Left Atrial Reverse Remodeling

Multi-modality assessment and role of left atrial function as an imaging biomarker in cardiovascular disease

The left atrium (LA) plays a vital role in maintaining normal cardiac function. LA volume and function have been utilised as important imaging biomarkers, with their prognostic value demonstrated in multiple cardiac conditions. More recently, there has been a sharp increase in the number of publications utilising LA strain by echocardiography and cardiac magnetic resonance (CMR) imaging. However, little is known about its prognostic value or reproducibility as a technique. In this review, we aim to highlight the conventional and novel imaging techniques available for LA assessment, using echocardiography and CMR, their role as an imaging biomarker in cardiovascular disease, the reproducibility of the techniques and the current limitations to their clinical application. We identify a need for further standardisation of techniques, with establishment of ‘normal’ cut-offs before routine clinical application can be made.

Association of Longitudinal Changes in NT-proBNP With Changes in Left Atrial Volume and Function: MESA

BACKGROUND

The mechanism of left atrial (LA) remodeling is poorly understood. The aim of this longitudinal study was to investigate whether changes in NT-proBNP levels relate to alterations of LA structure and function over time in a multiethnic population.

METHODS

From the prospective cohort study, the Multi-Ethnic Study of Atherosclerosis, our analysis included 1,838 participants who underwent cardiac magnetic resonance imaging at the baseline and 10-year examinations, had NT-proBNP levels available at both time points, and did not develop heart failure, myocardial infarction, and/or atrial fibrillation. Multivariable linear regression was used to analyze the association between NT-proBNP level (log-transformed) at the 2 time points and change in LA volumes, LA emptying fractions (total, active, and passive), and LA longitudinal strain. Log NT-proBNP was categorized into Low-Low (N = 681), Low-High (N = 238), High-Low (N = 237), and High-High (N = 682) based on the median value at both time points.

RESULTS

With the Low-Low group as the reference group, the High-High group experienced a greater increase in LA maximum and minimum indexed volumes: 3.1 ml/m2 (95% confidence interval 1.98, 4.20) and 2.7 ml/m2 (1.89, 3.51), respectively. The High-High group also experienced a greater decrease in LA total, passive, active emptying fraction, and longitudinal strain: -3.3% (-4.46, -2.11), -0.9% (-1.80, -0.02), -4.2% (-5.55, -2.76), and -2.3% (-3.80, -0.72), respectively. The Low-High group had similar associations, but the effect sizes were not as high.

CONCLUSIONS

Adverse LA remodeling over 10 years of follow-up strongly correlates with prolonged elevated levels of intracardiac stress, as assessed by NT-proBNP levels.

Prevention of Pathological Atrial Remodeling and Atrial Fibrillation: JACC State-of-the-Art Review

Atrial enlargement in response to pathological stimuli (e.g., hypertension, mitral valve disease) and physiological stimuli (exercise, pregnancy) can be comparable in magnitude, but the diseased enlarged atria is associated with complications such as atrial fibrillation (AF), whereas physiological atrial enlargement is not. Pathological atrial enlargement and AF is also observed in a small percentage of athletes undergoing extreme/intense endurance sport and pregnant women with preeclampsia. Differences between physiological and pathological atrial enlargement and underlying mechanisms are poorly understood. This review describes human and animal studies characterizing atrial enlargement under physiological and pathological conditions and highlights key knowledge gaps and clinical challenges, including: 1) the limited ability of atria to reverse remodel; and 2) distinguishing physiological and pathological enlargement via imaging/biomarkers. Finally, this review discusses how targeting distinct molecular mechanisms underlying physiological and pathological atrial enlargement could provide new therapeutic and diagnostic strategies for preventing or reversing atrial enlargement and AF.

The immediate trends in atrial electrical remodeling for paroxysmal atrial fibrillation across different modes of catheter ablation

Background

Catheter ablation has emerged as a major strategy for paroxysmal atrial fibrillation (PAF). Atrial electrical remodeling (AER) plays a critical role in the recurrence of PAF after ablation.

Hypothesis

To characterize the immediate trends of AER during ablations in patients with PAF, and assess the relationship between immediate trends and recurrence.

Methods

We performed this prospective observational study of 135 patients to investigate AER following three ablation modes: radiofrequency ablation (RFA), cryoablation (CA) and 3D mapping‐guided cryoablation (3D‐CA). The atrial effective refractory period (AERP) and atrial conduction time (ACT) were measured via electrophysiology before and immediately after ablation, and P‐wave indices were measured via electrocardiography before and within 24 h after ablation. Follow‐up visits were conducted for at least 1 year or until relapse.

Results

Different approaches of ablation caused a fairly significant increase in the shortest P‐wave duration and AERP in both the proximal coronary sinus (PCS) and distal coronary sinus (DCS) but caused a shortened P‐wave dispersion. No different effect was found at the AERP among the three modes. Compared to patients who received CA, among patients who received RFA, a significant reduction in total ACT and right ACT was seen. Statistically, there was a weakly positive association between changes in total ACT and early recurrence.

Conclusions

Injury during ablation for PAF was associated with an increase in the AERP but not in the ACT. Total ACT and right ACT were shorter after RFA than after CA. The increase in total ACT were slightly predictive of early recurrence.

Is Adiponectin Elevation Associated with Left Atrial Remodeling and Impaired Mechanical Functions? (a Speckle Tracking Study)

Objectives    Recent studies demonstrated that elevated adiponectin levels predicted an increased risk of atrial fibrillation (AF) and stroke; however, a causal relationship is yet to be unknown. Reduced left atrium (LA) functions detected by two-dimensional echocardiographic speckle tracking (2D-STE) can predict AF development. We aimed to investigate the relationship between adiponectin level and LA functions in hypertensive and diabetic patients at high risk for incident AF.Material and methods    The study consisted of 80 hypertensive diabetic patients. All patients underwent echocardiography, and venous blood samples were taken. The relationship between adiponectin levels and LA functions was analyzed.Results    We divided patients into two groups according to the mean adiponectin level (13.63 ng / ml). In the high adiponectin group, the mean age (p=0.001) and high-density lipoprotein (HDL) cholesterol (p=0.015) were higher, whereas estimated glomerular filtration rate (eGFR) (p=0.036) and hemoglobin (p=0.014) levels were lower. Although LA maximum volume, LA minimum volume, and LA pre-A volume were higher in the group with high adiponectin levels, they did not reach a statistical significance. Peak early diastolic LA strain (S-LAe) (p=0.048) and strain rate (SR-LAe) (p=0.017) were lower in this group. Multivariate logistic regression analysis demonstrated that age (p=0.003) and hemoglobin (p=0.006) were predictors of elevated adiponectin levels. On the contrary, S-LAe, HDL cholesterol, and eGFR lost their statistical significance.Conclusion    In patients with HT and DM, elevated adiponectin level is associated with impaired LA mechanical functions. Increased age and hemoglobin level are independent predictors of elevated adiponectin levels.

Imaging Techniques for the Study of Fibrosis in Atrial Fibrillation Ablation: From Molecular Mechanisms to Therapeutical Perspectives

Atrial fibrillation (AF) is the most prevalent form of cardiac arrhythmia. It is often related to diverse pathological conditions affecting the atria and leading to remodeling processes including collagen accumulation, fatty infiltration, and amyloid deposition. All these events generate atrial fibrosis, which contribute to beget AF. In this scenario, cardiac imaging appears as a promising noninvasive tool for monitoring the presence and degree of LA fibrosis and remodeling. The aim of this review is to comprehensively examine the bench mechanisms of atrial fibrosis moving, then to describe the principal imaging techniques that characterize it, such as cardiac magnetic resonance (CMR) and multidetector cardiac computed tomography (MDCT), in order to tailor atrial fibrillation ablation to each individual.

Role of pre-operative transthoracic echocardiography in predicting post-operative atrial fibrillation after cardiac surgery: a systematic review of the literature and meta-analysis

AIMS

This systematic review and meta-analysis aims to evaluate the role of pre-operative transthoracic echocardiography in predicting post-operative atrial fibrillation (POAF) after cardiac surgery.

METHODS AND RESULTS

Electronic databases were searched for studies reporting on pre-operative echocardiographic predictors of POAF in PubMed, Cochrane library, and Embase. A meta-analysis of echocardiographic predictors of POAF that were identified by at least five different publications was performed. Forty-three publications were included in this systematic review. Echocardiographic predictors for POAF included surrogate parameters for total atrial conduction time (TACT), structural cardiac changes, and functional disturbances. Meta-analysis showed that prolonged pre-operative PA-TDI interval [5 studies, Cohen's d = 1.4, 95% confidence interval (CI) 0.9-1.9], increased left atrial volume indexed for body surface area (LAVI) (23 studies, Cohen's d = 0.8, 95% CI 0.6-1.0), and reduced peak atrial longitudinal strain (PALS) (5 studies, Cohen's d = 1.4, 95% CI 1.0-1.8), were associated with POAF incidence. Left atrial volume indexed for body surface was the most important predicting factor in patients without a history of AF. These parameters remained important predictors of POAF in heterogeneous populations with variable age and comorbidities such as coronary artery disease and valvular disease.

CONCLUSION

This meta-analysis shows that increased TACT, increased LAVI, and reduced PALS are valuable parameters for predicting POAF in the early post-operative phase in a large variety of patients.

EphA4 is highly expressed in the atria of heart and its deletion leads to atrial hypertrophy and electrocardiographic abnormalities in rats

AIMS

EphA4 is a member of the Eph receptor family, and expressed mainly in central nervous system (CNS), which is involved in CNS development and multiple diseases. Due to the variability in EphA4 expression, we wondered if EphA4 is expressed in other tissues, and what role does EphA4 play?

MATERIALS AND METHODS

We generated an EphA4 knockout (KO) rat line with red fluorescent marker protein encoded by the mCherry cassette inserted downstream of the EphA4 promoter as a reporter. Using this system, we observed high expression of EphA4 in the heart atria and in the brain.

KEY FINDINGS

EphaA4 KO rats (EphA4^-/-) developed obvious atrial hypertrophy with an increased atria-to-heart weight ratio and atrial cardiomyocyte cross-sectional area at six months of age. EphA4^-/- rats had reduced atrial end diastolic volume (EDV), atrial ejection fraction (EF) and left ventricular EF. They also exhibited increased amplitude of QRS complexes and QT intervals, with invisible p waves. RNA sequencing revealed that EphA4 KO altered the transcription of multiple genes involved in regulation of transcription and translation, ion binding, metabolism and cell adhesion. Deletion of EphA4 reduced IGF1 mRNA and protein expression, which is involved in cardiac remodeling.

SIGNIFICANCE

Our data demonstrated that EphA4 was highly expressed in the atria and its deletion caused atrial dysfunction. Our findings also suggested that the EphA4 KO rat could be a potential model for studies on atrial remodeling.

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking-All About the Left Ventricle?

Purpose of Review

Cardiac magnetic resonance-feature-tracking (CMR-FT)-based deformation analyses are key tools of cardiovascular imaging and applications in heart failure (HF) diagnostics are expanding. In this review, we outline the current range of application with diagnostic and prognostic implications and provide perspectives on future trends of this technique.

Recent Findings

By applying CMR-FT in different cardiovascular diseases, increasing evidence proves CMR-FT-derived parameters as powerful diagnostic and prognostic imaging biomarkers within the HF continuum partly outperforming traditional clinical values like left ventricular ejection fraction. Importantly, HF diagnostics and deformation analyses by CMR-FT are feasible far beyond sole left ventricular performance evaluation underlining the holistic nature and accuracy of this imaging approach.

Summary

As an established and continuously evolving technique with strong prognostic implications, CMR-FT deformation analyses enable comprehensive cardiac performance quantification of all cardiac chambers.

Precision Medicine Approaches to Cardiac Arrhythmias: JACC Focus Seminar 4/5

In the initial 3 papers in this Focus Seminar series, the fundamentals and key concepts of precision medicine were reviewed, followed by a focus on precision medicine in the context of vascular disease and cardiomyopathy. For the remaining 2 papers, we focus on precision medicine in the context of arrhythmias. Specifically, in this fourth paper we focus on long QT syndrome, Brugada syndrome, and atrial fibrillation. The final (fifth) paper will deal with catecholaminergic polymorphic ventricular tachycardia. These arrhythmias represent a spectrum of disease ranging from common to relatively rare, with very different genetic and environmental causative factors, and with differing clinical manifestations that range from almost no consequences to lethality in childhood or adolescence if untreated. Accordingly, the emerging precision medicine approaches to these arrhythmias vary significantly, but several common themes include increased use of genetic testing, avoidance of triggers, and personalized risk stratification to guide the use of arrhythmia-specific therapies.

Assessment of the relationship between semaphorin4D level and recurrence after catheter ablation in paroxysmal atrial fibrillation

OBJECTIVE

Semaphorin4D (Sema4D), a novel integral membrane glycoprotein, plays a role in atherosclerosis, angiogenesis and chronic inflammation. Elevated levels of sema4D were presented in myocardial infarction, heart failure and atrial fibrillation. Aim of the study was to investigate the relation between sema4D and recurrence after catheter ablation (CA) in paroxysmal AF.

METHODS

The present study included 161 paroxysmal AF patients (PAF) (101 patients undergone CA) and 60 healthy subjects. Serum levels of sema4D were measured and study participants were followed-up for 3 months and 1 year since CA in terms of recurrence respectively.

RESULTS

Sema4D levels were significantly elevated in the recurrent group compared to the non-recurrent PAF patients (p < 0.001). Sema4D was importantly positively correlated with both left atrial volume index (r = 0.51, p < 0.013) and high sensitive C-reactive protein (r = 0.38), p < 0.011). In multivariate analysis, sema4D [odds ratio (OR) = 1.23, 95% CI 1.11-1.42; p < 0.001] and left atrial diameter (OR = 1.13, 95% CI 1.02-1.23; p = 0.012) were found to be significant independent risk parameters for recurrence.

CONCLUSIONS

Sema4D is a novel biomarker that may help to identify individuals with recurrence after CA procedure in long term period in PAF.

Left atrial strain in the assessment of diastolic function: providing new insights into primary myocardial dysfunction in Marfan syndrome

Previous studies using conventional echocardiographic measurements have reported subclinical left ventricular (LV) diastolic abnormalities in patients with Marfan syndrome (MFS). Left atrial (LA) strain allows an accurate categorization of LV diastolic dysfunction. We aimed to characterize LV myocardial performance in a cohort of MFS patients using STE-derived measurements (LV and LA strain) along with conventional echocardiographic parameters. We studied 127 adult patients with MFS (no prior cardiac surgery or significant valvular regurgitation) and 38 healthy controls. We performed detailed echocardiograms and selected left atrial reservoir strain (LASr) as a surrogate of impaired relaxation. Additionally, we searched for possible determinants of LASr in patients with MFS, with a special focus on the elastic properties of the aorta. In spite of lower E-wave, septal and lateral e' velocities and average E/e' ratio in MFS patients, all participants had normal diastolic function according to current guidelines. MFS patients exhibited reduced LV global longitudinal strain (19.3 ± 2.6 vs 21.6 ± 2.1%, p < 0.001) and reduced LASr (32.9 ± 8.5 vs 43.3 ± 7.8%, p < 0.001) compared to controls. In the MFS cohort, we found weak significant (p < 0.05) correlations between LASr and certain parameters: E/A ratio (R = 0.258), E wave (R = 0.226), aortic distensibility (R = 0.222), stiffness index (R = - 0.216), LV ejection fraction (R = 0.214), lateral e' (R = 0.210), LV end-systolic volume index (R =  - 0.210), LV global longitudinal strain (R = 0.201), septal e' (R = 0.185). After multivariate analysis, only LV end-systolic volume index and E/A ratio maintained a weak independent association with LASr (R =  - 0.220; p = 0.017 and R = 0.199; p = 0.046, respectively). In conclusion, LASr is reduced in patients with MFS, which may represent an early stage of LV diastolic dysfunction. LASr is not determined by the elastic properties of the aorta, suggesting that impaired myocardial relaxation is a primary condition in MFS.

Novel Approaches in Cardiac Imaging for Non-invasive Assessment of Left Heart Myocardial Fibrosis

In the past, the identification of myocardial fibrosis was only possible through invasive histologic assessment. Although endomyocardial biopsy remains the gold standard, recent advances in cardiac imaging techniques have enabled non-invasive tissue characterization of the myocardium, which has also provided valuable insights into specific disease processes. The diagnostic accuracy, incremental yield and prognostic value of speckle tracking echocardiography, late gadolinium enhancement and parametric mapping modules by cardiac magnetic resonance and cardiac computed tomography have been validated against tissue samples and tested in broad patient populations, overall providing relevant clinical information to the cardiologist. This review describes the patterns of left ventricular and left atrial fibrosis, and their characterization by advanced echocardiography, cardiac magnetic resonance and cardiac computed tomography, allowing for clinical applications in sudden cardiac death and management of atrial fibrillation.

Treatment-Related Changes in Left Atrial Structure in Atrial Fibrillation: Findings From the CABANA Imaging Substudy

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Left Atrial Diameter and Atrial Ectopic Burden in Patients with Embolic Stroke of Undetermined Source: Risk Stratification of Atrial Fibrillation with Insertable Cardiac Monitor Analysis

Background and Purpose

An insertable cardiac monitor (ICM) has been demonstrated to be a useful tool for detecting subclinical atrial fibrillation (AF) in patients with embolic stroke of undetermined source (ESUS). This study aimed to identify the clinical predictors of AF in ESUS patients with ICMs.

Methods

We retrospectively selected consecutive patients with an ICM implanted for AF detection following ESUS. The primary endpoint was defined as any AF episode lasting for longer than 5 min. The atrial ectopic burden (AEB) was calculated as the percentage of the number of conducted QRS from atrial ectopy on Holter monitoring.

Results

This study included 136 patients. AF lasting ≥5 min was detected in 20 patients (14.7%) during a median follow-up period of 6.6 months (interquartile range, 3.3–10.8 months). AF patients had a higher AEB (0.20% vs. 0.02%, p<0.001) and a larger left atrial diameter (LAD, 41.0 mm vs. 35.3 mm, p<0.001) than those without AF. The areas under the receiver operating characteristic curves were 0.795 and 0.816 for the LAD and log-transformed AEB, respectively, for the best cutoff values of 38.5 mm for LAD and 0.050% for AEB. AF lasting ≥5 min was detected in 34.6% (9/26) of patients with LAD ≥38.5 mm and AEB ≥0.050%, and in 0% (0/65) of those with LAD <38.5 mm and AEB <0.050%.

Conclusions

AF was detected in a significant proportion of ESUS patients during a 6.6-month follow-up. The LAD and AEB are good predictors of AF and might be useful for AF risk stratification in ESUS patients.

Extracellular Vesicles From Epicardial Fat Facilitate Atrial Fibrillation

BACKGROUND

The role of epicardial fat (eFat)-derived extracellular vesicles (EVs) in the pathogenesis of atrial fibrillation (AF) has never been studied. We tested the hypothesis that eFat-EVs transmit proinflammatory, profibrotic, and proarrhythmic molecules that induce atrial myopathy and fibrillation.

METHODS

We collected eFat specimens from patients with (n=32) and without AF (n=30) during elective heart surgery. eFat samples were grown as organ cultures, and the culture medium was collected every 2 days. We then isolated and purified eFat-EVs from the culture medium, and analyzed the EV number, size, morphology, specific markers, encapsulated cytokines, proteome, and microRNAs. Next, we evaluated the biological effects of unpurified and purified EVs on atrial mesenchymal stromal cells and endothelial cells in vitro. To establish a causal association between eFat-EVs and vulnerability to AF, we modeled AF in vitro using induced pluripotent stem cell-derived cardiomyocytes.

RESULTS

Microscopic examination revealed excessive inflammation, fibrosis, and apoptosis in fresh and cultured eFat tissues. Cultured explants from patients with AF secreted more EVs and harbored greater amounts of proinflammatory and profibrotic cytokines, and profibrotic microRNA, as well, than those without AF. The proteomic analysis confirmed the distinctive profile of purified eFat-EVs from patients with AF. In vitro, purified and unpurified eFat-EVs from patients with AF had a greater effect on proliferation and migration of human mesenchymal stromal cells and endothelial cells, compared with eFat-EVs from patients without AF. Last, whereas eFat-EVs from patients with and without AF shortened the action potential duration of induced pluripotent stem cell-derived cardiomyocytes, only eFat-EVs from patients with AF induced sustained reentry (rotor) in induced pluripotent stem cell-derived cardiomyocytes.

CONCLUSIONS

We show, for the first time, a distinctive proinflammatory, profibrotic, and proarrhythmic signature of eFat-EVs from patients with AF. Our findings uncover another pathway by which eFat promotes the development of atrial myopathy and fibrillation.

Latest Insights into Mechanisms behind Atrial Cardiomyopathy: It Is Not always about Ventricular Function

Atrial cardiomyopathy (ACM) represents a constantly evolving concept, with increasing importance in contemporary research and clinical practice. A better understanding of the mechanisms involved in atrial remodeling and its clinical correlations especially with atrial fibrillation (AF) and other cardiometabolic comorbidities may induce a significant impact on the diagnosis, prognosis, and therapeutic approach of ACM-related comorbidities. Although initially described several decades ago, investigators have only recently highlighted that several renal, metabolic, and cardiovascular diseases are determining factors for atrial remodeling and subsequent ACM. Based on data from multiple recent studies, our research emphasizes the correlations between ACM and other coexisting pathologies including cardiovascular, respiratory, or metabolic diseases, with fibrosis being the most incriminated pathophysiological mechanism. In addition to the usual tests, the paraclinical assessment of ACM is increasingly based on the use of various cardiac biomarkers, while the cardiac magnetic resonance (CMR) has become an increasingly tempting diagnostic too for describing morphofunctional aspects of the heart chambers, with the gadolinium contrast enhanced CMR (LGE-CMR) emerging as a commonly used technique aiming to identify and quantify the precise extent of atrial fibrosis. Further research should be conducted in order to clarify our knowledge regarding atrial remodeling and, therefore, to develop new and improved therapeutic approaches in these patients.

Left Atrial Remodeling Mechanisms Associated with Atrial Fibrillation

Heart disease has always been one of the important diseases that endanger health and cause death. Therefore, it is particularly important to understand left atrium reconstruction and atrial fibrillation before heart image processing. The purpose of this paper is to provide an important review of the mechanisms of left atrial remodeling (LAR) associated with atrial fibrillation (AF). LAR refers to the spectrum of pathophysiological changes in (i) atrial structure and physiological function, and (ii) electric, ionic, and molecular milieu of the LA, in response to stresses imposed by conditions such as hypertension, myocardial ischemia, autonomic denervation and congestive heart failure. The main mechanisms of LAR include electrical remodeling, structural remodeling, metabolic remodeling, autonomic remodeling, neurohormones and inflammation, and other influencing factors. LAR is not only the basic mechanism of AF and heart failure, but also the pathophysiological basis of its progression. In clinical practice, AF is the most common persistent arrhythmia, and is believed to be the result of a combination of mechanisms that have triggers and maintenance mechanisms, including spontaneous ectopic pacing and multiple wavelet reentry. While LA electrophysiological, structural, and ultra-structural changes trigger AF, in turn, AF alters the LA electrical and structural properties that promote its maintenance and recurrence. Chronic AF leads to extensive changes in atrial cellular substructures, including loss of myofibrils, accumulation of glycogen, changes in mitochondrial shape and size, fragmentation of sarcoplasmic reticulum, and dispersion of nuclear chromatin. Electrical remodeling and structural remodeling of the atria during AF, involving structural changes and functional impairment of the left atrium, can lead to serious decline in left ventricular function and severe heart failure. Therefore, LAR and AF are inter-activating phenomena, and the resulting complications can cause serious disabling and fatal events. In this paper, we present (i) the mechanisms of LAR, in the form of structural, electrical, metabolic, and neurohormonal changes, and (ii) their interactive roles in initiating and maintaining AF. These in-depth understanding of the atrial remodeling mechanisms can in turn provide useful insights into the treatment of AF and heart failure.

Exercise Stress Real-Time Cardiac Magnetic Resonance Imaging for Noninvasive Characterization of Heart Failure With Preserved Ejection Fraction: The HFpEF-Stress Trial

BACKGROUND

Right heart catheterization using exercise stress is the reference standard for the diagnosis of heart failure with preserved ejection fraction (HFpEF) but carries the risk of the invasive procedure. We hypothesized that real-time cardiac magnetic resonance (RT-CMR) exercise imaging with pathophysiologic data at excellent temporal and spatial resolution may represent a contemporary noninvasive alternative for diagnosing HFpEF.

METHODS

The HFpEF-Stress trial (CMR Exercise Stress Testing in HFpEF; URL: https://www.clinicaltrials.gov; Unique identifier: NCT03260621. URL: https://dzhk.de/; Unique identifier: DZHK-17) prospectively recruited 75 patients with echocardiographic signs of diastolic dysfunction and dyspnea on exertion (E/e'>8, New York Heart Association class ≥II) to undergo echocardiography, right heart catheterization, and RT-CMR at rest and during exercise stress. HFpEF was defined according to pulmonary capillary wedge pressure (≥15 mm Hg at rest or ≥25 mm Hg during exercise stress). RT-CMR functional assessments included time-volume curves for total and early (1/3) diastolic left ventricular filling, left atrial (LA) emptying, and left ventricular/LA long axis strain.

RESULTS

Patients with HFpEF (n=34; median pulmonary capillary wedge pressure at rest, 13 mm Hg; at stress, 27 mm Hg) had higher E/e' (12.5 versus 9.15), NT-proBNP (N-terminal pro-B-type natriuretic peptide; 255 versus 75 ng/L), and LA volume index (43.8 versus 36.2 mL/m²) compared with patients with noncardiac dyspnea (n=34; rest, 8 mm Hg; stress, 18 mm Hg; P≤0.001 for all). Seven patients were excluded because of the presence of non-HFpEF cardiac disease causing dyspnea on imaging. There were no differences in RT-CMR left ventricular total and early diastolic filling at rest and during exercise stress (P≥0.164) between patients with HFpEF and noncardiac dyspnea. RT-CMR revealed significantly impaired LA total and early (P<0.001) diastolic emptying in patients with HFpEF during exercise stress. RT-CMR exercise stress LA long axis strain was independently associated with HFpEF (adjusted odds ratio, 0.657 [95% CI, 0.516-0.838]; P=0.001) after adjustment for clinical and imaging measures and emerged as the best predictor for HFpEF (area under the curve at rest 0.82 versus exercise stress 0.93; P=0.029).

CONCLUSIONS

RT-CMR allows highly accurate identification of HFpEF during physiologic exercise and qualifies as a suitable noninvasive diagnostic alternative. These results will need to be confirmed in multicenter prospective research studies to establish widespread routine clinical use. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03260621. URL: https://dzhk.de/; Unique identifier: DZHK-17.

Cadherin-11 deficiency mitigates high-fat diet-induced inflammatory atrial remodeling and vulnerability to atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia nowadays. The occurrence of AF is closely associated with obesity. Cadherin-11 (Cad-11), as a member of the cadherin family, can make a contribution to diet-induced obesity and it will be informative to know whether Cad-11 exerts its effects on atrial remodeling and AF vulnerability in a diet-induced obesity model. In this study, we demonstrated that the expression of Cad-11 was significantly upregulated in the left atrium of AF patients with obesity and mice following 16 weeks of high-fat diet (HFD) feeding. Further confirmed that Cad-11 could regulate the activity of atrial fibroblasts by participating in inducing proinflammatory cytokines production. At animal levels, we found that although there was a lack of statistical difference in body weight, Cad-11^-/- mice could markedly improve impaired glucose tolerance and hyperlipidemia. Adverse atrial structural remodeling, including atrial enlargement, inflammation, and fibrosis provoked by HFD feeding were mitigated in Cad-11^-/- mice. Mechanistically, Cad-11 activated mitogen-activated protein kinases and nuclear factor-κB for interleukin-6 production in atrial fibroblasts that may contribute to the atrial fibrosis process in obesity-related AF, suggesting Cad-11 might be a new therapeutic target for obesity-related AF.

Diabetes Mellitus Promotes Atrial Structural Remodeling and PARP-1/Ikkα/NF-κB Pathway Activation in Mice

BACKGROUND

Diabetes mellitus (DM) has been demonstrated to be linked to atrial fibrillation (AF). However, the underlying mechanisms of the DM-associated increase in AF susceptibility and the potential effects of DM on atrial remodeling remain unclear.

METHODS AND RESULTS

Twenty-five C57BL/6 mice were randomly assigned to the normal/control group (Con, n=10) and model group (n=15). Mice in the model group were administered a high-fat diet combined with multiple injections of low-dose streptozocin (STZ) (35 mg/kg). Eleven mice were ultimately included in DM group. Left atrial tissue structural and inflammatory alterations were assessed. In our study, the atrial weights of DM mice were markedly heavier than those of mice in the Con group. DM mice exhibited significantly increased fasting plasma glucose, fasting insulin, and dyslipidaemia. Furthermore, H&E and Masson's staining revealed broadened interstitial spaces, myocyte disarray and atrial fibrosis in DM mice. The expression levels of the atrial inflammation-associated factor nuclear factor κB (NF-κB) and its pathway were significantly altered in the atria of DM mice.

CONCLUSION

DM could induce atrial structural remodeling and inflammation in mice.

Clinical significance of left atrial geometry in dilated cardiomyopathy patients: A cardiovascular magnetic resonance study

Background

Clinical significance of left atrial (LA) function and geometry in patients with dilated cardiomyopathy (DCM) remains uncertain.

Hypothesis

LA geometric parameters assessed by cardiac magnetic resonance (CMR) predict the prognosis in patients with DCM.

Methods

The present study included patients with DCM and sinus rhythm who underwent CMR between December 2007 and April 2018. LA volume was measured using CMR. LA sphericity index was computed as the ratio of the measured maximum LA volume by the volume of a sphere with maximum LA length diameter.

Results

We included 255 patients in this study. During the mean follow‐up of 3.92 years, hospitalization for HF occurred in 37 patients. The LA sphericity index was significantly higher in patients with hospitalization for HF than in those without (0.78 ± 0.35 vs. 0.58 ± 0.18, p < .001). Multivariable Cox regression analysis identified a higher LA sphericity index as an independent predictor of hospitalization for HF. Patients were categorized based on the median of LA sphericity index. The Kaplan–Meier curve showed that patients with a high LA sphericity index (≥0.57) had a significantly higher risk of hospitalization for HF than those with a low LA sphericity index (<0.57).

Conclusion

LA sphericity index was an independent predictor of hospitalization for HF. Assessment of LA geometric parameters might be useful for risk stratification in patients with DCM.

Left atrial scar identification and quantification in sinus rhythm and atrial fibrillation

Identification and quantification of low voltage areas (LVA) in atrial fibrillation (AF), identified by their bipolar voltages (BiV) via electro-anatomical voltage mapping is an area of interest to prognosis of AF free burden. LVAs have been linked to diseased left atrial (LA) tissue which results in pro-fibrillatory potentials. These LVAs are dominantly found within the pulmonary veins, however, as the disease progresses other areas of the LA show low voltage. The scar burden of the LA is linked to recurrence of the arrhythmia and can be a target of further modification. This burden is classically assessed once sinus rhythm (SR) is attained, but this is susceptible to operator variability with overestimated dense LA scar (<0.2 mV) and underestimated diseased LA tissue (<0.5 mV). The novel automated voltage histogram analysis (VHA) tool may increase accuracy, however, is yet to be fully validated. A recent study indicates that LVAs can be assessed just as reliably in AF as SR, but BiV is lower with linear correlation to SR values (0.24-0.5 mV respectively). In this paper, we review current data as well as review current methods of identifying, quantifying, and grading LA scar. We also compared AF vs SR voltages of a patient undergoing catheter ablation in our site using our VHA tool to compare the results. In keeping with the cited papers, we found lower voltages in our patient measured in AF. This area warrants further study to assess correlation in more patients, with view to developing prognostic and therapeutic grading systems.

Determinants of LA reservoir strain: Independent effects of LA volume and LV global longitudinal strain

BACKGROUND

Left atrial (LA) deformation during the reservoir phase (LASr) has demonstrated strong prognostic value in different clinical settings. Although determinants of left atrial reservoir strain including left atrial relaxation, left atrial compliance, and left ventricular longitudinal systolic function are fairly well defined, there is incomplete information regarding the effect of left atrial volume on this relationship which is the focus of our study.

METHOD

Consecutive patients without prior cardiac disease referred for transthoracic echocardiography were prospectively recruited. All participants underwent clinical assessment, transthoracic echocardiography (TTE), and screening exercise stress test. Only patients with normal left ventricular ejection fraction (LVEF) without left ventricular hypertrophy (LVH) or myocardial ischemia on stress testing were included.

RESULTS

A total of 260 patients (57% male, mean age 59 ± 14 years) were included. 70% had hypertension, 33% had diabetes mellitus, and 31% had both HTN and DM. On multivariate analysis, age, e', LAVI, and LV GLS (P < .01 for all) showed an independent association with LASr. Of interest, at lower tertiles of LAVI, a linear decrease in LASr was observed parallel to worsening LV GLS, whilst at higher tertiles of LAVI, the reduction in LASr was non-linear implying that LA enlargement, consequent to LA remodeling, had an incremental effect on LASr.

CONCLUSION

Age, e', LV GLS, and LAVI were independently associated with LASr. LA remodeling reflected by larger LAVI had an incremental negative association with LASr independent of LV GLS.

The effect of left atrial remodeling after cryoballoon ablation and radiofrequency ablation for paroxysmal atrial fibrillation

Background

Cryoballoon ablation (CBA) and radiofrequency ablation (RFA) are the most common procedures used to treat refractory atrial fibrillation (AF) and are performed through pulmonary vein isolation (PVI). Studies have shown that CBA can approximately match the therapeutic effects of RFA against AF. However, few studies have investigated the difference between CBA and RFA of the effects on left atrial remodeling for paroxysmal AF.

Objective

Atrial remodeling is considered pivotal to the occurrence and development of AF, therefore we sought to assess the influence of atrial remodeling in patients with paroxysmal AF after CBA and RFA in this study.

Methods

In this nonrandomized retrospective observational study, we enrolled 328 consecutive patients who underwent CBA or RFA for refractory paroxysmal AF in May 2014 to May 2017 in our hospital. After propensity score matching, 96 patients were included in the CBA group, and 96 were included in the RFA group. Patients were asked to undergo a 12‐lead electrocardiogram, a 24‐h Holter monitor, and an echocardiogram and to provide their clinical history and symptoms at 6 months and 1, 2, and 3 years postprocedurally. Electrical remodeling of the left atrium was assessed by P wave dispersion (Pdis); structural remodeling was assessed by the left atrium diameter (LAD) and left atrial volume index (LAVI) during scheduled visits.

Results

As of January 2020, compared with baseline, at 1 year, 2 years, and 3 years after ablation, the average changes in Pdis (∆Pdis), LAD (∆LAD), and LAVI (∆LAVI) were significant in both the CBA and RFA groups. Six months after ablation, ∆Pdis, ∆LAD, and ∆LAVI were greater in the CBA group than in the RFA group. There was no significant difference between the two groups in AF/flutter recurrence, but the AF/flutter‐free survival time of CBA group may be longer than RFA group after 2 years after ablation. A higher ∆Pdis, ∆LAD, or ∆LAVI at 1 year after ablation may increase AF/flutter‐free survival.

Conclusions

Although CBA and RFA are both effective in left atrial electrical and structural reverse‐remodeling in paroxysmal AF, CBA may outperform RFA for both purposes 6 months after ablation. However, during long‐term follow‐up, there was no significant intergroup difference.

Impaired left atrial mechanical functions as indicators for increased aortic root diameter in hypertensive and diabetic patients

OBJECTIVES

Previous studies have demonstrated that increased aortic root diameter (ARD) is frequently associated with increased cardiovascular (CV) events and is a predictor of stroke. Two-dimensional speckle tracking echocardiography (2D-STE) provides a better evaluation of left atrial (LA) functions. Left atrial mechanical dispersion is a useful predictor of new-onset atrial fibrillation (AF) independent of LA enlargement and dysfunction. We aimed to investigate the relationship between ARD and LA mechanical functions.

METHODS

The present study included 93 consecutive patients with hypertension and diabetes. The relationships between ARD and LA functions was evaluated.

RESULTS

Study population was divided into two groups according to the mean ARD values: group 1 (ARD ≤30.03 mm, n = 53) and group 2 (ARD >30.03 mm, n = 40). In group 2, age, LA max volume (vol), LA pre A vol, LA min vol, LA emptying fraction, LA active ejection fraction (EF), and LA expansion index were significantly higher compared to group 1. S‑LAs and SR-LAs (peak LA strain and strain rate, respectively, during ventricular systole) and S‑LAe and SR-LAe (peak early diastolic LA strain and strain rate, respectively) were significantly lower in group 2 compared to group 1. Age, LA max vol, LA pre A vol, LA min vol, LA emptying fraction, LA active EF, LA expansion index, S‑LAs, S‑LAe, SR-LAs, and SR-LAe were significantly associated with increased ARD. In multivariate logistic regression analysis, age, LA expansion index, and SR-LAe were independent predictors for ARD.

CONCLUSION

Impaired LA mechanical functions determined by speckle tracking methods are related with increased ARD independent of LV diastolic dysfunction.

Long Noncoding RNA HOTAIR Functions as a Competitive Endogenous RNA to Regulate Connexin43 Remodeling in Atrial Fibrillation by Sponging MicroRNA-613

Several studies have indicated that long noncoding RNAs (lncRNAs)-HOX transcript antisense RNA (HOTAIR) is involved in some cardiovascular diseases by regulating gene expression as a competitive endogenous RNA (ceRNA). GJA1 encoding Cx43 is one potential target gene of microRNA-613 (miR-613). Meanwhile, there is a potential target regulatory relationship between HOTAIR and miR-613. The present study is aimed at investigating whether HOTAIR functions as a ceRNA to regulate the Cx43 expression in atrial fibrillation (AF) by sponging miR-613. The expressions of HOTAIR, miR-613, and Cx43 were detected in the right atrial appendages of 45 patients with heart valve disease, including 23 patients with chronic AF. The HOTAIR overexpressed and underexpressed HL-1 cell model were constructed to confirm the effect of HOTAIR on Cx43. Then, the Cx43 expression was detected to testify the interplay between HOTAIR and miR-613 after cotransfecting HOTAIR and miR-613. Furthermore, luciferase assays were performed to verify that HOTAIR could regulate Cx43 remolding as a ceRNA by sponging miR-613. The expression of HOTAIR and Cx43 was significantly downregulated in chronic AF group. HOTAIR regulated positively the Cx43 expression in HL-1 cells. The upregulated effect of HOTAIR on the Cx43 expression could be remarkably attenuated by miR-613. Moreover, the inhibitory effect of miR-613 on the Cx43 expression could be obviously mitigated by HOTAIR. At last, luciferase assays confirmed HOTAIR functioned as a ceRNA in the Cx43 expression by sponging miR-613. Our study suggests that HOTAIR, functioning as a ceRNA by sponging miR-613, is an important contributor to Cx43 remolding in AF.

Cardiac fibrosis

Myocardial fibrosis, the expansion of the cardiac interstitium through deposition of extracellular matrix proteins, is a common pathophysiologic companion of many different myocardial conditions. Fibrosis may reflect activation of reparative or maladaptive processes. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. Immune cells, vascular cells and cardiomyocytes may also acquire a fibrogenic phenotype under conditions of stress, activating fibroblast populations. Fibrogenic growth factors (such as transforming growth factor-β and platelet-derived growth factors), cytokines [including tumour necrosis factor-α, interleukin (IL)-1, IL-6, IL-10, and IL-4], and neurohumoral pathways trigger fibrogenic signalling cascades through binding to surface receptors, and activation of downstream signalling cascades. In addition, matricellular macromolecules are deposited in the remodelling myocardium and regulate matrix assembly, while modulating signal transduction cascades and protease or growth factor activity. Cardiac fibroblasts can also sense mechanical stress through mechanosensitive receptors, ion channels and integrins, activating intracellular fibrogenic cascades that contribute to fibrosis in response to pressure overload. Although subpopulations of fibroblast-like cells may exert important protective actions in both reparative and interstitial/perivascular fibrosis, ultimately fibrotic changes perturb systolic and diastolic function, and may play an important role in the pathogenesis of arrhythmias. This review article discusses the molecular mechanisms involved in the pathogenesis of cardiac fibrosis in various myocardial diseases, including myocardial infarction, heart failure with reduced or preserved ejection fraction, genetic cardiomyopathies, and diabetic heart disease. Development of fibrosis-targeting therapies for patients with myocardial diseases will require not only understanding of the functional pluralism of cardiac fibroblasts and dissection of the molecular basis for fibrotic remodelling, but also appreciation of the pathophysiologic heterogeneity of fibrosis-associated myocardial disease.

Exercise training in the treatment of paroxysmal atrial fibrillation: study protocol of the Cologne ExAfib Trial

INTRODUCTION

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia and is associated with a number of comorbidities such as coronary artery disease and heart failure. While physical activity is already implemented in current international guidelines for the prevention and treatment of AF, the precise role of different types of exercise in the management of AF remains to be elucidated. The primary aim of the Cologne ExAfib Trial is to assess the feasibility and safety of different exercise modes in patients diagnosed with paroxysmal AF. Secondary outcomes include assessments of physical function, AF burden, quality of life and inflammation, as well as morphological and cardiac adaptations.

METHODS AND ANALYSIS

The study opened for recruitment in September 2019. In the initial pilot phase of this four-armed randomised controlled trial, we aim to enrol 60 patients between 60 years and 80 years of age with paroxysmal AF. After screening and pretesting, patients are randomised into one of the following groups: high-intensity interval training (4×4 min at 75%-85% peak power output (PPO)), moderate-intensity continuous training (25 min at 55%-65% PPO), strength training (whole body, 3 sets of 6-12 repetitions at 70%-90% one repetition maximum [1RM]) or a usual-care control group. Training is performed two times per week for 12 weeks. If the feasibility and safety can be confirmed through the initial pilot phase, the recruitment will be continued and powered for a clinical endpoint.Feasibility and safety are assessed by measures of recruitment and completion, programme tolerance and adherence as well as reported adverse events, including hospitalisation rates. Secondary endpoints are assessed by measures of peak oxygen consumption and the 1RM of selected muscle groups, questionnaires concerning quality of life and AF burden, serum blood samples for the analysis of C reactive protein, interleukin-6, tumour necrosis factor alpha and N-terminal pro-brain natriuretic peptide concentrations and ultrasound for muscle and heart morphology as well as cardiac function.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the ethics committee of the German Sport University Cologne (No.: 175/2018). All procedures performed in studies involving human participants are in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Manuscripts will be written based on international authorship guidelines. No professional writers will be commissioned for manuscript drafting. The findings of this study will be published in peer-reviewed journals and presented at leading exercise and medicine conferences TRIAL REGISTRATION NUMBER: The study is registered both at the German and at the WHO trial registers (DRKS00016637); Pre-results.

Cardiac magnetic resonance imaging for assessment of mitral stenosis before and after percutaneous balloon valvuloplasty in comparison to two- and three-dimensional echocardiography

BACKGROUND

The experience with cardiac magnetic resonance (CMR) in mitral stenosis (MS) is limited in contrast to mitral regurgitation.

PURPOSE

To compare CMR versus 2D and 3D transthoracic (TTE) and 3D transesophgeal (TEE) echocardiography in assessment of rheumatic MS before and after percutaneous balloon mitral valvuloplasty (PBMV).

MATERIAL AND METHODS

Twenty consecutive symptomatic patients with MS were evaluated prospectively and independently by CMR, TTE, and TEE pre-PBMV, and by CMR and TTE post-PBMV. Mitral valve area (MVA) was assessed by CMR planimetry, TTE and TEE planimetry, and pressure half time (PHT). Further assessment included trans-mitral velocity, mitral regurgitation (MR), and left atrial (LA) volume.

RESULTS

PBMV was successful in 18 patients and failed in two patients (one with MVA <1.5 cm², one developed severe MR). Pre-PBMV and MVA by CMR, 2D TTE, biplane, 3D TTE, 3D TEE, and PHT were 1.16, 1.16, 1.10, 1.02, 1.05, and 0.99 cm², respectively. Post-PBMV, a significant increase in MVA was observed (2.15, 2.06, 2.07, 2.04, and 2.03 cm², respectively). High agreement was observed between CMR and echocardiography before and after PBMV, except for PHT method. CMR significantly underestimated trans-mitral velocity and gradients compared to echocardiography (P<0.001). Before PBMV, mild MR was observed in 11, 12, and 19 patients by 2D TTE, 3D TTE, and CMR. After PBMV, MR was observed in all patients (19 mild, one severe) by all modalities. Echocardiography significantly underestimated LA volume compared to CMR (P<0.001). LA volume decreased significantly after PBMV (P<0.001).

CONCLUSION

CMR provides comprehensive assessment of several parameters in MS patients before and after intervention. Agreement with echocardiography is acceptable.

Interleukin-22 is elevated in the atrium and plasma of patients with atrial fibrillation and increases collagen synthesis in transforming growth factor-β1-treated cardiac fibroblasts via the JNK pathway

Our previous studies demonstrated that interleukin (IL)-22 is involved in cardiovascular diseases such as hypertension, cardiac fibrosis and aortic dissection. The purpose of the present study was to detect IL-22 expression in patients with atrial fibrillation (AF). Atrial tissue was collected from donors with sinus rhythm and patients with permanent AF, and the expression level of IL-22 and its receptors (IL-22R1 and IL-10R2) in both the left atrium (LA) and right atrium (RA) of each sample was detected. Blood samples were also obtained from donors with paroxysmal, persistent and permanent AF and from donors without AF history, and IL-22 levels were measured. In addition, the effects of IL-22 on collagen synthesis in TGF-β1-treated cardiac fibroblasts were investigated. IL-22R1, IL-10R2 and IL-22 expression was elevated in both the LA and RA in permanent AF patients. Elevated IL-22 expression positively correlated with the collagen areas and fibrosis marker levels in the atria of these patients. Plasma IL-22 levels were higher in AF patients compared with healthy donors and increased with increasing AF duration (from paroxysmal to persistent to permanent AF). A positive correlation was observed between IL-22 levels and TGF-β1 levels in AF patients. In vitro, recombinant mouse IL-22 treatment upregulated α-SMA, collagen I and collagen III expression in TGF-β1-treated cardiac fibroblasts. These effects were reversed by SP600125, an inhibitor of the JNK pathway. To conclude, IL-22 levels are elevated in patients with AF and may exacerbate collagen synthesis in TGF-β1-induced cardiac fibroblasts. IL-22 may also influence AF by activating the JNK pathway.

Global Left Atrial Longitudinal Strain Using 3-Beat Method Improves Risk Prediction of Stroke Over Conventional Echocardiography in Atrial Fibrillation

Background:

Atrial fibrillation (AF) is associated with a risk of ischemic stroke, and functional myocardial imaging has offered novel insights on its pathophysiology and prognosis, but its use in AF-related stroke remains limited. We aimed to evaluate the feasibility of left atrial (LA) deformations and its prognostic values of ischemic stroke in a large-scale AF population.

Methods:

Peak atrial longitudinal strain (LA strain), left ventricular strain (global longitudinal strain), LA strain rate (LA SR) at reservoir (LA longitudinal systolic strain rate), and early diastolic conduit (LA longitudinal early diastolic strain rate) phases were analyzed using 2-dimensional speckle tracking echocardiography. Consecutive 3-beat averaged values of strain and SR were used. The clinical end point was ischemic stroke.

Results:

Among 1457 AF participants, the mean LA strain, LA longitudinal systolic strain rate, and LA longitudinal early diastolic strain rate values were 12.9±4.8%, 0.80±0.28 s − 1 , and −1.17±0.46 s − 1 , respectively. There were strong positive linear relationships of 3-beat average with index-beat analysis (R=0.94, 0.94, and 0.94 for LA strain, LA longitudinal systolic strain rate, and LA longitudinal early diastolic strain rate, respectively; all P <0.001). Multivariate Cox regression models incorporating conventional echocardiography parameters demonstrated LA strain and SRs to be independent prognosticators of ischemic stroke during a median follow-up of 37.6 months. Utilization of LA strain further provided incremental value over CHA 2 DS 2 -VASc scoring ( C statistics, 0.78–0.81; P =0.006) for ischemic stroke. Overall, the prognostic performances of LA deformations were attenuated after adding global longitudinal strains in models.

Conclusions:

LA deformations by the 3-beat method are feasible and reproducible during AF. LA strain provided additional prognostic implication over clinical information and conventional echocardiographic measures for ischemic stroke in the AF population but not incremental to global longitudinal strains.

Hyperuricemia Is Associated with Left Ventricular Dysfunction and Inappropriate Left Ventricular Mass in Chronic Kidney Disease

Background. Hyperuricemia is common in patients with chronic kidney disease (CKD), and this may lead to poor cardiovascular (CV) outcomes. The aim of this cross-sectional study was to assess associations among serum uric acid (UA) and echocardiographic parameters, ankle-brachial index (ABI), and brachial-ankle pulse wave velocity (baPWV) in patients with CKD. Methods. A total of 418 patients with CKD were included. The echocardiographic measurements included left atrial diameter (LAD), left ventricular ejection fraction (LVEF) and the ratio of observed to predict left ventricular mass (LVM). ABI, baPWV and medical records were obtained. Results. Multivariable forward logistic regression analysis showed that a high UA level was significantly associated with LAD > 47 mm (odds ratio [OR], 1.329; p = 0.002), observed/predicted LVM > 128% (OR, 1.198; p = 0.008) and LVEF < 50% (OR, 1.316; p = 0.002). No significant associations were found between UA and ABI < 0.9 or baPWV > 1822 cm/s. Multivariate stepwise linear regression analysis showed that a high UA level correlated with high LAD (unstandardized coefficient β, 0.767; p < 0.001), high observed/predicted LVM (unstandardized coefficient β, 4.791; p < 0.001) and low LVEF (unstandardized coefficient β, −1.126; p = 0.001). No significant associations between UA and low ABI and high baPWV were found. Conclusion. A high serum UA level was associated with a high LAD, high observed/predicted LVM and low LVEF in the patients with CKD. A high serum UA level may be correlated with abnormal echocardiographic parameters in patients with stage 3–5 CKD.

Early recurrence during the blanking period and left atrial reverse remodeling after catheter ablation for non-paroxysmal atrial fibrillation

Background

Early recurrence of atrial tachyarrhythmia (ERAT) during a 90-day blanking period (BP) often occurs after atrial fibrillation (AF) ablation. Left atrial reverse remodeling (LARR), which is the reduction in LA volume (LAV), also occurs during the BP. Both ERAT and LARR are associated with late recurrence (LR, greater than 90 days after ablation). We investigated the association between ERAT and LARR following non-paroxysmal AF (NPAF) ablation.

Methods

We retrospectively reviewed 330 consecutive patients undergoing initial NPAF ablation (median follow-up: 4.0 years). Based on the timing of the final ERAT, we divided the patients into No-ERAT (N = 154, without ERAT), Early (N = 39, 0–7 days after ablation), Intermediate (N = 67, 8–30), and Late-ERAT (N = 70, 31–90) groups. We assessed the extent of LARR, defined as the percentage of decrease in LAV (%ΔLAV). The %ΔLAV cutoff value was determined by receiver operating characteristic analysis, and incorporated into a multivariate analysis to assess the association between ERAT and LARR.

Results

Late-ERAT was associated with LR (hazard ratio: 6.31, 95% confidence interval (CI): 4.21–9.47, p = 0.0001). The %ΔLAV in the Late-ERAT group was significantly smaller than the other groups (p < 0.0001). The predictive power of %ΔLAV for LR was slight (AUC, 0.604; best cutoff, 18.8% decrease; p = 0.0011). In the multivariate logistic regression analysis, Late-ERAT was associated with poor LARR (%ΔLAV < 18.8% decrease) (odds ratio, 0.13; 95%CI, 0.06–0.27; p < 0.001), whereas Early- and Intermediate-ERAT did not show any correlation.

Conclusions

Late-ERAT was strongly associated with poor LARR after NPAF ablation. Both Late-ERAT and poor LARR might reflect a residual arrhythmogenic substrate causing LR.

Effects of danicamtiv, a novel cardiac myosin activator, in heart failure with reduced ejection fraction: experimental data and clinical results from a phase 2a trial

AIMS

Both left ventricular (LV) and left atrial (LA) dysfunction and remodelling contribute to adverse outcomes in heart failure with reduced ejection fraction (HFrEF). Danicamtiv is a novel, cardiac myosin activator that enhances cardiomyocyte contraction.

METHODS AND RESULTS

We studied the effects of danicamtiv on LV and LA function in non-clinical studies (ex vivo: skinned muscle fibres and myofibrils; in vivo: dogs with heart failure) and in a randomized, double-blind, single- and multiple-dose phase 2a trial in patients with stable HFrEF (placebo, n = 10; danicamtiv, n = 30; 50-100 mg twice daily for 7 days). Danicamtiv increased ATPase activity and calcium sensitivity in LV and LA myofibrils/muscle fibres. In dogs with heart failure, danicamtiv improved LV stroke volume (+10.6 mL, P < 0.05) and LA emptying fraction (+10.7%, P < 0.05). In patients with HFrEF (mean age 60 years, 25% women, ischaemic heart disease 48%, mean LV ejection fraction 32%), treatment-emergent adverse events, mostly mild, were reported in 17 patients (57%) receiving danicamtiv and 4 patients (40%) receiving placebo. Danicamtiv (at plasma concentrations ≥2000 ng/mL) increased stroke volume (up to +7.8 mL, P < 0.01), improved global longitudinal (up to -1.0%, P < 0.05) and circumferential strain (up to -3.3%, P < 0.01), decreased LA minimal volume index (up to -2.4 mL/m² , P < 0.01) and increased LA function index (up to 6.1, P < 0.01), when compared with placebo.

CONCLUSIONS

Danicamtiv was well tolerated and improved LV systolic function in patients with HFrEF. A marked improvement in LA volume and function was also observed in patients with HFrEF, consistent with pre-clinical findings of direct activation of LA contractility.

Serum osteoprotegerin level is independently related to subclinical left atrial mechanical function in patients with hypertension and diabetes

OBJECTIVES

Previous studies showed that subclinical abnormal left atrial (LA) function could be diagnosed with LA speckle tracking evaluation long before chamber enlargement. Osteoprotegerin (OPG) is a member of the tumor necrosis factor (TNF) receptor superfamily and was recently found to be an indicator for adverse cardiovascular outcomes and a risk factor for new onset atrial fibrillation. The authors hypothesized that OPG values could predict LA mechanical dysfunction and LA remodeling assessed by two-dimensional speckle tracking echocardiography (2D-STE) in patients with hypertension (HT) and diabetes mellitus (DM).

METHODS

A single center study was conducted including consecutive patients presenting to the authors' outpatient clinic. Enrolled patients needed to have been treated for HT and DM for at least 1 year.

RESULTS

The study included 80 patients (mean age, 57.5 ± 8.3 years). Patients in the impaired LA strain group were older (p = 0.035), had lower low density lipoprotein (LDL) cholesterol (mg/dl) (p = 0.021), and higher OPG (pmol/l) (p = 0.004) values than patients in the normal LA strain group. Univariate logistic regression analysis demonstrated that age (p = 0.039), LDL cholesterol (mg/dl) (p = 0.025), and OPG (pmol/l) (p = 0.008) values were associated with impaired LA strain. Backward multivariate logistic regression analysis showed that LDL cholesterol (mg/dl) (OR: 0.982, CI 95% 0.964-0.999, p = 0.049) and OPG (pmol/l) (OR: 1.438, CI 95% 1.043-1.983, p = 0.027) were independently associated with impaired LA strain.

CONCLUSION

In hypertensive and diabetic patients, higher OPG values were associated with impaired LA function assessed by 2D-STE. In this high-risk patient group, serum OPG can be used as a risk predictor for LA mechanical dysfunction.

Omentin-1 is associated with atrial fibrillation in patients with cardiac valve disease

BACKGROUND

Epicardial adipose tissue (EAT) remodeling and adipocytokines are associated with structural remodeling in atrial fibrillation (AF). However, the role of omentin-1, a novel adipocytokine, in structural remodeling remains unknown.

METHODS

Hematoxylin and eosin (H&E) and Masson's trichrome stains were used to investigate the histology of EAT and right atrial appendages. The expression levels of adipocytokines in these human samples were determined by immunohistochemical assay and western blotting. Models of transforming growth factor (TGF)-β1-induced activation of cardiac fibroblasts (CFs) and TGF-β1-induced endothelial-mesenchymal transition (EndMT) of human umbilical vein endothelial cell (HUVEC) were established to explore roles of omentin-1 in these processes. To determine changes in adipocytokines secretion under hypoxia conditions, adipocytes were treated with 5% O₂ and 95% N₂, and then CFs and HUVECs were co-cultured with the conditioned medium of adipocytes to determine the effects of hypoxia-treated adipocytes on these cells.

RESULTS

Expression of omentin-1 was downregulated in the EAT and right atrial appendages from patients with AF compared to samples from patients without AF, while the TGF-β1 level was upregulated in EAT from patients with AF. EAT from patients with AF exhibited adipocyte hypertrophy and severe interstitial fibrosis. Omentin-1 inhibited TGF-β1-induced CF activation and reversed TGF-β1-induced HUVEC EndMT. Adipocytes treated with hypoxia exhibited downregulation of omentin-1 and partly activated CFs.

CONCLUSIONS

This study demonstrated that omentin-1 was an antifibrotic adipocytokine and was downregulated in patients with AF, which was partly mediated by hypoxia.

Regulation of left atrial fibrosis induced by mitral regurgitation by SIRT1

SIRT1 (silent information regulator 1) is a histone deacetylase. It can sense the energy level in cells and delay cell senescence, leading to resistance to external stress and improving metabolism. Mitral regurgitation (MR) is a common disease in cardiac surgery. However, there are no previous studies on SIRT1 and left atrial fibrosis caused by MR. In this study, we aimed to explore the regulatory effect of SIRT1 on left atrial fibrosis induced by MR. We used Guizhou miniature pigs to establish an MR model and a sham operation model after anaesthesia induction and respiratory intubation, and these model animals were followed for 30 months after the surgery. The differential distribution and expression of SIRT1 and collagen I in the left atrium was determined by immunofluorescence and Western blotting. Furthermore, we treated NIH3T3 fibroblasts (CFs) with resveratrol and Angiotensin II (Ang II) to analyse the specific mechanism involved in the development of myocardial fibrosis. The results showed that the MR model was successfully constructed. There were 8 pigs in the MR group and 6 pigs in the control group. In both the animal experiments and the cell experiments, the expression of collagen I in the MR group was increased significantly compared to that in the control group, while the expression of SIRT1 was decreased.

Molecular Mechanisms, Diagnostic Aspects and Therapeutic Opportunities of Micro Ribonucleic Acids in Atrial Fibrillation

Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules responsible for regulation of gene expression. They are involved in many pathophysiological processes of a wide spectrum of diseases. Recent studies showed their involvement in atrial fibrillation. They seem to become potential screening biomarkers for atrial fibrillation and even treatment targets for this arrhythmia. The aim of this review article was to summarize the latest knowledge about miRNA and their molecular relation to the pathophysiology, diagnosis and treatment of atrial fibrillation.

The Effect of Sacubitril/Valsartan on Device Detected Arrhythmias and Electrical Parameters among Dilated Cardiomyopathy Patients with Reduced Ejection Fraction and Implantable Cardioverter Defibrillator

Sacubitril/valsartan therapy reduces sudden cardiac death (SCD) among patients with reduced ejection fraction (HFrEF) when compared to guidelines recommended doses of enalapril, however the mechanism is still not clear. There are few, contrasting results about the effect of sacubitril/valsartan on arrhythmias in the clinical context of dilated cardiomyopathy (DCM) and there are no clinical data about its effect on measured implantable cardioverter defibrillator (ICD) electrical parameters, such as atrial/ventricular electrograms sensing and pacing threshold. We conducted a 12 month follow-up observational study in 167 ischemic and nonischemic DCM patients (mean age 68.1 ± 11.6 years; 85% male), with dual-chamber ICD on sacubitril/valsartan treatment, to evaluate the incidence of device detected tachyarrhythmia events, both atrial and ventricular, and the change in measured ICD electrical parameters. We collected data on clinical, electrocardiographic and echocardiographic parameters to find a possible electro-mechanical correlation within results. Our results show that DCM patients with reduced ejection fraction and ICD on sacubitril/valsartan treatment experienced a reduction in both atrial and ventricular arrhythmias incidence and an improvement in ICD electrical atrial parameters. The findings might be explained by the electro-mechanical cardiac reverse remodeling induced by sacubitril/valsartan therapy.

Atrial Function and Its Role in the Non-invasive Evaluation of Diastolic Function in Congenital Heart Disease

Diastolic dysfunction has correlated with adverse outcomes in various forms of unrepaired and repaired or palliated congenital heart disease (CHD). The non-invasive assessment of diastolic function in pediatric and adult patients with CHD remains challenging. Atrial size has a pivotal role in the evaluation of diastolic function; however, a growing body of evidence supports the additional role of atrial function as a more sensitive parameter of ventricular diastolic dysfunction. While the importance of atrial function is becoming clearer in adult acquired heart disease, it remains ambiguous in those with CHD. In this review we set the stage with the current understanding of diastolic function assessment in CHD, followed by insight into atrial form and function including its non-invasive assessment, and conclude with the current knowledge of atrial function in CHD. A general pattern of decrease in reservoir and conduit function with compensatory increase followed by decompensatory decrease in contractile function seems to be the common pathway of atrial dysfunction in most forms of CHD.

Sacubitril/Valsartan Induces Global Cardiac Reverse Remodeling in Long-Lasting Heart Failure with Reduced Ejection Fraction: Standard and Advanced Echocardiographic Evidences

Sacubitril/valsartan reduces mortality in heart failure with reduced ejection fraction (HFrEF) patients, partially due to cardiac reverse remodeling (RR). Little is known about the RR rate in long-lasting HFrEF and the evolution of advanced echocardiographic parameters, despite their known prognostic impact in this setting. We sought to evaluate the rates of left ventricle (LV) and left atrial (LA) RR through standard and advanced echocardiographic imaging in a cohort of HFrEF patients, after the introduction of sacubitril/valsartan. A multi-parametric standard and advanced echocardiographic evaluation was performed at the moment of introduction of sacubitril/valsartan and at 3 to 18 months subsequent follow-up. LVRR was defined as an increase in the LV ejection fraction ≥10 points associated with a decrease ≥10% in indexed LV end-diastolic diameter; LARR was defined as a decrease >15% in the left atrium end-systolic volume. We analyzed 77 patients (65 ± 11 years old, 78% males, 40% ischemic etiology) with 76 (28-165) months since HFrEF diagnosis. After a median follow-up of 9 (interquartile range 6-14) months from the beginning of sacubitril/valsartan, LVRR occurred in 20 patients (26%) and LARR in 33 patients (43%). Moreover, left ventricular global longitudinal strain (LVGLS) improved from -8.3 ± 4% to -12 ± 4.7% (p < 0.001), total left atrial emptying fraction (TLAEF) from 28.2 ± 14.4% to 32.6 ± 13.7% (p = 0.01) and peak atrial longitudinal strain (PALS) from 10.3 ± 6.9% to 13.7 ± 7.6% (p < 0.001). In HFrEF patients, despite a long history of the disease, the introduction of sacubitril/valsartan provides a rapid global (i.e., LV and LA) RR in >25% of cases, both at standard and advanced echocardiographic evaluations.

Different Types of Atrial Fibrillation Share Patterns of Gut Microbiota Dysbiosis

Atrial fibrillation has been identified to be associated with disordered gut microbiota. Notably, atrial fibrillation is a progressive disease and could be categorized as paroxysmal and persistent based on the duration of the episodes. The persistent atrial fibrillation patients are accompanied by higher risk of stroke and lower success rate of rhythm control. However, the microbial signatures of different categories of atrial fibrillation patients remain unknown. We sought to determine whether disordered gut microbiota occurs in the self-terminating PAF or intestinal flora develops dynamically during atrial fibrillation progression. We found that different types of atrial fibrillation show a limited degree of gut microbiota shift. Gut microbiota dysbiosis has already occurred in mild stages of atrial fibrillation, which might act as an early modulator of disease, and therefore may be regarded as a potential target to postpone atrial fibrillation progression.

Dysbiotic gut microbiota (GM) and disordered metabolic patterns are known to be involved in the clinical expression of atrial fibrillation (AF). However, little evidence has been reported in characterizing the specific changes in fecal microbiota in paroxysmal AF (PAF) and persistent AF (psAF). To provide a comprehensive understanding of GM dysbiosis in AF types, we assessed the GM signatures of 30 PAF patients, 20 psAF patients, and 50 non-AF controls based on metagenomic and metabolomic analyses. Compared with control subjects, similar changes of GM were identified in PAF and psAF patients, with elevated microbial diversity and similar alteration in the microbiota composition. PAF and psAF patients shared the majority of differential taxa compared with non-AF controls. Moreover, the similarity was also illuminated in microbial function and associated metabolic alterations. Additionally, minor disparity was observed in PAF compared with psAF. Several distinctive taxa between PAF and psAF were correlated with certain metabolites and atrial diameter, which might play a role in the pathogenesis of atrial remodeling. Our findings characterized the presence of many common features in GM shared by PAF and psAF, which occurred at the self-terminating PAF. Preventative and therapeutic measures targeting GM for early intervention to postpone the progression of AF are highly warranted.

IMPORTANCE Atrial fibrillation has been identified to be associated with disordered gut microbiota. Notably, atrial fibrillation is a progressive disease and could be categorized as paroxysmal and persistent based on the duration of the episodes. The persistent atrial fibrillation patients are accompanied by higher risk of stroke and lower success rate of rhythm control. However, the microbial signatures of different categories of atrial fibrillation patients remain unknown. We sought to determine whether disordered gut microbiota occurs in the self-terminating PAF or intestinal flora develops dynamically during atrial fibrillation progression. We found that different types of atrial fibrillation show a limited degree of gut microbiota shift. Gut microbiota dysbiosis has already occurred in mild stages of atrial fibrillation, which might act as an early modulator of disease, and therefore may be regarded as a potential target to postpone atrial fibrillation progression.

Left Atrial Structural Remodelling in Non-Valvular Atrial Fibrillation: What Have We Learnt from CMR?

Left atrial structural, functional and electrical remodelling are linked to atrial fibrillation (AF) pathophysiology and mirror the phrase “AF begets AF”. A structurally remodelled left atrium (LA) is fibrotic, dysfunctional and enlarged. Fibrosis is the hallmark of LA structural remodelling and is associated with increased risk of stroke, heart failure development and/or progression and poorer catheter ablation outcomes with increased recurrence rates. Moreover, increased atrial fibrosis has been associated with higher rates of stroke even in sinus-rhythm individuals. As such, properly assessing the fibrotic atrial cardiomyopathy in AF patients becomes necessary. In this respect, late-gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging is the gold standard in imaging myocardial fibrosis. LA structural remodelling extension offers both diagnostic and prognostic information and influences therapeutic choices. LGE-CMR scans can be used before the procedure to better select candidates and to aid in choosing the ablation technique, during the procedure (full CMR-guided ablations) and after the ablation (to assess the ablation scar). This review focuses on imaging several LA structural remodelling CMR parameters, including size, shape and fibrosis (both extension and architecture) and their impact on procedure outcomes, recurrence risk, as well as their utility in relation to the index procedure timing.

Pathophysiology of Hypertensive Heart Disease: Beyond Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Given that the life expectancy and the burden of hypertension are projected to increase over the next decade, hypertensive heart disease (HHD) may be expected to play an even more central role in the pathophysiology of cardiovascular disease (CVD). A broader understanding of the features and underlying mechanisms that constitute HHD therefore is of paramount importance.

RECENT FINDINGS

HHD is a condition that arises as a result of elevated blood pressure and constitutes a key underlying mechanism for cardiovascular morbidity and mortality. Historically, studies investigating HHD have primarily focused on left ventricular (LV) hypertrophy (LVH), but it is increasingly apparent that HHD encompasses a range of target-organ damage beyond LVH, including other cardiovascular structural and functional adaptations that may occur separately or concomitantly. HHD is characterized by micro- and macroscopic myocardial alterations, structural phenotypic adaptations, and functional changes that include cardiac fibrosis, and the remodeling of the atria and ventricles and the arterial system. In this review, we summarize the structural and functional alterations in the cardiac and vascular system that constitute HHD and underscore their underlying pathophysiology.

Computed Tomography of the Left Atrium and Left Atrial Appendage: A Pictorial Essay on the Anatomy, Normal Variants, and Pathology

전산화단층촬영(이하 CT) 영상 기술의 발전으로 박동하는 심장에 대한 섬세한 영상의학적 평가가 가능해졌다. 심초음파 및 MRI에 비해 심장 CT의 강점은 대부분의 의료기관에 보급되어 있고 고품질 이미지의 빠른 생산이 가능하며 해부학적 묘사가 뛰어나다는 것이다. 좌심방과 좌심방이에서 생기는 대부분의 변이 혹은 병리적 상태들은 CT 상의 소견만으로도 추정진단을 내릴 수 있다. 또한 CT 영상은 성공적인 카테터 기반 시술 또는 수술에 중요한 해부학적 정보들을 제공한다. 특히 좌심방과 좌심방이는 심방세동 환자들의 치료 및 관리에 중요한데, 이는 다양한 카테터 기반 시술들이 두 구조물의 기계적 혹은 전기적 차단을 목표로 하기 때문이다. 따라서 임상적으로 의미 있는 판독을 위해서는 병리적 상태의 CT 소견 기술과 함께 좌심방 및 좌심방이의 모양, 크기 및 주변 구조물과의 상대적 위치 관계 등에 대한 포괄적인 검토를 해야 한다.