Heart failure and atrial fibrillation: from basic science to clinical practice

Development and validation of a prediction model for heart failure in patients with heart valvular regurgitation

AIMS

Patients with heart valvular regurgitation is increasing; early screening of potential patients developing heart failure (HF) is crucial.

METHODS

From 1 November 2019 to 31 October 2023, a total of 509 patients with heart valvular regurgitation hospitalized in the Department of Cardiovascular Disease of the First Affiliated Hospital of Guangzhou University of Traditional Medicine were enrolled. Three hundred fifty-six cases were selected as the training set for modelling, and 153 cases were selected as the validation set for the internal validation of the model.

RESULTS

A predictive model of heart failure with the following nine risk factors was developed: atrial fibrillation (AF), pulmonary infection (PI), coronary artery disease (CAD), creatinine (CREA), low-density lipoprotein cholesterol (LDL-C), d-dimer (DDi), left ventricular end-diastolic diameter (LVEDd), mitral regurgitation (MR) and aortic regurgitation (AR). The model was evaluated by the C-index [the training set: area under curve (AUC) 0.937, 95% confidence interval (CI) 0.911-0.963; the validation set: AUC 0.928, 95% CI 0.890-0.967]. Hosmer-Lemeshow test (the training set: χ2 10.908, P = 0.207; the validation set: χ2 4.896, P = 0.769) revealed that both the training and validation sets performed well in terms of model differentiation and calibration. Decision curve analysis showed that both the training and validation sets have higher net benefits, indicating that the model has good utility. Ten-fold cross-validation showed that the training set has high similarities with the validation set, which means that the model has good stability.

CONCLUSIONS

The occurrence of heart failure in patients with valvular regurgitation has a significant correlation with AF, PI, CAD, CREA, LDL-C, DDi, LVEDd, MR and AR. Based on these risk factors, a prediction model for heart failure was developed and validated, which showed good differentiation and utility, high accuracy and stability, providing a method for predicting heart failure.

Four-year follow-up of outcomes of the hybrid epicardial-endocardial ablation: A single-center experience

BACKGROUND

The CONVERGE trial demonstrated that hybrid epicardial and endocardial ablation was more effective than catheter ablation for the treatment of persistent atrial fibrillation (AF) at 1 year. Long-term real-world outcome data are scarce.

OBJECTIVE

We described a single-center experience by evaluating the long-term effectiveness and safety of hybrid epicardial-endocardial ablation.

METHODS

This is a retrospective single-center study. Patients were followed up to 4 years. The primary end point was the rate of AF recurrence up to 4 years postablation. Secondary end points included reduction in antiarrhythmic therapy use, the effect of the ligament of Marshall removal, epicardial posterior wall, 3-dimensional mapping during epicardial ablation, and left atrial appendage exclusion as adjunct intraoperative interventions for AF recurrence.

RESULTS

Of the 170 patients, 86.5% had persistent AF and 13.5% had long-standing persistent AF. AF-free survival was 87.6% at 1 year, 76.9% at 2 years, 70.4% at 3 years, and 59.3% at 4 years. Antiarrhythmic drug use was 87.6% at baseline and reduced to 21%, 20.6%, 18%, and 14.1% at year 1, 2, 3, and 4, respectively (P < .01 for all). Three-dimensional epicardial mapping showed a significant reduction in combined recurrence from 42% to 25% over 4 years of follow-up (P = .023). Ligament of Marshall and left atrial appendage exclusion showed numerical reduction in AF recurrence from 35% to 26% (P = .49) and from 44% to 30% (P = .07).

CONCLUSION

The hybrid convergent procedure reduces AF recurrence and the need for antiarrhythmic drugs and, while maintaining a good safety profile, for the treatment of persistent and long-standing persistent AF.

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.

Catheter Ablation for Atrial Fibrillation in Patients with Left Ventricular Ejection Fraction ≤ 45%: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Atrial fibrillation (AF) and heart failure (HF) frequently coexist, resulting in adverse outcomes. However, controversies remain regarding the efficacy of catheter ablation (CA) in AF patients with severe left ventricular dysfunction.

OBJECTIVES

The purpose of this study was to perform a meta-analysis of prospective randomized controlled trials to evaluate the efficacy of CA versus medical therapy (MT) in AF patients with left ventricular ejection fraction (LVEF) ≤45%.

METHODS

We searched the literature for studies that compared CA to MT in AF patients with LVEF ≤45%. A meta-analysis of 7 clinical trials was performed, including 1163 patients with AF and HF. Subgroup analysis was performed based on baseline LVEF. All tests were 2-sided; only the p-value <0.05 was considered statistically significant.

RESULTS

We found that CA was associated with lower all-cause mortality (risk ratio: 0.52, 95% CI: 0.37 to 0.72; p<0.01) and greater improvements in LVEF (mean difference: 4.80%, 95% CI: 2.29% to 7.31%; p<0.01) compared to MT. Patients in the CA group had a lower risk of HF hospitalization and AF recurrence and a significantly better quality of life than those in the MT group. The results of subgroup analysis indicated that patients with milder left ventricular dysfunction improved LVEF after AF ablation (mean difference: 6.53%, 95% CI: 6.18% to 6.88%; p<0.01) compared to patients with more severe disease (mean difference: 2.02%, 95% CI: 0.87% to 3.16%; p<0.01).

CONCLUSIONS

Our meta-analysis demonstrated that CA was associated with significant improvements in outcomes of AF patients with LVEF ≤45%. Additionally, AF patients with milder left ventricular dysfunction could benefit more from CA.

Ivabradine could not decrease mitral regurgitation triggered atrial fibrosis and fibrillation compared with carvedilol

BACKGROUND

Ivabradine, a medical treatment for heart failure (HF), reduces heart rate (HR) and prolongs diastolic perfusion time. It is frequently prescribed to patients with HF who have a suboptimal response or intolerance to beta-blockers. Degenerative mitral regurgitation (MR) is a valvular heart disease often associated with the development of HF and atrial fibrillation (AF). However, studies comparing the effects of ivabradine and beta-blockers on MR are lacking. Therefore, this study aimed to explore the potential therapeutic effects of ivabradine and carvedilol on MR using a rat model.

METHODS AND RESULTS

Using a novel echo-guided mini-invasive surgery, MR was created in 12-weeks-old Sprague-Dawley rats. After 2 weeks, the rats were randomized to receive either ivabradine or carvedilol for 4 weeks. Echocardiography was performed at baseline and at two-week intervals. Following haemodynamic studies, postmortem tissues were analysed. Notably, the MR-induced myocardial dysfunction did not improve considerably after treatment with ivabradine or carvedilol. However, in haemodynamic studies, pharmacological therapies, particularly carvedilol, mitigated MR-induced chamber dilatation (end-systolic volume and end-diastolic volume; MR vs. MR + Carvedilol; P < 0.05) and decreased compliance (end-systolic pressure-volume relationship; MR vs. MR + Carvedilol; P < 0.05). Compared with ivabradine, a shorter duration (MR vs. MR + Carvedilol; P < 0.05) and reduced inducibility (MR vs. MR + Carvedilol and MR vs. MR + Ivabradine; P < 0.05) of AF were observed in MR rats treated with carvedilol. Similarly, reduced cardiac fibrosis and apoptosis were observed in the MR rat model in the treatment groups, especially in those treated with carvedilol (MR vs. MR + Carvedilol; P < 0.01).

CONCLUSIONS

Although both ivabradine and carvedilol, at least in part, mitigated MR-induced chamber dilatation and decreased compliance, carvedilol had a better effect on reversing MR-induced cardiac fibrosis, apoptosis, and arrhythmogenesis than ivabradine. When compared with Ivabradine, MR rats treated with carvedilol exhibited a shorter duration and reduced inducibility of AF, thus providing more effective suppression of HCN4. Further investigations are required to validate our findings.

Clinical Outcomes of Decompensated Heart Failure With Reduced Ejection Fraction Admissions With or Without Atrial Fibrillation and Atrial Flutter

The aim of our retrospective study is to determine the influence of co-morbid atrial fibrillation or flutter (AF) on decompensated congestive heart failure (CHF) admissions using data from the 2020 nationwide inpatient sample. We identified 76,835 adults admitted nonelectively with decompensated CHF. After multivariate adjustment, we found decompensated heart failure with reduced ejection fraction (HFrEF) admissions with AF had 37% higher odds of in-hospital mortality, (OR 1.38 [95% CI 1.1-1.72] P < 0.01), 33% higher odds for mechanical ventilation (MV) (OR 1.33 [95% CI 1.14-1.55] P < 0.01), 39% higher odds of early MV (OR 1.39 [95% CI 1.16-1.66] P < 0.01), 54% higher odds of cardiogenic shock (OR 1.54 [95% CI 1.29-1.84] P < 0.01), 61% increased odds of mechanical circulatory support (MCS) requirement (OR 1.61 [95% CI 1.12-2.31] P < 0.02), significantly higher odds of acute renal failure (AKI) necessitating dialysis (OR 2.20 [95% CI 1.39-2.48] P < 0.01), 1-day increase in mean length of stay (LOS) (6.7 vs 5.7 days, adjusted difference: 0.99, P < 0.01), $13,281 increase in total hospitalization charges ($84,316 vs $74,279, adjusted difference: $13,281, P < 0.05) compared to the non-AF cohort. Moreover, we found decompensated heart failure with preserved ejection fraction (HFpEF) admissions with AF had a 23% increased odds of MV (OR 1.23 [95% CI 1.01-1.50] P < 0.01), 24% higher odds of early MV (OR 1.24 [95% CI 1.00-1.53] P < 0.01), 0.36 days increase in mean LOS (5.5 vs 5.2 days, adjusted difference: 0.36, P = < 0.01), but no significant difference in in-hospital mortality (OR 1.23 [95% CI 0.86-1.75] P = 0.25), cardiogenic shock (OR 1.75 [95% CI 0.96-3.19] P < 0.07), dialysis-dependent AKI (OR 0.46 [95% CI 0.18-1.17] P < 0.10), or mean total hospitalization charges ($52,086 vs $47,990, adjusted difference: $5584, P = 0.06) compared to the non-AF cohort.

Clinical outcomes in heart failure patients with and without atrial fibrillation receiving sodium-glucose cotransporter-2 inhibitor

We report a retrospective analysis of a nationwide health database to study the association between sodium-glucose cotransporter-2 inhibitor (SGLT2I) use and the incidence of adverse clinical outcomes among heart failure (HF) patients with and without atrial fibrillation (AF) stratified by CHA2DS2-VASc score. The outcome of this study was on the development of adverse events, including acute myocardial infarction (AMI), hemorrhagic stroke, ischemic stroke, cardiovascular (CV) death, and all-cause mortality. By dividing the number of adverse events by the total person-years, the incidence rate was calculated. The hazard ratio (HR) was estimated by the Cox proportional hazard model. A total of 95% confidence interval (CI) was also presented to show the risk of adverse events for HF patients with and without AF taking SGLT2I. SGLT2I users had a lower risk of AMI (adjusted HR = 0.83; 95% CI = 0.74, 0.94), CV death (adjusted HR = 0.47; 95% CI = 0.42, 0.51), and all-cause death (adjusted HR = 0.39; 95% CI = 0.37, 0.41). Considering HF patients without AF and SGLT2I as the reference group, HF patients without AF but with SGLT2I had a reduced risk of adverse outcomes of 0.48 (95% CI = 0.45, 0.50), and HF patients with AF and SGLT2I had the decreased hazard ratio of 0.55 (95% CI = 0.50, 0.61). The adjusted HR of adverse outcomes for HF patients with CHA2DS2-VASc score less than 2 and SGLT2I without and with AF relative to HF patients without AF nor SGLT2I were 0.53 (95% CI = 0.41, 0.67) and 0.24 (95% CI = 0.12, 0.47), respectively. Compared to HF patients with no history of AF and SGLT2I, if patients additionally with SGLT2I and CHA2DS2-VASc score ≥ 2, the risk of the adverse outcomes was reduced with adjusted HR of 0.48 (95% CI = 0.45, 0.50); if patients additionally with AF and CHA2DS2-VASc score ≥ 2, the risk of the adverse outcomes was decreased with adjusted HR of 0.88 (95% CI = 0.80, 0.97); if patients additionally with AF, SGLT2I, and CHA2DS2-VASc score ≥ 2, the risk of the adverse outcomes was diminished with adjusted HR of 0.52 (95% CI = 0.47, 0.58). We concluded that SGLT2I has a protective effect in HF patients, and the risk reduction is greater with a score of < 2 and without AF.

Quivering hand and heart: Parkinson's disease is not associated with increased in-hospital mortality in atrial fibrillation hospitalizations: A nationwide analysis

Background

Autonomic dysfunction in Parkinson's disease (PD) includes cardiovascular dysregulations which may manifest as an increased risk of atrial fibrillation (AF). However, data on the impact of PD in AF patients is lacking. Our study aimed to investigate the differences in in-hospital mortality of patients admitted for AF with underlying PD versus those without PD.

Methods

We examined the National Inpatient Sample (NIS) database from 2016 to 2019 for hospitalizations of AF as a principal diagnosis with and without PD as a secondary diagnosis. The primary outcome was inpatient mortality. The secondary endpoints were ventricular tachycardia (VT), ventricular fibrillation (VF), acute heart failure (AHF), cardiogenic shock (CS), cardiac arrest (CA), total hospital charge (THC), and length of stay (LOS).

Results

Of 1,861,859 A F hospitalizations, 0.01% (19,490) had coexisting PD. Cohorts of PD vs No-PD had a mean age of 78.1 years [CI 77.9-78.4] vs 70.5 years [CI 70.4-70.5]; male (56.3% vs 50.7%), female (43.7% vs 49.3%). The PD category had similar in-hospital mortality with the no-PD category (OR_Adj = 1.18 [0.89-1.57] P = 0.240). The PD group had a lesser incidence of AHF (OR_Adj = 0.79 [0.72-0.86] P < 0.001) and VT (OR_Adj = 0.77 [0.62-0.95] P = 0.015).

Conclusion

Co-existing PD in patients admitted for AF was not associated with increased in-hospital mortality; however, there were lower odds of AHF and VT. The diminished arrhythmogenic neurohormonal axis may explain these cardiovascular benefits. Notwithstanding, to better understand the outcomes of AF in patients with PD, additional studies are required.

Echocardiographic changes and heart failure hospitalizations following rhythm control for arrhythmia-induced cardiomyopathy: results from a multicenter, retrospective study

BACKGROUND

The incidence and prevalence of arrhythmia-induced cardiomyopathy (AIC) are unclear but likely underrecognized. LV dysfunction is common among patients with atrial fibrillation (AF), atrial flutter (AFL), and frequent premature ventricular contractions (PVC). The hallmark of AIC is the improvement of left ventricular ejection fraction (LVEF) following arrhythmia treatment. Changes in echocardiographic parameters and their effect on outcomes after rhythm control for AIC are not well understood. We aimed to study echocardiographic parameters and outcomes following rhythm control for AIC.

METHODS

A multicenter, retrospective study was conducted at 4 different medical centers involving patients with AIC. Clinical, echocardiographic, and outcome (mortality and heart failure hospitalizations [HFH]) parameters were extracted from the medical record.

RESULTS

Two hundred fifty-five patients (age 66 ± 11 years, 73% male) with AIC caused by AF (51%), atrial tachycardia/AFL (20%), and PVCs (29%) were included and followed for a median period of 6 months after successful rhythm control. Significant improvements in left ventricular (LV) ejection fraction (P < 0.0001), LV end-systolic volume (ml) (90 ± 48 to 58 ± 30; P < 0.0001), LV internal diameter end diastole (cm) (5.5 ± 0.78 to 5.3 ± 0.64; P = 0.0001) and end systole (4.7 ± 0.95 to 4.3 ± 1.02; P < 0.0001), right atrial pressure (mmHg) (11.3 ± 5.0 to 7.4 ± 3.2; P = 0.0001), and right ventricular function (n (%)) (42 (44) to 9 (11); P < 0.0001) were noted following arrhythmia treatment. No deaths occurred during follow-up. HFH occurred in 7 patients. Arrhythmia recurrence rate was 50.5%. Neither echocardiographic parameters nor recurrence of arrhythmia correlated with HFH.

CONCLUSION

Arrhythmia treatment significantly improved echocardiographic LV dimensions, LVEF, and RAP in this multicenter AIC cohort, underscoring the need for early recognition and aggressive rhythm control in suspected AIC patients. The event rate was too low to assess for outcome predictors.

The susceptibility of cardiac arrhythmias after spinal cord crush injury in rats

High-level spinal cord injury (SCI) often interrupts supraspinal regulation of sympathetic input to the heart. Although it is known that dysregulated autonomic control increases the risk for cardiac disorders, the mechanisms mediating SCI-induced arrhythmias are poorly understood. Here, we employed a rat model of complete spinal cord crush injury at the 2nd/3rd thoracic (T2/3) level to investigate cardiac rhythm disorders resulting from SCI. Rats with T9 injury and naïve animals served as two controls. Four weeks after SCI, rats were implanted with a radio-telemetric device for electrocardiogram and blood pressure monitoring. During 24-h recordings, heart rate variability in rats with T2/3 but not T9 injury exhibited a significant reduction in the time domain, and a decrease in power at low frequency but increased power at high frequency in the frequency domain which indicates reduced sympathetic and increased parasympathetic outflow to the heart. Pharmacological blockade of the sympathetic or parasympathetic branches confirmed the imbalance of cardiac autonomic control. Activation of sympatho-vagal input during the induction of autonomic dysreflexia by colorectal distention triggered various severe arrhythmic events in T2/3 injured rats. Meanwhile, intravenous infusion of the β1-adrenergic receptor agonist, dobutamine, caused greater incidence of arrhythmias in rats with T2/3 injury than naïve and T9 injured controls. Together, the results indicate that high-level SCI increases the susceptibility to developing cardiac arrhythmias likely owing to compromised autonomic homeostasis. The T2/3 crush model is appropriate for studying abnormal cardiac electrophysiology resulting from SCI.

Cardiac Remodeling and Diastolic Dysfunction in Paroxysmal Atrial Fibrillation

Background: Atrial fibrillation (AF) leads to the development of cardiac remodeling/diastolic dysfunction and vice versa. We intended to determine whether cardiac remodeling/diastolic dysfunction is present at early stages of AF. Methods: We studied 175 patients with paroxysmal AF, compared with 175 matched control subjects, who had available echocardiography data to investigate the association between echocardiographic variables and AF from the STANISLAS cohort. Results: In this study (mean age 55 years; 70.3% male), patients with paroxysmal AF had greater left ventricular mass compared to matched controls (p < 0.05). Patients with paroxysmal AF were also likely to have larger left atrial volume and a higher peak tricuspid regurgitation velocity, leading to higher prevalence (though <10% in the AF group) of diastolic dysfunction (all-p < 0.05). Multivariable conditional logistic regression models showed that paroxysmal AF was significantly associated with increased left ventricular mass and left atrial enlargement (all-p < 0.001), but not with e’ and deceleration time of E wave (all-p > 0.1). Conclusions: Left ventricular mass and left atrial enlargement rather than diastolic dysfunction (as evaluated by echocardiography) were associated with paroxysmal AF irrespective of body mass index, blood pressure and renal function. These findings suggest that cardiac remodeling may occur very early in the natural history of AF.

Weekend versus weekday admission and clinical outcomes in heart failure patients with and without atrial fibrillation in Taiwan

PURPOSE

We conduct this study to explore the associations of weekend and weekdays admission with the clinical events among heart failure (HF) patients with and without comorbid atrial fibrillation (AF).

METHODS

In this study, we recruited 57919 HF patients without AF hospitalized in weekends and 57919 HF patients without AF hospitalized in weekdays. There were 21467 and 21467 HF patients with AF admisson in weekends and weekdays, respectively. The outcomes of interest included all-cause mortality, CV death (ICD-9-CM 390-459), and heart failure recurrence. Cox proportional hazard regression model was applied to estimate the hazard ratio. Variables found to be statistically significant in a univariable Cox proportional hazard regression model were further examined in a multivariable Cox proportional hazard regression model. The cumulative incidence curves were obtained by the Kaplan-Meier method and assessed by the Log-rank test.

RESULTS

HF patients with AF and hospitalized in weekends had the highest incidence rates of rehospitalization due to HF (233.8 per1000 person-years), and CV death (23.9 per 1000 person-years) among four groups. Kaplan-Meier method shows that HF patients with AF had the higher cumulative incidence of HF recurrence than that of patients without AF.

CONCLUSION

HF patients with AF and hospitalized in weekends are at highest risk of HF recurrence among these four groups.

Managing Atrial Fibrillation in Patients With Heart Failure and Reduced Ejection Fraction: A Scientific Statement From the American Heart Association

Atrial fibrillation and heart failure with reduced ejection fraction are increasing in prevalence worldwide. Atrial fibrillation can precipitate and can be a consequence of heart failure with reduced ejection fraction and cardiomyopathy. Atrial fibrillation and heart failure, when present together, are associated with worse outcomes. Together, these 2 conditions increase the risk of stroke, requiring oral anticoagulation in many or left atrial appendage closure in some. Medical management for rate and rhythm control of atrial fibrillation in heart failure remain hampered by variable success, intolerance, and adverse effects. In multiple randomized clinical trials in recent years, catheter ablation for atrial fibrillation in patients with heart failure and reduced ejection fraction has shown superiority in improving survival, quality of life, and ventricular function and reducing heart failure hospitalizations compared with antiarrhythmic drugs and rate control therapies. This has resulted in a paradigm shift in management toward nonpharmacological rhythm control of atrial fibrillation in heart failure with reduced ejection fraction. The primary objective of this American Heart Association scientific statement is to review the available evidence on the epidemiology and pathophysiology of atrial fibrillation in relation to heart failure and to provide guidance on the latest advances in pharmacological and nonpharmacological management of atrial fibrillation in patients with heart failure and reduced ejection fraction. The writing committee's consensus on the implications for clinical practice, gaps in knowledge, and directions for future research are highlighted.

Atrial Fibrillation Burden and Clinical Outcomes in Heart Failure: The CASTLE-AF Trial

OBJECTIVES

This subanalysis of the CASTLE-AF (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF) trial aimed to address the association between atrial fibrillation (AF) recurrence, AF burden, and hard clinical outcomes in heart failure (HF) patients with AF.

BACKGROUND

The CASTLE-AF trial demonstrated the benefit of CA compared to pharmacological treatment in decreasing mortality and CV hospitalizations in patients with AF and HFrEF. However, the impact of AF recurrence and AF burden after ablation on long-term treatment benefit remains unknown.

METHODS

The CASTLE-AF protocol randomized 363 patients with coexisting HF and AF in a multicenter prospective controlled fashion to catheter ablation (n = 179) versus pharmacological therapy (n = 184). Two hundred eighty patients were included in this subanalysis (as-treated), 128 of them underwent ablation and 152 received pharmacological treatment. All patients had implanted dual chamber or biventricular implantable defibrillators with activated home monitoring capabilities. The individual AF burden was calculated as the percentage of the atrial arrhythmia time per day.

RESULTS

AF burden at baseline was not predictive of the primary endpoint (p = 0.473) or all-cause mortality (p = 0.446). AF recurrence (defined as any episode >30 s) did not show any relationship with the primary endpoints of mortality and occurrence of HF, irrespective of the treatment arm. An AF burden below 50% after 6 months of catheter ablation, was associated with a significant decrease in primary composite outcome (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.15 to 0.71; p = 0.014) and all-cause mortality (HR: 0.23; 95% CI: 0.07 to 0.71; p = 0.031). The risk of the primary endpoint or mortality was directly related to a low (<50%) or high (≥50%) AF burden at 6 months post-ablation.

CONCLUSIONS

AF burden at 6 months was predictive of hard clinical outcomes in HF patients with AF. The first recurrent atrial tachyarrhythmia episode >30 s after ablation was not associated with improvement in mortality and hospitalization for HF. (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF [CASTLE-AF]; NCT00643188).

Relevance of glycans in the interaction between T lymphocyte and the antigen presenting cell

The immunological synapse promotes receptors and ligands interaction in the contact interface between the T lymphocyte and the antigen presenting cell; glycosylation of the proteins involved in this biological process favors regulation of molecular interactions and development of the T lymphocyte effector response. Glycans in the immunological synapse influence cellular and molecular processes such as folding, expression, and structural stability of proteins, they also mediate ligand-receptor interaction and propagation of the intracellular signaling or inhibition of uncontrolled cellular activation that could lead to the development of autoimmunity, among others. It has been suggested that altered glycosylation of proteins that participate in the immunological synapse affects the signaling processes and cell proliferation, as well as exacerbation of the effector mechanisms of T cells that trigger systemic damage and autoimmunity. Understanding the role of glycans in the immune response has allowed for advances in the development of immunotherapies in different fields through the controlled and specific activation of the immune response. This review describes the structural and biological aspects of glycans associated with some molecules present in the immunological synapse, providing information that allows understanding the function of glycosylation in the interaction between the T lymphocyte and the antigen-presenting cell, as well as its impact on signaling and development regulation of T lymphocytes effector response.

Impact of Left Ventricular Function and Heart Failure Symptoms on Outcomes Post Ablation of Atrial Fibrillation in Heart Failure: CASTLE-AF Trial

BACKGROUND

Recent data demonstrate promising effects on left ventricular dysfunction and left ventricular ejection fraction (LVEF) improvement following ablation for atrial fibrillation (AF) in patients with heart failure. We sought to study the relationship between LVEF, New York Heart Association class on presentation, and the end points of mortality and heart failure admissions in the CASTLE-AF study (Catheter Ablation for Atrial Fibrillation With Heart Failure) population. Furthermore, predictors for LVEF improvement were examined.

METHODS

The CASTLE-AF patients with coexisting heart failure and AF (n=363) were randomized in a multicenter prospective controlled fashion to ablation (n=179) versus pharmacological therapy (n=184). Left ventricular function and New York Heart Association class were assessed at baseline (after randomization) and at each follow-up visit.

RESULTS

In the ablation arm, a significantly higher number of patients experienced an improvement in their LVEF to >35% at the end of the study (odds ratio, 2.17; P<0.001). Compared with the pharmacological therapy arm, both ablation patient groups with severe (<20%) or moderate/severe (≥20% and <35%) baseline LVEF had a significantly lower number of composite end points (hazard ratio [HR], 0.60; P=0.006), all-cause mortality (HR, 0.54; P=0.019), and cardiovascular hospitalizations (HR, 0.66; P=0.017). In the ablation group, New York Heart Association I/II patients at the time of treatment had the strongest improvement in clinical outcomes (primary end point: HR, 0.43; P<0.001; mortality: HR, 0.30; P=0.001).

CONCLUSIONS

Compared with pharmacological treatment, AF ablation was associated with a significant improvement in LVEF, independent from the severity of left ventricular dysfunction. AF ablation should be performed at early stages of the patient's heart failure symptoms.

Characteristics and 2-year outcomes of dabigatran treatment in patients with heart failure and atrial fibrillation: GLORIA-AF

Aims

This study aimed to describe baseline characteristics of patients with atrial fibrillation (AF) at risk of stroke with and without history of heart failure (HF) and report 2‐year outcomes in the dabigatran‐treated subset of a prospective, global, observational study (GLORIA‐AF).

Methods and results

Newly diagnosed patients with AF and CHA₂DS₂‐VASc score ≥ 1 were consecutively enrolled. Baseline characteristics were assessed by the presence or absence of HF diagnosis at enrolment. Incidence rates for outcomes in dabigatran‐treated patients were estimated with and without standardization by stroke (excluding HF component) and bleeding risk scores. A total of 15 308 eligible patients were enrolled, including 15 154 with known HF status; of these, 3679 (24.0%) had been diagnosed with HF, 11 475 (75.0%) had not. Among 4873 dabigatran‐treated patients, 1169 (24.0%) had HF, and 3658 (75.1%) did not; the risk of stroke was high (CHA₂DS₂‐VASc score ≥ 2) for 94.3% of patients with HF and 85.8% without, while 6.0% and 7.0%, respectively, had a high bleeding risk (HAS‐BLED ≥ 3). Incidence rates of all‐cause death in dabigatran‐treated patients with and without HF, standardized for CHA₂DS₂‐VASc and HAS‐BLED scores, were 4.76 vs. 1.80 per 100 patient years (py), with roughly comparable rates of stroke (0.82 vs. 0.60 per 100 py) and major bleeding (1.20 vs. 0.92 per 100 py).

Conclusions

Patients with AF and history of HF may have greater disease burden at AF diagnosis and increased mortality rates vs. patients without HF. Stroke and major bleeding rates were roughly comparable between groups confirming the long‐term safety and effectiveness of dabigatran in patients with HF.

Relationship Between 25-Hydroxyvitamin D, Renin, and Collagen Remodeling Biomarkers in Atrial Fibrillation

The interplay between vitamin D, the renin-angiotensin system (RAS), and collagen remodeling has been implicated in the pathogenesis of various cardiovascular diseases. This study sought to explore this relationship in atrial fibrillation (AF) by profiling plasma levels of 25-hydroxyvitamin D, RAS biomarkers, and collagen remodeling biomarkers using the enzyme-linked immunosorbent assay method. We hypothesized that 25-hydroxyvitamin D levels would inversely correlate with RAS biomarkers and that levels of RAS and collagen remodeling biomarkers would positively correlate with each other. Although our AF cohort (n = 37) did not exhibit decreased 25-hydroxyvitamin D levels compared to normal controls (n = 26), these levels inversely correlated with renin (Spearman r = -0.57, P = 0.005). Renin levels were elevated in patients with AF compared to normal controls (1233 ± 238 ng/mL vs 401 ± 27 ng/mL, P = 0.0002) and positively correlated with levels of matrix metalloproteinase 1 (MMP-1; Spearman r = 0.89, P = 0.01) and MMP-2 (Spearman r = 0.82, P = 0.03). These data suggest that 25-hydroxyvitamin D may influence RAS activation, and renin may help mediate the collagen remodeling process in AF. Understanding mediators of RAS dysregulation in AF may elucidate targets for therapeutic intervention to prevent collagen remodeling.

Atrial Fibrillation in Heart Failure: Focus on Antithrombotic Management

Heart failure (HF) and atrial fibrillation (AF), increasingly common in the aging population, are closely related and commonly found together. This article explores the relationship between AF and HF and the thromboembolic effect of these diseases. Morbidity and mortality are increased when the 2 conditions are seen together. Stroke risks are significant with AF and all subtypes of HF. This article suggests that all patients with AF and HF should be considered for anticoagulation. Current evidence suggests that non-vitamin K antagonist oral anticoagulants are effective and safe in AF and HF in comparison with warfarin.

Incidence, Risk Factors and Subsequent Prognostic Impact of New-Onset Atrial Fibrillation in Infective Endocarditis

BACKGROUND

Few studies with a large sample size have been performed to evaluate the incidence, risk factors and prognostic value of new-onset atrial fibrillation (AF) in patients with infective endocarditis (IE).Methods and Results:A total of 1,063 IE patients were included and 83 developed new AF. Compared with no-AF, the incidence of in-hospital death (6.0% vs. 22.9%, P<0.001) was higher in patients with new-onset AF. New-onset AF was independently associated with increased risk of in-hospital (adjusted odds ratio [OR]=3.92, P=0.001) and 1-year death (adjusted hazard ratio=2.91, P=0.001), while prior AF was not an independent factor. Kaplan-Meier curve analysis demonstrated new-onset AF mainly affected short-term death (180 days). Age (OR=1.04, P<0.001), rheumatic heart disease (OR=1.88, P=0.022), NYHA Class III or IV (OR=2.09, P=0.003), and left atrial diameter (LAD; OR=1.05, P=0.006) were independent risk factors for development of new AF.

CONCLUSIONS

New-onset AF, not prior AF, was a prognostic factor in IE patients, which was mainly associated with increased risk of short-term death. Patients with concomitant rheumatic heart disease, poor cardiac function, and larger LAD had higher risk of developing new AF.

Anticoagulation in atrial fibrillation with heart failure

Heart failure (HF) and atrial fibrillation (AF) frequently coexist, and they can beget one another due to similar factors and shared pathophysiology. These pathophysiologic changes promote the episodes of AF, while they in turn predispose to the exacerbation of HF. In this review, we will discuss pathophysiological mechanisms shared by AF and HF. Patients with concomitant HF and AF are at a particularly high risk of thromboembolism, which contribute to even worse symptoms and poorer prognosis. Vitamin K antagonists (VKA) (warfarin) were the traditional medication in AF patients for the prevention of stroke, whereas the advance of novel non-VKA oral anticoagulants (NOACs) (dabigatran, apixaban, rivaroxaban, and edoxaban) is challenging these standard prescriptions. NOACs' potential advantages over warfarin, including fixed dosing regimens, wide therapeutic window, and more sustained anticoagulant response, promote clinicians to consider these novel agents in the first place. However, some data suggested patients with AF and HF may receive different therapeutic response than those with AF alone in anticoagulant treatment. Accordingly, we aim to assess the potential role of oral anticoagulants, especially NOACs, in the management of patients with concomitant AF and HF.

Characteristics and outcomes of atrial fibrillation patients with or without specific symptoms: results from the PREFER in AF registry

Aims

Atrial fibrillation (AF) is a common condition that is a major cause of stroke. A significant proportion of patients with AF are not classically symptomatic at diagnosis or soon after diagnosis. There is little information comparing their characteristics, treatment, and outcomes of patients with symptoms, which predominate in clinical trials to those without.

Methods and results

We analysed data from the Prevention of Thromboembolic Events-European Registry in Atrial Fibrillation. This was a prospective, real-world registry with a 12-month follow-up that included AF patients aged 18 years and over. Patients were divided into those with and without AF symptoms using the European Heart Rhythm Association (EHRA) score (Category I vs. Categories II-IV). Of the 6196 patients (mean age 72 years) with EHRA scores available, 501 (8.1%) were asymptomatic. A lower proportion of asymptomatic patients was female (22.8 vs. 41.2%), with less noted to have heart failure and coronary artery disease (P < 0.01 for all). There were no differences in terms of the prevalence of diabetes, obesity, or prior stroke. Asymptomatic patients had a lower CHA2DS2-VASc score (2.9 ± 1.7 vs. 3.4 ± 1.8; P < 0.01) and HAS-BLED score (1.8 ± 1.1 vs. 2.1 ± 1.2; P < 0.01). During the 1-year follow-up, adverse events occurred at similar frequencies in asymptomatic and symptomatic patients (1.6 vs. 0.8% for ischaemic stroke; P = 0.061; 1.4 vs. 1.3% for transient ischaemic attack; P = 0.840). Patients with higher CHA2DS2-VASc and HAS-BLED scores experienced more events, independent of symptoms. Antithrombotic therapy was comparable for both groups at baseline and at follow-up.

Conclusions

The similar clinical characteristics and frequency of adverse events between asymptomatic and symptomatic AF patients revives the question of whether screening programmes to detect people with asymptomatic AF are worthwhile, particularly in those aged 65 and over potentially likely to have clinical and economic benefits from anticoagulants. This evidence may be informative if clinicians may not be comfortable participating in future clinical trials, leaving asymptomatic patients with AF and high stroke risk without anticoagulation.

Arrhythmia-Induced Cardiomyopathies: Mechanisms, Recognition, and Management

Arrhythmia-induced cardiomyopathy (AIC) is a potentially reversible condition in which left ventricular dysfunction is induced or mediated by atrial or ventricular arrhythmias. Cellular and extracellular changes in response to the culprit arrhythmia have been identified, but specific pathophysiological mechanisms remain unclear. Early recognition of AIC and prompt treatment of the culprit arrhythmia using pharmacological or ablative techniques result in symptom resolution and recovery of ventricular function. Although cardiomyopathy in response to an arrhythmia may take months to years to develop, recurrent arrhythmia can result in rapid decline in ventricular function with development of heart failure, suggesting residual ultrastructural abnormalities. Reports of sudden death in patients with normalized left ventricular ejection fraction cast doubt on the complete reversibility of this condition. Several aspects of AIC, including specific pathophysiological mechanisms, predisposing factors, optimal therapeutic strategies to prevent ultrastructural changes, and long-term risk of sudden death remain unresolved and need further research.

Heart Failure and Atrial Fibrillation

Atrial fibrillation is commonly experienced by patients with heart failure, and as the heart failure progresses and worsens, the more likely the patient is to develop atrial fibrillation. Several factors play into this, including common risk factors, such as advanced age, hypertension, and ischemic or valvular heart disease. Treatment is aimed at anticoagulation, to prevent thromboembolic stroke, and rate control to prevent further hemodynamic compromise. Rhythm control may be beneficial for many patients and this can be accomplished through the use of antiarrhythmic medications, cardioversion, and/or ablation.

TNF receptor-associated factor 6 (TRAF6) mediates the angiotensin-induced non-canonical TGF-β pathway activation of c-kit(+) cardiac stem cells

Cardiac stem cells (CSCs) can differentiate into cardiac muscle-like cells upon stimulation by angiotensin II (Ang II). TNF receptor-associated factor 6 (TRAF6) has been shown to promote JNK- and p38-induced myogenic differentiation and mediate Smad-independent activation of TGF-β. However, the detailed mechanisms underlying the activation of these signaling pathways are not entirely known. Herein, we hypothesized that Ang II could promote the differentiation of CSCs into cardiac muscle-like cells by non-canonical TGF-β/TRAF6 signaling pathway, and sought to test the hypothesis. C-kit(+) CSCs were isolated from neonatal Sprague Dawley (SD) rats, and their c-kit status was confirmed with immunofluorescence staining. A TGF-β type I receptor inhibitor (SB431542) was used to inhibit SMAD2/3 phosphorylation. The small interfering RNA (siRNA)-mediated knockdown of TRAF6 was used to investigate the role of TRAF6 in TGF-β signaling. Rescue of TRAF6 siRNA transfected cells with a 3'UTR-deleted siRNA insensitive construct was performed to rule out any off-target effects of the siRNA. TRAF6 dominant-negative (TRAF6DN) vector was constructed and used to infect c-kit(+) CSCs. Our results showed that the increase in JNK and p38 activation by Ang-II was blocked by siRNA. After transfection by TRAF6-siRNA or Ad-TRAF6, the cardiac specific markers and Wnt signaling proteins were tested by Western blotting. Physical interactions between TRAF6 and TGF-β receptors were studied by co-immunoprecipitation. Forced expression of TRAF6 enhanced the expression of cTnT and Cx-43 but inhibited the expression of Wnt3a.Our data suggested that TRAF6 mediated Ang II-induced differential responses in c-kit(+) CSCs via the non-canonical TGF-β signaling pathway.

Bioptic Study of Left and Right Atrial Interstitium in Cardiac Patients with and without Atrial Fibrillation: Interatrial but Not Rhythm-Based Differences

One of the generally recognized factors contributing to the initiation and maintenance of atrial fibrillation (AF) is structural remodeling of the myocardium that affects both atrial cardiomyocytes as well as interstitium. The goal of this study was to characterize morphologically and functionally interstitium of atria in patients with AF or in sinus rhythm (SR) who were indicated to heart surgery. Patient population consisted of 46 subjects (19 with long-term persistent AF, and 27 in SR) undergoing coronary bypass or valve surgery. Peroperative bioptic samples of the left and the right atria were examined using immunohistochemistry to visualize and quantify collagen I, collagen III, elastin, desmin, smooth muscle actin, endothelium and Vascular Endothelial Growth Factor (VEGF). The content of interstitial elastin, collagen I, and collagen III in atrial tissue was similar in AF and SR groups. However, the right atrium was more than twofold more abundant in elastin as compared with the left atrium and similar difference was found for collagen I and III. The right atrium showed also higher VEGF expression and lower microvascular density as compared to the left atrium. No significant changes in atrial extracellular matrix fiber content, microvascular density and angiogenic signaling, attributable to AF, were found in this cohort of patients with structural heart disease. This finding suggests that interstitial fibrosis and other morphological changes in atrial tissue are rather linked to structural heart disease than to AF per se. Significant regional differences in interstitial structure between right and left atrium is a novel observation that deserves further investigation.

Optimization of catheter ablation of atrial fibrillation: insights gained from clinically-derived computer models

Atrial fibrillation (AF) is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA) is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation.