Atrial Fibrillation–Mediated Cardiomyopathy

Heart rate variability in patients with atrial fibrillation of sinus rhythm or atrial fibrillation: chaos or merit?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia characterized by consistently irregular atrial and ventricular contractions. Heart rate variability (HRV) refers to the changes in the intervals between consecutive ventricular heartbeats. In sinus rhythm, HRV may be subtle and is quantitatively reflecting the dynamic interplay of the cardiac autonomic nervous system, which plays a crucial role in the onset, development, and maintenance of AF. HRV metrics, consisting of time-domain, frequency-domain, and nonlinear parameters, have been verified to vary significantly before and after AF episodes, and AF treatment-related procedures such as electrical cardioversion, ablation, and surgery of AF. Therefore, HRV may serve as a digital biomarker in predicting AF risk in long-term and acute risk period, identification of patients with AF risk in sinus rhythm and recurrence risk stratification after procedures. HRV in AF rhythm, predominantly influenced by dynamic atrioventricular node conduction under the onslaught of irregular atrial impulses, shows a huge disparity compared to that in sinus rhythm. Despite this, HRV in AF rhythm still provides valuable prognostic information, as reduced HRV may indicate a poor heart function and outcomes in patients with AF. Despite being influenced by lots of variables, HRV can still serve as an independent digital biomarker in the clinical management of AF throughout its entire lifecycle.

Impact of catheter ablation on atrial fibrillation outcomes in various cardiomyopathies: findings from LGE-MRI quantified atrial fibrosis analysis

BACKGROUND

Cardiomyopathy (CM) is associated with atrial remodeling and atrial fibrillation (AF), often complicating rhythm management. Ventricular dysfunction contributes to AF through pressure and volume overload, while AF worsens ventricular function via tachycardia and irregular activation. Evidence suggests catheter ablation improves outcomes in CM patients, though success is influenced by the extent of atrial and ventricular remodeling.

METHODS

Patients undergoing their first catheter ablation for AF were divided into hypertrophic (HCM), ischemic (ICM), non-ischemic (NICM), and no-CM groups. Pre-ablation late-gadolinium enhancement cardiac magnetic imaging (LGE-MRI) was used to assess left atrial (LA) fibrosis burden and anatomical distribution. Patients were followed prospectively for arrhythmia recurrence.

RESULTS

A total of 552 patients, 39 HCM (69% obstructive), 39 ICM, 115 with NICM, and 359 without CM were included between January 2015 and December 2022. LA fibrosis was significantly higher in patients with CM (19.1 ± 7.5% vs. 16.5 ± 6.9%; P = 0.01). HCM and ICM had the greatest LA fibrosis among the different CM subtypes (21.3 ± 8.7% and 21.9 ± 9.1%, respectively). There was no significant difference in the regional distribution of fibrosis among the various groups. AF recurrence was observed in 321 (58.2%) after 456 (175-1204) days. Multivariate analysis revealed that compared to no CM, HCM was associated with a three-fold increase in AF recurrence (HR = 3.07, 95% CI 2.06-4.58, P < 0.001), followed by ICM (HR 1.61, 95%, CI 0.95-2.72; P = 0.07) and NICM (HR of 1.53, 95% CI 1.14-2.06; P = 0.05). LA fibrosis and volume index were independently associated with recurrence (HR = 1.03, 95% CI 1.01-1.06, P = 0.01 and HR = 1.02, 95% CI 1.01-1.03, P = 0.01). Genetic testing revealed key distinctions between HCM and NICM, with MYBPC3 and MYH7 as prominent genes in HCM and a heterogeneous genetic basis in NICM.

CONCLUSION

Hypertrophic cardiomyopathy is associated with the highest risk of AF recurrence followed by ischemic and non-ischemic cardiomyopathy after catheter ablation. LA fibrosis regional patterns did not differ between cardiomyopathy types, while overall fibrosis and volume predicted recurrence.

Gut microbiota and atrial cardiomyopathy

Atrial cardiomyopathy is a multifaceted heart disease characterized by structural and functional abnormalities of the atria and is closely associated with atrial fibrillation and its complications. Its etiology involves a number of factors, including genetic, infectious, immunologic, and metabolic factors. Recent research has highlighted the critical role of the gut microbiota in the pathogenesis of atrial cardiomyopathy, and this is consistent with the gut-heart axis having major implications for cardiac health. The aim of this work is to bridge the knowledge gap regarding the interactions between the gut microbiota and atrial cardiomyopathy, with a particular focus on elucidating the mechanisms by which gut dysbiosis may induce atrial remodeling and dysfunction. This article provides an overview of the role of the gut microbiota in the pathogenesis of atrial cardiomyopathy, including changes in the composition of the gut microbiota and the effects of its metabolites. We also discuss how diet and exercise affect atrial cardiomyopathy by influencing the gut microbiota, as well as possible future therapeutic approaches targeting the gut-heart axis. A healthy gut microbiota can prevent disease, but ecological dysbiosis can lead to a variety of symptoms, including the induction of heart disease. We focus on the pathophysiological aspects of atrial cardiomyopathy, the impact of gut microbiota dysbiosis on atrial structure and function, and therapeutic strategies exploring modulation of the microbiota for the treatment of atrial cardiomyopathy. Finally, we discuss the role of gut microbiota in the treatment of atrial cardiomyopathy, including fecal microbiota transplantation and oral probiotics or prebiotics. Our study highlights the importance of gut microbiota homeostasis for cardiovascular health and suggests that targeted interventions on the gut microbiota may pave the way for innovative preventive and therapeutic strategies targeting atrial cardiomyopathy.

Prognostic implications of system inflammation response index in atrial fibrillation patients with type 2 diabetes mellitus

Systemic inflammation plays a crucial role in the pathogenesis and prognosis of diabetes and cardiovascular diseases. System inflammation response index (SIRI), is an emerging biomarker designed to assess the extent of systemic inflammation. We aimed to delineate the prognostic significance of SIRI in patients with both AF and type 2 diabetes mellitus (T2DM). Utilizing the Medical Information Mart for Intensive Care IV (MIMIC-IV) (v2.2) repository, subjects divided into three groups based on the SIRI index. The primary endpoint of our study was all-cause mortality during hospitalization, with one-year mortality serving as the secondary endpoint. A cohort of 2054 AF and T2DM patients participated. COX regression analysis revealed elevated SIRI levels as an independent risk factor for both in-hospital and 1-year mortality. 192 patients died during hospitalization, and 265 died during the follow-up of 1 year. When treating the SIRI as a continuous variable, a higher SIRI was significantly associated with increased all-cause mortality both in-hospital [hazard ratio (HR) 1.015, 95%CI 1.010-1.020, P = 0.015] and 1-year (HR 1. 016, 95%CI 1.008-1.015, P = 0.012). Additionally, compared to patients with the lowest tertiles of SIRI, those with the highest tertiles of SIRI possessed significantly higher all-cause mortality both in-hospital and 1-year after multivariable adjustment, and this relationship remained pronounced in AF and T2DM patients [in-hospital mortality (HR: 1.863, 95% CI 1.189-2.918, P = 0.007); one-year mortality (HR: 2.143, 95% CI 1.621-2.831, P < 0.001)]. Our RCS analyses indicated a pronounced linear association between SIRI and mortality in T2DM (p-value for non-linear < 0.001). In AF patients with T2DM, high SIRI is an independent predictor of poor survival and may be helpful for patient's risk stratification.

Catheter ablation in rate-controlled atrial fibrillation with severely reduced ejection fraction: intervention for irregularity-mediated cardiomyopathy

BACKGROUND

Recent evidence suggests atrial fibrillation (AF) causes cardiomyopathy due to remodeling driven by both irregular rate and rhythm. Atrial fibrillation (AF) ablation in patients with reduced ejection fraction (EF) ≤ 35% has been shown to improve EF and mortality. It is unknown whether the benefits of AF ablation among patients with reduced EF are affected by the degree of pre-ablation rate control.

OBJECTIVES

To evaluate AF ablation echocardiographic outcomes for patients who have EF ≤ 35% with varying degrees of pre-ablation rate control.

METHODS

Single-center, retrospective study of patients with EF ≤ 35% undergoing first-time ablation of persistent AF. Primary analyses evaluated the degree to which pre-ablation rate control impacted echocardiographic outcomes. Rates of EF recovery to > 35% were compared at three different cutoffs: 110 bpm, 90 bpm, and 70 bpm. A linear regression analysis was then performed to evaluate whether baseline heart rate (HR) predicted change in EF.

RESULTS

Among 73 patients, the mean pre-ablation resting HR was 90 ± 25 bpm, and baseline EF was 27 ± 7%. Patients experienced significant improvements in EF by mean + 14% ± 11% (p < 0.001). Post-ablation EF recovery occurred in 60% of patients. No differences in EF improvement were detected at HR control targets of ≤ 110 bpm or ≤ 90 bpm, while patients achieving HR ≤ 70 bpm had less improvement in EF (+ 9% ± 9%) compared to those with HR above the cutoff (+ 16% ± 11%; p = 0.01). Linear regression analysis did not reveal baseline HR as a significant predictor of change in LVEF (slope = 0.09, r2 = 0.05, p = 0.07).

CONCLUSIONS

Catheter ablation of persistent AF in patients with reduced EF frequently resulted in recovery in EF > 35%, irrespective of pre-ablation achieved rate control. While patients with HR > 70 bpm experienced a greater improvement in EF compared to those ≤ 70 bpm, patients with baseline HR below this target still experienced significant EF improvements. Further investigation into irregularity-mediated cardiomyopathy is warranted.

Prediction of incident atrial fibrillation using deep learning, clinical models, and polygenic scores

BACKGROUND AND AIMS

Deep learning applied to electrocardiograms (ECG-AI) is an emerging approach for predicting atrial fibrillation or flutter (AF). This study introduces an ECG-AI model developed and tested at a tertiary cardiac centre, comparing its performance with clinical models and AF polygenic score (PGS).

METHODS

Electrocardiograms in sinus rhythm from the Montreal Heart Institute were analysed, excluding those from patients with pre-existing AF. The primary outcome was incident AF at 5 years. An ECG-AI model was developed by splitting patients into non-overlapping data sets: 70% for training, 10% for validation, and 20% for testing. The performance of ECG-AI, clinical models, and PGS was assessed in the test data set. The ECG-AI model was externally validated in the Medical Information Mart for Intensive Care-IV (MIMIC-IV) hospital data set.

RESULTS

A total of 669 782 ECGs from 145 323 patients were included. Mean age was 61 ± 15 years, and 58% were male. The primary outcome was observed in 15% of patients, and the ECG-AI model showed an area under the receiver operating characteristic (AUC-ROC) curve of .78. In time-to-event analysis including the first ECG, ECG-AI inference of high risk identified 26% of the population with a 4.3-fold increased risk of incident AF (95% confidence interval: 4.02-4.57). In a subgroup analysis of 2301 patients, ECG-AI outperformed CHARGE-AF (AUC-ROC = .62) and PGS (AUC-ROC = .59). Adding PGS and CHARGE-AF to ECG-AI improved goodness of fit (likelihood ratio test P < .001), with minimal changes to the AUC-ROC (.76-.77). In the external validation cohort (mean age 59 ± 18 years, 47% male, median follow-up 1.1 year), ECG-AI model performance remained consistent (AUC-ROC = .77).

CONCLUSIONS

ECG-AI provides an accurate tool to predict new-onset AF in a tertiary cardiac centre, surpassing clinical and PGS.

Exploring the role of exosomes in the pathogenesis and treatment of cardiomyopathies: A comprehensive literature review

Exosomes, a subset of small extracellular vesicles that play a crucial role in intercellular communication, have garnered significant attention for their potential applications in the diagnosis and treatment of cardiomyopathies. Cardiomyopathies, which encompass a spectrum of heart muscle disorders, present complex challenges in diagnosis and management. Understanding the role of exosomes in the etiology of cardiomyopathies such as dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RCM), arrhythmogenic cardiomyopathy (AC), and hypertrophic cardiomyopathy (HCM) may open new possibilities for therapeutic intervention and diagnosis. Exosomes have indeed demonstrated promise as diagnostic biomarkers, particularly in identifying cardiac conditions such as atrial fibrillation (AF) and in the timely classification of high-risk patients with different forms of cardiomyopathy. In DCM, exosomes have been implicated in mediating pathological responses in cardiomyocytes, potentially exacerbating disease progression. Moreover, in RCM, AC, and HCM, exosomes present significant potential as diagnostic biomarkers and therapeutic targets, offering insights into disease pathogenesis and potential avenues for intervention. Understanding the influence of exosomes on disease progression and identifying the specific molecular pathways involved in cardiomyopathy pathogenesis may significantly advance diagnostic and treatment strategies. While key findings highlight the multifaceted role of exosomes in cardiomyopathy, they also emphasize the need for further research to elucidate molecular mechanisms and translate findings into clinical practice. This review highlights the evolving landscape of exosome research in cardiomyopathies and underscores the importance of ongoing investigations to harness the full potential of exosomes in improving patient outcomes.

Characteristics, Predictors, and Clinical Outcomes in Heart Failure With Reduced Ejection Fraction According to a 1-Year Left Ventricular Ejection Fraction Following Sacubitril/Valsartan Treatment

BACKGROUND

Optimal medical treatment can lead to improvement in left ventricular ejection fraction (LVEF) in patients with heart failure with reduced EF (HFrEF). We investigated the characteristics, predictors, and outcomes of HFrEF according to the 1-year LVEF following angiotensin receptor-neprilysin inhibitors therapy (ARNI).

METHODS AND RESULTS

Using the STRATS-HF-ARNI (Strain for Risk Assessment and Therapeutic Strategies in Patients With Heart Failure Treated With Angiotensin Receptor-Neprilysin Inhibitor) registry, we identified 1074 patients with HFrEF who took ARNI and underwent baseline and 1-year echocardiography. Patients were classified as HF with improved ejection fraction (HFimpEF) and persistent HFrEF (perHFrEF) (1-year LVEF >40% and ≤40%). The primary and secondary outcomes were all-cause and cardiac mortality from the 1-year follow-up. Among 1074 included patients, 498 (46.4%) had HFimpEF, and 576 (53.6%) had perHFrEF. Older age, male sex, and large LV end-diastolic volumes were positive predictors of perHFrEF, whereas atrial fibrillation and high systolic blood pressure were identified as inverse predictors. Patients with HFimpEF showed lower all-cause and cardiac mortality rates (both log-rank P<0.001). In the multivariable analysis, perHFrEF (hazard ratio, 2.402 [95% CI, 1.251-4.610]; P=0.008) was an independent predictor of poor outcomes. The risk of all-cause mortality decreased as the 1-year LVEF increased up to 40%; however, no additional risk reduction was observed beyond 40%. Compared with patients taking renin-angiotensin-aldosterone system inhibitors in the STRATS-AHF (Strain for Risk Assessment and Therapeutic Strategies in Patients With Acute Heart Failure) registry, those in the STRATS-HF-ARNI registry demonstrated better outcomes in both HFimpEF and perHFrEF.

CONCLUSIONS

Patients with HFimpEF had better prognosis than those with perHFrEF, and ARNI treatment in HFrEF could be more beneficial than renin-angiotensin-aldosterone system inhibitors for both HFimpEF and perHFrEF.

REGISTRATION

URL: https://www.who.int/clinical-trials-registry-platform; Unique identifier: KCT0008098.

The Impact of Frailty on Patients With AF and HFrEF Undergoing Catheter Ablation: A Nationwide Population Study

Background

Frailty is a common geriatric syndrome often coexisting with cardiovascular diseases such as atrial fibrillation (AF) and heart failure (HF) with reduced ejection fraction (HFrEF). While catheter ablation (CA) has demonstrated efficacy in reducing major adverse cardiovascular events and improving mortality and quality of life, the influence of frailty among this population remains unknown.

Objectives

The authors aimed to identify the prevalence of frailty among patients with HFrEF and AF undergoing CA and its influence on cardiovascular mortality and discharge disposition.

Methods

From January 2016 to December 2019, we used the Nationwide Inpatient Sample to identify patients with AF and HFrEF. Frailty was identified by the presence of ≥1 diagnostic cluster utilizing the Johns Hopkins Adjusted Clinical Groups with malnutrition, dementia, impaired vision, decubitus ulcer, urinary incontinence, loss of weight, poverty, barriers to access to care, difficulty walking, and falls as indicators. We compared clinical outcomes among frail vs nonfrail patients, including all-cause in-hospital mortality, major adverse cardiovascular events, other major complications, discharge disposition, and hospital length of stay using multivariable regression analysis.

Results

Of 113,115 weighted admissions, 11,725 (10.4%) were classified as frail. Frail patients were older (median age: 76 [IQR: 15] years vs 70 [IQR: 15] years, P < 0.001) than nonfrail patients. Frailty was associated with increased odds of all-cause hospital mortality (adjusted odds ratio [aOR]: 2.64; 95% CI: 1.87-3.72; P < 0.001), major adverse cardiovascular events (aOR: 2.00; 95% CI: 1.62-2.47; P < 0.001), and nonhome discharge (aOR: 3.31; 95% CI: 2.78-3.94; P < 0.001). Frail patients also experienced longer hospital length of stay (median 9 [IQR: 10] days vs 5 [IQR: 5] days, P < 0.001) after adjustment by Poisson regression (coefficient: 0.53; 95% CI: 0.46-0.59; P < 0.001).

Conclusions

Frailty is associated with worse outcomes in patients with HFrEF undergoing CA for AF. The integration of frailty models in clinical practice may facilitate prognostication and risk stratification to optimize patient selection for CA.

Genetic testing in early-onset atrial fibrillation

Atrial fibrillation (AF) is a globally prevalent cardiac arrhythmia with significant genetic underpinnings, as highlighted by recent large-scale genetic studies. A prominent clinical and genetic overlap exists between AF, heritable ventricular cardiomyopathies, and arrhythmia syndromes, underlining the potential of AF as an early indicator of severe ventricular disease in younger individuals. Indeed, several recent studies have demonstrated meaningful yields of rare pathogenic variants among early-onset AF patients (∼4%-11%), most notably for cardiomyopathy genes in which rare variants are considered clinically actionable. Genetic testing thus presents a promising opportunity to identify monogenetic defects linked to AF and inherited cardiac conditions, such as cardiomyopathy, and may contribute to prognosis and management in early-onset AF patients. A first step towards recognizing this monogenic contribution was taken with the Class IIb recommendation for genetic testing in AF patients aged 45 years or younger by the 2023 American College of Cardiology/American Heart Association guidelines for AF. By identifying pathogenic genetic variants known to underlie inherited cardiomyopathies and arrhythmia syndromes, a personalized care pathway can be developed, encompassing more tailored screening, cascade testing, and potentially genotype-informed prognosis and preventive measures. However, this can only be ensured by frameworks that are developed and supported by all stakeholders. Ambiguity in test results such as variants of uncertain significance remain a major challenge and as many as ∼60% of people with early-onset AF might carry such variants. Patient education (including pretest counselling), training of genetic teams, selection of high-confidence genes, and careful reporting are strategies to mitigate this. Further challenges to implementation include financial barriers, insurability issues, workforce limitations, and the need for standardized definitions in a fast-moving field. Moreover, the prevailing genetic evidence largely rests on European descent populations, underscoring the need for diverse research cohorts and international collaboration. Embracing these challenges and the potential of genetic testing may improve AF care. However, further research-mechanistic, translational, and clinical-is urgently needed.

Innovative approaches to atrial fibrillation prediction: should polygenic scores and machine learning be implemented in clinical practice?

Atrial fibrillation (AF) prediction and screening are of important clinical interest because of the potential to prevent serious adverse events. Devices capable of detecting short episodes of arrhythmia are now widely available. Although it has recently been suggested that some high-risk patients with AF detected on implantable devices may benefit from anticoagulation, long-term management remains challenging in lower-risk patients and in those with AF detected on monitors or wearable devices as the development of clinically meaningful arrhythmia burden in this group remains unknown. Identification and prediction of clinically relevant AF is therefore of unprecedented importance to the cardiologic community. Family history and underlying genetic markers are important risk factors for AF. Recent studies suggest a good predictive ability of polygenic risk scores, with a possible additive value to clinical AF prediction scores. Artificial intelligence, enabled by the exponentially increasing computing power and digital data sets, has gained traction in the past decade and is of increasing interest in AF prediction using a single or multiple lead sinus rhythm electrocardiogram. Integrating these novel approaches could help predict AF substrate severity, thereby potentially improving the effectiveness of AF screening and personalizing the management of patients presenting with conditions such as embolic stroke of undetermined source or subclinical AF. This review presents current evidence surrounding deep learning and polygenic risk scores in the prediction of incident AF and provides a futuristic outlook on possible ways of implementing these modalities into clinical practice, while considering current limitations and required areas of improvement.

Antiarrhythmic drug therapy and catheter ablation in patients with paroxysmal or persistent atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

Catheter ablation and antiarrhythmic drug therapy are utilized for rhythm control in atrial fibrillation (AF), but their comparative effectiveness, especially with contemporary treatment modalities, remains undefined. We conducted a systematic review and meta-analysis contrasting current ablation techniques against antiarrhythmic medications for AF.

METHODS

We searched PubMed, SCOPUS, Cochrane CENTRAL, and Web of Science until November 2023 for randomized trials comparing AF catheter ablation with antiarrhythmics, against antiarrhythmic drug therapy alone, reporting outcomes for > 6 months. Four investigators extracted data and appraised risk of bias (ROB) with ROB 2 tool. Meta-analyses estimated pooled efficacy and safety outcomes using R software.

RESULTS

Twelve trials (n = 3977) met the inclusion criteria. Catheter ablation was associated with lower AF recurrence (relative risk (RR) = 0.44, 95%CI (0.33, 0.59), P ˂ 0.0001) and hospitalizations (RR = 0.44, 95%CI (0.23, 0.82), P = 0.009) than antiarrhythmic medications. Catheter ablation also improved the physical quality of life component score (assessed by a 36-item Short Form survey) by 7.61 points (95%CI -0.70-15.92, P = 0.07); but, due to high heterogeneity, it was not statistically significant. Ablation was significantly associated with higher procedural-related complications [RR = 15.70, 95%CI (4.53, 54.38), P < 0.0001] and cardiac tamponade [RR = 9.22, 95%CI (2.16, 39.40), P = 0.0027]. All-cause mortality was similar between the two groups.

CONCLUSIONS

For symptomatic AF, upfront catheter ablation reduces arrhythmia and hospitalizations better than continued medical therapy alone, albeit with moderately more adverse events. Careful patient selection and risk-benefit assessment are warranted regarding the timing of ablation.

Arrhythmia-Induced Cardiomyopathy: JACC State-of-the-Art Review

Arrhythmias frequently accompany heart failure and left ventricular dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions can induce a reversible form of dilated cardiomyopathy (CM) known as arrhythmia-induced CM (AiCM). The intriguing question is why certain individuals are more susceptible to AiCM, despite similar arrhythmia burdens. The primary challenge is determining the extent of arrhythmias' contribution to left ventricular systolic dysfunction. AiCM should be considered in patients with a mean heart rate of >100 beats/min, atrial fibrillation, or a PVC burden of >10%. Confirmation of AiCM occurs when CM reverses upon eliminating the responsible arrhythmia. Therapy choice depends on the specific arrhythmia, patient comorbidities, and preferences. After left ventricular function is restored, ongoing follow-up is essential if an abnormal myocardial substrate persists. Accurate diagnosis and treatment of AiCM have the potential to enhance patients' quality of life, improve clinical outcomes, and reduce hospital admissions and overall health care costs.

Premature Ventricular Contraction-Induced Cardiomyopathy: Contemporary Evidence from Risk Stratification, Pathophysiology, and Management

Premature ventricular complexes (PVCs) are commonly encountered problems in clinical settings. The range of symptoms can be from asymptomatic to palpitations, fatigue, or heart failure symptoms. A higher burden of PVCs is a risk factor for development of PVC-induced cardiomyopathy (PIC). Rhythm evaluation by 12-lead ECG and an ambulatory monitoring device are essential. Currently, several imaging modalities, such as echocardiography and cardiac magnetic resonance imaging, are utilized to evaluate the underlying structure that may be related to PIC. Beta blockers and antiarrhythmic drugs are typically part of the initial management strategy. If these fail, catheter ablation of PVCs is typically the next step. The purpose of this article is to summarize the current evidence/knowledge about PIC.

Determining The Risk of Atrial Fibrillation Paroxysm in Patients With Chronic Heart Failure With Intact and Reduced Ejection Fraction

AIM

To determine predictors for the development of atrial fibrillation (AF) in patients with chronic heart failure (CHF) with preserved and reduced ejection fraction by echocardiography (EchoCG) according to an extended protocol with determination of diastolic function and left atrial global strain.

MATERIAL AND METHODS

Data of 168 patients with stage I-III CHF without a history of AF were analyzed. All patients underwent echocardiography according to an extended protocol with the determination of diastolic dysfunction (DD), left atrial ejection fraction (LA EF), and left atrial global strain (LA GS). Tissue Doppler imaging (TDI) was used to evaluate the early (E) and late (A) LV filling velocity and the early (E') and late (A') diastolic mitral annular velocity. In all patients, Holter ECG monitoring (HM ECG) of heart rhythm was performed for 3 days, and ECG monitoring with telemedicine technologies was performed for 7 days, 3 times a day for 3 minutes. The follow-up period was 3 months or until an AF episode.

RESULTS

During the study, paroxysmal AF (pAF) was detected in 41 (24.4%) patients using various methods of heart rhythm monitoring. Complaints of palpitations were noted for 10 (24.4%) patients during pAF, which was recorded using a CardioQVARK® device, HM ECG or a 12-lead ECG. In 5 (12.2%) patients, daily ECG monitoring revealed pAF without associated complaints. HM ECG detected 8, 2, 4 (19.5%, 4.8%, and 9.7%) cases during 24, 48 and 72 hours, respectively; a single-channel CardioQVARK® detected 30 (73.2%) cases when used 3 times a day for 7 days. These results showed that AF frequently develops in CHF without accompanying symptoms. The method for detecting pAF with CardioQVARK® showed good results: it was twice more effective than HM ECG and three times more effective than 12-lead ECG. Also, according to ultrasound data, significant changes in the following parameters were noted in patients with AF: LA EF <36% (OR 1.04, 95% CI: 1.02-1.08), p=0.003; LA GS <9.9% (OR 1.16, 95% CI: 1.02-1.38), p<0.001; TDI E med <5.7 cm/s (OR 0.97, 95% CI: 0.94-1.00), p=0.026. Grade 2 DD did not show statistically significant results (OR 1.1, 95% CI: 0.7-1.5, p=0.54). However, it was detected more frequently in patients with AF, in 34% of cases, compared to 29% of cases in patients without AF, which requires further study on a larger patient sample.

CONCLUSION

Patients with CHF have a high risk of developing pAF (24.4%). 75% of patients with AF do not feel the development of paroxysm. All CHF patients should undergo EchoCG with assessment of LA EF, TDI E med and LA GS to identify a group at risk for the development of AF. Heart rhythm remote monitoring with CardioQVARK® devices can be considered a reliable method for early detection of pAF and timely initiation of anticoagulant therapy in patients with CHF.

Ablation versus medical therapy for patients with atrial fibrillation: An updated meta-analysis

To investigate the effect of ablation compared to medical therapy on clinical outcomes of patients with atrial fibrillation (AF). PubMed, Scopus, Embase, and Web of Science databases were searched using ablation, medical treatment, AF, and related words. The effect of ablation and medical therapy was sought to be gathered on stroke or transitional ischemic attack, mortality, hospitalization, recurrence of AF, progression of AF, and left ventricular ejection fraction. Analyses were performed using R software. 31 studies (the results of 27 randomized controlled trials), compromising an overall 6965 patients (Ablation, n = 3643; Medical treatment, n = 3322) were reviewed in our study, revealed that catheter ablation would result in substantial benefits for patients with AF without significant difference in serious adverse events compared to medical management (Risk Ratio: 0.92, [95% Confidence Interval (CI), 0.64-1.33]). Catheter ablation in patients with AF significantly resulted in a 29% reduction in all-cause mortality (RR: 0.71, [95% CI, 0.57-0.88]), a 57% reduction in hospitalization (RR: 0.43, [95% CI, 0.27-0.67]), a 53% reduction in AF recurrence (RR: 0.47, [95% CI, 0.36-0.61]), and a dramatic reduction, 89%, in progression of paroxysmal to persistent AF (RR: 0.11, [95% CI, 0.02-0.65]); also associated with a remarkable improvement in their left ventricular ejection fraction (LVEF) (Mean Difference, MD: 6.84%, [95% CI, 3.27-10.42]) compared to medical therapy. Our study showed that ablation may be superior to medical therapy in patients with AF regarding AF recurrence, mortality, LVEF improvement, hospitalization, and AF progression outcomes.

Myosin-binding protein H-like regulates myosin-binding protein distribution and function in atrial cardiomyocytes

Mutations in atrial-enriched genes can cause a primary atrial myopathy that can contribute to overall cardiovascular dysfunction. MYBPHL encodes myosin-binding protein H-like (MyBP-HL), an atrial sarcomere protein that shares domain homology with the carboxy-terminus of cardiac myosin-binding protein-C (cMyBP-C). The function of MyBP-HL and the relationship between MyBP-HL and cMyBP-C is unknown. To decipher the roles of MyBP-HL, we used structured illumination microscopy, immuno-electron microscopy, and mass spectrometry to establish the localization and stoichiometry of MyBP-HL. We found levels of cMyBP-C, a major regulator of myosin function, were half as abundant compared to levels in the ventricle. In genetic mouse models, loss of MyBP-HL doubled cMyBP-C abundance in the atria, and loss of cMyBP-C doubled MyBP-HL abundance in the atria. Structured illumination microscopy showed that both proteins colocalize in the C-zone of the A-band, with MyBP-HL enriched closer to the M-line. Immuno-electron microscopy of mouse atria showed MyBP-HL strongly localized 161 nm from the M-line, consistent with localization to the third 43 nm repeat of myosin heads. Both cMyBP-C and MyBP-HL had less-defined sarcomere localization in the atria compared to ventricle, yet areas with the expected 43 nm repeat distance were observed for both proteins. Isometric force measurements taken from control and Mybphl null single atrial myofibrils revealed that loss of Mybphl accelerated the linear phase of relaxation. These findings support a mechanism where MyBP-HL regulates cMyBP-C abundance to alter the kinetics of sarcomere relaxation in atrial sarcomeres.

Relationship between coronary blood flow and improvement of cardiac function after catheter ablation for persistent atrial fibrillation

BACKGROUND

The relationship between coronary blood flow during atrial fibrillation (AF) and improvement of cardiac function after catheter ablation (CA) for persistent AF (PeAF) is not prominent; this study was conducted to evaluate this relationship.

METHODS

This was a retrospective case-control study. Eighty-five patients with PeAF (resting heart rate < 100 bpm) and heart failure with reduced ejection fraction (left ventricular ejection fraction (LVEF) < 40%) who had undergone coronary angiography within 1 week before CA were included. All patients could maintain a sinus rhythm for > 6 months after CA. The primary outcome was improvement of cardiac function with an LVEF cutoff value of > 50% during sinus rhythm 6 months after CA.

RESULTS

In the LVEF improvement group (N = 57), patients were younger, with a higher baseline diastolic blood pressure and lower baseline brain natriuretic peptide level than the no LVEF improvement group (N = 28). Heart rate at baseline and 6 months after CA and AF duration did not differ between the two groups. Thrombolysis in myocardial infarction frame count parameters was significantly higher in the LVEF improvement (P < 0.001) than in the no LVEF improvement group. Multivariate logistic regression analysis revealed mean thrombolysis in myocardial infarction frame count as an independent factor for LVEF improvement (odds ratio, 1.72 (95% confidence interval 1.17-2.54); P = 0.006).

CONCLUSION

Coronary blood flow in patients with PeAF is strongly associated with improved left ventricular systolic function after the restoration of sinus rhythm by CA for PeAF and heart failure with reduced ejection fraction.

Prevalence of Heart Failure With Preserved Ejection Fraction in Patients Undergoing Atrial Fibrillation Ablation Based on Resting and Post-Tachycardia Pacing Left Atrial Pressure

Atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) are frequent co-morbid conditions. In patients with symptomatic AF and preserved left ventricular ejection fraction the clinical diagnosis of HFpEF may be difficult, as history, examination, and echocardiography are not sensitive or specific. This study sought to assess the prevalence of HFpEF in patients undergoing AF ablation utilizing resting and post-tachycardia pacing left atrial pressure (LAP) measurements. This retrospective cohort study consisted of consecutive patients with symptomatic AF and preserved left ventricular ejection fraction who had invasive hemodynamic assessment (IHA) of LAP under resting and post-tachycardia pacing conditions while undergoing AF ablation from 2020 to 2022 at a tertiary care academic medical center. Elevated LAP was defined as ≥15 mm Hg at rest and ≥15 mm Hg post-tachycardia pacing. Patients were stratified into 3 groups: (1) normal resting and post-tachycardia pacing LAP (control group), (2) elevated resting LAP (apparent HFpEF), (3) normal resting but elevated post-tachycardia pacing LAP (occult HFpEF). A total of 78 patients were included with age 64.6 ± 9.1 years, 28 (36%) female, body mass index 33.3 ± 6.5 kg/m2, 5 (6%) paroxysmal and 73 (94%) persistent AF, and CHA2DS2-VASc 3.0 ± 1.5. IHA categorized 31 (40%), 32 (41%), and 15 patients (19%) into groups 1, 2, and 3 respectively. Notably, while only 9 patients (12%) were diagnosed with HFpEF based on clinical evaluation, 47 patients (60%) were diagnosed by IHA. IHA in patients undergoing AF ablation suggests a high prevalence of clinically undiagnosed HFpEF through a novel methodology measuring resting and post-tachycardia pacing LAP.

The impact of age on ablation outcomes in AF-mediated cardiomyopathy

INTRODUCTION

The absence of ventricular scar in patients with atrial fibrillation (AF) and systolic heart failure (HF) predicts left ventricular (LV) recovery following AF ablation. It is unknown whether age impacts the degree of LV recovery, reverse remodeling, or AF recurrence following catheter ablation (CA) among this population.

OBJECTIVES

To evaluate the impact of age on LV recovery and AF recurrence in a population with AF and systolic HF without fibrosis (termed AF-mediated cardiomyopathy) following CA.

METHODS

Consecutive patients undergoing CA between 2013 and 2021 with LV ejection fraction (LVEF) < 45% and absence of cardiac magnetic resonance imaging (CMR) detected LV myocardial fibrosis were stratified by age (<65 vs. ≥65 years). Following CA, participants underwent remote rhythm monitoring for 12 months with repeat CMR for HF surveillance.

RESULTS

The study population consisted of 70 patients (10% female, mean LVEF 33 ± 9%), stratified into younger (age < 65 years, 63%) and older (age ≥ 65 years, 37%) cohorts. Baseline comorbidities, LVEF (34 ± 9 vs. 33 ± 8 ≥65 years, p = .686), atrial and ventricular dimensions (left atrial volume index: 55 ± 21 vs. 56 ± 14 mL/m2 age ≥ 65, p = .834; indexed left ventricular end-diastolic volume: 108 ± 40 vs. 104 ± 28 mL/m2 age ≥ 65, p = .681), pharmacotherapy and ablation strategy (pulmonary vein isolation in all; posterior wall isolation in 27% vs. 19% age ≥ 65, p = .448; cavotricuspid isthmus in 9% vs. 11.5% age ≥ 65) were comparable (all p > .05) albeit a higher CHADS2 VASc score in the older cohort (2.7 ± 0.9 vs. 1.6 ± 0.6 age < 65, p < .001).   Freedom from AF was comparable (hazard ratio: 0.65, 95% confidence interval: 0.38-1.48, LogRank p = .283) as was AF burden [0% (interquartile range, IQR: 0.0-2.1) vs. age ≥ 65: [0% (IQR 0.0-1.7), p = .516], irrespective of age. There was a significant improvement in LV systolic function in both groups (ΔLVEF + 21 ± 14% vs. +21 ± 12% age ≥ 65, p = .913), with LV recovery in the vast majority (73% vs. 69%, respectively, p = .759) at 13 (IQR: 12-16) months. This was accompanied by comparable improvements in functional status (New York Heart Association class p = .851; 6-min walk distance 50 ± 61 vs. 93 ± 134 m in age ≥ 65, p = .066), biomarkers (ΔN-terminal-pro brain natriuretic peptide -139 ± 246 vs. -168 ± 181 age ≥ 65,p = .629) and HF symptoms (Short Form-36 survey Δphysical component summary p = .483/Δmental component summary, p = .841).

CONCLUSION

In patients undergoing CA for AF with systolic HF in the absence of ventricular scar, comparable improvements in ventricular function, symptoms, and freedom from AF are achieved irrespective of age.

Atrial fibrillation ablation in patients with arrhythmia-induced cardiomyopathy: a prospective multicentre study

AIMS

This study aims to investigate the clinical and biochemical characteristics of patients with atrial fibrillation (AF) referred for ablation who develop arrhythmia-induced cardiomyopathy (AiCM) as well as their long-term outcomes after catheter ablation (CA).

METHODS AND RESULTS

A prospective multicentre study was conducted on consecutive AF patients who underwent CA. AiCM was defined as the development of heart failure in the presence of AF and an improvement of left ventricular fraction by at least 10% at 6 months after ablation. A subgroup of patients underwent peripheral and left atrial blood samples [galectin-3, fatty acid-binding protein 4 (FABP4), and soluble receptor for advanced glycation end products (sRAGE)] at the time of the procedure. Of the 769 patients who underwent AF ablation, 135 (17.56%) met the criteria for AiCM. Independent predictors of AiCM included persistent AF, male gender, left atrial volume, QRS width, active smoking, and chronic kidney disease (CKD). Biomarker analysis revealed that sRAGE, FABP4, and galectin-3 levels were not predictive of AiCM development nor did they differ between groups or predict recurrence. There were no differences in AF recurrence between patients with and without AiCM (30.83% vs. 27.77%; P = 0.392) during a median follow-up of 23.83 months (inter-quartile range 9-36).

CONCLUSIONS

In the subset of patients referred for AF ablation, the development of AiCM was associated with persistent AF and CKD. Biomarker analysis was not different between groups nor predicted recurrence. Patients with AiCM benefited from ablation, with a significant improvement in left ventricular ejection fraction and similar AF recurrence rates to those without AiCM.

Association between systemic inflammatory response index and left ventricular remodeling and systolic dysfunction in atrial fibrillation patients

BACKGROUND

Cardiac remodeling and dysfunction can be caused by atrial fibrillation (AF). The aim of this research is to investigate the relationship between the systemic inflammatory response index (SIRI) and left ventricular (LV) remodeling and systolic function in individuals with AF.

METHODS

416 patients with AF who were admitted to the Second Department of Cardiology in the East Ward of the Qingdao Municipal Hospital between January 2020 and May 2022 were included in the present retrospective research. The relationship between SIRI and various cardiac parameters was analyzed. The patients' left atrial (LA) enlargement and left ventricular (LV) hypertrophy and systolic dysfunction were evaluated. SIRI was calculated by the formula: neutrophil × monocyte/lymphocyte.

RESULTS

SIRI significantly correlated with LV end-diastolic diameter (LVDd), LV posterior wall thickness at end-diastole (LVPWTd), interventricular septal thickness at end-diastole (IVSTd), LV mass index (LVMI), LV ejection fraction (LVEF), LA diameter (LAD), C-reactive protein (CRP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with AF. In multivariate linear regression analyses, SIRI was discovered to be significantly related to LVMI (ln-transformed) (p = 0.025), LVEF (ln-transformed) (p = 0.005), and LAD (ln-transformed) (p = 0.007). In multivariate logistic regression, the highest quartile of SIRI (SIRI > 1.62) was significantly associated with LV hypertrophy (p = 0.026), impaired LV systolic function (p = 0.002), and LA enlargement (p = 0.025).

CONCLUSIONS

SIRI was significantly associated with LV remodeling and systolic function impairment in patients with AF. SIRI may serve as a reliable and convenient inflammatory biomarker for detecting impaired cardiac structure and systolic function in patients with AF.

ANMCO-SIMEU consensus document: appropriate management of atrial fibrillation in the emergency department

Atrial fibrillation (AF) accounts for 2% of the total presentations to the emergency department (ED) and represents the most frequent arrhythmic cause for hospitalization. It steadily increases the risk of thromboembolic events and is often associated with several comorbidities that negatively affect patient's quality of life and prognosis. AF has a considerable impact on healthcare resources, making the promotion of an adequate and coordinated management of this arrhythmia necessary in order to avoid clinical complications and to implement the adoption of appropriate technological and pharmacological treatment options. AF management varies across regions and hospitals and there is also heterogeneity in the use of anticoagulation and electric cardioversion, with limited use of direct oral anticoagulants. The ED represents the first access point for early management of patients with AF. The appropriate management of this arrhythmia in the acute setting has a great impact on improving patient's quality of life and outcomes as well as on rationalization of the financial resources related to the clinical course of AF. Therefore, physicians should provide a well-structured clinical and diagnostic pathway for patients with AF who are admitted to the ED. This should be based on a tight and propositional collaboration among several specialists, i.e. the ED physician, cardiologist, internal medicine physician, anesthesiologist. The aim of this ANMCO-SIMEU consensus document is to provide shared recommendations for promoting an integrated, accurate, and up-to-date management of patients with AF admitted to the ED or Cardiology Department, in order to make it homogeneous across the national territory.

[Left atrium remodeling after catheter ablation of atrial fibrillation]

Atrial fibrillation (AF) is the most common cardiac arrhythmia. It has a high association with cardiovascular embolic events and heart failure. Structural and functional changes are a fundamental part of the pathophysiological process, leading to left atrial myopathy and progressive left ventricular dysfunction that modifies the prognosis of patients. We present the case of a 75-year-old patient with symptomatic paroxysmal AF with good functional class who was referred for pulmonary vein ablation after antiarrhythmic therapy failure. The initial echocardiogram showed preserved biventricular systolic function, mild diastolic dysfunction, and normal left atrium (LA) volumes. However, functional LA impairment was observed with decreased reservoir phase strain. Pulmonary vein isolation was successfully performed without evidence of new arrhythmic events, in addition to improvement in LA reservoir strain, left ventricular (LV) global longitudinal strain, and myocardial work index at three months follow-up. The patient has remained asymptomatic and is under clinical follow-up. LA and LV strain as new advanced echocardiography techniques is useful in the assessment of reverse remodeling of atrial myopathy and LV structural assessment.

Ability of Left Atrial Distensibility After Radiofrequency Catheter Ablation to Predict Recurrence of Atrial Fibrillation

This study sought to assess the left atrial (LA) functional recovery after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) and to evaluate the determining factor of procedural success of RFCA, using a novel preload stress echocardiography. A total of 111 patients with AF were prospectively recruited. The echocardiographic parameters were obtained during the leg-positive pressure (LPP) maneuver, both at baseline and midterm after RFCA. As an index of LA distensibility, the LA expansion index was calculated as (LAV_max - LAV_min) × 100 / LAV_min. During a median follow-up period of 14.2 months, AF recurrence was observed in 23 patients (20.7%). In LA functional parameters at baseline, only the Δ LA expansion index was significantly larger in the success group (16 ± 11% vs 4 ± 9%, p <0.05). At midterm follow-up, the Δ LA expansion index significantly increased to 32 ± 19% (p <0.05), together with structural LA reverse remodeling only in the success group. Moreover, the Δ stroke volume index during the LPP stress test significantly increased only in the success group (from 2.3 ± 1.3 ml/m² to 3.1 ± 4.8 ml/m², p <0.05). In a multivariate analysis, left ventricular ejection fraction (hazard ratio 0.911, p <0.05) and baseline Δ LA expansion index (hazard ratio 0.827, p <0.001) were independent predictors of AF recurrence. In conclusion, the baseline Δ LA expansion index during LPP stress is a reliable marker for predicting procedural success after RFCA. Moreover, maintenance of sinus rhythm resulted in an improvement of the preload reserve after RFCA.

Gene therapy to terminate tachyarrhythmias

INTRODUCTION

To date, the treatment option for tachyarrhythmia is classified into drug therapy, catheter ablation, and implantable device therapy. However, the efficacy of the antiarrhythmic drugs is limited. Although the indication of catheter ablation is expanding, several fatal tachyarrhythmias are still refractory to ablation. Implantable cardioverter-defibrillator increases survival, but it is not a curable treatment. Therefore, a novel therapy for tachyarrhythmias refractory to present treatments is desired. Gene therapy is being developed as a promising candidate for this purpose, and basic research and translational research have been accumulated in recent years.

AREAS COVERED

This paper reviews the current state of gene therapy for arrhythmias, including susceptible arrhythmias, the route of administration to the heart, and the type of vector to use. We also discuss the latest progress in the technology of gene delivery and genome editing.

EXPERT OPINION

Gene therapy is one of the most promising technologies for arrhythmia treatment. However, additional technological innovation to achieve safe, localized, homogeneous, and long-lasting gene transfer is required for its clinical application.

ExPheWas: a platform for cis-Mendelian randomization and gene-based association scans

Establishing the relationship between protein-coding genes and phenotypes has the potential to inform on the molecular etiology of diseases. Here, we describe ExPheWas (exphewas.ca), a gene-based phenome-wide association study browser and platform that enables the conduct of gene-based Mendelian randomization. The ExPheWas data repository includes sex-stratified and sex-combined gene-based association results from 26 616 genes with 1746 phenotypes measured in up to 413 133 individuals from the UK Biobank. Interactive visualizations are provided through a browser to facilitate data exploration supported by false discovery rate control, and it includes tools for enrichment analysis. The interactive Mendelian randomization module in ExPheWas allows the estimation of causal effects of a genetically predicted exposure on an outcome by using genetic variation in a single gene as the instrumental variable.

Atrial fibrillation-induced tachycardiomyopathy and heart failure: an underappreciated and elusive condition

Many patients with persistent, chronic, or frequently recurring paroxysmal atrial fibrillation (AF) may develop a tachycardiomyopathy (TCM) with left ventricular (LV) dysfunction and heart failure (HF), which is reversible upon restoration and maintenance of sinus rhythm, when feasible, or via better and tighter ventricular rate (VR) control. Mechanisms involved in producing this leading cause of TCM (AF-TCM) include loss of atrial contraction, irregular heart rate, fast VR, neurohumoral activation, and structural myocardial changes. The most important of all mechanisms relates to optimal VR control, which seems to be an elusive target. Uncontrolled AF may also worsen preexisting LV dysfunction and exacerbate HF symptoms. Data, albeit less robust, also point to deleterious effects of slow VRs on LV function. Thus, a J-shaped relationship between VR and clinical outcome has been suggested, with the optimal VR control hovering at ~ 65 bpm, ranging between 60 and 80 bpm; VRs above and below this range may confer higher morbidity and mortality rates. A convergence of recent guidelines is noted towards a stricter rather than a more lenient VR control with target heart rate < 80 bpm at rest and < 110 bpm during moderate exercise which seems to prevent TCM or improve LV function and exercise capacity and relieve TCM-related symptoms and signs. Of course, restoring and maintaining sinus rhythm is always a most desirable target, when feasible, either with drugs or more likely with ablation. All these issues are herein reviewed, current guidelines are discussed and relevant data are tabulated and pictorially illustrated.

Identification of Functional Genetic Determinants of Cardiac Troponin T and I in a Multiethnic Population and Causal Associations With Atrial Fibrillation

BACKGROUND

Elevated cardiac troponin levels in blood are associated with increased risk of cardiovascular diseases and mortality. Cardiac troponin levels are heritable, but their genetic architecture remains elusive.

METHODS

We conducted a transethnic genome-wide association analysis on high-sensitivity cTnT (cardiac troponin T; hs-cTnT) and high-sensitivity cTnI (cardiac troponin I; hs-cTnI) levels in 24 617 and 14 336 participants free of coronary heart disease and heart failure from 6 population-based cohorts, followed by a series of bioinformatic analyses to decipher the genetic architecture of hs-cTnT and hs-cTnI.

RESULTS

We identified 4 genome-wide significant loci for hs-cTnT including a novel locus rs3737882 in PPFIA4 and 3 previously reported loci at NCOA2, TRAM1, and BCL2. One known locus at VCL was replicated for hs-cTnI. One copy of C allele for rs3737882 was associated with a 6% increase in hs-cTnT levels (minor allele frequency, 0.18; P=2.80×10-9). We observed pleiotropic loci located at BAG3 and ANO5. The proportions of variances explained by single-nucleotide polymorphisms were 10.15% and 7.74% for hs-cTnT and hs-cTnI, respectively. Single-nucleotide polymorphisms were colocalized with BCL2 expression in heart tissues and hs-cTnT and with ANO5 expression in artery, heart tissues, and whole blood and both troponins. Mendelian randomization analyses showed that genetically increased hs-cTnT and hs-cTnI levels were associated with higher odds of atrial fibrillation (odds ratio, 1.38 [95% CI, 1.25-1.54] for hs-cTnT and 1.21 [95% CI, 1.06-1.37] for hs-cTnI).

CONCLUSIONS

We identified a novel genetic locus associated with hs-cTnT in a multiethnic population and found that genetically regulated troponin levels were associated with atrial fibrillation.

Mortality risk and temporal patterns of atrial fibrillation in the nationwide registry

AIMS

Persistent and permanent atrial fibrillation (AF) often occurs in the presence of multiple comorbidities and is linked to adverse outcomes. It is unclear whether the sustained pattern of AF itself is prognostic or if it is confounded by underlying comorbidities. Here, we tested the association between the temporal patterns of AF and the risks of ischemic stroke and all-cause mortality.

METHODS AND RESULTS

In a prospective multicenter cohort, 3046 non-valvular AF patients were consecutively enrolled and followed for adverse outcomes of all-cause mortality and ischemic stroke. The risks of both outcomes were adjusted for underlying comorbidities, and compared between the patterns of AF. At baseline, the patients were classified as paroxysmal (N = 963, 31.6%), persistent (N = 604, 19.8%), and permanent AF (N = 1479, 45.6%) according to the standard definition. Anticoagulants were administered in 75% of all patients and 83% of those with CHA2DS2-VASc score ≥2 in males or ≥3 in females. During a mean follow up of 26 (SD 10.5) months, all-cause mortality occurred less in paroxysmal AF (2.5 per 100 patient-years) than in persistent AF (4.4 per 100 patient-years; adjusted hazard ratio [HR] 0.66, 95% CI, 0.46-0.96; P = .029) and permanent AF (4.1 per 100 patient-years; adjusted HR 0.71, 95% CI, 0.52-0.98; P = .036). The risk of ischemic stroke was similar across all patterns of AF.

CONCLUSIONS

In this multicenter cohort of AF patients, persistent and permanent AF was associated with higher all-cause mortality than paroxysmal AF, independent of baseline comorbidities.

CLINICAL TRIAL REGISTRATION

Thai Clinical Trial Registration; Study ID: TCTR20160113002 (http://www.thaiclinicaltrials.org/show/TCTR20160113002).

A high throughput lipidomics method and its application in atrial fibrillation based on 96-well plate pretreatment and liquid chromatography-mass spectrometry

Successful applications of lipidomics in clinic need study large-scale samples, and the bottlenecks are in throughput and robustness of the lipid analytical method. Here, we report an untargeted lipidomics method by combining high throughput pretreatment in the 96-well plate with ultra-high performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry. The developed method was validated to have satisfactory analytical characteristics in terms of linearity, repeatability and extraction recovery. It can be used to handle 96 samples simultaneously in 25 min and detect 441 lipids in plasma sample. Storage stability investigation on lipid extracts provided an operable procedure for large-scale sample analysis and demonstrated most lipids were stable in autosampler at 10 °C within 36 h and at -80 °C within 72 h after the pretreatment. To prove the usefulness, the method was employed to investigate abnormal plasma lipidome related to atrial fibrillation. A biomarker panel with the area under the curve (AUC) values of 0.831 and 0.745 was achieved in the discovery and external validation sets, respectively. These results showed that the developed method is applicable for large-scale biological sample handling and lipid analysis of plasma.

Suppression of amiodarone-induced torsade de pointes by landiolol in a patient with atrial fibrillation-mediated cardiomyopathy

An elderly Japanese woman developed acute decompensated heart failure caused by persistent atrial fibrillation (AF) and left ventricular systolic dysfunction. Approximately 6 days after starting intravenous administration of amiodarone (600 mg/day) for maintaining sinus rhythm after cardioversion of AF, electrocardiograms revealed a prolonged QT interval associated with torsade de pointes (TdP). The amiodarone-induced TdP disappeared after intravenous administration of landiolol plus magnesium and potassium, without discontinuation of amiodarone or overdrive cardiac pacing, although the prolonged QT interval persisted. To the best of our knowledge, this is the first report that landiolol could be effective for amiodarone-induced TdP.

Heart Failure in Atrial Fibrillation - An Update on Clinical and Echocardiographic Implications

Atrial fibrillation (AF) is the most common sustained arrhythmia in adults and has unfavorable consequences such as stroke, heart failure (HF), and death. HF is the most common adverse event following AF and the leading cause of death. Therefore, identifying the association between AF and HF is important to establish risk stratification for HF in AF. Recent studies suggested that left atrial and ventricular fibrosis is an important link between AF and HF, and the prognostic impact may differ with respect to HF subtype, stratified with left ventricular ejection fraction (EF). Mortality risk in patients with concurrent AF and HF with reduced EF (HFrEF) appears slightly higher compared with those with concurrent AF and HF with preserved EF (HFpEF). On the other hand, the prognostic impact of HF in AF is similar between HFrEF and HFpEF. Further, left atrial size, as well as left atrial and left ventricular functional assessment, are reported to be useful for the prediction of HF in AF, incremental to the conventional risk factors. In this review, we focus on the epidemiological, pathophysiological, and prognostic associations between AF and HF, and review the clinical and echocardiographic predictors for HF in AF.

Epidemiology of Atrial Fibrillation in the 21st Century: Novel Methods and New Insights

Accompanying the aging of populations worldwide, and increased survival with chronic diseases, the incidence and prevalence of atrial fibrillation (AF) are rising, justifying the term global epidemic. This multifactorial arrhythmia is intertwined with common concomitant cardiovascular diseases, which share classical cardiovascular risk factors. Targeted prevention programs are largely missing. Prevention needs to start at an early age with primordial interventions at the population level. The public health dimension of AF motivates research in modifiable AF risk factors and improved precision in AF prediction and management. In this review, we summarize current knowledge in an attempt to untangle these multifaceted associations from an epidemiological perspective. We discuss disease trends, preventive opportunities offered by underlying risk factors and concomitant disorders, current developments in diagnosis and risk prediction, and prognostic implications of AF and its complications. Finally, we review current technological (eg, eHealth) and methodological (artificial intelligence) advances and their relevance for future prevention and disease management.