Atrial Cardiomyopathy in Valvular Heart Disease: From Molecular Biology to Clinical Perspectives

The Complex Connection Between Myocardial Dysfunction and Cancer Beyond Cardiotoxicity: Shared Risk Factors and Common Molecular Pathways

Cardiovascular diseases and cancer represent the largest disease burden worldwide. Previously, these two conditions were considered independent, except in terms of cardiotoxicity, which links cancer treatment to subsequent cardiovascular issues. However, recent studies suggest that there are further connections between cancer and heart disease beyond cardiotoxicity. It has been revealed that myocardial dysfunction may promote carcinogenesis, indicating that additional common pathophysiological mechanisms might be involved in the relationship between cardiology and oncology, rather than simply a connection through cardiotoxic effects. These mechanisms may include shared risk factors and common molecular pathways, such as persistent inflammation and neurohormonal activation. This review explores the connection between myocardial dysfunction and cancer, emphasizing their shared risk factors, similar biological mechanisms, and causative factors like cardiotoxicity, along with their clinical implications.

Cardiac tissue engineering: an emerging approach to the treatment of heart failure

Heart failure is a major health problem in which the heart is unable to pump enough blood to meet the body's needs. It is a progressive disease that becomes more severe over time and can be caused by a variety of factors, including heart attack, cardiomyopathy and heart valve disease. There are various methods to cure this disease, which has many complications and risks. The advancement of knowledge and technology has proposed new methods for many diseases. One of the promising new treatments for heart failure is tissue engineering. Tissue engineering is a field of research that aims to create living tissues and organs to replace damaged or diseased tissue. The goal of tissue engineering in heart failure is to improve cardiac function and reduce the need for heart transplantation. This can be done using the three important principles of cells, biomaterials and signals to improve function or replace heart tissue. The techniques for using cells and biomaterials such as electrospinning, hydrogel synthesis, decellularization, etc. are diverse. Treating heart failure through tissue engineering is still under development and research, but it is hoped that there will be no transplants or invasive surgeries in the near future. In this study, based on the most important research in recent years, we will examine the power of tissue engineering in the treatment of heart failure.

Current and Clinically Relevant Echocardiographic Parameters to Analyze Left Atrial Function

The evaluation of the left atrial (LA) size using the LA volume index (LAVI) is clinically relevant due to its prognostic significance in various conditions. Nonetheless, adding a LA function assessment to the LAVI provides further clinical and prognostic information in different cardiovascular (CV) diseases. The assessment of LA function by echocardiography primarily includes volumetric measurements (LA ejection fraction [LAEF]), tissue Doppler imaging (TDI) (mitral annular late diastolic velocity [a']), and speckle-tracking methods, such as LA longitudinal reservoir strain (LA strain). This review analyzes and discusses the current medical evidence and potential clinical usefulness of these different methods to analyze LA function.

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

The association between antiphospholipid syndrome and atrial fibrillation: a single center retrospective case-control study

Antiphospholipid syndrome (APS) is a systemic autoimmune syndrome characterized by arterial or venous thrombosis, pregnancy complications and thrombocytopenia. The aim of this study is to investigate the association between APS and atrial fibrillation (AF) among patients in Peking University People's Hospital. A single center retrospective study was conducted. Cases were hospitalized patients diagnosed with AF by a cardiologist while the control group patients did not exhibit cardiac diseases. The results of the study revealed that in multivariable logistic regression, APS, anticardiolipin antibody (aCL) positivity and anti-beta-2-glycoprotein antibody (anti-β2GPI) positivity are independent risk factors of AF. APS, aCL positivity and anti-β 2GPI positivity are statistically different between AF patients and non-AF patients. Forthcoming studies are needed to clarify the potential link between APS and AF.

Automatic 3D left atrial strain extraction framework on cardiac computed tomography

BACKGROUND AND OBJECTIVE

Strain analysis provides insights into myocardial function and cardiac condition evaluation. However, the anatomical characteristics of left atrium (LA) inherently limit LA strain analysis when using echocardiography. Cardiac computed tomography (CT) with its superior spatial resolution, has become critical for in-depth evaluation of LA function. Recent studies have explored the feasibility of CT-derived strain; however, they relied on manually selected regions of interest (ROIs) and mainly focused on left ventricle (LV). This study aimed to propose a first-of-its-kind fully automatic deep learning (DL)-based framework for three-dimensional (3D) LA strain extraction on cardiac CT.

METHODS

A total of 111 patients undergoing ECG-gated contrast-enhanced CT for evaluating subclinical atrial fibrillation (AF) were enrolled in this study. We developed a 3D strain extraction framework on cardiac CT images, containing a 2.5D GN-U-Net network for LA segmentation, axis-oriented 3D view extraction, and LA strain measure. The segmentation accuracy was evaluated using Dice similarity coefficient (DSC). The model-extracted LA volumes and emptying fraction (EF) were compared with ground-truth measurements using intraclass correlation coefficient (ICC), correlation coefficient (r), and Bland-Altman plot (B-A). The automatically extracted LA strains were evaluated against the LA strains measured from 2D echocardiograms. We utilized this framework to gauge the effect of AF burden on LA strain, employing the atrial high rate episode (AHRE) burden as the measurement parameter.

RESULTS

The GN-U-Net LA segmentation network achieved a DSC score of 0.9603 on the test set. The framework-extracted LA estimates demonstrated excellent ICCs of 0.949 (95 % CI: 0.93-0.97) for minimal LA volume, 0.904 (95 % CI: 0.86-0.93) for maximal LA volume, and 0.902 (95 % CI: 0.86-0.93) for EF, compared with expert measurements. The framework-extracted LA strains demonstrated moderate agreement with the LA strains based on 2D echocardiography (ICCs >0.703). Patients with AHRE > 6 min had significantly lower global strain and LAEF, as extracted by the framework than those with AHRE ≤ 6 min.

CONCLUSION

The promising results highlighted the feasibility and clinical usefulness of automatically extracting 3D LA strain from CT images using a DL-based framework. This tool could provide a 3D-based alternative to echocardiography for assessing LA function.

Right Atrial Remodeling and Outcome in Patients with Secondary Tricuspid Regurgitation

BACKGROUND

In patients with secondary tricuspid regurgitation (STR), right atrial remodeling (RAR) is a proven marker of disease progression. However, the prognostic value of RAR, assessed by indexed right atrial volume (RAVi) and reservoir strain (RAS), remains to be clarified. Accordingly, the aim of our study is to investigate the association with outcome of RAR in patients with STR.

METHODS

We enrolled 397 patients (44% men, 72.7 ± 13 years old) with mild to severe STR. Complete two-dimensional and speckle-tracking echocardiography analysis of right atrial and right ventricular (RV) size and function were obtained in all patients. The primary end point was the composite of death from any cause and heart failure hospitalization.

RESULTS

After a median follow-up of 15 months (interquartile range, 6-23), the end point was reached by 158 patients (39%). Patients with RAS <13% and RAVi >48 mL/m2 had significantly lower survival rates compared to patients with RAS ≥13% and RAVi ≤48 mL/m2 (log-rank P < .001). On multivariable analysis, RAS <13% (hazard ratio, 2.11; 95% CI, 1.43-3.11; P < .001) and RAVi > 48 mL/m2 (hazard ratio, 1.49; 95% CI, 1.01-2.18; P = .04) remained associated with the combined end point, even after adjusting for RV free-wall longitudinal strain, significant chronic kidney disease, and New York Heart Association class. Secondary tricuspid regurgitation excess mortality increased exponentially with values of 18.2% and 51.3 mL/m2 for RAS and RAVi, respectively. In nested models, the addition of RAS and RAVi provided incremental prognostic value over clinical, conventional echocardiographic parameters of RV size and function and RV free-wall longitudinal strain.

CONCLUSIONS

In patients with STR, RAR was independently associated with mortality and heart failure hospitalization. Assessment of RAR could improve risk stratification of patients with STR, potentially identifying those who may benefit from optimization of medical therapy and a closer follow-up.

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.

Potential Diagnostic and Prognostic Values of Left Atrial Strain in Valvular Heart Disease

There has been increasing evidence supporting the importance of left atrial (LA) functional analysis and measurement in various physiologic and pathologic cardiovascular conditions due to its high diagnostic and prognostic values. Assessment of LA strain (LAS) has emerged as an early marker of subclinical LA dysfunction. Using speckle-tracking echocardiography, LAS can be measured in all phases of LA function (reservoir, conduit, and booster pump). In valvular heart disease (VHD), surgical and nonsurgical interventions should be performed before irreversible left ventricular (LV) and/or LA myocardial dysfunction. The current guidelines recommended using LV strain as a parameter for early detection and timely intervention. Currently, many published data have shown the diagnostic and prognostic values of LAS in VHD, which is encouraging to integrate LAS during echo assessment. In this review, we aim to collect the current data about the clinical utility of LAS changes in risk stratification, predicting outcome, and guiding the time of intervention in VHD. The review summarized these data according to the type of valve pathologies.

Dexmedetomidine Pretreatment Confers Myocardial Protection and Reduces Mechanical Ventilation Duration for Patients Undergoing Cardiac Valve Replacement under Cardiopulmonary Bypass

PURPOSE

The study aims to assess the effects of dexmedetomidine (Dex) pretreatment on patients during cardiac valve replacement under cardiopulmonary bypass.

METHODS

For patients in the Dex group (n = 52), 0.5 μg/kg Dex was given before anesthesia induction, followed by 0.5 μg/kg/h pumping injection before aortic occlusion. For patients in the control group (n = 52), 0.125 ml/kg normal saline was given instead of Dex.

RESULTS

The patients in the Dex group had longer time to first dose of rescue propofol than the control group (P = 0.003). The Dex group required less total dosage of propofol than the control group (P = 0.0001). The levels of cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) were lower in the Dex group than the control group at T4, 8 h after the operation (T5), and 24 h after the operation (T6) (P <0.01). The Dex group required less time for mechanical ventilation than the control group (P = 0.003).

CONCLUSION

The study suggests that 0.50 µg/kg Dex pretreatment could reduce propofol use and the duration of mechanical ventilation, and confer myocardial protection without increased adverse events during cardiac valve replacement.

Novel Biomarkers and Advanced Cardiac Imaging in Aortic Stenosis: Old and New

Currently, the symptomatic status and left ventricular ejection fraction (LVEF) play a crucial role in aortic stenosis (AS) assessment. However, the symptoms are often subjective, and LVEF is not a sensitive marker of left ventricle (LV) decompensation. Over the past years, the cardiac structure and function research on AS has increased due to advanced imaging modalities and potential therapies. New imaging parameters emerged as predictors of disease progression in AS. LV global longitudinal strain has proved useful for risk stratification in asymptomatic severe AS patients with preserved LVEF. The assessment of myocardial fibrosis by cardiac magnetic resonance is the most studied application and offers prognostic information on AS. Moreover, the usage of biomarkers in AS as objective measures of LV decompensation has recently gained more interest. The present review focuses on the transition from compensatory LV hypertrophy (H) to LV dysfunction and the biomarkers associated with myocardial wall stress, fibrosis, and myocyte death. Moreover, we discuss the potential impact of non-invasive imaging parameters for optimizing the timing of aortic valve replacement and provide insight into novel biomarkers for possible prognostic use in AS. However, data from randomized clinical trials are necessary to define their utility in daily practice.