%, respectively; p < 0.001). The LACI was positively correlated with the LA and LV stiffness indices. Decreased levels of LV GLS, adjusted for age, sex, blood pressure, and BMI, have emerged as identified risk factors for DM.

Conclusions

LA stiffness, LV stiffness, and the LACI are greater in DM patients than in normal individuals.

Myocardial strain of the left ventricle by speckle tracking echocardiography: From physics to clinical practice

Speckle tracking echocardiography (STE) is a reliable imaging technique of recognized clinical value in several settings. This method uses the motion of ultrasound backscatter speckles within echocardiographic images to derive myocardial velocities and deformation parameters, providing crucial insights on several cardiac pathological and physiological processes. Its feasibility, reproducibility, and accuracy have been widely demonstrated, being myocardial strain of the various chambers inserted in diagnostic algorithms and guidelines for various pathologies. The most important parameters are Global longitudinal strain (GLS), Left atrium (LA) reservoir strain, and Global Work Index (GWI): based on large studies the average of the lower limit of normality are -16%, 23%, and 1442 mmHg%, respectively. For GWI, it should be pointed out that myocardial work relies primarily on non-invasive measurements of blood pressure and segmental strain, both of which exhibit high variability, and thus, this variability constitutes a significant limitation of this parameter. In this review, we describe the principal aspects of the theory behind the use of myocardial strain, from cardiac mechanics to image acquisition techniques, outlining its limitation, and its principal clinical applications: in particular, GLS have a role in determine subclinical myocardial dysfunction (in cardiomyopathies, cardiotoxicity, target organ damage in ambulatory patients with arterial hypertension) and LA strain in determine the risk of AF, specifically in ambulatory patients with arterial hypertension.