Structural and functional remodeling of the left atrium: clinical and therapeutic implications for atrial fibrillation

Extensive ablation for persistent atrial fibrillation patients with mitral regurgitation: Insights from the EARNEST-PVI prospective randomized trial

BACKGROUND

Extensive ablation in addition to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) has not yielded consistent results, indicating diversity in their efficacy. Mitral regurgitation (MR) associated with AF may indicate a higher prevalence of arrhythmogenic substrate, suggesting potential benefits of extensive ablation for these patients.

METHODS

This post-hoc analysis of the EARNEST-PVI trial compared PVI alone versus an extensive ablation strategy (PVI-plus) in persistent AF patients, stratified by MR presence. The primary endpoint of the study was the recurrence of AF. The secondary endpoints included death, cerebral infarction, and procedure-related complications.

RESULTS

The trial included 495 eligible patients divided into MR and non-MR groups. The MR group consisted of 192 patients (89 in the PVI-alone arm and 103 in the PVI-plus arm), while the non-MR group had 303 patients (158 in the PVI-alone arm and 145 in the PVI-plus arm). In the non-MR group, recurrence rates were similar between PVI-alone and PVI-plus arms (Log-rank P = 0.47, Hazard ratio = 0.85 [95%CI: 0.54-1.33], P = 0.472). However, in the MR group, PVI-plus was significantly more effective in preventing AF recurrence (Log-rank P = 0.0014, Hazard ratio = 0.40 [95%CI: 0.22-0.72], P = 0.0021). No significant differences were observed in secondary endpoints between the two arms.

CONCLUSIONS

For persistent AF patients with mild or greater MR, receiving PVI-plus was superior to PVI-alone in preventing AF recurrence. Conversely, for patients without MR, the effectiveness of extensive ablation was not demonstrated. These findings suggest tailoring ablation strategies based on MR presence can lead to better outcomes in AF management.

Outcomes of maze procedure and mitral valve surgery in atrial functional mitral regurgitation: a retrospective study

BACKGROUND

Atrial functional mitral regurgitation (AFMR) is a newly discovered condition associated with longstanding atrial fibrillation. This retrospective study aimed to analyze the outcomes of the maze procedure and mitral regurgitation (MR) surgery in AFMR and atrial fibrillation in comparison with those in degenerative MR (DMR).

METHODS

Patients who underwent mitral valve repair/replacement with a maze procedure at a hospital (July 2012-August 2021) were included. We excluded patients aged below 18 years undergoing concomitant coronary artery bypass grafting or atrial septal defect repair and those with MR etiology other than ARMR or DMR.

RESULTS

We included 35 patients with AFMR and 50 patients with DMR. Patient characteristics and postoperative outcomes were not significantly different between the two groups. Long-term outcomes revealed no significant differences in the ratio of cardiac mortality, stroke, or hospital readmission. However, after the maze procedure, the sinus rhythm restoration rate was significantly lower (62% vs. 28.5%, p < 0.001), a junctional rhythm state (p < 0.001) and permanent pacemaker insertion for sick sinus syndrome (SSS) (p = 0.03) were significantly more common in AFMR than DMR. On postoperative transthoracic echocardiography (TTE), the pulmonary artery systolic pressure was significantly less decreased in the AFMR group than in the DMR group compared with that on preoperative TTE (p = 0.04).

CONCLUSIONS

AFMR showed excellent mitral valve surgery outcomes, similar to DMR, but had a significantly higher risk of pacemaker insertion for SSS after the maze procedure.

Left atrial reservoir strain is a marker of atrial fibrotic remodeling in patients undergoing cardiovascular surgery: Analysis of gene expression

Left atrial strain (LAS) measured by two-dimensional speckle tracking echocardiography (2DSTE) is considered to be a marker of LA structural remodeling, but it remains unsettled. We investigated the potential usefulness and clinical relevance of LAS to detect atrial remodeling including fibrosis by analyzing gene expression in cardiovascular surgery patients. Preoperative 2DSTE was performed in 131 patients (92 patients with sinus rhythm [SR] patients including paroxysmal AF [PAF], 39 atrial fibrillation [AF]) undergoing cardiovascular surgery. Atrial samples were obtained from the left atrial appendages, and mRNA expression level was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR) in 59 cases (24 PAF, 35 AF). Mean value of left atrial reservoir strain (mLASr) correlated with left atrial volume index (LAVI), and left atrial conduit strain (mLAScd). mLASr also correlated with left atrial contractile strain (mLASct) in SR patients including PAF. mLASr was significantly lower, and LAVI was higher, in the AF group, compared with SR patients including PAF. The expression of COL1A1 mRNA encoding collagen type I α1 significantly increased in AF patients (p = 0.031). mLASr negatively correlated with COL1A1 expression level, and multivariate regression analysis showed that mLASr was an independent predictor of atrial COL1A1 expression level, even after adjusting for age, sex, and BMI. But, neither mLAScd / mLASct nor LAVI (bp) correlated with COL1A1 gene expression. The expression level of COL1A1 mRNA strongly correlated with ECM-related genes (COL3A1, FN1). It also correlated ECM degradation-related genes (MMP2, TIMP1, and TIMP2), pro-fibrogenic cytokines (TGFB1 encoding TGFβ1, END1, PDGFD, CTGF), oxidant stress-related genes (NOX2, NOX4), ACE, inflammation-related genes (NLRP, IL1B, MCP-1), and apoptosis (BAX). Among the fibrosis-related genes examined, univariable regression analysis showed that log (COL1A1) was associated with log (TGFB1) (adjusted R2 = 0.685, p<0.001), log (NOX4) (adjusted R2 = 0.622, p<0.001), log (NOX2) (adjusted R2 = 0.611, p<0.001), suggesting that TGFB1 and NOX4 was the potent independent determinants of COL1A1 expression level. mLASr negatively correlated with the ECM-related genes, and fibrosis-related gene expression level including TGFB1, NOX2, and NLRP3 in PAF patients. PAF patients with low mLASr had higher expression of the fibrosis-related gene expression, compared with those with high mLASr. These results suggest that LASr correlates with atrial COL1A1 gene expression associated with fibrosis-related gene expression. Patients with low LASr exhibit increased atrial fibrosis-related gene expression, even those with PAF, highlighting the utility of LAS as a marker for LA fibrosis in cardiovascular surgery patients.

The Clinical Applications of Left Atrial Strain: A Comprehensive Review

Left atrial (LA) strain imaging, which measures the deformation of the LA using speckle-tracing echocardiography (STE), has emerged recently as an exciting tool to help provide diagnostic and prognostic information for patients with a broad range of cardiovascular (CV) pathologies. Perhaps due to the LA's relatively thin-walled architecture compared with the more muscular structure of the left ventricle (LV), functional changes in the left atrium often precede changes in the LV, making LA strain (LAS) an earlier marker for underlying pathology than many conventional echocardiographic parameters. LAS imaging is typically divided into three phases according to the stage of the cardiac cycle: reservoir strain, which is characterized by LA filling during systole; conduit strain, which describes LA deformation during passive LV filling; and booster strain, which provides information on the LA atrium during LA systole in late ventricular diastole. While additional large-population studies are still needed to further solidify the role of LAS in routine clinical practice, this review will discuss the current evidence of its use in different pathologies and explore the possibilities of its applications in the future.

The effect of body weight on left atrial function determined by longitudinal strain analysis in young adults

PURPOSE

Obesity is a risk factor for various cardiovascular disorders. Left atrial (LA) function is vital for predicting adverse outcomes in many diseases. LA strain was recently proposed as a noninvasive and valuable parameter for LA functional evaluation. We investigated the effect of body mass index (BMI) values on left atrial functions determined by longitudinal strain analysis in young adults without concomitant disease.

METHODS

We prospectively included 134 subjects in our study. Participants were categorized into three subgroups, obese, overweight, and control, according to their BMI. Conventional echocardiographic measurements and strain analysis were performed on all patients.

RESULTS

There were 41 patients (30.5%) in the obesity group, 46 patients (34.3%) in the overweight group, and 47 patients (35.0%) in the control group. Obese patients had significantly larger LA volume (46.9 ± 12.1 ml; p < 0.001) compared to overweight and control subjects; however, LA volume index (21.4 ± 6.1 ml/m2 vs. 22.4 ± 6.1 ml/m2 vs. 22.4 ± 5.0 ml/m2; p = 0.652) were similar between groups. In the LA strain analysis, obese patients were found to have lower left atrial reservoir longitudinal strain (LASr) compared to both the overweight and control group (44.2 ± 5.8% vs. 39.1 ± 3.7% vs. 36.5 ± 4.9%; p < 0.001); moreover obese patients had significantly worse left atrial contraction phase longitudinal strain (LASct) (-15.1 ± 3.1% vs. -13.1 ± 2.5%; p = 0.007) and left atrial conduit phase longitudinal strain (LAScd) (-29.0 ± 7.1% vs. -23.3 ± 5.4%; p < 0.001) values compared to the control group. However, LASct and LAScd values did not differ between overweight and obese patients.

CONCLUSION

LA function determined by LA strain analysis was impaired in obese and overweight individuals compared to the control group, even in the early stages of life. The prognostic significance of this finding should be investigated in prospective studies.

Toll-like Receptor 4 Differentially Modulates Cardiac Function in Response to Chronic Exposure to High-Fat Diet and Pressure Overload

BACKGROUND/AIM

The impact of myocardial stressors such as high-fat diet (HFD) and pressure overload has been extensively studied. Toll-like receptor 4 (TLR4) deficiency has been suggested to have a protective role in response to these stressors, although some conflicting data exist. Furthermore, there is limited information about the role of TLR4 on cardiac remodeling in response to long-term exposure to stressors. This study aims to investigate the effects of TLR4 deficiency on cardiac histology and physiology in response to chronic stressors.

METHODS

TLR4-deficient (TLR4-/-) and wild-type (WT) mice were subjected to either HFD or a normal diet (ND) for 28 weeks. Another group underwent abdominal aortic constriction (AAC) or a sham procedure and was monitored for 12 weeks. Inflammatory markers, histology, and echocardiography were used to assess the effects of these interventions.

RESULTS

TLR4-/- mice exhibited reduced cardiac hypertrophy and fibrosis after long-term HFD exposure compared to ND without affecting cardiac function. On the other hand, TLR4 deficiency worsened cardiac function in response to AAC, leading to decreased ejection fraction (EF%) and increased end-systolic volume (ESV).

CONCLUSIONS

TLR4 deficiency provided protection against HFD-induced myocardial inflammation but impaired hemodynamic cardiac function under pressure overload conditions. These findings highlight the crucial role of TLR4 and its downstream signaling pathway in maintaining cardiac output during physiologic cardiac hypertrophy in response to pressure overload.

Obesity-hyperlipidemia, Hypertension, and Left Atrial Enlargement During Stroke in Young Adults

BACKGROUND

This study investigated the association between left atrial enlargement and stroke severity in young adults. We also studied the differences between the normal and left atrial enlargement groups in clinical data.

METHODS

A total of 135 young stroke patients admitted to the Department of Neurology of the Taizhou People's Hospital were recruited from January 2018 to December 2021. The patients were divided into normal and enlarged groups by left atrial size. The relationship between the left atrial diameter and the National Institutes of Health Stroke Scale score was analyzed apart from the differences in clinical variables.

RESULTS

No relationship was observed between the left atrial diameter and the National Institutes of Health Stroke Scale score ( r =-0.045 P =0.603). The univariate analysis of both groups revealed that hypertension ( P =0.004), hyperlipidemia ( P =0.001), body mass index ( P =0.000), obesity ( P =0.015), and not stroke etiologic subtypes were associated with left atrial enlargement. In binary logistic regression analysis models, hyperlipidemia 3.384 (95% CI, 1.536 to 7.452), hypertension 2.661 (95% CI, 1.066 to 6.639), and obesity 2.858 (95% CI, 1.158 to 7.052) were significantly associated with the young stroke of left atrial enlargement.

CONCLUSIONS

In young adults, obesity-hyperlipidemia and hypertension were significantly associated with left atrial enlargement in stroke.

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

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

Breathless nights and heart flutters: Understanding the relationship between obstructive sleep apnea and atrial fibrillation

There is an extraordinary and increasing global burden of atrial fibrillation (AF) and obstructive sleep apnea (OSA), two conditions that frequently accompany one another and that share underlying risk factors. Whether a causal pathophysiologic relationship connects OSA to the development and/or progression of AF, or whether shared risk factors promote both conditions, is unproven. With increasing recognition of the importance of controlling AF-related risk factors, numerous observational studies now highlight the potential benefits of OSA treatment in AF-related outcomes. Physicians are regularly faced with caring for this important and increasing population of patients despite a paucity of clinical guidance on the topic. Here, we review the clinical epidemiology and pathophysiology of AF and OSA with a focus on key clinical studies and major outstanding questions that should be addressed in future studies.

Effect of atrial fibrillation on plasma galectin-3 and soluble CD40 ligand levels in patients with ischemic cardiomyopathy

OBJECTIVE

To reveal the significance of plasma galectin-3 and soluble CD40 ligand (sCD40L) levels in patients with ischemic cardiomyopathy (ICM) combined with atrial fibrillation.

METHODS

In this case-control study, the case group comprised 60 patients with ICM combined with atrial fibrillation and the control group comprised patients with ICM without atrial fibrillation. Plasma galectin-3 and sCD40L levels, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), and left ventricular diameter (LVD) were compared.

RESULTS

The plasma galectin-3 and sCD40L levels, LAD, and LVD were higher and the LVEF was lower in the case than control group. In the case group, the plasma galectin-3 and sCD40L levels were positively correlated with the LAD and LVD but negatively correlated with the LVEF. The area under the receiver operating characteristic curve of the plasma galectin-3 and sCD40L levels in the diagnosis of ICM combined with atrial fibrillation was 0.857 (95% confidence interval, 0.792-0.923) and 0.724 (95% confidence interval, 0.634-0.814), respectively.

CONCLUSION

The plasma galectin-3 and sCD40L levels are significantly elevated in patients with ICM combined with atrial fibrillation. Although both may have predictive value in the diagnosis of ICM combined with atrial fibrillation, galectin-3 may have the higher predictive value.

P-wave terminal force in lead V1 and atrial fibrillation burden in cryptogenic stroke with implantable loop recorders

Implantable loop recorders (ILRs) are useful for the detection of atrial fibrillation (AF) in patients with cryptogenic stroke (CS). P-wave terminal force in lead V₁ (PTFV₁) is associated with AF detection; however, data on the association between PTFV₁ and AF detection using ILRs in patients with CS are limited. Consecutive patients with CS with implanted ILRs from September 2016 to September 2020 at eight hospitals in Japan were studied. PTFV₁ was calculated by 12-lead ECG before ILRs implantation. An abnormal PTFV₁ was defined as ≥ 4.0 mV × ms. The AF burden was calculated as a proportion based on the duration of AF to the total monitoring period. The outcomes included AF detection and large AF burden, which was defined as ≥ 0.5% of the overall AF burden. Of 321 patients (median age, 71 years; male, 62%), AF was detected in 106 patients (33%) during the median follow-up period of 636 days (interquartile range [IQR], 436-860 days). The median time from ILRs implantation to AF detection was 73 days (IQR, 14-299 days). An abnormal PTFV₁ was independently associated with AF detection (adjusted hazard ratio, 1.71; 95% confidence interval [CI], 1.00-2.90). An abnormal PTFV₁ was also independently associated with a large AF burden (adjusted odds ratio, 4.70; 95% CI, 2.50-8.80). In patients with CS with implanted ILRs, an abnormal PTFV₁ is associated with both AF detection and a large AF burden.Clinical Trial Registration Information: UMIN Clinical Trials Registry 000044366.

Epidemiology, Mechanisms, and Management of Atrial Fibrillation in Cardiac Amyloidosis

Cardiac amyloidosis (CA) is a restrictive disease that results from intramyocardial amyloid deposition due to immunoglobulin light chain or transthyretin proteins. Up to two-third of CA patients have atrial fibrillation (AF) due to electromechanical, autonomic, and hemodynamic disturbances. AF in CA carries particularly increased risk of thromboembolism, prompting anticoagulation therapy irrespective of CHA₂DS₂VASc score. However, CA is also associated with enhanced bleeding risk that warrants thorough assessment of bleeding profile before initiation of anticoagulation. Management of AF in CA is challenging because these patients poorly tolerate rate control agents, while cardiomyopathy precludes most antiarrhythmic agents, leaving amiodarone as the preferred antiarrhythmic drug. The effectiveness of direct current cardioversion in restoring sinus rhythm in CA is comparable with that in the general population, although intraprocedural complication rates could be higher. Transesophageal echocardiogram should be performed prior to direct current cardioversion, given high incidence of intracardiac thrombus in these patients. Finally, the data on catheter ablation is limited.

Intermittent fasting attenuates obesity-related atrial fibrillation via SIRT3-mediated insulin resistance mitigation

OBJECTIVE

Atrial fibrillation (AF) is the most common tachyarrhythmia in urgent need of therapeutic optimization. Obesity engenders AF, and its pathogenesis is closely intertwined with insulin resistance (IR), but mechanism-based management is still underinvestigated. Intermittent fasting (IF) is a novel lifestyle intervention that mitigates IR, a potential AF driver, yet whether IF can prevent obesity-related AF remains elusive. Here, we aimed to evaluate the impacts of short-term IF on AF and to uncover the underlying mechanism.

METHODS

We subjected obese mice (high-fat diet for 8-week) to IF (alternative-day fasting for another 5-week) for AF vulnerability and substrate formation assessment, and similarly treated neonatal atrial cardiomyocytes (NRCMs) and fibroblasts (NRCFs) (palmitate, 200 μM) with IF (alternative-day short-term starvation for 8-day) for mechanism investigation.

RESULTS

Obese mice were prone to AF and atrial remodeling. IF reduced AF inducibility, duration, and reversed atrial remodeling including channel disturbance, left atrial dilation, cardiac hypertrophy and fibrosis in obese mice independent of weight loss. Mechanistically, IF up-regulated the SIRT3 protein level both in vivo and in vitro, and pharmacologic inhibition (3-(1H-1,2,3-Triazol-4-yl) pyridine, 50 μM) and genetic suppression of SIRT3 could attenuate the IF-mediated benefits against hypertrophy and fibrosis. Furthermore, IF activated AMPK and Akt signaling, two positive downstream targets of SIRT3, and inactivated HIF1α signaling, a negative downstream target of SIRT3 in both obese mice atria and palmitate-treated cells, while inhibition of SIRT3 reversed these effects.

CONCLUSION

IF prevents obesity-related AF via SIRT3-mediated IR mitigation, thus representing a feasible lifestyle intervention to improve AF management.

Electro-Mechanical Alterations in Atrial Fibrillation: Structural, Electrical, and Functional Correlates

Atrial fibrillation is the most common arrhythmia encountered in clinical practice affecting both patients’ survival and well-being. Apart from aging, many cardiovascular risk factors may cause structural remodeling of the atrial myocardium leading to atrial fibrillation development. Structural remodelling refers to the development of atrial fibrosis, as well as to alterations in atrial size and cellular ultrastructure. The latter includes myolysis, the development of glycogen accumulation, altered Connexin expression, subcellular changes, and sinus rhythm alterations. The structural remodeling of the atrial myocardium is commonly associated with the presence of interatrial block. On the other hand, prolongation of the interatrial conduction time is encountered when atrial pressure is acutely increased. Electrical correlates of conduction disturbances include alterations in P wave parameters, such as partial or advanced interatrial block, alterations in P wave axis, voltage, area, morphology, or abnormal electrophysiological characteristics, such as alterations in bipolar or unipolar voltage mapping, electrogram fractionation, endo-epicardial asynchrony of the atrial wall, or slower cardiac conduction velocity. Functional correlates of conduction disturbances may incorporate alterations in left atrial diameter, volume, or strain. Echocardiography or cardiac magnetic resonance imaging (MRI) is commonly used to assess these parameters. Finally, the echocardiography-derived total atrial conduction time (PA-TDI duration) may reflect both atrial electrical and structural alterations.

The predictive value of left atrium epicardial adipose tissue on recurrence after catheter ablation in patients with different types of atrial fibrillation

BACKGROUND

A growing body of evidence supports that the left atrium epicardial adipose tissue (LA-EAT) is related to the occurrence and recurrence of atrial fibrillation (AF). The relationship between LA-EAT and the recurrence after radiofrequency catheter ablation (RFCA) in patients with different types of AF is still unclear. This study aims to evaluate the predictive value of LA-EAT on the recurrence of AF after RFCA in patients with different types of AF.

METHODS

301 AF patients who underwent RFCA for the first time were divided into the paroxysmal atrial fibrillation (PAF) group (n = 181) and the persistent atrial fibrillation (PersAF) group(n = 120), which were followed up at 3, 6, and 12 months. All patients underwent left atrial computed tomography angiography (CTA) examination before the operation, and LA-EAT was measured using software (Advantage Workstation4.6, GE, USA).

RESULTS

After a median follow-up of 10.7 months, 73/301 patients (24.25%) had a recurrence of AF, including 43 /120(35.83%) patients with PersAF and 30/181(16.57%) patients with PAF. In multivariable Cox regression analysis, LA-EAT volume (OR = 1.053;95%CI: 1.024-1.083, p < 0.001), attenuation (OR = 0.949;95%CI:0.911-0.988, p = 0.012) and left atrial diameter (LAD) (OR = 1.063;95%CI:1.002-1.127，p = 0.043) were independent risk factors for recurrence in patients with PersAF but not in patients with PAF.

CONCLUSION

LA-EAT volume and attenuation are independent risk factors for recurrence after RFCA in patients with PersAF.

Quantification of left atrial function by the area-length method overestimates left atrial emptying fraction

PURPOSE

The biplane area-length method is commonly used in cardiac magnetic resonance (CMR) to assess left atrial (LA) volume (LAV) and function. Associations between left atrial emptying fraction (LAEF) and clinical outcomes have been reported. However, only limited data are available on the calculation of LAEF using the biplane method compared to 3D assessment. This study aimed to compare volumetric and functional LA parameters obtained from the biplane method with 3D assessment in a large, multiethnic cohort.

METHOD

158 participants of MESA (Multi-Ethnic Study of Atherosclerosis) underwent CMR that included standard two- and four-chamber steady-state free precession (SSFP) cine imaging for the biplane method. For 3D-based assessment, short-axis SSFP cine series covering the entire LA were obtained, followed by manual delineation of LA contours to create a time-resolved 3D LAV dataset. Paired t-tests and Bland-Altman plots were used to analyze the data.

RESULTS

Standard volumetric assessment showed that LAVmin (bias: -8.35 mL, p < 0.001), LAVmax (bias: -9.38 mL, p < 0.001) and LAVpreA (bias: -10.27 mL, p < 0.001) were significantly smaller using the biplane method compared to 3D assessment. Additionally, the biplane method reported significantly higher LAEFtotal (bias: 7.22 %, p < 0.001), LAEFactive (bias: 6.08 %, p < 0.001), and LAEFpassive (bias: 4.51 %, p < 0.001) with wide limits of agreement.

CONCLUSIONS

LA volumes were underestimated using the biplane method compared to 3D assessment, while LAEF parameters were overestimated. These findings demonstrate a lack of precision using the biplane method for LAEF assessment. Our results support the usage of 3D assessment in specific settings when LA volumetric and functional parameters are in focus.

What Strain Analysis Adds to Diagnosis and Prognosis in Heart Failure Patients

Heart failure (HF) is a common disease that requires appropriate tools to correctly predict cardiovascular outcomes. Echocardiography represents the most commonly used method for assessing left ventricular ejection fraction and a cornerstone in the detection of HF, but it fails to procure an optimal level of inter-observer variability, leading to unsatisfactory prediction of cardiovascular outcomes. In this review, we discuss emerging clinical tools (global longitudinal strain of the left ventricle, the right ventricle, and the left atrium) that permitted an improvement in the diagnosis and ameliorated the risk stratification across different HF phenotypes. The review analyzes the speckle-tracking contributions to the field, discussing the limitations and advantages in clinical practice.

miR-135a Regulates Atrial Fibrillation by Targeting Smad3

Background

Atrial fibrillation (AF) is the most common arrhythmia in clinical. Atrial fibrosis is a hallmark feature of atrial structural remodeling in AF, which is regulated by the TGF-β1/Smad3 pathway. Recent studies have implicated that miRNAs are involved in the process of AF. However, the regulatory mechanisms of miRNAs remain largely unknown. This study is aimed at investigating the function and regulatory network of miR-135a in AF.

Methods

In vivo, the plasma was collected from patients with AF and non-AF subjects. Adult SD rats were induced by acetylcholine (ACh) (66 μg/ml)-CaCl₂ (10 mg/ml) to establish an AF rat model. In vitro, atrial fibroblasts (AFs), isolated from adult SD rats, were treated with high-frequency electrical stimulation (HES) (12 h) and hypoxia (24 h) to mimic the AF and atrial fibrosis, respectively. miR-135a expression was detected through quantitative real-time polymerase chain reaction (qRT-PCR). The association between miR-135a and Smad3 was speculated by the TargetScan database and confirmed by the luciferase reporter assay. Fibrosis-related genes, Smad3, and TRPM7 were all assessed.

Results

The expression of miR-135a was markedly decreased in the plasma of AF patients and AF rats, which was consistent with that in HES-treated and hypoxia-treated AFs. Smad3 was identified as a target of miR-135a. the downregulation of miR-135a was associated with the enhancement of Smad3/TRPM7 expressions in AFs. Additionally, the knockdown of Smad3 significantly reduced the expression of TRPM7 and further inhibited atrial fibrosis.

Conclusions

Our study demonstrates that miR-135a regulates AF via Smad3/TRPM7, which is a potential therapeutic target for AF.

Prediction of Recurrence of Atrial Fibrillation Post-ablation Based on Atrial Fibrosis Seen on Late Gadolinium Enhancement MRI: A Metaanalysis

OBJECTIVES

This meta-analysis aims to investigate the recurrence of atrial fibrillation (AF) post-ablation based on the various stages of fibrosis seen in the late gadolinium enhancement magnetic resonance imaging (LGE-MRI).

METHODS

Electronic databases were searched using specific terms and identified nine studies that met the inclusion criteria. A total of 1,787 patients underwent LGE-MRI to assess atrial fibrosis before catheter ablation for AF. We performed three analyses: first, we compared stage IV versus stage I (reference group). The second set examined the combined stages III and IV versus stages I and II (reference group). The third set compared stage IV versus combined stages I, II, and III. The metanalysis relied on a random-effects model to pool the odds ratios (OR) and 95% confidence intervals (CI) using the DerSimonian and Laird method. The data was analyzed using StatsDirect software in England.

RESULTS

The study showed a higher rate of AF recurrence after ablation in stage IV atrial fibrosis than in stage I (OR, 9.54; 95% CI, 3.81 to 28.89; P<00001). Also, in patients with combined stages III & IV of atrial fibrosis, AF recurrence was significantly higher after ablation than in stages I & II groups (OR, 2.37; 95% CI, 1.61 to 3.50; P<00001). Similarly, compared to combined stages I, II, and III, patients with stage IV have higher odds of recurrence post-ablation (OR, 4.24; 95% CI, 2.39- 7.52, P < 0.001).

CONCLUSION

This metanalysis demonstrates the strong association between left atrial fibrosis in LGE-MRI and AF post-ablation recurrence. The finding of this study will further assist clinicians in predicting the recurrence rate of AF based on the amount of fibrosis and tailor therapeutic decisions for further management.

Protocol of BEYOND trial: Clinical BEnefit of sodium-glucose cotransporter-2 (SGLT-2) inhibitors in rhYthm cONtrol of atrial fibrillation in patients with diabetes mellitus

SGLT-2 inhibitor, traditionally used for glycemic control, has several beneficial effects that can help manage heart failure (HF). SGLT-2 inhibitors reduce the risk of cardiovascular mortality in patients with HF. As atrial fibrillation (AF) is closely associated with HF and diabetes mellitus (DM) is a risk factor for AF, we assume that SGLT-2 inhibitors will also show therapeutic benefits regarding AF, especially for rhythm control. This trial has a multicenter, prospective, open, blinded endpoint design. It is a 1:1 randomized and controlled study. A total of 716 patients who are newly diagnosed of AF and DM within 1 year will be enrolled from 7 tertiary medical centers. The trial is designed to compare the effects of SGLT-2 inhibitors and other oral hypoglycemic agents on atrial rhythm control in patients with AF and DM. The primary outcome is the recurrence of AF within a year (including post-antiarrhythmic drugs (AAD) or ablation). The secondary outcomes are the ablation rate within a year, change in AF burden, size of the left atrium, NT-proBNP, the AF symptom score, and the quality of life. This trial will prospectively evaluate the effect and safety of SGLT-2 inhibitors on AF rhythm control in patients with DM. It will provide an invaluable dataset on rhythm control in AF with DM for future studies and offer novel information to assist in clinical decisions. (BEYOND trial, ClinicalTrials.gov number: NCT05029115. https://clinicaltrials.gov/ct2/show/NCT05029115).

Sex differences in the association between blood pressure and atrial fibrillation: A case-control study

Background

To examine the association of hypertension (HBP) and its control with atrial fibrillation (AF) and how patient sex affects this association.

Materials and methods

A case control study of patients admitted to our hospital from 2015 to 2019 was conducted. Patients were divided into subgroups according to their blood pressure (BP) levels and control status, in which odd ratios (OR) by sex for AF was estimated using a logistic regression model and restrictive cubic splines before and after propensity score matching.

Results

A total of 3,212 patients with AF and 8,307 without AF were investigated. Compared to patients with normal BP, patients with HBP had more AF [OR = 1.75 (1.52-2.02), OR = 2.66 (2.24-3.15), and OR = 4.30 (3.40-5.44) in patients with grade 1, 2, and 3 HBP, respectively]. In HBP patients with grade 3, the OR of AF was much higher in women than in men (OR = 7.15, 95% CI: 4.43-11.50 vs. OR = 2.48, 95% CI: 1.66-3.72). BP over 133.1/79.9 mmHg in men or 127.1/75.1 mmHg in women was positively associated with AF. In patients with HBP, uncontrolled BP was more associated with AF (OR = 3.00, 95% CI: 2.53-3.56), especially in women (OR = 3.09, 95% CI: 2.27-4.19). BP and prevalence of AF correlated with each other positively in patients admitted to a cardiology ward. Lowering BP to 145.1/85.8 mmHg in men or 140.5/82.5 mmHg in women led to less AF.

Conclusion

There is more significant relationship between HBP and AF in female patients. A lower and individualized BP target may be formulated to prevent AF in women.

Clinical implications of left atrial changes after optimization of medical therapy in patients with heart failure

AIMS

Limited data exist regarding the prognostic relevance of changes in left atrial (LA) dimensions in patients with heart failure (HF). We assessed changes in LA dimension and their relation with outcomes after optimization of guideline-directed medical therapy (GDMT) in patients with new-onset or worsening HF.

METHODS AND RESULTS

Left atrial diameter was assessed at baseline and 9 months after GDMT optimization in 632 patients (mean age 65.8 ± 12.1 years, 22.3% female) enrolled in BIOSTAT-CHF. LA adverse remodelling (LAAR) was defined as an increase in LA diameter on transthoracic echocardiography between baseline and 9 months. After the 9-month visit, patients were followed for a median of 13 further months. LAAR was observed in 247 patients (39%). Larger baseline LA diameter (odds ratio [OR] 0.90; 95% confidence interval [CI] 0.87-0.93; p < 0.001) and up-titration to higher doses of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEi/ARBs) (OR 0.56; 95% CI 0.34-0.92; p = 0.022) were independently associated with lower likelihood of LAAR. LAAR was associated with an increased risk of the composite of all-cause mortality or HF hospitalization (log-rank p = 0.007 and adjusted hazard ratio 1.73, 95% CI 1.22-2.45, p = 0.002). The association was more pronounced in patients without a history of atrial fibrillation (p for interaction = 0.009).

CONCLUSION

Among patients enrolled in BIOSTAT-CHF, LAAR was associated with an unfavourable outcome and was prevented by ACEi/ARB up-titration. Changes in LA dimension may be a useful marker of response to treatment and improve risk stratification in patients with HF.

Risk factors for new-onset atrial fibrillation during critical illness: A Delphi study

Background

New-onset atrial fibrillation (NOAF) is common during critical illness and is associated with poor outcomes. Many risk factors for NOAF during critical illness have been identified, overlapping with risk factors for atrial fibrillation in patients in community settings. To develop interventions to prevent NOAF during critical illness, modifiable risk factors must be identified. These have not been studied in detail and it is not clear which variables warrant further study.

Methods

We undertook an international three-round Delphi process using an expert panel to identify important predictors of NOAF risk during critical illness.

Results

Of 22 experts invited, 12 agreed to participate. Participants were located in Europe, North America and South America and shared 110 publications on the subject of atrial fibrillation. All 12 completed the three Delphi rounds. Potentially modifiable risk factors identified include 15 intervention-related variables.

Conclusions

We present the results of the first Delphi process to identify important predictors of NOAF risk during critical illness. These results support further research into modifiable risk factors including optimal plasma electrolyte concentrations, rates of change of these electrolytes, fluid balance, choice of vasoactive medications and the use of preventative medications in high-risk patients. We also hope our findings will aid the development of predictive models for NOAF.

Diagnostic Accuracy of the 2016 Guideline-Based Echocardiographic Algorithm to Estimate Invasively-Measured Left Atrial Pressure by Direct Atrial Cannulation

BACKGROUND

Although estimation of left ventricular filling pressure (LVFP) using an integrated echocardiographic algorithm is recommended, the usefulness of this algorithm has not been fully validated.

OBJECTIVES

The purpose of this study was to investigate the reliability of an algorithmic classification system using invasively measured left atrial pressure (LAP) in a large-scale cohort.

METHODS

The authors enrolled 1,967 patients (age 68 ± 10 years) whose LAP was directly measured within the left atrium during catheter ablation for atrial fibrillation. Patients were classified into 3 groups based on the echocardiographic algorithm: normal (group N, n = 1,282), undetermined (group U, n = 160), and elevated (group E, n = 346) LAP groups. Invasively measured LAP and echocardiographic parameters estimating LVFP were compared among the groups.

RESULTS

The median LAP was 12.6 ± 5.7 mm Hg in the entire cohort. LAP was significantly higher in group E than that in the other groups (groups E vs U vs N, 14.2 ± 6.3 mm Hg vs 13.5 ± 5.9 mm Hg vs 12.0 ± 5.5 mm Hg; P < 0.001). Among group E patients, 43.1% had elevated LAP (≥15 mm Hg), whereas 56.9% had normal LAP (<15 mm Hg). Of the patients in group N, 69.0% had normal LAP, whereas 31% had elevated LAP. Although the correlation between invasively measured LAP and E/e', peak tricuspid regurgitant velocity, and left atrial volume index was modest, the number of abnormal values correlated significantly with elevated LAP (P < 0.001).

CONCLUSIONS

The classification using combined echocardiographic parameters in the recommendations may be useful for detecting patients with normal LVFP but may be limited for detecting elevated LVFP.

Effects and pharmacological mechanism of Zhigancao Decoction on electrical and structural remodeling of the atrium of rabbits induced by rapid atrial pacing

BACKGROUND

Zhigancao decoction (ZD) has a long history in China as a traditional Chinese medicine compound for the treatment of tachyarrhythmias. This study mainly explored the pharmacological mechanism of Zhigancao Decoction in preventing atrial fibrillation by altering the electrical and structural remodeling of the atrial in rabbits.

METHODS

In total, 30 male New Zealand white rabbits were randomly divided into 3 groups (ten rabbits for each). The first group was sham-operated (control group). The second group was intervened by the rapid right atrium pacing (RAP) to induce atrial fibrillation (AF group), while the third group was given ZD gavage and RAP (AF + ZD group). All rabbits were anesthetized before two monophasic action potential (MAP) catheters were sequentially inserted into the right atrium. After 8 h of rapid right atrial pacing, the electrophysiological indexes and the induction rate of atrial fibrillation were observed in the three groups of rabbits, and the left atrial myocardium samples were taken to observe the ultrastructure. Single atrial myocytes were separated by enzymolysis, and the L-type calcium current (I_Ca-L) of atrial myocytes in different experimental groups was observed by whole-cell patch clamp technique. The fluorescence intensity of Ca²⁺ in atrial myocytes was observed after Fluo-3/AM fluorescent staining. The main components of ZD were identified by liquid chromatography-mass spectrometry-mass spectrometry (LC-MS/MS) method.

RESULTS

Compared with the AF group, the maximum ascent rate (Max dV/dt) and plateau potential were significantly reduced in the ZD group, the action potential duration at 10% and 20% (APD₁₀, APD₂₀) were significantly shortened (P < 0.01), action potential duration at 50%, 70%, and 90% (APD₅₀, APD₇₀, APD₉₀) were significantly prolonged, and atrial effective refractory period (AERP) was significantly prolonged (P < 0.01) in the ZD group. In the ZD group, the I_Ca-L amplitudes of rabbit atrial myocytes under each clamping voltage were significantly smaller than those in the AF group (P < 0.01) and the control group (P < 0.05). The Ca²⁺ fluorescence intensity in the rabbit atrial myocytes in the ZD group was significantly weaker than that in the AF group (P < 0.01) and the control group (P < 0.05). Electron microscopy displayed that the control group had neatly arranged atrial tissue myofilaments and intact mitochondria. However, the ultrastructural damage of the AF group was severe compared with that of the ZD group. LC-MS/MS analysis confirmed that ZD contained several antiarrhythmic compounds including ginsenoside, isoliensinine, catalpol, glycyrrhizinate and hesperetin.

CONCLUSION

Rapid atrial pacing (RAP) could cause the electrical and structural remodeling of rabbit atrial myocytes. ZD might reverse the atrial electrical remodeling but could have little effect on structural remodeling, which might be the mechanism of ZD treatment on atrial fibrillation.

Forward-Solution Noninvasive Computational Arrhythmia Mapping: The VMAP Study

BACKGROUND

The accuracy of noninvasive arrhythmia source localization using a forward-solution computational mapping system has not yet been evaluated in blinded, multicenter analysis. This study tested the hypothesis that a computational mapping system incorporating a comprehensive arrhythmia simulation library would provide accurate localization of the site-of-origin for atrial and ventricular arrhythmias and pacing using 12-lead ECG data when compared with the gold standard of invasive electrophysiology study and ablation.

METHODS

The VMAP study (Vectorcardiographic Mapping of Arrhythmogenic Probability) was a blinded, multicenter evaluation with final data analysis performed by an independent core laboratory. Eligible episodes included atrial and ventricular: tachycardia, fibrillation, pacing, premature atrial and ventricular complexes, and orthodromic atrioventricular reentrant tachycardia. Mapping system results were compared with the gold standard site of successful ablation or pacing during electrophysiology study and ablation. Mapping time was assessed from time-stamped logs. Prespecified performance goals were used for statistical comparisons.

RESULTS

A total of 255 episodes from 225 patients were enrolled from 4 centers. Regional accuracy for ventricular tachycardia and premature ventricular complexes in patients without significant structural heart disease (n=75, primary end point) was 98.7% (95% CI, 96.0%-100%; P<0.001 to reject predefined H0 <0.80). Regional accuracy for all episodes (secondary end point 1) was 96.9% (95% CI, 94.7%-99.0%; P<0.001 to reject predefined H0 <0.75). Accuracy for the exact or neighboring segment for all episodes (secondary end point 2) was 97.3% (95% CI, 95.2%-99.3%; P<0.001 to reject predefined H0 <0.70). Median spatial accuracy was 15 mm (n=255, interquartile range, 7-25 mm). The mapping process was completed in a median of 0.8 minutes (interquartile range, 0.4-1.4 minutes).

CONCLUSIONS

Computational ECG mapping using a forward-solution approach exceeded prespecified accuracy goals for arrhythmia and pacing localization. Spatial accuracy analysis demonstrated clinically actionable results. This rapid, noninvasive mapping technology may facilitate catheter-based and noninvasive targeted arrhythmia therapies.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04559061.

Clinical utility of left atrial strain in predicting atrial fibrillation recurrence after catheter ablation: An up-to-date review

Rhythm control is the core part of the integrated management of atrial fibrillation (AF), especially in the early stages. Despite advances in catheter ablation (CA), the recurrence rate of AF after CA remains high. As a result, stratification and early management of AF recurrence after CA are critical. Currently, predictors of recurrence of AF after CA are mostly based on dysfunction caused by structural remodeling, apart from traditional risk factors. Atrial strain is a recently developed important parameter for detecting the deformability of atrial myocardium during the cardiac cycle prior to atrial remodeling. Although there is only preliminary evidence, atrial strain is still a promising parameter in predicting the recurrence of AF after CA at an early stage. This review focuses on the evaluation of atrial strain, the current applications of atrial strain in assessing atrial function, and predicting the recurrence of AF after CA. We summarize the contents related as follows: (1) CA for rhythm control in AF; (2) Evaluation methods of atrial strain; (3) Atrial strain in the remodeling and reverse remodeling of AF; and (4) Clinical applications of atrial strain in predicting the recurrence of AF after CA. Although there is accumulating evidence on the role of decreased atrial strain in the early prediction of AF recurrence, atrial strain is limited in clinical practice for lacking exact cut-off values and difficulty in distinguishing specific function phases of the atrium. More research is needed in the future to add strength to the early prediction value of atrial strain in AF recurrences.

Risk Factors of Early Atrial Fibrillation Recurrence Following Electrical Cardioversion When Left Ventricular Ejection Fraction Is Preserved

Background and objectives: To identify clinical, echocardiographic, and laboratory parameters that affect the early recurrence of atrial fibrillation (AF) after restoring sinus rhythm (SR) by electrical cardioversion (ECV), and to determine whether left atrial (LA) strain, as a noninvasive indicator reflecting fibrosis, is associated with laboratory indicators affecting the development of fibrosis, interleukin 6 (IL-6) or tumor necrosis factor α (TNF-α). Materials and Methods: The study included 92 persistent AF patients who underwent elective ECV. The effective maintenance of SR was evaluated after 40 ± 10 days of ECV. Echocardiography, inflammatory markers (high-sensitivity c-reactive protein (hs-CRP), IL-6, and TNF-α), and natriuretic peptides (N-terminal pro b-type natriuretic peptide (NT-proBNP) and N-terminal pro a-type natriuretic peptide (NT-proANP)) were assessed. Results: After a 40 ± 10 days observation period, 51 patients (55.4%) were in SR. Patients with AF recurrence had a significantly longer duration of AF (p = 0.008) and of arterial hypertension (p = 0.035), lower LA ejection fraction (p = 0.009), lower LA strain (p < 0.0001), higher left ventricular global longitudinal strain (p = 0.001), and a higher E/e‘ ratio (p < 0.0001). LA strain was an independent predictor of early AF recurrence (OR: 0.65; 95% Cl 0.5−0.9, p = 0.004). LA strain < 11.85% predicted AF recurrence with 70% sensitivity and 88% specificity (AUC 0.855, 95% CI 0.77−0.94, p < 0.0001). LA strain demonstrated the association with NT-proBNP (r = −0.489, p < 0.0001) and NT-proANP (r = −0.378, p = 0.002), as well as with hs-CRP (r = −0.243, p = 0.04). Conclusions: LA strain appeared to be the most accurate predictor of early AF recurrence after ECV in patients with persistent AF. LA strain inversely correlated with NT-proBNP and NT-proANP, but no significant association with any of the inflammatory markers was identified.

The Role of the Left Atrium: From Multimodality Imaging to Clinical Practice: A Review

In recent years, new interest is growing in the left atrium (LA). LA functional analysis and measurement have an essential role in cardiac function evaluation. Left atrial size and function are key elements during the noninvasive analysis of diastolic function in several heart diseases. The LA represents a “neuroendocrine organ” with high sensitivity to the nervous, endocrine, and immune systems. New insights highlight the importance of left atrial structural, contractile, and/or electrophysiological changes, introducing the concept of “atrial cardiomyopathy”, which is closely linked to underlying heart disease, arrhythmias, and conditions such as aging. The diagnostic algorithm for atrial cardiomyopathy should follow a stepwise approach, combining risk factors, clinical characteristics, and imaging. Constant advances in imaging techniques offer superb opportunities for a comprehensive evaluation of LA function, underlying specific mechanisms, and patterns of progression. In this literature review, we aim to suggest a practical, stepwise algorithm with integrative multimodality imaging and a clinical approach for LA geometry and functional analysis. This integrates diastolic flow analysis with LA remodelling by the application of traditional and new diagnostic imaging techniques in several clinical settings such as heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), and mitral regurgitation (MR).

Low Left Atrial Appendage Emptying Velocity is a Predictor of Atrial Fibrillation Recurrence After Catheter Ablation

BACKGROUND

Recurrence of atrial fibrillation (AF) after catheter ablation (CA) remains common and studies have shown about 5%-9% annual recurrence rate after CA. We sought to assess the echocardiogram derived left atrial appendage (LAA) emptying velocity as a predictor of AF recurrence after CA.

OBJECTIVE

To determine if LAA emptying is a marker of recurrence of AF post-CA METHODS: A total of 303 consecutive patients who underwent CA for AF between 2014 and 2020 were included. Baseline clinical characteristics and echocardiographic data of the patients were obtained by chart review. LAA emptying velocities were obtained from TEE. LA voltage was obtained during the mapping for CA. Chi-square test and nominal logistic regression were used for statistical analysis. An ROC curve was used to determine LAA velocity cut-off.

RESULTS

Mean patient age was 61.7±10.5; 32% were female. Mean LAA emptying velocity was 47.5±20.2. A total of 103 (40%) patients had recurrence after CA. In the multivariable model, after adjusting for potential confounders, LAA emptying velocity of ≥52.3 was associated with decreased AF recurrence post-ablation (OR 0.55; 95% CI: 0.31-0.97; p = 0.03*). There were 190 (73%) patients in normal sinus rhythm during TEE and CA, and sensitivity analysis of these patients showed that LAA velocity ≥52.3 remained associated with decreased AF recurrence (OR 0.35; 95% CI 0.15-0.82; p = 0.01*).

CONCLUSION

LAA emptying velocity measured during pre-procedural TEE can serve as a predictor of AF recurrence in patients undergoing CA. This article is protected by copyright. All rights reserved.

MR-proANP measured at admission is associated with incident atrial fibrillation in STEMI patients

Atrial fibrillation (AF) is common following ST-segment elevation myocardial infarction (STEMI). Increased blood levels of mid regional pro atrial natriuretic peptide (MR-proANP) have been associated with a greater risk of incident AF. However, knowledge of the value of MR-proANP in predicting incident AF after STEMI is sparse. To assess whether MR-proANP measured at admission is associated with development of incident AF in patients with STEMI. 673 STEMI patients with no history of AF treated with primary percutaneous coronary intervention (pPCI) were prospectively enrolled from September 2006 to December 2008. Blood samples were drawn before the procedure. MR-proANP was measured by an automated processing assay. End point was incident AF. Median follow-up time was 5.5 years (interquartile-range 4.7-6.0), during which 63 patients developed AF. In a multivariable Cox regression model adjusted for relevant clinical and biochemical variables, MR-proANP was significantly associated with the development of AF (HR 1.18 per 100 pmol, 95% CI 1.11-1.28, p < 0.001). In a subgroup of patients who underwent echocardiography (N = 360), MR-proANP remained significantly associated with the development of AF (HR 1.39 per 100 pmol, 95% CI 1.13-1.71, p = 0.002) after adjusting for clinical and biochemical variables and left ventricular ejection fraction. When stratifying patients according to tertiles of MR-proANP, patients in the upper tertile displayed an 11 times greater risk of developing AF during follow-up as compared to patients in the lower tertile (HR 11.1, 95% CI 4.4-28.2, p < 0.001). Plasma MR-proANP measured at admission is an independent predictor of incident AF after STEMI.

The Correlation of Fibroblast Growth Factor 23 with Cardiac Remodeling in Essential Hypertension with Normal Renal Function

Background Fibroblast growth factor 23 (FGF23), a glycoprotein regulating calcium phosphorus homeostasis, has been linked to cardiovascular diseases. We aimed to evaluate the correlation of FGF23 levels and cardiac remodeling (left atrial [LA] enlargement and left ventricular hypertrophy [LVH]) in essential hypertension (EH) with normal renal function, and explore the diagnostic values of FGF23 and B-type natriuretic peptide (BNP) in cardiac remodeling. Methods and Results We enrolled 40 healthy control subjects (Group I) and 146 EH patients (Group II). Plasma FGF23 concentration was measured in all subjects. In this study, FGF23 level was significantly higher in Group II (660.77[446.26, 1001.72]) pg/mL compared with the controls (73.23[52.92, 103.69]) pg/mL (P<0.001). Logistic regression analysis revealed that FGF23 was independently correlated to LVH and LA enlargement. Receiver operating characteristic (ROC) curve indicated FGF23 had an optimal cutoff of 834.63 pg/mL for LVH (area under ROC curve [AUC], 0.913; 95%CI, 0.863-0.963), and 497.06 pg/mL for LA enlargement (AUC, 0.694; 95%CI, 0.612-0.768). The DeLong test was performed to compare AUCs of FGF23 and BNP, and the AUC of FGF23 (0.913) was statistically higher compared to AUC of BNP (0.661) (DeLong test: P < 0.001) in the diagnosis of LVH. Conclusion Plasma FGF23 level elevated in EH, increased with the progress of cardiac remodeling, and was independently related to LVH and LA enlargement. The diagnostic value of FGF23 in cardiac remodeling, especially for LVH, was superior to BNP.

Association of Female Menopause With Atrioventricular Mechanics and Outcomes

Background

Despite known sex differences in cardiac structure and function, little is known about how menopause and estrogen associate with atrioventricular mechanics and outcomes.

Objective

To study how, sex differences, loss of estrogen in menopause and duration of menopause, relate to atrioventricular mechanics and outcomes.

Methods

Among 4051 asymptomatic adults (49.8 ± 10.8 years, 35%women), left ventricular (LV) and left atrial (LA) mechanics were assessed using speckle-tracking.

Results

Post-menopausal (vs. pre-menopausal) women had similar LV ejection fraction but reduced GLS, reduced PALS, increased LA stiffness, higher LV sphericity and LV torsion (all p &lt; 0.001). Multivariable analysis showed menopause to be associated with greater LV sphericity (0.02, 95%CI 0.01, 0.03), higher indexed LV mass (LVMi), lower mitral e’, lower LV GLS (0.37, 95%CI 0.04–0.70), higher LV torsion, larger LA volume, worse PALS (∼2.4-fold) and greater LA stiffness (0.028, 95%CI 0.01–0.05). Increasing years of menopause was associated with further reduction in GLS, markedly worse LA mechanics despite greater LV sphericity and higher torsion. Lower estradiol levels correlated with more impaired LV diastolic function, impaired LV GLS, greater LA stiffness, and increased LV sphericity and LV torsion (all p &lt; 0.05). Approximately 5.5% (37/669) of post-menopausal women incident HF over 2.9 years of follow-up. Greater LV sphericity [adjusted hazard ratio (aHR) 1.04, 95%CI 1.00–1.07], impaired GLS (aHR 0.87, 95%CI 0.78–0.97), reduced peak left atrial longitudinal strain (PALS, aHR 0.94, 95%CI 0.90–0.99) and higher LA stiffness (aHR 10.5, 95%CI 1.69–64.6) were independently associated with the primary outcome of HF hospitalizations in post-menopause. Both PALS &lt; 23% (aHR:1.32, 95%CI 1.01–3.49) and GLS &lt; 16% (aHR:5.80, 95%CI 1.79–18.8) remained prognostic for the incidence of HF in post-menopausal women in dichotomous analyses, even after adjusting for confounders. Results were consistent with composite outcomes of HF hospitalizations and 1-year all-cause mortality as well.

Conclusion

Menopause was associated with greater LV/LA remodeling and reduced LV longitudinal and LA function in women. The cardiac functional deficit with menopause and lower estradiol levels, along with their independent prognostic value post-menopause, may elucidate sex differences in heart failure further.

Sacubitril/valsartan attenuates atrial structural remodelling in atrial fibrillation patients

Aims

Radiofrequency catheter ablation (RFCA) is now an established therapeutic option for patients with atrial fibrillation (AF), but the long‐term recurrence rate of AF is still high. Sacubitril/valsartan (Sac/Val) is superior to valsartan in attenuating ventricular remodelling and improving clinical outcomes in heart failure patients, but whether this additional benefit exists in reversing atrial remodelling and reducing AF recurrence of RFCA‐treated AF patients remains uncovered.

Methods and results

Patients that had undergone RFCA were enrolled and randomly assigned 1:1 to valsartan (160 mg/day) or Sac/Val (200 mg/day) treatment group, in addition to other standard treatment of AF. Patients were followed up for 24 weeks. Echocardiography and ambulatory Holter monitoring for 24 h was performed at 24 weeks after RFCA. The primary end point was the change of atrial diameter from baseline to 24 weeks after RFCA. Second end points included the recurrence rate of AF, all‐cause hospitalization and all‐cause death. A total of 64 AF patients were enrolled, 32 of which received Sac/Val and 32 received valsartan treatment. There was no difference in the age (64.8 ± 9.8 vs. 63.7 ± 9.0, P = 0.634), gender (per cent of male: 59.4% vs. 50.0%, P = 0.616), heart rate (84.7 ± 4.1 b.p.m. vs. 80.9 ± 2.6 b.p.m., P = 0.428), systolic (127.5 ± 15.4 mmHg vs. 130.0 ± 17.8 mmHg, P = 0.549) or diastolic (81.7 ± 9.8 mmHg vs. 79.9 ± 12.6, P = 0.537) blood pressure upon admission between valsartan and Sac/Val treatment groups. The percentage of persistent AF was also comparable (43.8% vs. 53.1%, P = 0.617) in both treatment groups. Patients receiving Sac/Val treatment displayed significant decrease in the left atrial diameter (4.3 ± 0.5 cm to 3.8 ± 0.5 cm, P < 0.001), volume index (48.0 ± 6.4 mL/m² to 41.7 ± 7.0 mL/m², P < 0.001), and right atrial diameter (4.4 ± 0.8 cm to 3.9 ± 0.7 cm, P = 0.017) from baseline to 24 weeks after RFCA. This effect was not observed in valsartan treatment group. There was a numerical decrease in AF recurrence rate in the Sac/Val group compared with valsartan group (9.4% vs. 15.6%), although this difference did not reach a statistical significance (P = 0.708). No difference in all‐cause hospitalization rate (6.3% in each group) or all‐cause death rate (0% in each group) was observed.

Conclusions

Our data indicate that Sac/Val is superior to valsartan in attenuating atrial structural remodelling in catheter ablation‐treated AF patients.

The Added Value of Atrial Strain Assessment in Clinical Practice

Speckle tracking echocardiography has emerged as a sensitive tool to analyze myocardial function with improved diagnostic accuracy and prognostic value. Left atrial strain assessment has become a novel imaging method in cardiology with superior prognostic value compared to conventional left atrial volume indices. Left atrial function is divided into three phases, reservoir function being the most important. This review summarizes the added value of speckle tracking echocardiography derived left atrial strain assessment in clinical practice. Recently published data suggest the prognostic value of left atrial reservoir function in heart failure, atrial fibrillation, stroke and valvular heart disease. Furthermore, left atrial reservoir strain proved to be a predictor of cardiovascular morbidity and mortality in the general population. Thus, routine assessment of left atrial function can be an optimal strategy to improve cardiovascular risk prediction and supplement the current risk prediction models.

Medical image analysis on left atrial LGE MRI for atrial fibrillation studies: A review

Late gadolinium enhancement magnetic resonance imaging (LGE MRI) is commonly used to visualize and quantify left atrial (LA) scars. The position and extent of LA scars provide important information on the pathophysiology and progression of atrial fibrillation (AF). Hence, LA LGE MRI computing and analysis are essential for computer-assisted diagnosis and treatment stratification of AF patients. Since manual delineations can be time-consuming and subject to intra- and inter-expert variability, automating this computing is highly desired, which nevertheless is still challenging and under-researched. This paper aims to provide a systematic review on computing methods for LA cavity, wall, scar, and ablation gap segmentation and quantification from LGE MRI, and the related literature for AF studies. Specifically, we first summarize AF-related imaging techniques, particularly LGE MRI. Then, we review the methodologies of the four computing tasks in detail and summarize the validation strategies applied in each task as well as state-of-the-art results on public datasets. Finally, the possible future developments are outlined, with a brief survey on the potential clinical applications of the aforementioned methods. The review indicates that the research into this topic is still in the early stages. Although several methods have been proposed, especially for the LA cavity segmentation, there is still a large scope for further algorithmic developments due to performance issues related to the high variability of enhancement appearance and differences in image acquisition.

Progression of Mitral Regurgitation in Rheumatic Valve Disease: Role of Left Atrial Remodeling

Introduction

Mitral regurgitation (MR) is the most common valve abnormality in rheumatic heart disease (RHD) often associated with stenosis. Although the mechanism by which MR develops in RHD is primary, longstanding volume overload with left atrial (LA) remodeling may trigger the development of secondary MR, which can impact on the overall progression of MR. This study is aimed to assess the incidence and predictors of MR progression in patients with RHD.

Methods

Consecutive RHD patients with non-severe MR associated with any degree of mitral stenosis were selected. The primary endpoint was a progression of MR, which was defined as an increase of one grade in MR severity from baseline to the last follow-up echocardiogram. The risk of MR progression was estimated accounting for competing risks.

Results

The study included 539 patients, age of 46.2 ± 12 years and 83% were women. At a mean follow-up time of 4.2 years (interquartile range [IQR]: 1.2–6.9 years), 54 patients (10%) displayed MR progression with an overall incidence of 2.4 per 100 patient-years. Predictors of MR progression by the Cox model were age (adjusted hazard ratio [HR] 1.541, 95% CI 1.222–1.944), and LA volume (HR 1.137, 95% CI 1.054–1.226). By considering competing risk analysis, the direction of the association was similar for the rate (Cox model) and incidence (Fine-Gray model) of MR progression. In the model with LA volume, atrial fibrillation (AF) was no longer a predictor of MR progression. In the subgroup of patients in sinus rhythm, 59 had an onset of AF during follow-up, which was associated with progression of MR (HR 2.682; 95% CI 1.133–6.350).

Conclusions

In RHD patients with a full spectrum of MR severity, progression of MR occurs over time is predicted by age and LA volume. LA enlargement may play a role in the link between primary MR and secondary MR in patients with RHD.

Biomarkers associated with rhythm status after cardioversion in patients with atrial fibrillation

Biomarkers may help to improve our knowledge about the complex pathophysiology of atrial fibrillation (AF). In this study we sought to identify significant changes in biomarkers and clinical measures in patients with and without AF recurrence after electrical cardioversion. We measured 21 conventional and new biomarkers before and 30 days after electrical cardioversion and assessed the associations of changes in biomarker levels with rhythm status at follow-up. Significant between-group changes were observed for bone morphogenetic protein 10 (BMP10), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and total bilirubin. Their respective changes were − 10.4%, − 62.0% and − 25.6% in patients with sinus rhythm, and 3.1%, 1.1% and − 9.4% in patients with recurrent AF, for a between-group difference of − 13.5% (95% confidence interval [CI] − 19.3% to − 7.6%; P < 0.001), − 63.1% (95% CI − 76.6% to − 49.6%; P < 0.001) and − 16.3% (95% CI − 27.9% to − 4.7%; P = 0.007). In multivariable models, the reductions of BMP10 and NT-proBNP were significantly associated with follow-up rhythm status (β coefficient per 1 − SD decrease, − 3.85; 95% CI − 6.34 to − 1.35; P = 0.003 for BMP10 and − 5.84; 95% CI − 10.22 to − 1.47; P = 0.009 for NT-proBNP. In conclusion, changes in BMP10 und NT-proBNP levels were independently associated with rhythm status after cardioversion, suggesting that these markers may be dependent on the actual heart rhythm.

Obesity in Older Adults and Associations with Cardiovascular Structure and Function

INTRODUCTION

Body mass index (BMI), despite being widely used as a marker of obesity, fails to fully capture cardiovascular risks as it is an insufficient biomarker of abdominal adiposity, unlike waist circumference (WC). We aimed to characterize associations between BMI and WC with cardiovascular structure and function in older adults.

METHODS

Among an observational cohort study of a community of older adults, transthoracic echocardiography determined cardiovascular structure and function, while aerobic capacity was determined by peak oxygen uptake (VO2) metrics. The cut-offs for obesity were 27.5 kg/m2 for BMI, and >90 cm for males and >80 cm for females for WC.

RESULTS

Of 970 older adults without cardiovascular disease (mean age 73 ± 4 years, 432 [44%] males), 124 (12.8%) were obese by BMI definition while 347 (35.7%) were obese by WC definition. Inter-definitional agreement was fair (Cohen's κ = 0.345). Unlike the BMI definition, participants defined as obese by WC were more likely to be women (65% vs. 50%, p < 0.001), older (65 ± 11 vs. 63 ± 14 years, p = 0.007), and had lower handgrip strength (24 ± 0.6 vs. 26 ± 0.4 kg, p = 0.022). Across BMI categories, high WC was associated with more impaired myocardial relaxation (E/A), and VO2 measurements (all p < 0.05). Among those with low BMI, high WC was associated with larger left atrial (LA) volumes (p = 0.003). WC, but not BMI, was independently associated with E/A (β = -0.114, SE -0.114 ± 0.024, p < 0.001) in regression analysis.

CONCLUSION

WC identified a higher prevalence of obesity, possibly related to central adiposity. Across BMI categories, WC identified more adverse measurements in E/A, aerobic capacity, and LA structure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02791139.

The Role of the Left Atrial Strain Parameters on Grading of Aortic Regurgitation

Background:

Grading the severity of aortic regurgitation (AR) is very important for clinical follow-up. In AR, left atrial (LA) mechanics can be affected in time and LA strain variations can be illuminating for the grading of AR. The purpose of this study is to determine whether the LA strain parameters are associated with the severity of AR or not.

Methodology:

Sixty-four consecutive patients with AR were included in this study. Patients divided into three groups as mild (n: 22), moderate (n: 15), or severe (n: 27). All patients' LA strain measurements were performed and results were compared between groups.

Results:

Between the groups, LA reservoir (LA-Res) in the mild, moderate, and severe AR groups was 42.0 ± 18.0, 41.4 ± 14.8, and 29.2 ± 6.0, respectively (P: 0.002) and LA pump in the mild, moderate, and severe AR groups was 21.2 ± 8.7, 19.3 ± 7.4, and 13.1 ± 4.4, respectively (P < 0.001), different, while no difference was noticed on LA SRs, LA SRe, and LA SRa.

Conclusion:

This study showed that LA-Res and LA pump parameters of the patients with severe AR significantly decreased compared to those of the mild and moderate AR group. The grading of the LA mechanics in patients with chronic AR might provide a supplementary contribution to the present parameters in the grading of AR.

Left atrial structural and mechanical remodelling in heart failure with reduced ejection fraction

Aims

In patients with heart failure with reduced ejection fraction (HFrEF), an association between left atrial (LA) dilatation and dysfunction is expected, but the degree of coexistence of the two abnormalities and their relative prognostic role is not known.

Methods and results

A total of 626 HFrEF patients formed the study population. All of them underwent a comprehensive echocardiographic evaluation. LA maximal volume was indexed to body surface area (LAVi); LA function was assessed using strain analysis during the reservoir phase: peak atrial longitudinal strain (PALS) analysis. Study primary endpoint was overall mortality or hospitalization for worsening heart failure. Four groups of patients were included in this study according to LAVi (≤34 or >34 mL/m²) and PALS (≤23% or >23%); 61 (10%) patients had normal LA volume and function (Group 1), 58 (9%) had LA dilatation but normal function (Group 2), 100 (16%) had normal volume but abnormal function (Group 3), and 407 (65%) had enlarged left atrium and abnormal function (Group 4). PALS was associated with primary endpoint in patients with both normal‐size [Groups 1 and 3: hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.88–0.96; P = 0.0006] and dilated left atria (Groups 2 and 4: HR 0.93, 95% CI 0.91–0.96; P < 0.0001). In contrast, LAVi was associated with the primary endpoint in patients with abnormal LA function (Groups 3 and 4: HR 1.018, 95% CI 1.011–1.024; P < 0.00001) but not in those with normal PALS (Groups 1 and 2: HR 1.023, 95% CI 0.99–1.057; P = 0.1).

Conclusions

Left atrial dilatation and dysfunction frequently but not invariably coexist. PALS emerged as a significant prognostic parameter in HFrEF even in the absence of LA dilation.

Association Between Apelin and Atrial Fibrillation in Patients With High Risk of Ischemic Stroke

Background: Atrial fibrillation (AF) is associated with high risk of stroke preventable by timely initiation of anticoagulation. Currently available screening tools based on ECG are not optimal due to inconvenience and high costs. Aim of this study was to study the diagnostic value of apelin for AF in patients with high risk of stroke.

Methods: We designed a multicenter, matched-cohort study. The population consisted of three study groups: a healthy control group (34 patients) and two matched groups of 60 patients with high risk of stroke (AF and non-AF group). Apelin levels were examined from peripheral blood.

Results: Apelin was significantly lower in AF group compared to non-AF group (0.694 ± 0.148 vs. 0.975 ± 0.458 ng/ml, p = 0.001) and control group (0.982 ± 0.060 ng/ml, p < 0.001), respectively. Receiver operating characteristic (ROC) analysis of apelin as a predictor of AF scored area under the curve (AUC) of 0.658. Apelin's concentration of 0.969 [ng/ml] had sensitivity = 0.966 and specificity = 0.467. Logistic regression based on manual feature selection showed that only apelin and NT-proBNP were independent predictors of AF. Logistic regression based on selection from bivariate analysis showed that only apelin was an independent predictor of AF. A logistic regression model using repeated stratified K-Fold cross-validation strategy scored an AUC of 0.725 ± 0.131.

Conclusions: Our results suggest that apelin might be used to rule out AF in patients with high risk of stroke.

Left atrial strain predicts incident atrial fibrillation in the general population: the Copenhagen City Heart Study

BACKGROUND

Left atrial (LA) strain parameters have been demonstrated to be valuable predictors of atrial fibrillation (AF) in several patient cohorts. The purpose of this study was to investigate whether LA strain, assessed by two-dimensional speckle-tracking echocardiography, can be used to predict the development of AF in the general population.

METHODS AND RESULTS

This prospective longitudinal study included 4466 participants from the fifth Copenhagen City Heart Study. All participants underwent a health examination, including echocardiographic measurements of LA strain. Participants with prevalent AF at baseline were excluded. The primary endpoint was incident AF. During a median follow-up period of 5.3 years, 154 (4.3%) participants developed AF. In univariable analysis, peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA strain during the conduit phase were significantly associated with the development of AF. PALS [hazard ratio (HR) 1.05, 95% confidence interval (CI) (1.03-1.07), P < 0.001, per 1% decrease] and PACS (HR 1.08, 95% CI (1.05-1.12), P < 0.001, per 1% decrease] remained independent predictors of AF in multivariable analysis. In addition, PALS and PACS remained significantly associated with AF development even in participants with normal-sized atria and normal left ventricular (LV) systolic function.

CONCLUSION

In the general population, PALS and PACS independently predict incident AF. These findings remained consistent even in participants with normal-sized LA and normal LV systolic function.

The role of brain natriuretic peptide in atrial fibrillation: a substudy of the Substrate Modification with Aggressive Blood Pressure Control for Atrial Fibrillation (SMAC-AF) trial

BACKGROUND

Catheter ablation is an established therapy for atrial fibrillation but is limited by recurrence; efforts have been made to identify biomarkers that predict recurrence. We investigated the effect of baseline NT-proBNP on AF recurrence following catheter ablation in patients randomized to aggressive (< 120/80 mmHg) or standard blood pressure management (< 140/90 mmHg) in the Substrate Modification with Aggressive Blood Pressure Control trial (SMAC-AF).

METHODS

The SMAC-AF study included 173 patients resistant or intolerant to at least one class I or III antiarrhythmic drug. We studied the effect of baseline NT-proBNP on the primary outcome of AF recurrence > 3 months post-ablation.

RESULTS

Of the 173 patients, 88 were randomized to the aggressive cohort, and 85 into the standard group. The primary outcome occurred in 61.4% of those in the aggressive arm, versus 61.2% in the standard arm. In the aggressive group, logNT-proBNP predicted recurrence (HR 1.28, p = 0.04, adjusted HR 1.43, p = 0.03), while in the standard cohort, it did not (HR 0.94, p = 0.62, adjusted HR 0.83, p = 0.22). NT-proBNP ≥ 280 pg/mL also predicted occurrence in the aggressive (HR 1.98, p = 0.02) but not the standard cohort (HR 1.00, p = 1.00).

CONCLUSION

We conclude that pre-ablation NT-proBNP may be useful in predicting recurrence in hypertensive patients and identifying patients who benefit from aggressive blood control and upstream therapies.

TRIAL REGISTRATION

NCT00438113, registered February 21, 2007.

The Central Role of Left Atrium in Heart Failure

In past cardiovascular medicine, the attention to the left ventricle-identified as the only indicator and determinant of healthy or unhealthy cardiac conditions- has systematically hidden the role of the left atrium (LA). The recent advances in cardiovascular imaging have provided a better understanding of LA anatomy, physiology, and pathology, making us realize that this functional structure is far from being an innocent spectator. We now know that the LA's mechanical and neuro-hormonal properties play a relevant part in several cardiovascular diseases, including atrial fibrillation, ischemic heart disease, valvular heart disease, and heart failure. The present review aims to describe the role of LA in the specific setting of heart failure. We provide currently available information on LA structure and function and summarize its role as a determinant of symptoms, prognosis, and potential therapeutic target in heart failure patients.

Electrocardiographic predictors of early recurrence of atrial fibrillation

BACKGROUND

Electrical cardioversion (ECV) is an effective method for restoring sinus rhythm after atrial fibrillation (AF). However, early recurrence of AF occurs in a significant number of patients after ECV. This study aimed to identify electrocardiographic (ECG) predictors of early AF recurrence after ECV.

METHODS

A total of 272 patients with persistent AF undergoing successful ECV were consecutively enrolled in this study. We investigated clinical, echocardiographic, and ECG data. The 12-lead ECG parameters were measured during sinus rhythm right after ECV using a digital caliper. The early AF recurrence was defined as recurrence within 2 months.

RESULTS

Of the 272 patients, 165 patients (60.7%) experienced an early AF recurrence. Maximum P-wave duration (PWD) in limb leads (OR: 1.086; 95% CI: 1.019-1.157; p = .012) and P-terminal force (PTF) in V₁ (OR: 1.019; 95% CI: 1.004-1.033; p = .011) were independent predictors of early AF recurrence after ECV. The optimal cutoff value of the maximum PWD in limb leads for predicting early AF recurrence was 134 ms, characterized by 90.3% sensitivity and 72.0% specificity. Likewise, the optimal cutoff value of PTF in V₁ was 50 ms × mm, characterized by 80.0% sensitivity and 64.5% specificity.

CONCLUSION

A longer PWD (>134 ms) and a larger PTF (>50 ms × mm) were useful predictors of early recurrence of AF after successful ECV in clinical practice. A more effective rhythm control therapy such as catheter ablation or rate control strategy rather than a repeat ECV should be considered.