The association between atrial fibrillation and sudden cardiac death: the relevance of heart failure

Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry

BACKGROUND AND AIMS

Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population.

METHODS

One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF.

RESULTS

Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF.

CONCLUSIONS

Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

Real-time machine learning model to predict in-hospital cardiac arrest using heart rate variability in ICU

Predicting in-hospital cardiac arrest in patients admitted to an intensive care unit (ICU) allows prompt interventions to improve patient outcomes. We developed and validated a machine learning-based real-time model for in-hospital cardiac arrest predictions using electrocardiogram (ECG)-based heart rate variability (HRV) measures. The HRV measures, including time/frequency domains and nonlinear measures, were calculated from 5 min epochs of ECG signals from ICU patients. A light gradient boosting machine (LGBM) algorithm was used to develop the proposed model for predicting in-hospital cardiac arrest within 0.5-24 h. The LGBM model using 33 HRV measures achieved an area under the receiver operating characteristic curve of 0.881 (95% CI: 0.875-0.887) and an area under the precision-recall curve of 0.104 (95% CI: 0.093-0.116). The most important feature was the baseline width of the triangular interpolation of the RR interval histogram. As our model uses only ECG data, it can be easily applied in clinical practice.

From the sideline: Tissue-specific nucleoporin function in health and disease, an update

The subcellular compartmentalisation of eukaryotic cells requires selective exchange between the cytoplasm and the nucleus. Intact nucleocytoplasmic transport is vital for normal cell function and mutations in the executing machinery have been causally linked to human disease. Central players in nucleocytoplasmic exchange are nuclear pore complexes (NPCs), which are built from ~30 distinct proteins collectively termed nucleoporins. Aberrant nucleoporin expression was detected in human cancers and autoimmune diseases since quite some time, while it was through the increasing use of next generation sequencing that mutations in nucleoporin genes associated with mainly rare hereditary diseases were revealed. The number of newly identified mutations is steadily increasing, as is the number of diseases. Mutational hotspots have emerged: mutations in the scaffold nucleoporins seemingly affect primarily inner organs, such as heart, kidney, and ovaries, whereas genetic alterations in peripheral, cytoplasmic nucleoporins affect primarily the central nervous system and development. In this review, we summarise latest insights on altered nucleoporin function in the context of human hereditary disorders, with a focus on those where mechanistic insights are beginning to emerge.

Prediction of Sudden Cardiac Death Manifesting With Documented Ventricular Fibrillation or Pulseless Ventricular Tachycardia

OBJECTIVES

This study aimed to develop a novel clinical prediction algorithm for avertable sudden cardiac death.

BACKGROUND

Sudden cardiac death manifests as ventricular fibrillation (VF)/ ventricular tachycardia (VT) potentially treatable with defibrillation, or nonshockable rhythms (pulseless electrical activity/asystole) with low likelihood of survival. There are no available clinical risk scores for targeted prediction of VF/VT.

METHODS

Subjects with out-of-hospital sudden cardiac arrest presenting with documented VF or pulseless VT (33% of total cases) were ascertained prospectively from the Portland, Oregon, metro area with population ≈1 million residents (n = 1,374, 2002-2019). Comparisons of lifetime clinical records were conducted with a control group (n = 1,600) with ≈70% coronary disease prevalence. Prediction models were constructed from a training dataset using backwards stepwise logistic regression and applied to an internal validation dataset. Receiver operating characteristic curves (C statistic) were used to evaluate model discrimination. External validation was performed in a separate, geographically distinct population (Ventura County, California, population ≈850,000, 2015-2020).

RESULTS

A clinical algorithm (VFRisk) constructed with 13 clinical, electrocardiogram, and echocardiographic variables had very good discrimination in the training dataset (C statistic = 0.808; [95% CI: 0.774-0.842]) and was successfully validated in internal (C statistic = 0.776 [95% CI: 0.725-0.827]) and external (C statistic = 0.782 [95% CI: 0.718-0.846]) datasets. The algorithm substantially outperformed the left ventricular ejection fraction (LVEF) ≤35% (C statistic = 0.638) and performed well across the LVEF spectrum.

CONCLUSIONS

An algorithm for prediction of sudden cardiac arrest manifesting with VF/VT was successfully constructed using widely available clinical and noninvasive markers. These findings have potential to enhance primary prevention, especially in patients with mid-range or preserved LVEF.

Catheter Ablation Compared with Medical Therapy for Atrial Fibrillation with Heart Failure: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background: The optimal strategy for patients with coexisting atrial fibrillation (AF) and heart failure (HF) was not settled. Our purpose was to conduct a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of catheter ablation compared with medical therapy for AF on mortality, HF hospitalization, left ventricular (LV) function, and quality of life among patients with HF and AF. Materials and Methods: We searched Pubmed (1966 to September 20, 2019), EMBASE (1966 to September 20, 2019), the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov for randomized controlled trials with a comparison of catheter ablation for AF with medical therapy among patients with coexisting AF and HF. Risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI) was used as a measure of the effect of catheter ablation versus medical therapy on endpoints. Our final analysis included 6 randomized control trials with 775 patients. Results: Pooled results from the random-effects model showed that compared with medical therapy for AF, catheter ablation was associated with reduced all-cause mortality (RR 0.52, 95%Cl, 0.35 to 0.76) and HF hospitalization (RR 0.56, 95%Cl, 0.44 to 0.71), as well as increased LV ejection fraction (LVEF), distance walked in six minutes, and improvements in quality of life. Conclusions: This updated meta-analysis showed that compared to medical therapy, catheter ablation for AF was associated with significant benefits in several key clinical and biomarker endpoints, including reductions in all-cause mortality and HF hospitalization.

RETRACTED: Safety of radiofrequency ablation for reducing inflammatory cytokine levels and the left atrial diameter in patients with atrial fibrillation

Objective

To investigate the safety of radiofrequency ablation for reducing inflammatory cytokines and the left atrial diameter in patients with atrial fibrillation (AF).

Methods

A total of 200 patients with AF who were admitted to our hospital from December 2015 to April 2017 were included in this prospective analysis. Fifty patients were treated with conventional AF medication alone (AF medication group) and 50 patients received radiofrequency ablation (RFA) on the basis of conventional medication (RFA group).

Results

After treatment, the AF medication group showed significantly higher levels of high-sensitivity C-reactive protein, interleukin-6, carboxyterminal propeptide of type-I procollagen, procollagen type III N-terminal propeptide, and matrix metallopeptidase-9 than the RFA group. The AF medication group had a significantly lower activated partial thromboplastin time, thrombin time, and prothrombin time than the RFA group. A significantly smaller left atrial diameter was observed in both groups after treatment, but this decrease was more pronounced in the RFA group than in the AF medication group. The total treatment efficacy rate was significantly lower in the AF medication group than in the RFA group.

Conclusions

For patients with AF, RFA leads to a lower incidence of inflammatory responses, faster recovery of cardiac function, and good safety.

Association Between Atrial Fibrillation and Sudden Cardiac Death

Emerging evidence suggests that atrial fibrillation (AF) may be associated with an increased risk of sudden cardiac death (SCD). However, AF shares risk factors with numerous cardiac conditions, including coronary heart disease and heart failure—the 2 most common substrates for SCD—making the AF-SCD relationship particularly challenging to address. A careful consideration of confounding factors is essential, since interventions for AF will be effective in reducing SCD only if there is a causal association between these 2 conditions. In this translational review, we detail the plausible underlying pathophysiological mechanisms through which AF may promote or lead to SCD, as well as the existing epidemiological evidence supporting an association between AF and SCD. While the role of AF in predicting SCD in the general population appears limited and not established, AF might be integrated to improve risk stratification in some specific phenotypes. Optimal AF management, including that of its associated conditions, appears to be of interest to prevent AF-related SCD, especially because the AF-SCD relationship is in part driven by heart failure.

[Risk of Coronary Events in Atrial Fibrillation]

It has been established that cardiovascular events due to coronary heart disease are highly prevalent in the population of patients with atrial fibrillation. In this review, pathophysiologic mechanisms explaining this association are detailed along with supporting epidemiological evidence. Various methods for the prediction and prevention of coronary events in atrial fibrillation are iscussed, including modification of shared risk factors, antithrombotic therapy and selection of the optimal direct oral anticoagulant in terms of favourable influence on ischemic cardiac outcomes.

A Wearable Electrocardiogram Telemonitoring System for Atrial Fibrillation Detection

In this paper we proposed a wearable electrocardiogram (ECG) telemonitoring system for atrial fibrillation (AF) detection based on a smartphone and cloud computing. A wearable ECG patch was designed to collect ECG signals and send the signals to an Android smartphone via Bluetooth. An Android APP was developed to display the ECG waveforms in real time and transmit every 30 s ECG data to a remote cloud server. A machine learning (CatBoost)-based ECG classification method was proposed to detect AF in the cloud server. In case of detected AF, the cloud server pushed the ECG data and classification results to the web browser of a doctor. Finally, the Android APP displayed the doctor's diagnosis for the ECG signals. Experimental results showed the proposed CatBoost classifier trained with 17 selected features achieved an overall F1 score of 0.92 on the test set (n = 7,270). The proposed wearable ECG monitoring system may potentially be useful for long-term ECG telemonitoring for AF detection.

Atrial Fibrillation Is Associated with Increased Mortality in Patients Presenting with Ventricular Tachyarrhythmias

Heterogenous data about the prognostic impact of atrial fibrillation (AF) in patients with ventricular tachyarrhythmias exist. Therefore, this study evaluates this impact of AF in patients presenting with ventricular tachyarrhythmias. 1,993 consecutive patients presenting with ventricular tachyarrhythmias (i.e. ventricular tachycardia and fibrillation (VT, VF)) on admission at one institution were included (from 2002 until 2016). All medical data of index and follow-up hospitalizations were collected during the complete follow-up period for each patient. Statistics comprised univariable Kaplan-Meier and multivariable Cox regression analyses in the unmatched consecutive cohort and after propensity-score matching for harmonization. The primary prognostic endpoint was long-term all-cause mortality at 2.5 years. AF was present in 31% of patients presenting with index ventricular tachyarrhythmias on admission (70% paroxysmal, 9% persistent, 21% permanent). VT was more common (67% versus 59%; p = 0.001) than VF (33% versus 41%; p = 0.001) in AF compared to non-AF patients. Long-term all-cause mortality at 2.5 years occurred more often in AF compared to non-AF patients (mortality rates 40% versus 24%, log rank p = 0.001; HR = 1.825; 95% CI 1.548-2.153; p = 0.001), which may be attributed to higher rates of all-cause mortality at 30 days, in-hospital mortality and mortality after discharge (p < 0.05) (secondary endpoints). Mortality differences were observed irrespective of index ventricular tachyarrhythmia (VT or VF), LV dysfunction or presence of an ICD. In conclusion, this study identifies AF as an independent predictor of death in patients presenting consecutively with ventricular tachyarrhythmias.

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.

Usefulness of the CHA2DS2-VASc Score to Predict the Risk of Sudden Cardiac Death and Ventricular Arrhythmias in Patients With Atrial Fibrillation

Sudden cardiac death (SCD), the most devastating manifestation of ventricular arrhythmias (VAs), is the leading cause of mortality in patients with atrial fibrillation (AF). We hypothesized that the CHA₂DS₂-VASc score, consisting of age and several clinical risk factors, could be used to estimate the individual risk of SCD/VAs for AF patients. From year 2000 to 2011, 288,181 newly-diagnosed AF patients without antecedent SCD/VAs were identified from "Taiwan National Health Insurance Research Database." During the follow-up of 1,065,751 person-years, 11,166 patients experienced SCD/VAs with an annual risk of 1.05% which increased from 0.34% for patients with a CHA₂DS₂-VASc score of 0% to 2.63% for those with a score of 9. The CHA₂DS₂-VASc score was a significant predictor of SCD/VAs with an adjusted hazard ratio of 1.21 (95% confidence interval 1.20 to 1.22) per 1 point increment of the score. As the CHA₂DS₂-VASc score increased from 1 to 9, the hazard ratio of SCD/VAs continuously increased from 1.28 to 4.17 compared with patients with a CHA₂DS₂-VASc score of 0. In conclusion, CHA₂DS₂-VASc score was a convenient scoring system which could be used to predict the risk of SCD/VAs in AF patients in addition to its ability for stroke risk stratification.

The Potential Application of Heavy Ion Beams in the Treatment of Arrhythmia: The Role of Radiation-Induced Modulation of Connexin43 and the Sympathetic Nervous System

It has been known that heart disease-such as myocardial infarction (MI), cardiac hypertrophy, or heart failure-alters the molecular structure and function of the gap junction, which can lead to an abnormal heart rhythm. Radiation has been shown to modulate intercellular communication in the skin and lungs by increasing connexin43 (Cx43) expression. Understanding how Cx43 upregulation is induced in a diseased heart can help provide a new perspective to radiation therapy for arrhythmias. In a recent study with rabbits after MI, carbon ions were accelerated to 290 MeV/u and extracted in the air; a biologically (cell kill) uniform 6-cm spread-out Bragg peak beam was generated, and beam tissue depth was set to 30 mm with energy degraders to the depth position. Targeted heavy ion irradiation (THIR) with 15 Gy to the left ventricle increased Cx43 expression, improved conductivity, decreased the spatial heterogeneity of repolarization, and reduced the vulnerability of rabbit hearts to ventricular arrhythmias after MI. In clinically normal rabbits, THIR > = 10 Gy caused a significant dose-dependent increase of Cx43 protein and messenger RNA 2 weeks after irradiation. The left (irradiated) and right (nonirradiated) ventricles exhibited circumferential upregulation of Cx43 lasting for at least 1 year. There were no significant changes in electrocardiograms and echocardiograms, indicating no apparent injury for 1 year. A single exposure of 135 MeV/u THIR with 15 Gy to a dog heart attenuated vulnerability to ventricular arrhythmia after the induction of MI for at least 1 year through the modulation of Cx43 expression. This long-lasting remodeling effect on gap junctions may lay the groundwork to novel therapies against life-threatening ventricular arrhythmias in structural heart disease. To date, there have been few investigations into the effects of carbon-ion irradiation on electrophysiological properties in the human heart. Patients with mediastinum cancer were investigated for 5 years after treatment that included irradiation to the heart, and investigators found that carbon-ion beam irradiation to the heart is not immediately cardiotoxic and demonstrates consistent signals of arrhythmia reduction. Its practical application in non-cancer treatment, such as in arrhythmia treatment, is highly anticipated.

Quantification of Ventricular Repolarization Variation for Sudden Cardiac Death Risk Stratification in Atrial Fibrillation

OBJECTIVE

Atrial fibrillation (AF) rhythm gives rise to an irregular response in ventricular activity, preventing the use of standard ECG-derived risk markers based on ventricular repolarization heterogeneity under this particular condition. In this study, we proposed new indices to quantify repolarization variations in AF patients, assessing their stratification performance in a chronic heart failure population with AF.

METHODS

We developed a method based on a selective bin averaging technique. Consecutive beats preceded by a similar RR interval were selected, from which the average variation within the ST-T complex for each RR range was computed. We proposed two sets of indices: 1) the 2-beat index of ventricular repolarization variation, ( I_V2), computed from pairs of stable consecutive beats; and 2) the 3-beat indices of ventricular repolarization variation, computed in triplets of stable consecutive beats ( I_V3).

RESULTS

These indices showed a significant association with sudden cardiac death (SCD) outcome in the study population. In addition, risk assessment based on the combination of the proposed indices improved stratification performance compared to their individual potential.

CONCLUSION

Patients with enhanced ventricular repolarization variation computed in terms of the proposed indices were successfully associated to a higher SCD incidence in our study population, evidencing their prognostic value.

SIGNIFICANCE

using a simple ambulatory ECG recording, it is possible to stratify AF patients at risk of SCD, which may help cardiologists in adopting most effective therapeutic strategies, with a positive impact in both the patient and healthcare systems.

Is atrial fibrillation a risk factor for in-hospital cardiac arrest?: a Swedish retrospective cohort study

INTRODUCTION

Atrial fibrillation (AF) is associated with increased morbidity and mortality. Recent findings suggest that AF is also associated with out-of-hospital cardiac arrest. However, whether that association can be generalised to in-hospital cardiac arrests (IHCAs) is still unknown.

AIMS

To examine whether there is a stronger association with IHCA among hospitalised patients with AF compared with patients without AF.

MATERIALS AND METHODS

All adult patients admitted to the Karolinska University Hospital, Stockholm, Sweden during 2014-2015 were included. Data were drawn from their medical file and matched against the Swedish Registry for Cardiopulmonary Resuscitation. Patients who were documented as ever having the International Classification of Diseases, 10th revision code I48 prior to the current hospitalisation were categorised to the AF group and the remaining were categorised to the non-AF group. The primary outcome was occurrence of an IHCA.

RESULTS

In all, 102 416 patients were included. Among these, 10% had been diagnosed with AF and <1% (n=326) suffered from an IHCA, only 42 (13%) had a VF/VT. In a multivariable model adjusting for sex, age, CharlsonComorbidity Index score and whether the patients had been admitted electively or urgently, having AF was significantly associated with IHCA (OR 1.760; 95% CI 1.356 to 2.269; p<0.001).

CONCLUSIONS

Within this observational cohort study, patients with AF had a stronger association with IHCA than patients without AF. AF might be an independent risk factor for IHCA.

NUP155 insufficiency recalibrates a pluripotent transcriptome with network remodeling of a cardiogenic signaling module

BACKGROUND

Atrial fibrillation is a cardiac disease driven by numerous idiopathic etiologies. NUP155 is a nuclear pore complex protein that has been identified as a clinical driver of atrial fibrillation, yet the precise mechanism is unknown. The present study employs a systems biology algorithm to identify effects of NUP155 disruption on cardiogenicity in a model of stem cell-derived differentiation.

METHODS

Embryonic stem (ES) cell lines (n = 5) with truncated NUP155 were cultured in parallel with wild type (WT) ES cells (n = 5), and then harvested for RNAseq. Samples were run on an Illumina HiSeq 2000. Reads were analyzed using Strand NGS, Cytoscape, DAVID and Ingenuity Pathways Analysis to deconvolute the NUP155-disrupted transcriptome. Network topological analysis identified key features that controlled framework architecture and functional enrichment.

RESULTS

In NUP155 truncated ES cells, significant expression changes were detected in 326 genes compared to WT. These genes segregated into clusters that enriched for specific gene ontologies. Deconvolution of the collective framework into discrete sub-networks identified a module with the highest score that enriched for Cardiovascular System Development, and revealed NTRK1/TRKA and SRSF2/SC35 as critical hubs within this cardiogenic module.

CONCLUSIONS

The strategy of pluripotent transcriptome deconvolution used in the current study identified a novel association of NUP155 with potential drivers of arrhythmogenic AF. Here, NUP155 regulates cardioplasticity of a sub-network embedded within a larger framework of genome integrity, and exemplifies how transcriptome cardiogenicity in an embryonic stem cell genome is recalibrated by nucleoporin dysfunction.

Better clinical outcome with direct oral anticoagulants in hospitalized heart failure patients with atrial fibrillation

Background

Atrial fibrillation (AF) is common in patients with heart failure and is associated with higher mortality. Although previous studies have reported that direct oral anticoagulants (DOACs) reduce the risk of cardiovascular events in out-patients with AF, it remains unclear whether DOACs reduce mortality in hospitalized heart failure (HHF) patients with AF. Therefore, we examined the impact of DOACs on mortality in this group of patients.

Methods

Consecutive 497 HHF patients with AF were retrospectively registered and divided into three groups on the basis of the presence of anticoagulant therapy: non-anticoagulant group (Non, n = 90), Vit K antagonists (VKAs) group (n = 257) and DOACs group (n = 150). We followed up all the patients for mortality.

Results

In the Kaplan-Meier analysis (mean follow-up of 1093 days), all-cause mortality was significantly lower in the VKAs and DOACs groups than in the Non group (31.1% and 15.3% vs. 43.3%, log-rank P < 0.001). In the multivariable Cox proportional hazard analysis after adjusting for other potential confounding factors, usage of DOACs and VKAs were independently associated with lower mortality in HHF patients AF (DOACs, HR 0.356, P = 0.001; VKAs, HR 0.472, P = 0.002). Furthermore, the propensity-matched 1:1 cohort was assessed based on the propensity score (DOACs, n = 114 and VKAs, n = 114). All-cause mortality was significantly lower in the DOACs group than in the VKAs group in the post-matched cohort (12.3% vs. 35.1%, log-rank P = 0.038). In the Cox proportional hazard analysis, the use of DOACs was associated with lower mortality in the post-matched cohort (HR 0.526, P = 0.041).

Conclusion

Appropriate use of anticoagulants in HHF patients with AF is important, and DOACs potentially improve all-cause mortality in such patients.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0746-z) contains supplementary material, which is available to authorized users.

Association of common genetic variants related to atrial fibrillation and the risk of ventricular fibrillation in the setting of first ST-elevation myocardial infarction

Background

Cohort studies have revealed an increased risk for ventricular fibrillation (VF) and sudden cardiac death (SCD) in patients with atrial fibrillation (AF). In this study, we hypothesized that single nucleotide polymorphisms (SNP) previously associated with AF may be associated with the risk of VF caused by first ST-segment elevation myocardial infarction (STEMI).

Methods

We investigated association of 24 AF-associated SNPs with VF in the prospectively assembled case–control study among first STEMI-patients of Danish ancestry.

Results

We included 257 cases (STEMI with VF) and 537 controls (STEMI without VF). The median age at index infarction was 60 years for the cases and 61 years for the controls (p = 0.100). Compared to the control group, the case group was more likely to be male (86% vs. 75%, p = 0.001), have a history of AF (7% vs. 2%, p = 0.006) or hypercholesterolemia (39% vs. 31%, p = 0.023), and a family history of sudden death (40% vs. 25%, p < 0.001). All 24 selected SNPs have previously been associated with AF. None of the 24 SNPs were associated with the risk of VF after adjustment for age and sex under additive genetic model of inheritance in the logistic regression model.

Conclusion

In this study, we found that the 24 AF-associated SNPs may not be involved in increasing the risk of VF. Larger VF cohorts and use of new next generation sequencing and epigenetic may in future identify additional AF and VF risk loci and improve our understanding of genetic pathways behind the two arrhythmias.

The future of atrial fibrillation management: integrated care and stratified therapy

Atrial fibrillation is one of the major cardiovascular health problems: it is a common, chronic condition, affecting 2-3% of the population in Europe and the USA and requiring 1-3% of health-care expenditure as a result of stroke, sudden death, heart failure, unplanned hospital admissions, and other complications. Early diagnosis of atrial fibrillation, ideally before the first complication occurs, remains a challenge, as shown by patients who are only diagnosed with the condition when admitted to hospital for acute cardiac decompensation or stroke. Once diagnosed, atrial fibrillation requires chronic, multidimensional management in five domains (acute management, treatment of underlying and concomitant cardiovascular conditions, stroke prevention therapy, rate control, and rhythm control). The consistent provision of these treatment options to all patients with atrial fibrillation is difficult, despite recent improvements in organisation of care, knowledge about atrial fibrillation, and treatment options. Integrated care models that provide patient-centred care in, or close to, the patient's community while maintaining access to all specialist treatment options, emerge as the best approach to achieve consistent delivery of these chronic treatments to all patients with atrial fibrillation. Ongoing research efforts will establish when to initiate oral anticoagulation in patients with device-detected atrial high-rate episodes, quantify the prognostic effect of early and comprehensive rhythm control therapy, including atrial fibrillation ablation, and delineate optimum methods to reduce bleeding complications in patients treated with anticoagulation. Additionally, research efforts are needed to define different types of atrial fibrillation on the basis of the main causes of atrial fibrillation to pave the way for the clinical development of stratified atrial fibrillation therapy.

Influence of Prevalent and Incident Atrial Fibrillation on Post-Trial Major Events in ALLHAT

AIMS

Limited information is available on long-term antihypertensive and lipid-lowering therapy effects on hypertensive patients with atrial fibrillation/flutter (AF/AFL) compared to those without. AF/AFL at baseline or during the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) (mean follow-up 4.9 years) markedly increased risk of stroke, heart failure, CHD, and all-cause mortality. We aimed to determine if AF/AFL continued to impact outcomes during post-trial follow-up (mean 3.8 years).

METHODS

Patients were randomized to chlorthalidone, amlodipine, or lisinopril, and to pravastatin vs. usual care in the lipid-lowering trial (LLT). Of 31,473 available subjects, AF/AFL occurred in 854; 383/14,371 chlorthalidone (2.7%), 247/8565 amlodipine (2.9%), and 224/8537 lisinopril (2.6%). Post-hoc analyses utilized administrative databases for post-trial data. Individuals with AF/AFL were compared to those without during post-trial. Outcomes were analyzed by treatment groups for the antihypertensive and LLT trials.

RESULTS

Among 854 AF/AFL participants, 491 (57.5%) died: 220 in-trial, 271 post-trial. Ten-year all-cause mortality rates for those with in-trial AF/AFL were similar for chlorthalidone and lisinopril, but lower for amlodipine (68, 66, and 49 per 100 persons, respectively); adjusted HR for amlodipine vs. chlorthalidone was 0.68 (95% CI, 0.54-0.87). Ten-year all-cause mortality rates were 57 vs. 65 per 100 persons (pravastatin vs. usual care); non-CVD mortality rates, 18 vs. 39 per 100 persons (pravastatin vs. usual care) (adjusted HR = 0.46, 95% CI, 0.24-0.86).

CONCLUSION

Post-trial follow-up revealed continued deleterious AF/AFL effects. The amlodipine (ALLHAT) and pravastatin (ALLHAT-LLT) treatment groups showed lower all-cause and non-CVD mortality compared to the chlorthalidone and usual-care groups, respectively.

Patients without comorbidities at the time of diagnosis of atrial fibrillation: causes of death during long-term follow-up compared to matched controls

BACKGROUND

Little is known about the long-term, cause-specific mortality risk in patients without comorbidities at the time of diagnosis of atrial fibrillation (AF).

METHODS

From a nation-wide registry of patients hospitalized with incident AF between 1995 and 2008 we identified 9 519 patients with a first diagnosed AF and no comorbidities at the time of AF diagnosis. They were matched with 12 468 controls. The follow-up continued until December 2008. Causes of death were classified according to the ICD-10 codes.

RESULTS

During follow-up, 11.1% of patients with AF and 8.3% of controls died. Cardiovascular diseases were the most common causes of death and the only diagnoses which showed significantly higher relative risk in patients with AF than controls (HR 2.0, 95% CI 1.8-2.3), and the relative risk was significantly higher in women than in men. Stroke was a more common cause among patients with AF, 13.1% versus 9.7% (HR 2.7, 95% CI 1.8-4.0), while cerebral hemorrhage was more common among controls, 4.7% versus 10.2% (HR 0.9, 95% CI 0.6-1.5). The time from AF diagnosis to death was 6.0 ± 3.1 years.

CONCLUSIONS

In patients with incident AF and no known comorbidities at the time of AF diagnosis, only cardiovascular diseases were more often causes of death as compared to controls. Women carried a significantly higher relative risk than men.

Digoxin Use and Subsequent Clinical Outcomes in Patients With Atrial Fibrillation With or Without Heart Failure in the ENGAGE AF-TIMI 48 Trial

BACKGROUND

Digoxin is widely used in patients with atrial fibrillation despite the lack of randomized controlled trials. Observational studies report conflicting results regarding its association with mortality, perhaps because of residual confounding by the presence of heart failure (HF).

METHODS AND RESULTS

In the ENGAGE AF-TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) trial, clinical outcomes of patients with atrial fibrillation with and without HF were examined by baseline digoxin use during a median follow-up of 2.8 years. HF was defined at baseline as prior or current clinical stage C or D HF. Of 21 105 patients enrolled, 6327 (30%) were treated with digoxin at baseline. Among patients without HF (n=8981), digoxin use (20%) was independently associated with sudden cardiac death (adjusted hazard ratio, 1.51; 95% CI, 1.10-2.08), with no significant interaction by age, sex, left ventricular ejection fraction, renal function, or concomitant medications (P>0.05 for each). Consistent results were observed using propensity matching (adjusted hazard ratio for sudden cardiac death, 1.90; 95% CI, 1.36-2.65). Among patients with HF (n=12 124), digoxin use (37%) was associated with an increase in all-cause death, cardiovascular death, sudden cardiac death, and death caused by HF/cardiogenic shock (P<0.01 for each), but not with noncardiovascular death, stroke/systemic embolism, or myocardial infarction.

CONCLUSIONS

In this observational analysis of patients with atrial fibrillation without investigator-reported HF, digoxin use was significantly associated with sudden cardiac death. While residual confounding cannot be excluded, the association between digoxin use and worse clinical outcomes highlights the need to examine digoxin use, particularly when prescribed to control heart rate in patients with atrial fibrillation in a randomized trial.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00781391.

Atrial fibrillation as a prognostic indicator of myocardial infarction and cardiovascular death: a systematic review and meta-analysis

This study aimed to investigate whether atrial fibrillation (AF) predicts myocardial infarction (MI) or cardiovascular (CV) death. AF is a well-established risk factor for thrombotic stroke and all-cause mortality. PubMed, EmBase, and Cochrane Central were searched for articles comparing the incidence rates of MI, CV death, or CV events between AF and non-AF patients. Relative risk ratio (RR) was used as effect estimate. Crude and adjusted RRs were calculated. Data were pooled using a random-effects model. The meta-analysis included 27 studies. In the unadjusted analysis, AF patients had a nonsignificant trend toward a higher risk of MI compared with non-AF patients; however, a significant association was found. The crude data analysis showed that AF was associated with increased risk of CV death (P < 0.05) and CV events (P < 0.05). These associations remained significant after pooling data from adjusted models (CV death: RR = 1.95, 95% CI 1.51–2.51, P < 0.05; CV events: RR = 2.10, 95% CI 1.50–2.95, P < 0.05). These results showed that AF is an independent risk factor for MI, CV death, and CV events.

Sudden Cardiac Death in Patients With Atrial Fibrillation: Insights From the ENGAGE AF-TIMI 48 Trial

Background

Recent findings suggest that atrial fibrillation is associated with sudden cardiac death (SCD). We examined the incidence, characteristics, and factors associated with SCD in patients with atrial fibrillation.

Methods and Results

SCD was defined as witnessed death ≤60 minutes from the onset of new symptoms or unwitnessed death 1 to 24 hours after being observed alive, without another known cause of death. Predictors of SCD were examined using multivariate competing risks models. Over 2.8 years (median), 2349 patients died (40.5 per 1000 patient‐years), of which 1668 (71%) were cardiovascular deaths. SCD was the most common cause of cardiovascular death (n=749; median age 73 years; 70.6% male). Most SCD events occurred out of hospital (92.8%) and without prior symptoms (66.0%). Predictors of SCD included low ejection fraction, heart failure, and prior myocardial infarction (P<0.001 for each). Additional significant baseline predictors of SCD, but not of other causes of death, included male sex, electrocardiographic left ventricular hypertrophy, higher heart rate, nonuse of beta blockers, and use of digitalis. The latter was associated with SCD in patients with or without heart failure (adjusted hazard ratio 1.55 [95% CI 1.29–1.86] and 1.56 [95% CI 1.14–2.11], respectively; P_interaction=0.73). The rate of SCD was numerically but not statistically lower with edoxaban (1.20% per year with lower dose edoxaban; 1.28% per year with higher dose edoxaban) compared with warfarin (1.40% per year).

Conclusion

SCD is the most common cause of cardiovascular death in patients with atrial fibrillation and has several distinct predictors, some of which are modifiable. These findings may be considered in planning research and treatment strategies for patients with atrial fibrillation.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00781391.

The Prognostic Significance of Cardiac Structure and Function in Atrial Fibrillation: The ENGAGE AF-TIMI 48 Echocardiographic Substudy

BACKGROUND

Atrial fibrillation (AF) is associated with increased risk for thromboembolism and death; however, the relationships between cardiac structure and function and adverse outcomes among individuals with AF are incompletely understood.

METHODS

The Effective Anticoagulation with Factor Xa Next Generation in AF-Thrombolysis in Myocardial Infarction 48 study tested the once-daily oral factor Xa inhibitor edoxaban in comparison with warfarin for the prevention of stroke (ischemic or hemorrhagic) or systemic embolism in 21,105 subjects with nonvalvular AF and increased risk for thromboembolic events (CHADS2 score ≥ 2). In a prospective substudy of 971 subjects who underwent transthoracic echocardiography at baseline, Cox proportional hazards models were used to evaluate associations between cardiac structure and function and the risks for death and thromboembolism (ischemic stroke, transient ischemic attack, or systemic embolism).

RESULTS

Over a median follow-up period of 2.5 years, 89 deaths (9.2%) and 48 incident thromboembolic events (4.9%) occurred in 971 subjects. In models adjusted for CHADS2 score, aspirin use, and randomized treatment, larger left ventricular (LV) end-diastolic volume index (hazard ratio per 1 SD [12.9 mL/m(2)], 1.49; 95% CI, 1.16-1.91) and higher LV filling pressures measured by E/e' ratio (hazard ratio per 1 SD [4.6], 1.32; 95% CI, 1.08-1.61) were independently associated with increased risks for death. E/e' ratio > 13 significantly improved the prediction of death beyond clinical factors alone. No features of cardiac structure and function were independently associated with thromboembolism in this population. Findings were similar when adjusted for CHA2DS2-VASc score in place of CHADS2 score.

CONCLUSIONS

In a contemporary population of patients with AF at increased risk for thromboembolic events, larger LV size and higher filling pressures were significantly associated with increased risk for death, but neither left atrial nor LV measures were associated with thromboembolic risk. LV size and filling pressures may help identify patients with AF at increased risk for death.

Cause of Death and Predictors of All-Cause Mortality in Anticoagulated Patients With Nonvalvular Atrial Fibrillation: Data From ROCKET AF

Background

Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all‐cause mortality may guide interventions.

Methods and Results

In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose‐adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all‐cause mortality in the 14 171 participants in the intention‐to‐treat population. The median age was 73 years, and the mean CHADS₂ score was 3.5. Over 1.9 years of median follow‐up, 1214 (8.6%) patients died. Kaplan–Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all‐cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33–1.70, P<0.0001) and age ≥75 years (hazard ratio 1.69, 95% CI 1.51–1.90, P<0.0001) were associated with higher all‐cause mortality. Multiple additional characteristics were independently associated with higher mortality, with decreasing creatinine clearance, chronic obstructive pulmonary disease, male sex, peripheral vascular disease, and diabetes being among the most strongly associated (model C‐index 0.677).

Conclusions

In a large population of patients anticoagulated for nonvalvular atrial fibrillation, ≈7 in 10 deaths were cardiovascular, whereas <1 in 10 deaths were caused by nonhemorrhagic stroke or systemic embolism. Optimal prevention and treatment of heart failure, renal impairment, chronic obstructive pulmonary disease, and diabetes may improve survival.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00403767.

The spectrum of epidemiology underlying sudden cardiac death

Sudden cardiac death (SCD) from cardiac arrest is a major international public health problem accounting for an estimated 15%-20% of all deaths. Although resuscitation rates are generally improving throughout the world, the majority of individuals who experience a sudden cardiac arrest will not survive. SCD most often develops in older adults with acquired structural heart disease, but it also rarely occurs in the young, where it is more commonly because of inherited disorders. Coronary heart disease is known to be the most common pathology underlying SCD, followed by cardiomyopathies, inherited arrhythmia syndromes, and valvular heart disease. During the past 3 decades, declines in SCD rates have not been as steep as for other causes of coronary heart disease deaths, and there is a growing fraction of SCDs not due to coronary heart disease and ventricular arrhythmias, particularly among certain subsets of the population. The growing heterogeneity of the pathologies and mechanisms underlying SCD present major challenges for SCD prevention, which are magnified further by a frequent lack of recognition of the underlying cardiac condition before death. Multifaceted preventative approaches, which address risk factors in seemingly low-risk and known high-risk populations, will be required to decrease the burden of SCD. In this Compendium, we review the wide-ranging spectrum of epidemiology underlying SCD within both the general population and in high-risk subsets with established cardiac disease placing an emphasis on recent global trends, remaining uncertainties, and potential targeted preventive strategies.

Atrial fibrillation and heart failure: cause or effect?

Atrial fibrillation (AF) and heart failure (HF) are two epidemics of the century that have a close and complex relationship. The mechanisms underlying this association remain an area of ongoing intense research. In this review, we will describe the relationship between these two public health concerns, the mechanisms that fuel the development and perpetuation of both, and the evolving concepts that may revolutionize our approach to this dual epidemic.

Digoxin use in patients with atrial fibrillation and adverse cardiovascular outcomes: a retrospective analysis of the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF)

BACKGROUND

Digoxin is a widely used drug for ventricular rate control in patients with atrial fibrillation (AF), despite a scarcity of randomised trial data. We studied the use and outcomes of digoxin in patients in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF).

METHODS

For this retrospective analysis, we included and classified patients from ROCKET AF on the basis of digoxin use at baseline and during the study. Patients in ROCKET AF were recruited from 45 countries and had AF and risk factors putting them at moderate-to-high risk of stroke, with or without heart failure. We used Cox proportional hazards regression models adjusted for baseline characteristics and drugs to investigate the association of digoxin with all-cause mortality, vascular death, and sudden death. ROCKET AF was registered with ClinicalTrials.gov, number NCT00403767.

FINDINGS

In 14,171 randomly assigned patients, digoxin was used at baseline in 5239 (37%). Patients given digoxin were more likely to be female (42% vs 38%) and have a history of heart failure (73% vs 56%), diabetes (43% vs 38%), and persistent AF (88% vs 77%; p<0·0001 for each comparison). After adjustment, digoxin was associated with increased all-cause mortality (5·41 vs 4·30 events per 100 patients-years; hazard ratio 1·17; 95% CI 1·04-1·32; p=0·0093), vascular death (3·55 vs 2·69 per 100 patient-years; 1·19; 1·03-1·39, p=0·0201), and sudden death (1·68 vs 1·12 events per 100 patient-years; 1·36; 1·08-1·70, p=0·0076).

INTERPRETATION

Digoxin treatment was associated with a significant increase in all-cause mortality, vascular death, and sudden death in patients with AF. This association was independent of other measured prognostic factors, and although residual confounding could account for these results, these data show the possibility of digoxin having these effects. A randomised trial of digoxin in treatment of AF patients with and without heart failure is needed.

FUNDING

Janssen Research & Development and Bayer HealthCare AG.

Electrocardiographic patch devices and contemporary wireless cardiac monitoring

Cardiac electrophysiologic derangements often coexist with disorders of the circulatory system. Capturing and diagnosing arrhythmias and conduction system disease may lead to a change in diagnosis, clinical management and patient outcomes. Standard 12-lead electrocardiogram (ECG), Holter monitors and event recorders have served as useful diagnostic tools over the last few decades. However, their shortcomings are only recently being addressed by emerging technologies. With advances in device miniaturization and wireless technologies, and changing consumer expectations, wearable “on-body” ECG patch devices have evolved to meet contemporary needs. These devices are unobtrusive and easy to use, leading to increased device wear time and diagnostic yield. While becoming the standard for detecting arrhythmias and conduction system disorders in the outpatient setting where continuous ECG monitoring in the short to medium term (days to weeks) is indicated, these cardiac devices and related digital mobile health technologies are reshaping the clinician-patient interface with important implications for future healthcare delivery.