Atrial fibrillation and heart failure: update 2015

Does asymptomatic atrial fibrillation exist?

Atrial fibrillation (AF) is currently defined as symptomatic by asking patients if they are aware of when they are in AF and if they feel better in sinus rhythm. However, this approach of defining AF as symptomatic and asymptomatic fails to adequately consider the adverse effects of AF in patients who are unaware of their rhythm including progression from paroxysmal to persistent AF, and the development of dementia, stroke, sinus node dysfunction, valvular regurgitation, ventricular dysfunction, and heart failure. Labeling these patients as asymptomatic falsely suggests that their AF requires less intense therapy and puts into question the notion of truly asymptomatic AF. Because focusing on patient awareness ignores other important consequences of AF, clinical endpoints that are independent of symptoms are being developed. The concept of AF burden has more recently been used as a clinical endpoint in clinical trials as a more clinically relevant endpoint compared to AF-related symptoms or time to first recurrence, but its correlation with symptoms and other clinical outcomes remains unclear. This review will explore the impact of AF on apparently asymptomatic patients, the use of AF burden as an endpoint for AF management, and potential refinements to the AF burden metric. The review is based on a presentation by the senior author during the 2023 16th annual European Cardiac Arrhythmia Society (ECAS) congress in Paris, France.

Increased Risk for Atrial Alternans in Rabbit Heart Failure: The Role of Ca2+/Calmodulin-Dependent Kinase II and Inositol-1,4,5-trisphosphate Signaling

Heart failure (HF) increases the probability of cardiac arrhythmias, including atrial fibrillation (AF), but the mechanisms linking HF to AF are poorly understood. We investigated disturbances in Ca2+ signaling and electrophysiology in rabbit atrial myocytes from normal and failing hearts and identified mechanisms that contribute to the higher risk of atrial arrhythmias in HF. Ca2+ transient (CaT) alternans-beat-to-beat alternations in CaT amplitude-served as indicator of increased arrhythmogenicity. We demonstrate that HF atrial myocytes were more prone to alternans despite no change in action potentials duration and only moderate decrease of L-type Ca2+ current. Ca2+/calmodulin-dependent kinase II (CaMKII) inhibition suppressed CaT alternans. Activation of IP3 signaling by endothelin-1 (ET-1) and angiotensin II (Ang II) resulted in acute, but transient reduction of CaT amplitude and sarcoplasmic reticulum (SR) Ca2+ load, and lowered the alternans risk. However, prolonged exposure to ET-1 and Ang II enhanced SR Ca2+ release and increased the degree of alternans. Inhibition of IP3 receptors prevented the transient ET-1 and Ang II effects and by itself increased the degree of CaT alternans. Our data suggest that activation of CaMKII and IP3 signaling contribute to atrial arrhythmogenesis in HF.

Neutrophil to lymphocyte ratio (NLR) prognostic effects on heart failure; a systematic review and meta-analysis

BACKGROUND

Neutrophil to lymphocyte ratio (NLR), as a recent inflammatory index, has been reported to be a prognostic tool in different diseases. However, implication of this ratio in heart failure (HF) is less investigated. In this systematic review and meta-analysis, we aimed to assess the potential impact of NLR on HF clinical outcomes.

METHODS

Relevant English published records in PubMed, Scopus, Embase, and Web of Science were screened up to July 2023. Articles reporting clinical outcomes (follow-up or in-hospital mortality, readmission, HF prediction, extended hospital stay length, pulmonary vascular resistance, atrial fibrillation, renal disease and functional capacity) in HF sufferers were collected for further analysis with addition of NLR difference stratified by death/survived and HF status.

RESULTS

Thirty-six articles (n = 18231) were finally selected which reported NLR in HF sufferers (mean: 4.38, 95% confidence interval (CI): 4.02-4.73). We found 25 articles reported NLR and total mortality (either follow-up death (N = 19): 4.52 (95% CI: 4.03-5.01) or in-hospital death (N = 10): 5.33 (95% CI: 4.08-6.57)) with mean NLR of 4.74 (95% CI: 4.28-5.20). NLR was higher among deceased patients compared to survived ones (standard mean difference: 0.67 (95% CI: 0.48-0.87), P < 0.001)). NLR was found to be related with higher mortality risk (continuous variable: hazard ratio (HR): 1.12, 95% CI: 1.02-1.23, P = 0.013), categorical variable: HR: 1.77, 95% CI: 1.27-2.46, P = 0.001, T2 vs. T1: HR:1.56, 95%CI: 1.21-2.00, P = 0.001, T3 vs. T1: HR:2.49, 95%CI: 1.85-3.35, P < 0.001). Other aforementioned variables were not feasible to analyze due to presence of few studies.

CONCLUSIONS

NLR is a simple and acceptable prognostic tool for risk stratification and prioritizing high risk patients in clinical settings, especially in resource limited nations.

Effect of sodium glucose cotransporter 2 inhibitors on atrial tachy-arrhythmia burden in patients with cardiac implantable electronic devices

INTRODUCTION

Use of sodium glucose cotransporter 2 inhibitors (SGLT2i) was associated with a reduction in atrial fibrillation hospitalizations. Therefore, we aim to evaluate the effects of SGLT2i on atrial tachy-arrhythmias (ATA) in patients with cardiac implantable electronic devices (CIEDs).

METHODS

All 13 888 consecutive patients implanted with a CIED in two tertiary medical centers were enrolled. Treatment with SGLT2i was assessed as a time dependent variable. The primary endpoint was the total number of ATA. Secondary endpoints included total number of ventricular tachy-arrhythmias (VTA), ATA and VTA, and death. All events were independently adjudicated blinded to the treatment. Multivariable propensity score modeling was performed.

RESULTS

During a total follow-up of 24 442 patient years there were 62 725 ATA and 10 324 VTA events. Use of SGLT2i (N = 696) was independently associated with a significant 22% reduction in the risk of ATA (hazard ratio [HR] = 0.78 [95% confidence interval {CI} = 0.70-0.87]; p < .001); 22% reduction in the risk of ATA/VTA (HR = 0.78 [95% CI = 0.71-0.85]; p < .001); and with a 35% reduction in the risk of all-cause mortality (HR = 0.65 [95% CI = 0.45-0.92]; p = .015), but was not significantly associated with VTA risk (HR = 0.92 [95% CI = 0.80-1.06]; p = .26). SGLT2i were associated with a lower ATA burden in heart failure (HF) patients but not among diabetes patients (HF: HR = 0.68, 95% CI = 0.58-0.80, p < .001 vs. Diabetes: HR = 0.95, 95% CI = 0.86-1.05, p = .29; p < .001 for interaction between SGLT2i indication and ATA burden).

CONCLUSION

Our real world findings suggest that in CIED HF patients, those with SGLT2i had a pronounced reduction in ATA burden and all-cause mortality when compared with those not on SGLT2i.

Prevalence and Prognostic Implication of Atrial Fibrillation in Heart Failure Subtypes: Systematic Review and Meta-Analysis

BACKGROUND

Atrial fibrillation (AF) and heart failure (HF) portends a poor outcome. The HF universal definition has incorporated Heart Failure with mildly reduced Ejection Fraction (HFmrEF). We sought to evaluate the relationship between AF and different HF subtypes, with emphasis on HFmrEF.

METHODS

PubMed and Embase databases were searched up to July 2022. Studies that classified HF with EF≥50% as Heart Failure with Preserved Ejection Fraction (HFpEF); EF 40%-49% as HFmrEF; and EF <40% as Heart Failure with Reduced Ejection Fraction (HFrEF) were included.

RESULTS

Fifty (50) eligible studies, with 126,720 acute HF and 109,683 chronic HF patients, were included. Ten percent (10%) and 12% of patients constituted HFmrEF subtype in patients with acute and chronic HF, respectively. The AF prevalence was 38% (95%CI [33, 44], I²=96.9%) in HFmrEF, as compared to 43% (95%CI [39, 47], I²=97.9%) in HFpEF, and 32% (95%CI [29, 35], I² =98.6%) in HFrEF in acute HF patients. Meta-regression showed HFmrEF shared age as a determinant for AF prevalence with HFrEF and HFpEF. Similar AF prevalence also was observed in chronic HF. Compared to sinus rhythm, AF was associated with an increased risk of all-cause mortality in all HF subtypes: HFmrEF (n=6; HR 1.28, 95%CI [1.08, 1.51], I²=71%), HFpEF (n=10; HR 1.14, 95%CI [1.06, 1.23], I²=55%) and HFrEF (n=9; HR 1.11, 95%CI [1.02, 1.21], I²=78%).

CONCLUSION

The prevalence of AF was intermediate for HFmrEF in between HFpEF and HFrEF, with determinants shared with either HF subtype. The co-existence of AF and HF predicts an increased all-cause mortality across all categories of HF. (PROSPERO registry: CRD42021189411).

Aging-induced atrial fibrosis in If current change and its effect on atrial fibrillation in dogs

BACKGROUND

Atrial fibrillation (AF) is a very common type of cardiac arrhythmia that threatens public health. Aging is an independent AF risk factor. However, the mechanism of age-related AF remains unclear.

METHODS

A total of 36 Beagle dogs were selected and divided into three groups (12 in each group): two groups were 9-year-old aged dogs, and one group was 4-year-old adult dogs. Electrophysiological testing was employed to determine if modeling is successful. Patch-clamp technique was employed to measure the I_f current. The expression of protein and mRNA related to I_f current were also tested. Collagen deposition was observed with the use of Masson staining.

RESULTS

Aging resulted in a higher collagen deposition percentage in the left atrium. The hyperpolarization-activated cyclic nucleotide-gated (HCN)2 and HCN4 expressions were increased in the atria and pulmonary veins but decreased in the sinus node of the aged group. Moreover, in the aged group, the left atrium mRNA expressions of Kcnd2 (Potassium voltage-gated channel subfamily D member 2), Kcnh2, Kcnq1, Kcnj2, Kcnj11, and CACNA1H were significantly downregulated. The aged AF group also demonstrated sustained AF and significant changes in electrophysiological characteristics. The I_f current demonstrated an increased amplitude and was easier to activate in the aged AF group than in younger group. Finally, AF occurrence exacerbated aging-induced cardiac fibrosis, thereby aggravating the above-listed symptoms.

CONCLUSION

With age, the increase in atrial fibrosis affected the expression of the ion channels, thereby modulating the I_f current. Moreover, AF also further exacerbated the degree of atrial fibrosis.

Reverse remodeling against the background of cardiac contractility modulation therapy in patients with heart failure and atrial fibrillation

Aim. To study myocardial remodeling in patients with heart failure (HF) with reduced ejection fraction (HFrEF) and atrial fibrillation (AF) against the background of cardiac contractility modulation (CCM) therapy.

Material and methods. In a group of 100 patients with HFrEF and AF, transthoracic echocardiography was performed before CCM device implantation and after 2, 6 and 12 months. All patients received longterm optimal medical therapy for HF before surgery.

Results. Against the background of CCM therapy, there was a  significant increase in left ventricular (LV) ejection fraction, a decrease in LV volume and linear dimensions, a decrease in left atrial volume in patients with coronary and non-coronary HFrEF, with an initial LVEF < and >35%, and also regardless of AF type.

Conclusion. CCM therapy in patients with HFrEF and AF led to favorable myocardial remodeling changes. Further study of CCM effect on  echocardiographic parameters in randomized clinical trials is needed.

Mobile Electrocardiogram Monitoring and Health-Related Quality of Life in Patients With Atrial Fibrillation: Findings From the iPhone Helping Evaluate Atrial Fibrillation Rhythm Through Technology (iHEART) Study

BACKGROUND

Atrial fibrillation (AF) is associated with high recurrence rates and poor health-related quality of life (HRQOL) but few effective interventions to improve HRQOL exist.

OBJECTIVE

The aim of this study was to examine the impact of the "iPhone Helping Evaluate Atrial Fibrillation Rhythm through Technology" (iHEART) intervention on HRQOL in patients with AF.

METHODS

We randomized English- and Spanish-speaking adult patients with AF to receive either the iHEART intervention or usual care for 6 months. The iHEART intervention used smartphone-based electrocardiogram monitoring and motivational text messages. Three instruments were used to measure HRQOL: the Atrial Fibrillation Effect on Quality of Life (AFEQT), the 36-item Short-Form Health survey, and the EuroQol-5D. We used linear mixed models to compare the effect of the iHEART intervention on HRQOL, quality-adjusted life-years, and AF symptom severity.

RESULTS

A total of 238 participants were randomized to the iHEART intervention (n = 115) or usual care (n = 123). Of the participants, 77% were men and 76% were white. More than half (55%) had an AF recurrence. Both arms had improved scores from baseline to follow-up for AFEQT and AF symptom severity scores. The global AFEQT score improved 18.5 and 11.2 points in the intervention and control arms, respectively (P < .05). There were no statistically significant differences in HRQOL, quality-adjusted life-years, or AF symptom severity between groups.

CONCLUSIONS

We found clinically meaningful improvements in AF-specific HRQOL and AF symptom severity for both groups. Additional research with longer follow-up should examine the influence of smartphone-based interventions for AF management on HRQOL and address the unique needs of patients diagnosed with different subtypes of AF.

Comorbidities Associated with One-Year Mortality in Patients with Atrial Fibrillation and Heart Failure

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) commonly coexist and patients with both diseases have a worse prognosis than those with HF or AF alone. The objective of our study was to identify the factors associated with one-year mortality in patients with HF and AF, depending on the left ventricular ejection fraction (LVEF).

METHODS

We included 727 patients with HF and AF consecutively admitted in a clinical emergency hospital between January 2018 and December 2019. The inclusion criteria were age of more than 18 years, diagnosis of chronic HF and AF (paroxysmal, persistent, permanent), and signed informed consent. The exclusion criteria were the absence of echocardiographic data, a suboptimal ultrasound view, and other cardiac rhythms than AF. The patients were divided into 3 groups: group 1 (337 patients with AF and HF with reduced ejection fraction (HFrEF)), group 2 (112 patients with AF and HF with mid-range ejection fraction (HFmrEF)), and group 3 (278 patients with AF and HF with preserved ejection fraction (HFpEF)).

RESULTS

The one-year mortality rates were 36.49% in group 1, 27.67% in group 2, and 27.69% in group 3. The factors that increased one-year mortality were chronic kidney disease (OR 2.35, 95% CI 1.45-3.83), coronary artery disease (OR 1.67, 95% CI 1.06-2.62), and diabetes (OR 1.66, 95% CI 1.05-2.67) in patients with HFrEF; and hypertension in patients with HFpEF (OR 2.45, 95% CI 1.36-4.39).

CONCLUSIONS

One-year mortality in patients with HF and AF is influenced by different factors, depending on the LVEF.

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.

Impact of atrial fibrillation in patients with heart failure and reduced, mid-range or preserved ejection fraction

Objective

To determine the prognostic value of atrial fibrillation (AF) in patients with heart failure (HF) and preserved, mid-range or reduced ejection fraction (EF).

Methods

Patients hospitalised for acute HF were enrolled in the Korean Acute Heart Failure registry, a prospective, observational, multicentre cohort study, between March 2011 and February 2014. HF types were defined as reduced EF (HFrEF, LVEF <40%), mid-range EF (HFmrEF, LVEF 40%–49%) or preserved EF (HFpEF, LVEF ≥50%).

Results

Of 5414 patients enrolled, HFrEF, HFmrEF and HFpEF were seen in 3182 (58.8%), 875 (16.2%) and 1357 (25.1%) patients, respectively. The prevalence of AF significantly increased with increasing EF (HFrEF 28.9%, HFmrEF 39.8%, HFpEF 45.2%; p for trend <0.001). During follow-up (median, 4.03 years; IQR, 1.39–5.58 years), 2806 (51.8%) patients died. The adjusted HR of AF for all-cause death was 1.06 (0.93–1.21) in the HFrEF, 1.10 (0.87–1.39) in the HFmrEF and 1.22 (1.02–1.46) in the HFpEF groups. The HR for the composite of all-cause death or readmission was 0.97 (0.87–1.07), 1.14 (0.93–1.38) and 1.03 (0.88–1.19) in the HFrEF, HFmrEF and HFpEF groups, respectively, and the HR for stroke was 1.53 (1.03–2.29), 1.04 (0.57–1.91) and 1.90 (1.13–3.20), respectively. Similar results were observed after propensity score matching analysis.

Conclusions

AF was more common with increasing EF. AF was seen to be associated with increased mortality only in patients with HFpEF and was associated with an increased risk of stroke in patients with HFrEF or HFpEF.

Trial registration number

NCT01389843

Left atrial appendage closure in patients with a reduced left ventricular ejection fraction: results from the multicenter German LAARGE registry

Background

Interventional left atrial appendage closure (LAAC) effectively prevents thromboembolic events in atrial fibrillation patients. Impaired left ventricular ejection fraction (LVEF) increases not only the thromboembolic risk but also the complication rates of cardiac interventions. The LAAC procedure’s benefit in patients with an impaired LVEF, therefore, has yet to be investigated.

Methods

LAARGE is a prospective, non-randomized registry depicting the clinical reality of LAAC in Germany. Procedure was conducted with different standard commercial devices, and follow-up period was one year. In the sense of an as-treated analysis, patients with started procedure and documented LVEF were selected from the whole database.

Results

619 patients from 37 centers were categorized into one of three groups: LVEF > 55% (56%), 36–55% (36%), and ≤ 35% (8%). Prevalence of cardiovascular comorbidity increased with LVEF reduction (p < 0.001 for trend). CHA₂DS₂-VASc score was 4.3, 4.8, and 5.1 (p < 0.001), and HAS-BLED score was 3.7, 4.1, and 4.2 (p < 0.001). Implantation success was consistently high (97.9%), rates of intra-hospital MACCE (0.5%), and other major complications (4.2%) were low (each p = NS). Kaplan–Meier estimation showed a decrease in survival free of stroke with LVEF reduction during one-year follow-up (89.3 vs. 87.0 vs. 79.8%; p = 0.067), a trend which was no longer evident after adjustment for relevant confounding factors. Rates of non-fatal strokes (0.4 vs. 1.1 vs. 0%) and severe bleedings (0.7 vs. 0.0 vs. 3.1%) were consistently low across all groups (each p = NS).

Conclusions

LVEF reduction neither influenced the procedural success nor the effectiveness and safety of stroke prevention by LAAC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02230748

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01627-8) contains supplementary material, which is available to authorized users.

Global research productions pertaining to atrial fibrillation from 2004 to 2018: A bibliometric analysis

BACKGROUND

We analyzed the scientific outputs of global atrial fibrillation (AF) researches, developed a model to qualitatively and quantitatively evaluate the AF research productions from 2004 to 2018.

METHODS

The data was retrieved from the Web of Science Core Collection (WOSCC) on June 15, 2019. Bibliometrics tools-CiteSpace V (Drexel university, Chaomei Chen) and VOSviewer (Leiden University, van Eck NJ) --were used for bibliometric analyzing published outputs and finding research hotspots.

RESULTS

There were a total of 21,839 research articles on AF, and the annual publication rate increased over time from 2004 to 2018. The Journal of Cardiovascular Electrophysiology published the greatest number of articles, and the leading country was the United States. The leading institution was the Mayo Clinic, and the most productive researchers were: LIP GYH, Natale A, Chen SA, DI Biase L, and Kuck KH. The keywords analysis showed that catheter ablation, risk, heart failure, stroke, and management were research hotspots.

CONCLUSION

Bibliometric analysis of the literature shows that research on AF continues to be a hot spot, and the clinical treatment of AF is an important research frontier. However, further research and collaboration are needed worldwide. Our findings aim to provide valuable information for the editors of journals that publish research on arrhythmia, and to help researchers identify new perspectives for future researches.

Arrhythmogenic mechanisms of obstructive sleep apnea in heart failure patients

Heart failure (HF) affects 23 million people worldwide and results in 300000 annual deaths. It is associated with many comorbidities, such as obstructive sleep apnea (OSA), and risk factors for both conditions overlap. Eleven percent of HF patients have OSA and 7.7% of OSA patients have left ventricular ejection fraction <50% with arrhythmias being a significant comorbidity in HF and OSA patients. Forty percent of HF patients develop atrial fibrillation (AF) and 30%-50% of deaths from cardiac causes in HF patients are from sudden cardiac death. OSA is prevalent in 32%-49% of patients with AF and there is a dose-dependent relationship between OSA severity and resistance to anti-arrhythmic therapies. HF and OSA lead to various downstream arrhythmogenic mechanisms, including metabolic derangement, remodeling, inflammation, and autonomic imbalance. (1) Metabolic derangement and production of reactive oxidative species increase late Na+ currents, decrease outward K+ currents and downregulate connexin-43 and cell-cell coupling. (2) remodeling also features downregulated K+ currents in addition to decreased Na+/K+ ATPase currents, altered Ca2+ homeostasis, and increased density of If current. (3) Chronic inflammation leads to downregulation of both Nav1.5 channels and K+ channels, altered Ca2+ homeostasis and reduced cellular coupling from alterations of connexin expression. (4) Autonomic imbalance causes arrhythmias by evoking triggered activity through increased Ca2+ transients and reduction of excitation wavefront wavelength. Thus, consideration of these multiple pathophysiological pathways (1-4) will enable the development of novel therapeutic strategies that can be targeted against arrhythmias in the context of complex disease, such as the comorbidities of HF and OSA.

β-blockers and risk of all-cause mortality in patients with chronic heart failure and atrial fibrillation-a meta-analysis

BACKGROUND

Effects of β-blockers on outcomes in patients with chronic heart failure (CHF) and atrial fibrillation (AF) is still in controversy.

METHODS

Searching was conducted by using keywords "atrial fibrillation", and "heart failure" in PubMed, MEDLINE and Embase databases before November 30, 2017. Prospective studies [i.e. randomized control trials (RCTs), post-hoc analysis of RCTs, prospective cohort studies and registry studies] that studied the effect of β-blockers and all-cause mortality in patients with CHF and AF were included. The analysis was stratified by study design.

RESULTS

We identified 12 studies, including 6 post-hoc analysis of RCTs and 6 observational studies (including prospective registry studies and prospective cohort studies), which enrolled 38,133 patients with CHF and AF. Overall, β-blockers treatment was associated with significant decrease in all-cause mortality [Risk Ratio (RR) =0.73; 95% Confidence Interval (CI) 0.65-0.82, P < 0.001]. When stratified by study design, β-blockers treatment was associated with 34% reduction in patients with CHF and AF in observational study (RR = 0.66; 95% CI 0.58-0.76, P < 0. 001), but not in post-hoc analysis of RCT (RR = 0.87; 95% CI 0.74-1.02, P = 0.09).

CONCLUSIONS

β-blockers treatment was associated with significantly decrease the risk of all-cause mortality in patients with AF-CHF and it was only seen in observational study group, but not in subgroup analysis of RCT group. Further large RCTs are required to verify the effect of β-blockers treatment on patients with CHF and AF. The main limitation of this study is the lack of individual data on patients in each study.

[Prognosis of the life of patients with chronic heart failure and atrial fibrilla-tion, depending on the control of hemodynamic parameters and tolerance to physical exertion in the background of basic therapy]

Actuality. In the basic therapy of CHF, drugs that reduce the pulse is one of the leading places. Target values of heart rate with sinus rhythm are established. Tere is still no consensus as to which heart rate is ideal in patients with CHF on the background of the rhythm of atrial fbrillation (AF). Te study of the prognosis in patients with CHF and AF depending on the achieved heart rate is relevant.

OBJECTIVE

To analyze the overall mortality and establish the stratifcation risks of death in patients with CHF and AF depending on the form of AF, functional class of CHF and the presence of tachycardia.

MATERIAL AND METHODS

A prospective cohort study was conducted in a group of patients with CHF who were observed at the City Center for CHF treatment (n = 591) during the year. Of these, 47.4% of patients had CHF and AF (n = 280) and 52.6% of patients with CHF without AF (n = 311).

RESULTS

In a year, a permanent AF registered among patients with CHF and AF in 55.4%, persistent - in 36.4%, and paroxysmal - in 8.2% of cases. In 12.2% of patients, the diagnosis of AF was frst diagnosed. According to functional class of CHF, LVEF, assessment of clinical assessment scale, the group with a permanent AF was signifcantly heavier than without AF. Te mortality of patients with tachycardia signifcantly increased as a function of the increase in CHF from I-II to III-IV class: from 3.6% to 14.9% in the group without AF (p=0.04), and in the group with paroxysmal and persistent AF from 6.7% to 25.9% (p = 0.043). Te presence of tachycardia increases the risk of death by 61%, and the transition to a heavier functional class is 4.9 times. With each increase in the clinical assessment scale exponent by 1 point, the mortality rate in the sample is increased by 16%.

CONCLUSION

Heart rate is not an independent predictor of death, but in combination with functional class III-IV CHF tachycardia signifcantly worsens the prognosis.

Recent approaches to His-Purkinje system pacing

OBJECTIVE

Physiologic cardiac pacing is a novel technique which has been largely popularized in recent decades. His bundle pacing (HBP) has been long considered the most physiologic pacing method; however, with the widespread implementation of this method, its disadvantages have become apparent. In this context, left bundle branch pacing (LBBP)-directly engaged in the His-Purkinje system-has been foreseen as the best pacing method to mimic physiologic activation patterns. This review aimed to summarize recent approaches to physiologic cardiac pacing.

DATA SOURCES

This review included fully peer reviewed publications up to July 2018, found in the PubMed database using the keywords "His bundle branch pacing," "right ventricular pacing," and "physiologic pacing."

STUDY SELECTION

All selected articles were in English, with no restriction on study design.

RESULTS

The HBP has been studied worldwide, and is currently considered the most physiologic pacing method. However, it has disadvantages, such as high pacing threshold, unsatisfactory sensing and long procedure times, among others. Although LBBP is theoretically superior to HBP, the clinical relevance of this difference remains under debate, as few large randomized clinical trials with LBBP have been published.

CONCLUSIONS

Although HBP indeed appears to be the most physiologic pacing method, it has certain shortcomings, such as high pacing threshold, difficult implantation due to specific anatomic features, and others. Further studies are required to clarify the clinical significance of LBBP.

Prevalence and risk factors for atrial fibrillation and its anticoagulant requirement in adults aged ≥40 in Jimma Town, Southwest Ethiopia: A community based cross-sectional study

BACKGROUND

There is no information on the prevalence and incidence of atrial fibrillation in Ethiopia. We aimed to investigate the prevalence, risk factors and anticoagulant requirements of atrial fibrillation in an elderly Jimma population.

METHODS

In a community-based cross-sectional study in 634 adult (≥40 years) Jimma population, we performed cardiovascular health examinations including a 12-lead electrocardiogram to estimate AF prevalence. A standardized questionnaire was used to collect information on medical history, lifestyle and use of medications. Stroke risk stratification was done using CHA2DS2-VASc score. We used logistic regressions to determine the potential risk factors of AF.

RESULTS

The overall prevalence of AF was 4.3%. AF was associated with sex, current smoking, hypertension and BMI. Nineteen out of twenty seven participants with AF were in need of anticoagulation to prevent risk of stroke.

CONCLUSION

The prevalence of AF is high and common risk factors were sex, current smoking, hypertension, and higher BMI in this cohort. More than two-third of study participants with AF were at higher need of oral anticoagulants.

Tongguan capsule-derived herb reduces susceptibility to atrial fibrillation by inhibiting left atrial fibrosis via modulating cardiac fibroblasts

Tongguan capsule is a compound Chinese medicine used to treat ischaemic heart diseases. This study aimed to investigate whether Tongguan capsule-derived herb (TGD) has a preventive effect on atrial fibrillation (AF) in post-myocardial infarction (MI) rats and to determine the underlying mechanisms. MI was induced by ligation of the left anterior descending coronary artery. TGD was administered to the post-MI rats over a 4-week period. The TGD-treated rats had lower rates of AF inducibility and shorter AF durations than the MI rats. TGD improved the left atrial (LA) conduction velocity and homogeneity. It reduced the fibrosis-positive areas and the protein levels of collagen types I and III in the left atrium. In vitro, it inhibited the expression of collagen types I and III by inhibiting the proliferation, migration, differentiation and cytokine secretion of cardiac fibroblasts (CFs). In conclusion, the current study demonstrated that TGD reduces susceptibility to AF and improves LA conduction function in rats with post-MI by inhibiting left atrial fibrosis and modulating CFs. Targeting the CF population may be a novel antiarrhythmic therapeutic approach.

Cardiac rhythm disorders in obstructive sleep apnea

Obstructive sleep apnea (OSA) is common among patients with cardiac rhythm disorders. OSA may contribute to arrhythmias due to acute mechanisms, such as generation of negative intrathoracic pressure during futile efforts to breath, intermittent hypoxia, and surges in sympathetic activity. In addition, OSA may lead to heart remodeling and increases arrhythmia susceptibility. Atrial distension and remodeling, that has been shown to be associated with OSA, is a well-known anatomical substrate for atrial fibrillation (AF). AF is the arrhythmia most commonly described in patients with OSA. Several observational studies have shown that the treatment of OSA with continuous positive airway pressure (CPAP) reduces recurrence of AF after electrical cardioversion and catheter ablation. There is also evidence that nocturnal hypoxemia, a hallmark of OSA, predicts sudden cardiac death (SCD) independently of well-established cardiovascular risk factors. Among patients with an implantable cardiac defibrillator, those with OSA have a higher risk of receiving treatment for life-threatening arrhythmias. Nocturnal hypoxemia may also increase vagal tone, which increases susceptibility to bradycardic and conduction rhythm disorders that have also been described in patients with OSA. In conclusion, there are several biological pathways linking OSA and increased cardiac arrhythmogenesis propensity. However, the independent association is derived from observational studies and the direction of the association still needs clarification due to the lack of large clinical trials. This review focuses on the current scientific evidence linking OSA to cardiac rhythm disorders and point out future directions.

Shensong Yangxin capsule reduces atrial fibrillation susceptibility by inhibiting atrial fibrosis in rats with post-myocardial infarction heart failure

Purpose

Shensong Yangxin (SSYX) capsule is a traditional Chinese medicine that has been used widely to treat cardiac arrhythmia. This study aimed to assess whether SSYX prevents atrial fibrillation (AF) after chronic myocardial infarction (MI)-induced heart failure and to determine the underlying mechanisms.

Materials and methods

The study included 45 male Sprague Dawley rats. The rats underwent MI induction or sham surgery. One week after MI induction surgery, we performed serial echocardiography and administered SSYX capsule to some rats that experienced MI. After 4 weeks of treatment, AF inducibility was assessed with transesophageal programmed electrical stimulation technology. Additionally, multielectrode array assessment, histological analysis, and Western blot analysis were performed.

Results

AF inducibility was significantly lower in SSYX rats than in MI rats (33.3% vs 73.3%, P<0.05). Additionally, conduction velocities in the left atrium were greater in SSYX rats than in MI rats. Moreover, SSYX decreased left atrial fibrosis, downregulated TGF-β1, MMP-9, TIMP-I, and type I and III collagen expressions, and inhibited the differentiation of cardiac fibroblasts to myofibroblasts.

Conclusion

SSYX reduces AF inducibility after MI by improving left atrial conduction function via the inhibition of left atrial fibrosis. It prevents the development of an MI-induced vulnerable substrate for AF.

Atrial Fibrillation and Heart Failure: Untangling a Modern Gordian Knot

Heart failure (HF) and atrial fibrillation (AF) share common risk factors and frequently coexist. Both are highly prevalent in our aging population, and mortality associated with the combination is significantly higher than for each alone. An intricate link exists between AF and HF, including interrelated mechanisms and pathophysiology. Asymptomatic left ventricular systolic or diastolic dysfunction can exacerbate or be exacerbated by AF, resulting in HF with reduced ejection fraction or preserved ejection fraction. A number of treatment strategies have improved symptoms, exercise tolerance, and quality of life for patients with HF, but few have resulted in alteration in prognosis. Sinus rhythm, achieved pharmacologically, has not altered important outcomes, including cardiovascular or total mortality in patients with HF. In recent studies, catheter ablation to achieve sinus rhythm seems to have a significant impact on symptoms, heart function, and possibly mortality. Until future studies can confirm or clarify the impact of catheter ablation on outcomes, the field remains cautious but optimistic that better treatment strategies for patients with HF with reduced ejection fraction or preserved ejection fraction are within reach.

Atrial Fibrillation Burden: Moving Beyond Atrial Fibrillation as a Binary Entity: A Scientific Statement From the American Heart Association

Our understanding of the risk factors and complications of atrial fibrillation (AF) is based mostly on studies that have evaluated AF in a binary fashion (present or absent) and have not investigated AF burden. This scientific statement discusses the published literature and knowledge gaps related to methods of defining and measuring AF burden, the relationship of AF burden to cardiovascular and neurological outcomes, and the effect of lifestyle and risk factor modification on AF burden. Many studies examine outcomes by AF burden classified by AF type (paroxysmal versus nonparoxysmal); however, quantitatively, AF burden can be defined by longest duration, number of AF episodes during a monitoring period, and the proportion of time an individual is in AF during a monitoring period (expressed as a percentage). Current guidelines make identical recommendations for anticoagulation regardless of AF pattern or burden; however, a review of recent evidence suggests that higher AF burden is associated with higher risk of stroke. It is unclear whether the risk increases continuously or whether a threshold exists; if a threshold exists, it has not been defined. Higher burden of AF is also associated with higher prevalence and incidence of heart failure and higher risk of mortality, but not necessarily lower quality of life. A structured and comprehensive risk factor management program targeting risk factors, weight loss, and maintenance of a healthy weight appears to be effective in reducing AF burden. Despite this growing understanding of AF burden, research is needed into validation of definitions and measures of AF burden, determination of the threshold of AF burden that results in an increased risk of stroke that warrants anticoagulation, and discovery of the mechanisms underlying the weak temporal correlations of AF and stroke. Moreover, developments in monitoring technologies will likely change the landscape of long-term AF monitoring and could allow better definition of the significance of changes in AF burden over time.

Risk factors for heart failure hospitalizations among patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) have an increased risk for the development of heart failure (HF). In this study, we aimed to detect predictors of HF hospitalizations in an unselected AF population.

Methods

The Basel Atrial Fibrillation Cohort Study is an ongoing observational multicenter cohort study in Switzerland. For this analysis, 1193 patients with documented AF underwent clinical examination, venous blood sampling and resting 12-lead ECG at baseline. Questionnaires about lifestyle and medical history were obtained in person at baseline and during yearly follow-up phone calls. HF hospitalizations were validated by two independent physicians. Cox regression analyses were performed using a forward selection strategy.

Results

Overall, 29.8% of all patients were female and mean age was 69 ±12 years. Mean follow-up time was 3.7 ±1.5 years. Hospitalization for HF occurred in 110 patients, corresponding to an incidence of 2.5 events per 100 person years of follow-up. Independent predictors for HF were body mass index (HR 1.40 [95%CI 1.17; 1.66], p = 0.0002), chronic kidney disease (2.27 [1.49; 3.45], p = 0.0001), diabetes mellitus (2.13 [1.41; 3.24], p = 0.0004), QTc interval (1.25 [1.04; 1.49], p = 0.02), brain natriuretic peptide (2.19 [1.73; 2.77], p<0.0001), diastolic blood pressure (0.79 [0.65; 0.96], p = 0.02), history of pulmonary vein isolation or electrical cardioversion (0.54 [0.36; 0.80], p = 0.003) and serum chloride (0.82 [0.70; 0.96], p = 0.02).

Conclusions

In this unselected AF population, several traditional cardiovascular risk factors and arrhythmia interventions predicted HF hospitalizations, providing potential opportunities for the implementation of strategies to reduce HF among AF patients.

Atrial Fibrillation in Heart Failure: a Therapeutic Challenge of Our Times

Atrial fibrillation (AF) and heart failure (HF) are growing cardiovascular disease epidemics worldwide. There has been an exponential increase in the prevalence of AF and HF correlating with an increased burden of cardiac risk factors and improved survival rates in patients with structural heart disease. AF is associated with adverse prognostic outcomes in HF and is most evident in mild-to-moderate left ventricular (LV) dysfunction where the loss of "atrial kick" translates into poorer quality of life and increased mortality. In the absence of underlying structural heart disease, arrhythmia can independently contribute to the development of cardiomyopathy. Together, these 2 conditions carry a high risk of thromboembolism due to stasis, inflammation and cellular dysfunction. Stroke prevention with oral anticoagulation (OAC) remains a mainstay of treatment. Pharmacologic rate and rhythm control remain limited by variable efficacy, intolerance and adverse reactions. Catheter ablation for AF has resulted in a paradigm shift with evidence indicating superiority over medical therapy. While its therapeutic success is high for paroxysmal AF, it remains suboptimal in persistent AF. A better mechanistic understanding of AF as well as innovations in ablation technology may improve patient outcomes in the future. Refractory cases may benefit from atrioventricular junction ablation and biventricular pacing. The value of risk factor modification, especially with regard to obesity, sleep apnea, hypertension and diabetes, cannot be emphasized enough. Close interdisciplinary collaboration between HF specialists and electrophysiologists is an essential component of good long-term outcomes in this challenging population.

Rosuvastatin reduces the recurrence rate following catheter ablation for atrial fibrillation in patients with heart failure

The aim of the present study was to assess whether rosuvastatin could reduce the recurrence rate of atrial fibrillation (AF) in patients with heart failure (HF) following catheter ablation (CA). A total of 107 patients with HF and AF who underwent CA of AF by endocardial mapping and radiofrequency between June 2012 and May 2014 were recruited. The patients were randomly divided into three subgroups: i) Administered with 10 mg rosuvastatin daily following ablation (group 1, n=36); ii) administered with 20 mg rosuvastatin daily following ablation (group 2, n=36); and iii) only treated with conventional treatment of HF following ablation (group 3, n=35). After the procedure, patients were followed in the outpatient clinic by interrogation of Holter monitoring. The AF recurrence rate of group 2 was low in comparison with group 1 (22.2% vs. 38.9%, P=0.013) and group 3 (22.2% vs. 48.6%, P=0.021). In comparison with baseline, the parameters of the left ventricular ejection fraction, left atrial diameter (LAD), and the levels of N-terminal pronatriuretic peptide and hypersensitive C-reactive protein (hs-CRP) were all improved in three groups. Furthermore, multivariate analysis demonstrated that LAD [hazard ratio (HR): 1.12, 95% confidence interval (CI): 1.06-1.67, P=0.049], hs-CRP (HR: 1.37, 95% CI: 1.11-1.92, P=0.002) and duration of AF (HR: 1.14, 95% CI: 1.09-1.18, P=0.011) were independent predictors of AF recurrence in patients with HF following CA. Therefore, the present study has demonstrated that treatment with 20 mg rosuvastatin daily following CA was able to significantly decrease the recurrence rate of AF in patients with HF, and LAD, hs-CRP, and duration of AF were independent predictors of AF recurrence in patients with HF following CA. In conclusion, the present study has also demonstrated that CA may improve cardiac function in patients with HF and AF.

The State of the Art: Atrial Fibrillation Epidemiology, Prevention, and Treatment

As the most common sustained arrhythmia in adults, atrial fibrillation (AF) is an established and growing epidemic. To provide optimal patient care, it is important for clinicians to be aware of AF's epidemiological trends, methods of risk reduction, and the various available treatment modalities. Our understanding of AF's pathophysiology has advanced, and with this new understanding has come advancements in prevention strategies as well as pharmacological and nonpharmacological treatment options. Following PubMed and MEDLINE searches for AF risk factors, epidemiology, and therapies, we reviewed relevant articles (and bibliographies of those articles) published from 2000 to 2016. This "state-of-the-art" review provides a comprehensive update on the understanding of AF in the world today, contemporary therapeutic options, and directions of ongoing and future study.

Evaluating the benefits of home-based management of atrial fibrillation: current perspectives

Atrial fibrillation (AF) is the most common arrhythmia worldwide, leading to an extensive public health and economic burden. The increasing incidence and prevalence of AF is due to the advancing age of the population, structural heart disease, hypertension, diabetes, and thyroid disease. The majority of costs associated with AF have been attributed to the cost of hospitalization. In order to minimize costs and decrease hospitalizations, counseling on modifiable risk factors contributing to AF has been strongly emphasized. With the release of novel oral anticoagulants bypassing the need for anticoagulant bridging or laboratory monitoring, post-discharge nurse-led home intervention, and novel methods of heart rate monitoring, home-based AF management has reached a new level of ease and sophistication. In this review, we aimed to review modifiable risk factors for AF and various methods of home-based management of AF, along with their benefits.

Heart Failure and Mortality in Patients With Nonvalvular Atrial Fibrillation Started on Novel Oral Anticoagulant Therapy: A Single-Center Experience

Heart failure (HF) is the leading cause of in-hospital morbidity and mortality in the elderly population. Coexistence of HF and atrial fibrillation (AF) increases the risk of thromboembolic events. Oral anticoagulant therapy reduces the risk of thromboembolic events in patients with AF. Novel oral anticoagulants (NOACs) have been introduced as an alternative drug for prevention from thromboembolic events in patients with nonvalvular AF. The primary aim of this study is to investigate the clinical effects of warfarin, dabigatran, and rivaroxaban in patients with nonvalvular AF. The secondary aim of this study is to reveal the predictors of all-cause mortality in patients with nonvalvular AF undergoing NOACs therapy. The study population consisted of 171 patients with nonvalvular AF. Patients were divided into 3 groups according to the usage of oral anticoagulant therapy including coumadin (51 patients), dabigatran (52 patients), and rivaroxaban (68 patients). Although CHA2DS2-VASc score was similar between groups, HAS-BLED score was significantly higher in patients using rivaroxaban. Dyspepsia and itching were more common in patients using dabigatran. Heart failure and vascular disease were more common in the nonsurviving group (10 patients) than in the surviving group (110 patients) in patients using NOACs. Among age, sex, HF, hypertension, vascular disease, and CHA2DS2-VASc, which were included in the regression model, only the presence of HF was an independent predictor of all-cause mortality in patients using NOACs. In conclusion, the mortality rate is significantly higher in patients with HF using NOACs. Moreover, HF is an independent predictor of all-cause mortality in patients using NOACs.