Atrial flutter: Clinical risk factors and adverse outcomes in the Framingham Heart Study

Long-term outcomes after catheter ablation for idiopathic atypical atrial flutter

BACKGROUND

Idiopathic atypical (non-cavotricuspid isthmus-dependent) atrial flutter (IAAFL) may be seen in patients without structural heart disease and without previous cardiac surgery or ablation.

OBJECTIVE

This study sought to determine the patient characteristics, electrophysiologic and electroanatomic properties, and clinical outcomes after ablation in patients with IAAFL.

METHODS

We retrospectively compared IAAFL patients with cavotricuspid isthmus-dependent AFL (C-AFL) patients undergoing catheter ablation. The primary outcome was a composite of death from cardiovascular causes, ischemic stroke, and hospitalization for worsening of heart failure.

RESULTS

Of 180 patients who underwent catheter ablation for AFL, 89 were included in this study (22 IAAFL and 67 C-AFL). Electrophysiologic study showed significantly longer intra-atrial conduction time and lower atrial voltage during sinus rhythm in the IAAFL group compared with the C-AFL group. The atrial scar was observed in all 22 IAAFL patients, with the most common sites being the posterior or lateral wall of the right atrium in 10 (45.5%) and the anterior wall of the left atrium in 8 (36.4%). During 3.5 ± 2.8 years of follow-up, the composite primary end point occurred significantly more frequently in the IAAFL group (hazard ratio [HR], 3.45; 95% confidence interval [CI], 1.20-9.89; P = .015). In multivariable analysis, brain natriuretic peptide levels (HR, 1.01; 95% CI, 1.00-1.01, per 1 pg/mL; P = .01) and IAAFL (HR, 4.14; 95% CI, 1.21-14.07; P = .02) were independently associated with the primary outcome.

CONCLUSION

IAAFL in patients had distinct electrophysiologic features suggestive of atrial cardiomyopathy. These patients are at risk for development of cardiovascular adverse events after ablation.

[Isthmus-dependent right atrial flutter : Clinical course after isthmus ablation]

Ablation of the cavotricuspid isthmus (CTI) to create bidirectional isthmus blockade is the most effective way to achieve rhythm control in typical atrial flutter. Compared with drug therapy, ablation reduces cardiovascular mortality, all-cause mortality, stroke risk, and the risk of cardiac decompensation. Concomitant arrhythmia of atrial flutter is atrial fibrillation (AF); therefore the duration of oral anticoagulation should be adapted according to the risk of stroke and bleeding. A combined procedure of CTI ablation and pulmonary vein isolation (PVI) in patients with typical atrial flutter but without evidence of AF should be evaluated individually especially in patients aged > 54 years depending on (cardiac) comorbidities. The comprehensive diagnostic view should keep in mind not only arrhythmias but also possibly underlying coronary artery disease.

Arrhythmias in Critically Ill Surgical and Non-surgical Patients: A National Propensity-Matched Study

BACKGROUND

Arrhythmias are common in critically ill patients, though the impact of arrhythmias on surgical patients is not well delineated. We aimed to characterize mortality following arrhythmias in critically ill patients.

METHODS

We performed a propensity-matched retrospective analysis of intensive care unit (ICU) patients from 2007 to 2017 in the Cerner Acute Physiology and Chronic Health Evaluation database. We compared outcomes between patients with and without arrhythmias and those with and without surgical indications for ICU admission. We also modeled predictors of arrhythmias in surgical patients.

RESULTS

467,951 patients were included; 97,958 (20.9%) were surgical patients. Arrhythmias occurred in 1.4% of the study cohorts. Predictors of arrhythmias in surgical patients included a history of cardiovascular disease (odds ratio [OR] 1.35, 95% confidence interval [CI95] 1.11-1.63), respiratory failure (OR 1.48, CI95 1.12-1.96), pneumonia (OR 3.17, CI95 1.98-5.10), higher bicarbonate level (OR 1.03, CI95 1.01-1.05), lower albumin level (OR 0.79, CI95 0.68-0.91), and vasopressor requirement (OR 27.2, CI95 22.0-33.7). After propensity matching, surgical patients with arrhythmias had a 42% mortality risk reduction compared to non-surgical patients (risk ratio [RR] 0.58, CI 95 0.43-0.79). Predicted probabilities of mortality for surgical patients were lower at all ages.

CONCLUSIONS

Surgical patients with arrhythmias are at lower risk of mortality than non-surgical patients. In this propensity-matched analysis, predictors of arrhythmias in critically ill surgical patients included a history of cardiovascular disease, respiratory complications, increased bicarbonate levels, decreased albumin levels, and vasopressor requirement. These findings highlight the differential effect of arrhythmias on different cohorts of critically ill populations.

Right atrial collision time (RACT): A novel marker of propensity for typical atrial flutter

INTRODUCTION

The risk of typical atrial flutter (AFL) is increased proportionately to right atrial (RA) size or right atrial scarring that results in reduced conduction velocity. These characteristics result in propagation of a flutter wave by ensuring the macro re-entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics and may provide a novel marker of propensity to develop AFL. Our goal was to investigate right atrial collision time (RACT) as a marker of existing typical AFL.

METHODS

This single-centre, prospective study recruited consecutive typical AFL ablation patients that were in sinus rhythm. Controls were consecutive electrophysiology study patients >18 years of age. While pacing the coronary sinus (CS) ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral right atrial wall. This RACT is a measure of conduction velocity and distance from CS to a collision point on the lateral right atrial wall.

RESULTS

Ninety-eight patients were included in the analysis, 41 with atrial flutter and 57 controls. Patients with atrial flutter were older, 64.7 ± 9.7 versus 52.4 ± 16.8 years (<.001), and more often male (34/41 vs. 31/57 [.003]). The AFL group mean RACT (132.6 ± 17.3 ms) was significantly longer than that of controls (99.1 ± 11.6 ms) (p < .001). A RACT cut-off of 115.5 ms had a sensitivity and specificity of 92.7% and 93.0%, respectively for diagnosis of atrial flutter. A ROC curve indicated an AUC of 0.96 (95% CI: 0.93-1.0, p < .01).

CONCLUSION

RACT is a novel and promising marker of propensity for typical AFL. This data will inform larger prospective studies.

Incremental healthcare cost burden in patients with atrial flutter only

Background

Limited information is available on the costs related to atrial flutter only. This study provides a comprehensive estimate of the cost in patients with atrial flutter only versus matched patients without any atrial arrhythmia.

Methods

Patients over 20 years of age with a minimum of one inpatient or two outpatient diagnosis codes for atrial flutter in 2005 and a minimum of 12 months of continuous enrollment pre- and post-index were identified using the MarketScan Commercial and Medicare databases. Atrial flutter patients were propensity matched to patients without atrial arrhythmias. Total costs for each patient for 12 months post-index were calculated. National cost was estimated using the projected prevalence of atrial flutter for 2010.

Results

A total of 1,042 patients with atrial flutter only were successfully matched with comparison patients. For atrial flutter patients compared to matched controls without atrial arrhythmias, total mean annual cost per patient was 81% higher ($23,008 vs. $12,717) and mean annual inpatient expenditure was 214% higher ($8,518 vs. $2,713). When applied to national atrial flutter prevalence data, total incremental cost burden was estimated to be $687.9 million per year more than patients without atrial arrhythmias, primarily due to cardiovascular specific expenditure ($377 million, 55% of total) with 58% ($218.5 million) of the increased inpatient expenditure due to cardiovascular specific admissions and $159 million (23%) for atrial flutter specific care. Sex-related differences were also present in atrial flutter only patients.

Conclusion

Although atrial flutter-only patients are less prevalent than atrial fibrillation patients, the national incremental cost burden in atrial flutter is substantial on a per-patient level.

Rare Paradoxical Response of Tachyarrhythmia to Adenosine Complicated by Novel ECG Artifact

Adenosine is widely used for the diagnosis and treatment of supraventricular tachyarrhythmia. We report a rare case of adenosine use associated with the development of 1:1 atrial flutter with aberrancy. The diagnosis was further complicated by a newly described ECG artifact associated with Wireless Acquisition Module (WAMTM) ECG acquisition mimicking rhythm irregularity.

The influence of atrial flutter in automated detection of atrial arrhythmias - are we ready to go into clinical practice?"

OBJECTIVE

To investigate the impact of atrial flutter (A_fl) in the atrial arrhythmias classification task. We additionally advocate the use of a subject-based split for future studies in the field in order to avoid within-subject correlation which may lead to over-optimistic inferences. Finally, we demonstrate the effectiveness of the classifiers outside of the initially studied circumstances, by performing an inter-dataset model evaluation of the classifiers in data from different sources.

METHODS

ECG signals of two private and three public (two MIT-BIH and Chapman ecgdb) databases were preprocessed and divided into 10s segments which were then subject to feature extraction. The created datasets were divided into a training and test set in two ways, based on a random split and a patient split. Classification was performed using the XGBoost classifier, as well as two benchmark classification models using both data splits. The trained models were then used to make predictions on the test data of the remaining datasets.

RESULTS

The XGBoost model yielded the best performance across all datasets compared to the remaining benchmark models, however variability in model performance was seen across datasets, with accuracy ranging from 70.6% to 89.4%, sensitivity ranging from 61.4% to 76.8%, and specificity ranging from 87.3% to 95.5%. When comparing the results between the patient and the random split, no significant difference was seen in the two private datasets and the Chapman dataset, where the number of samples per patient is low. Nonetheless, in the MIT-BIH dataset, where the average number of samples per patient is approximately 1300, a noticeable disparity was identified. The accuracy, sensitivity, and specificity of the random split in this dataset of 93.6%, 86.4%, and 95.9% respectively, were decreased to 88%, 61.4%, and 89.8% in the patient split, with the largest drop being in A_fl sensitivity, from 71% to 5.4%. The inter-dataset scores were also significantly lower than their intra-dataset counterparts across all datasets.

CONCLUSIONS

CAD systems have great potential in the assistance of physicians in reliable, precise and efficient detection of arrhythmias. However, although compelling research has been done in the field, yielding models with excellent performances on their datasets, we show that these results may be over-optimistic. In our study, we give insight into the difficulty of detection of A_fl on several datasets and show the need for a higher representation of A_fl in public datasets. Furthermore, we show the necessity of a more structured evaluation of model performance through the use of a patient-based split and inter-dataset testing scheme to avoid the problem of within-subject correlation which may lead to misleadingly high scores. Finally, we stress the need for the creation and use of datasets with a higher number of patients and a more balanced representation of classes if we are to progress in this mission.

Differences in Stroke or Systemic Thromboembolism Readmission Risk After Hospitalization for Atrial Fibrillation and Atrial Flutter

Background

Although atrial fibrillation (AF) and atrial flutter (AFL) are different arrhythmias, they are assumed to confer the same risk of stroke and systemic thromboembolism (STE) despite a lack of available evidence. In this study, we investigated the difference in the risk of stroke or STE after AF and AFL hospitalizations.

Methodology

The National Readmission Database (NRD) 2018 was used to identify AF and AFL patients using appropriate International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes and were followed until the end of the calendar year to identify stroke or STE readmissions. Survival estimates were calculated, and a Cox proportional hazards model was used to calculate the adjusted hazards ratio (aHR) and compare the risk of stroke or STE readmissions between AF and AFL groups.

Results

A total of 215,810 AF and 15,292 AFL patients were identified. AFL patients were more likely to be younger (66 vs. 70 years), male (68% vs. 47%), and had higher prevalence of obesity (25% vs. 22%), obstructive sleep apnea (14% vs. 12%), diabetes mellitus (31% vs. 26%), and alcohol use (6.9% vs. 5.5%) (all p < 0.01). After adjusting for potential patient and hospital-level characteristics, there was a statistically significant decrease in one-year stroke or STE readmission risk in AFL patients compared to AF patients (aHR 0.79 (0.66-0.95); p = 0.01).

Conclusions

AFL patients are commonly younger males with a higher burden of medical comorbidity. There is a decrease in the one-year risk of stroke or STE events in AFL patients compared to AF. The predictors of stroke and STE are similar in both AFL and AF groups. Further studies with longer follow-up and anticoagulation data are needed to verify the results.

Long-term mortality and cardiovascular outcomes in patients with atrial flutter after catheter ablation

AIMS

For patients with typical and atypical atrial flutter (AFL) but without history of atrial fibrillation (AF), the long-term cardiovascular (CV) outcomes after catheter ablation for AFL remain unclear. We compared the long-term all-cause mortality and CV outcomes in patients with AFL receiving catheter ablation compared with the results with medical therapy.

METHODS AND RESULTS

Atrial flutter patients receiving catheter ablation for typical AFL were identified using the Health Insurance Database, and constituted the 'AFL ablation group'. Patients with typical and atypical AFL but without ablation (AFL without ablation group) were propensity matched to the AFL ablation group. Patients with prior AF diagnosis were excluded. Primary outcomes included all-cause and CV mortality, heart failure (HF) hospitalization, and stroke. The multivariable cox hazards regression model was used to evaluate the hazard ratio (HR) for study outcomes. A total of 3784 AFL patients (1892 patients in each group) was studied. Their mean follow-up durations were 7.85 ± 2.57 years (AFL without ablation group) and 8.31 ± 4.53 years (AFL ablation group). Atrial flutter with ablation patients had lower risks of all-cause mortality (HR: 0.68, P < 0.001), CV deaths (HR: 0.78, P = 0.001), HF hospitalization (HR: 0.84, P = 0.01), and stroke (HR: 0.80, P = 0.01).

CONCLUSIONS

Catheter ablation for AFL in patients without prior AF was associated with lower risks of all-cause mortality and CV events compared with AFL patients without ablation during long-term follow-ups.

Cardiovascular efficacy and safety of dipeptidyl peptidase-4 inhibitors: A meta-analysis of cardiovascular outcome trials

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a generally safe and well tolerated antidiabetic drug class with proven efficacy in type 2 diabetes mellitus (T2DM). Recently, a series of large, randomized controlled trials (RCTs) addressing cardiovascular outcomes with DPP-4 inhibitors have been published.

AIM

To pool data from the aforementioned trials concerning the impact of DPP-4 inhibitors on surrogate cardiovascular efficacy outcomes and on major cardiac arrhythmias.

METHODS

We searched PubMed and grey literature sources for all published RCTs assessing cardiovascular outcomes with DPP-4 inhibitors compared to placebo until October 2020. We extracted data concerning the following “hard” efficacy outcomes: fatal and non-fatal myocardial infarction, fatal and non-fatal stroke, hospitalization for heart failure, hospitalization for unstable angina, hospitalization for coronary revascularization and cardiovascular death. We also extracted data regarding the risk for major cardiac arrhythmias, such as atrial fibrillation, atrial flutter, ventricular fibrillation and ventricular tachycardia.

RESULTS

We pooled data from 6 trials in a total of 52520 patients with T2DM assigned either to DPP-4 inhibitor or placebo. DPP-4 inhibitors compared to placebo led to a non-significant increase in the risk for fatal and non-fatal myocardial infarction [risk ratio (RR) = 1.02, 95%CI: 0.94-1.11, I² = 0%], hospitalization for heart failure (RR = 1.09, 95%CI: 0.92-1.29, I² = 65%) and cardiovascular death (RR = 1.02, 95%CI: 0.93-1.11, I² = 0%). DPP-4 inhibitors resulted in a non-significant decrease in the risk for fatal and non-fatal stroke (RR = 0.96, 95%CI: 0.85-1.08, I² = 0%) and coronary revascularization (RR = 0.99, 95%CI: 0.90-1.09, I² = 0%), Finally, DPP-4 inhibitors demonstrated a neutral effect on the risk for hospitalization due to unstable angina (RR = 1.00, 95%CI: 0.85-1.18, I² = 0%). As far as cardiac arrhythmias are concerned, DPP-4 inhibitors did not significantly affect the risk for atrial fibrillation (RR = 0.95, 95%CI: 0.78-1.17, I² = 0%), while they were associated with a significant increase in the risk for atrial flutter, equal to 52% (RR = 1.52, 95%CI: 1.03-2.24, I² = 0%). DPP-4 inhibitors did not have a significant impact on the risk for any of the rest assessed cardiac arrhythmias.

CONCLUSION

DPP-4 inhibitors do not seem to confer any significant cardiovascular benefit for patients with T2DM, while they do not seem to be associated with a significant risk for any major cardiac arrhythmias, except for atrial flutter. Therefore, this drug class should not be the treatment of choice for patients with established cardiovascular disease or multiple risk factors, except for those cases when newer antidiabetics (glucagon-like peptide-1 receptor agonists and sodium-glucose co-transporter-2 inhibitors) are not tolerated, contraindicated or not affordable for the patient.

Heart failure and atrial flutter: a systematic review of current knowledge and practices

While the interplay between heart failure (HF) and atrial fibrillation (AF) has been extensively studied, little is known regarding HF and atrial flutter (AFL), which may be managed differently. We reviewed the incidence, prevalence, and predictors of HF in AFL and vice versa, and the outcomes of treatment of AFL in HF. A systematic literature review of PubMed/Medline and EMBASE yielded 65 studies for inclusion and qualitative synthesis. No study described the incidence or prevalence of AFL in unselected patients with HF. Most cohorts enrolled patients with AF/AFL as interchangeable diagnoses, or highly selected patients with tachycardia‐induced cardiomyopathy. The prevalence of HF in AFL ranged from 6% to 56%. However, the phenotype of HF was never defined by left ventricular ejection fraction (LVEF). No studies reported the predictors, phenotype, and prognostic implications of AFL in HF. There was significant variation in treatments studied, including the proportion that underwent ablation. When systolic dysfunction was tachycardia‐mediated, catheter ablation demonstrated LVEF normalization in up to 88%, as well as reduced cardiovascular mortality. In summary, AFL and HF often coexist but are understudied, with no randomized trial data to inform care. Further research is warranted to define the epidemiology and establish optimal management.

Reconstituting electrical conduction in soft tissue: the path to replace the ablationist

Cardiac arrhythmias are a leading cause of morbidity and mortality in the developed world. A common mechanism underlying many of these arrhythmias is re-entry, which may occur when native conduction pathways are disrupted, often by myocardial infarction. Presently, re-entrant arrhythmias are most commonly treated with antiarrhythmic drugs and myocardial ablation, although both treatment methods are associated with adverse side effects and limited efficacy. In recent years, significant advancements in the field of biomaterials science have spurred increased interest in the development of novel therapies that enable restoration of native conduction in damaged or diseased myocardium. In this review, we assess the current landscape of materials-based approaches to eliminating re-entrant arrhythmias. These approaches potentially pave the way for the eventual replacement of myocardial ablation as a preferred therapy for such pathologies.

Automated Arrhythmia Detection Based on RR Intervals

Abnormal heart rhythms, also known as arrhythmias, can be life-threatening. AFIB and AFL are examples of arrhythmia that affect a growing number of patients. This paper describes a method that can support clinicians during arrhythmia diagnosis. We propose a deep learning algorithm to discriminate AFIB, AFL, and NSR RR interval signals. The algorithm was designed with data from 4051 subjects. With 10-fold cross-validation, the algorithm achieved the following results: ACC = 99.98%, SEN = 100.00%, and SPE = 99.94%. These results are significant because they show that it is possible to automate arrhythmia detection in RR interval signals. Such a detection method makes economic sense because RR interval signals are cost-effective to measure, communicate, and process. Having such a cost-effective solution might lead to widespread long-term monitoring, which can help detecting arrhythmia earlier. Detection can lead to treatment, which improves outcomes for patients.

Pathophysiological background and prognosis of common atrial flutter in non-elderly patients: Comparison to Atrial Fibrillation

BACKGROUND

It is unclear whether there is any difference in the background and prognosis between non-elderly patients who undergo catheter ablation of atrial fibrillation (AF) and common atrial flutter (CAFL).

PURPOSE

To investigate the difference between the patient background of both CAFL and AF in the non-elderly.

METHODS

In 526 consecutive patients who underwent catheter ablation of clinical paroxysmal/persistent CAFL or AF in our hospital, we enrolled only patients under 60 years old. Cases harboring both AFL and AF were excluded. We analyzed the patient characteristics, echocardiographic findings, electrocardiographic (ECG) abnormalities during sinus rhythm, and clinical course after ablation.

RESULTS

In total, 196 patients (Cohort 1: 142 males, 156 AF cases) were analyzed. AFL patients were younger than AF patients (47.4 ± 10.6 vs. 50.2 ± 6.4years, p = 0.031) and organic heart disease (OHD) was significantly more common in AFL patients than AF patients (42.5% vs. 11.5%, p<0.001). In 161 patients excluding OHD (Cohort 2), ECG abnormalities were more frequent in AFL than in AF patients (78.3% vs. 39.1%, p = 0.001). There were no significant differences in all-cause death, onset of heart failure, and cerebral strokes. On the other hand, the number of cases that required a pacemaker was significantly higher in the CAFL group than AF group (0.0% vs. 26.1%, p-value <0.001). These results suggested that CAFL may reflect occurrence of any atrial myocardial damage, even if it does not lead to heart failure.

CONCLUSIONS

Our present study suggested that CAFL may be associated with a broader atrial myocardial disorder in non-elderly patients.

World Heart Federation Roadmap on Atrial Fibrillation - A 2020 Update

The World Heart Federation (WHF) commenced a Roadmap initiative in 2015 to reduce the global burden of cardiovascular disease and resultant burgeoning of healthcare costs. Roadmaps provide a blueprint for implementation of priority solutions for the principal cardiovascular diseases leading to death and disability. Atrial fibrillation (AF) is one of these conditions and is an increasing problem due to ageing of the world’s population and an increase in cardiovascular risk factors that predispose to AF. The goal of the AF roadmap was to provide guidance on priority interventions that are feasible in multiple countries, and to identify roadblocks and potential strategies to overcome them.

Since publication of the AF Roadmap in 2017, there have been many technological advances including devices and artificial intelligence for identification and prediction of unknown AF, better methods to achieve rhythm control, and widespread uptake of smartphones and apps that could facilitate new approaches to healthcare delivery and increasing community AF awareness. In addition, the World Health Organisation added the non-vitamin K antagonist oral anticoagulants (NOACs) to the Essential Medicines List, making it possible to increase advocacy for their widespread adoption as therapy to prevent stroke. These advances motivated the WHF to commission a 2020 AF Roadmap update. Three years after the original Roadmap publication, the identified barriers and solutions were judged still relevant, and progress has been slow.

This 2020 Roadmap update reviews the significant changes since 2017 and identifies priority areas for achieving the goals of reducing death and disability related to AF, particularly targeted at low-middle income countries. These include advocacy to increase appreciation of the scope of the problem; plugging gaps in guideline management and prevention through physician education, increasing patient health literacy, and novel ways to increase access to integrated healthcare including mHealth and digital transformations; and greater emphasis on achieving practical solutions to national and regional entrenched barriers. Despite the advances reviewed in this update, the task will not be easy, but the health rewards of implementing solutions that are both innovative and practical will be great.

Lenient rate control versus strict rate control for atrial fibrillation: a protocol for the Danish Atrial Fibrillation (DanAF) randomised clinical trial

INTRODUCTION

Atrial fibrillation is the most common heart arrhythmia with a prevalence of approximately 2% in the western world. Atrial fibrillation is associated with an increased risk of death and morbidity. In many patients, a rate control strategy is recommended. The optimal heart rate target is disputed despite the results of the the RAte Control Efficacy in permanent atrial fibrillation: a comparison between lenient vs strict rate control II (RACE II) trial.Our primary objective will be to investigate the effect of lenient rate control strategy (<110 beats per minute (bpm) at rest) compared with strict rate control strategy (<80 bpm at rest) on quality of life in patients with persistent or permanent atrial fibrillation.

METHODS AND ANALYSIS

We plan a two-group, superiority randomised clinical trial. 350 outpatients with persistent or permanent atrial fibrillation will be recruited from four hospitals, across three regions in Denmark. Participants will be randomised 1:1 to a lenient medical rate control strategy (<110 bpm at rest) or a strict medical rate control strategy (<80 bpm at rest). The recruitment phase is planned to be 2 years with 3 years of follow-up. Recruitment is expected to start in January 2021. The primary outcome will be quality of life using the Short Form-36 (SF-36) questionnaire (physical component score). Secondary outcomes will be days alive outside hospital, symptom control using the Atrial Fibrillation Effect on Quality of Life, quality of life using the SF-36 questionnaire (mental component score) and serious adverse events. The primary assessment time point for all outcomes will be 1 year after randomisation.

ETHICS AND DISSEMINATION

Ethics approval was obtained through the ethics committee in Region Zealand. The design and findings will be published in peer-reviewed journals as well as be made available on ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT04542785.

Comparison of in-hospital outcomes of patients undergoing catheter ablation for typical versus atypical atrial flutter

BACKGROUND

Catheter ablation (CA) is indicated as definitive therapy for patients with either typical or atypical atrial flutter (TAFlutter and AAFlutter, respectively) which is unresponsive to medical therapy. There is a paucity of data regarding in-hospital outcomes of patients undergoing CA.

METHODS

Retrospective study using the NIS to identify patients ≥18 years who underwent CA between 2015 and 2017. Individuals were identified using ICD-10-CM/PCS for TAFlutter, AAFlutter, and CA.

RESULTS

A total of 17,390 patients underwent CA for Aflutter (33% AAFlutter and 67% TAFlutter). The TAFlutter group was younger (mean 65.9 years vs. 67.2 years), with less females (30% vs. 43%, p ≤ 0.001 for both) compared to the AAFlutter group. The TAFlutter group had a higher rate of diabetes, tobacco use, obesity, and chronic obstructive pulmonary disease (p ≤ 0.001 for all). The AAFlutter cohort had increased prior strokes and atrial fibrillation (p ≤ 0.001 for both). The mean CHA₂DS₂-VASc score was found to be 2.3 in AAFlutter compared to 2.1 in TAFlutter (p ≤ 0.001). There were significantly higher proportions of thromboembolic events, transfusions, and longer length of stay in the TAFlutter group (p ≤ 0.001 for all) with the AAFlutter group having significantly higher rates of cardioversion, implantation of cardiac devices, and increased hospital charges (p ≤ 0.001 for all); no significant difference was found in mortality after controlling for comorbidities.

CONCLUSIONS

We found higher complication rates in CA for patients with TAFlutter, but no difference in in-hospital all-cause mortality. Variation in CA depending upon the mechanism of AFlutter may underlie these differences, and warrant further study.

Typical atrial flutter but not fibrillation predicts coronary artery disease in formerly healthy patients

AIMS

Long-term mortality after ablation of typical atrial flutter has been found to be increased two-fold in comparison to atrial fibrillation ablations through a period of 5 years with unclear mechanism.

METHODS AND RESULTS

We analysed 189 consecutive patients who underwent ablation for typical atrial flutter (AFL), in which the incidence of AF was the first manifestation of cardiac disease. According to the clinical standards of our centre, the routine recommendation was to evaluate for coronary artery disease (CAD) by invasive angiogram or computed tomography scan. We compared the AFL patients to 141 patients with paroxysmal atrial fibrillation (AFIB) without known structural heart disease who underwent ablation in the same period and who had routine coronary angiograms performed. Out of 189 patients who presented with AFL, coronary status was available in 152 patients (80.4%). Both groups were balanced for mean age (64.9 years in AFL vs. 63.2 years in AFIB; P = 0.15), body mass index (BMI; 28.8 vs. 28.5 kg/m2; P = 0.15), CHA2DS2-VASc-Score (2.20 vs. 2.04; P = 0.35), smoking status (22.2% smokers vs. 28.4%; P = 0.23), and renal function (GFR >60 mL/min in 96.7% of all patients vs. 95.7%; P = 0.76). There were significantly lower values for left ventricular ejection fraction (52.5% vs. 59.7%; P < 0.001), female sex (17.0% vs. 47.5%; P < 0.001), hyperlipidaemia (37.9% vs. 58.9%; P < 0.001), and family history of cardiovascular disease (CVD) (15.0 vs. 31.9%; P = 0.001) in the AFL vs. AFIB cohorts. Coronary artery disease with stenoses >50% was found in 26.3% of all patients with available coronary status in AFL and in 7.0% in AFIB (P < 0.001). Coronary artery disease with stenoses >75% in 16.4% in AFL whereas only in 1.4% in AFIB (P < 0.001). Multivessel disease was detected in 10.5% in AFL and 0.7% in AFIB (P < 0.001). After correction for age, left ventricular ejection fraction, BMI, CHA2DS2-VASc-Score and its individual components, smoking status, hyperlipidaemia, and family history of CVD, there was a more than five-fold increase in the likelihood of CAD with stenosis >50% in AFL as compared to AFIB [odds ratio (OR 5.26)]. A multivariate analysis was performed in the AFL group. Patients with clinically relevant stenoses (>75%) were older (70.6 years vs. 63.8 years; P = 0.001), had a higher number of risk factors (3.08 vs. 2.24; P ≤ 0.0016) and a higher CHA2DS2-VASc-Score (3.20 vs. 2.00; P < 0.0001). With logistic regression, significant CAD could be predicted by higher values for CHA2DS2-VASc-Score with an exponential rise to a pretest-probability of 42.1% at a value of 4 points.

CONCLUSION

These data suggest that typical atrial flutter constitutes a manifestation of previously asymptomatic CAD. Due to the inclusion criteria, CAD has to be considered silent and chronic in most of the patients. Therefore, the presence of typical atrial flutter in formerly healthy patients should raise suspicion of otherwise silent CAD and initiate further investigations and risk stratification with particular emphasis on the individual CHA2DS2-VASc-Scores.

Diagnosis and Management of 1:1 Atrial Flutter in the Setting of Aortic Valve Endocarditis and Embolic Stroke

Atrial flutter is a rapid, regular atrial tachyarrhythmia that occurs most commonly in patients with underlying structural heart disease. Spontaneous 1:1 conduction of atrial flutter is indeed rare, but its diagnosis and management is of critical importance. We describe a case of a 65-year-old man with hypertension, preserved ejection fraction heart failure, end-stage renal disease, Parkinson’s disease, and Alzheimer’s dementia, in whom atrial flutter was associated with 1:1 atrioventricular conduction. Our patient was hemodynamically unstable with aortic valve endocarditis and recent septic embolic stroke. This case report emphasizes the importance of recognition and management to avoid hemodynamic compromise.

Characterization of atrial flutter after pulmonary vein isolation by cryoballoon ablation

PURPOSE

Pulmonary vein isolation (PVI) by cryoballoon ablation (CBA) has emerged as a commonly used technique for the treatment of atrial fibrillation. We sought to explore the incidence, risk factors for, and characterization of post-CBA-PVI atrial flutter.

METHODS

We analyzed a prospective registry of patients who underwent CBA-PVI at a single institution. We included patients with more than 3 months of follow-up data and excluded those with a history of cavotricuspid isthmus (CTI) ablation. Locations of post-CBA-PVI atrial flutters were determined by analysis of intracardiac electrograms and electroanatomic maps.

RESULTS

There were 556 patients included in the analysis. The mean age was 61.0 ± 10.6 years, 67.4% were male, the number of failed anti-arrhythmic medication trials was 1.2 ± 0.8, and the duration of atrial fibrillation pre-CBA was 54.3 ± 69.1 months. The 28-mm second-generation cryoballoon was used almost exclusively. Over a median follow-up time of 22.7 ± 17.9 months, 25 (4.5%) patients developed post-CBA-PVI atrial flutter after the 3-month blanking period. Of those 25 patients, 15 (60%) underwent subsequent ablation to eliminate the atrial flutter circuit, with 60% being CTI-dependent and the remainder left-sided (p value not significant). Risk factors for the development of atrial flutter included NYHA class ≥ 2 (OR 5.02, p < 0.001), presence of baseline bundle branch block (OR 4.33, p = 0.006), and left ventricular ejection fraction < 50% (OR 3.36, p = 0.007).

CONCLUSIONS

The rate of post-CBA-PVI atrial flutter is low after the blanking period even with medium-term follow-up. The origin of atrial flutter is equally divided between the right and left atria.

[Atrial Flutter: up-to-date Problem Evaluation with Clinical Positions]

The review provides current ideas about the etiology and prevalence of atrial flutter (AF), mechanism and substrate of arrhythmogenesis, and principles of clinical and electrophysiological classification of this arrhythmia. Methods for conservative and surgical treatments of AF, including their comparative aspect, are described in detail. The review presented recent data on efficacy and potential risks of different approaches to reversing the arrhythmia. The authors indicated a need for early diagnosis and strict control of the sinus rhythm in AF, which would help a successful intervention not only to completely cure the existing arrhythmia but also to prevent other heart rhythm disorders, primarily atrial fibrillation.

Sex differences of resource utilisation and outcomes in patients with atrial arrhythmias and heart failure

Objective

Atrial fibrillation or atrial flutter (AF) and heart failure (HF) often go hand in hand and, in combination, lead to an increased risk of death compared with patients with just one of both entities. Sex-specific differences in patients with AF and HF are under-reported. Therefore, the aim of this study was to investigate sex-specific catheter ablation (CA) use and acute in-hospital outcomes in patients with AF and concomitant HF in a retrospective cohort study.

Methods

Using International Statistical Classification of Diseases and Related Health Problems and Operations and Procedures codes, administrative data of 75 hospitals from 2010 to 2018 were analysed to identify cases with AF and HF. Sex differences were compared for baseline characteristics, right and left atrial CA use, procedure-related adverse outcomes and in-hospital mortality.

Results

Of 54 645 analysed cases with AF and HF, 46.2% were women. Women were significantly older (75.4±9.5 vs 68.7±11.1 years, p<0.001), had different comorbidities (more frequently: cerebrovascular disease (2.4% vs 1.8%, p<0.001), dementia (5.3% vs 2.2%, p<0.001), rheumatic disease (2.1% vs 0.8%, p<0.001), diabetes with chronic complications (9.7% vs 9.1%, p=0.033), hemiplegia or paraplegia (1.7% vs 1.2%, p<0.001) and chronic kidney disease (43.7% vs 33.5%, p<0.001); less frequently: myocardial infarction (5.4% vs 10.5%, p<0.001), peripheral vascular disease (6.9% vs 11.3%, p<0.001), mild liver disease (2.0% vs 2.3%, p=0.003) or any malignancy (1.0% vs 1.3%, p<0.001), underwent less often CA (12.0% vs 20.7%, p<0.001), had longer hospitalisations (6.6±5.8 vs 5.2±5.2 days, p<0.001) and higher in-hospital mortality (1.6% vs 0.9%, p<0.001). However, in the multivariable generalised linear mixed model for in-hospital mortality, sex did not remain an independent predictor (OR 0.96, 95% CI 0.82 to 1.12, p=0.579) when adjusted for age and comorbidities. Vascular access complications requiring interventions (4.8% vs 4.2%, p=0.001) and cardiac tamponade (0.3% vs 0.1%, p<0.001) occurred more frequently in women, whereas stroke (0.6% vs 0.5%, p=0.179) and death (0.3% vs 0.1%, p=0.101) showed no sex difference in patients undergoing CA.

Conclusions

There are sex differences in patients with AF and HF with respect to demographics, resource utilisation and in-hospital outcomes. This needs to be considered when treating women with AF and HF, especially for a sufficient patient informed decision making in clinical practice.

Comparison of Clinical Outcomes Among Patients With Atrial Fibrillation or Atrial Flutter Stratified by CHA2DS2-VASc Score

Importance

Current guidelines support treating atrial fibrillation (AF) and atrial flutter (AFL) as equivalent risk factors for ischemic stroke stratified by CHA2DS2-VASc scores, recommending anticoagulation therapy for patients with a CHA2DS2-VASc score of 2 or higher, but some studies found differences in clinical outcomes.

Objective

To investigate differences in clinical outcomes among AF, AFL, and matched control cohorts.

Design, Setting, and Participants

This nationwide cohort study analyzed data from the Taiwan National Health Insurance Research Database from January 1, 2001, through December 31, 2012. Follow-up and data analysis ended December 31, 2012. A total of 219 416 age- and sex-matched individuals participated in the study. Clinical outcomes were compared after stratification by CHA2DS2-VASc score (possible score range, 0-9; higher scores indicate greater risk of ischemic stroke).

Main Outcomes and Measures

Ischemic stroke, heart failure hospitalization, and all-cause mortality among the AF, AFL, and matched control cohorts were analyzed using Cox proportional hazards regression.

Results

This study comprised 188 811 patients in the AF cohort (mean [SD] age, 73.8 [13.4] years; 104 703 [55.5%] male), 6121 patients in the AFL cohort (mean [SD] age, 67.7 [15.8] years; 3735 [61.0%] male), and 24 484 patients in the matched control cohort (mean [SD] age, 67.3 [15.6] years; 14 940 [61.0%] male). The patients with AF were older, were more predominantly female, and had higher CHA2DS2-VASc scores than the patients with AFL and the control participants. After stratification by CHA2DS2-VASc score, the incidence densities (IDs; events per 100 person-years) of ischemic stroke (AF cohort: ID, 3.08; 95% CI, 3.03-3.13; AFL cohort: ID, 1.45; 95% CI, 1.28-1.62; controls: ID, 0.97; 95% CI, 0.92-1.03), heart failure hospitalization (AF cohort: ID, 3.39; 95% CI, 3.34-3.44; AFL cohort: ID, 1.57; 95% CI, 1.39-1.74; controls: ID, 0.32; 95% CI, 0.29-0.35), and all-cause mortality (AF cohort: ID, 17.8; 95% CI, 17.7-17.9; AFL cohort: ID, 13.9; 95% CI, 13.4-14.4; controls: ID, 4.2; 95% CI, 4.1-4.4) were significantly higher in the AF cohort than in the matched control cohort. For the AFL cohort vs the matched control cohort, the incidences of heart failure hospitalization and all-cause mortality were significantly higher across all levels, but the incidence of ischemic stroke was only significantly higher at CHA2DS2-VASc scores of 5 to 9. For the AF cohort vs the AFL cohort, the incidences of ischemic stroke and heart failure hospitalization were significantly higher at a CHA2DS2-VASc score of 1 or higher, but the incidence of all-cause mortality was significantly higher only at CHA2DS2-VASc scores of 1 to 3.

Conclusions and Relevance

This study found different clinical outcomes between patients with AFL and AF and those without AF and AFL. The current recommended level of the CHA2DS2-VASc score in preventing ischemic stroke in patients with AFL should be reevaluated.

Digoxin for atrial fibrillation and atrial flutter: A systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

Background

During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials.

Methods

We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm. We performed both random-effects and fixed-effect meta-analyses and chose the more conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. We used GRADE to assess the quality of the body of evidence.

Results

28 trials (n = 2223 participants) were included. All were at high risk of bias and reported only short-term follow-up. When digoxin was compared with all control interventions in one analysis, we found no evidence of a difference on all-cause mortality (risk ratio (RR), 0.82; TSA-adjusted confidence interval (CI), 0.02 to 31.2; I² = 0%); serious adverse events (RR, 1.65; TSA-adjusted CI, 0.24 to 11.5; I² = 0%); quality of life; heart failure (RR, 1.05; TSA-adjusted CI, 0.00 to 1141.8; I² = 51%); and stroke (RR, 2.27; TSA-adjusted CI, 0.00 to 7887.3; I² = 17%). Our analyses on acute heart rate control (within 6 hours of treatment onset) showed firm evidence of digoxin being superior compared with placebo (mean difference (MD), -12.0 beats per minute (bpm); TSA-adjusted CI, -17.2 to -6.76; I² = 0%) and inferior compared with beta blockers (MD, 20.7 bpm; TSA-adjusted CI, 14.2 to 27.2; I² = 0%). Meta-analyses on acute heart rate control showed that digoxin was inferior compared with both calcium antagonists (MD, 21.0 bpm; TSA-adjusted CI, -30.3 to 72.3) and with amiodarone (MD, 14.7 bpm; TSA-adjusted CI, -0.58 to 30.0; I² = 42%), but in both comparisons TSAs showed that we lacked information. Meta-analysis on acute conversion to sinus rhythm showed that digoxin compared with amiodarone reduced the probability of converting atrial fibrillation to sinus rhythm, but TSA showed that we lacked information (RR, 0.54; TSA-adjusted CI, 0.13 to 2.21; I² = 0%).

Conclusions

The clinical effects of digoxin on all-cause mortality, serious adverse events, quality of life, heart failure, and stroke are unclear based on current evidence. Digoxin seems to be superior compared with placebo in reducing the heart rate, but inferior compared with beta blockers. The long-term effect of digoxin is unclear, as no trials reported long-term follow-up. More trials at low risk of bias and low risk of random errors assessing the clinical effects of digoxin are needed.

Systematic review registration

PROSPERO CRD42016052935

Antithrombotic Therapy Underutilization in Patients With Atrial Flutter

BACKGROUND

Patients with atrial fibrillation not being adequately treated with oral anticoagulant (OAC) therapy, with therapy underutilization or premature termination, have been commonly reported. However, studies on the utilization pattern of OAC therapy for patients with atrial flutter (AFL) are few. The aim of this study was to investigate the utilization of OAC therapy, and its influencing factors for patients with AFL in South Korea, as well as the types and percentages of anticoagulants used.

METHODS

We analyzed Aged Population Sample data compiled by the Health Insurance Review & Assessment Service from 2011 to 2015. We identified patients with AFL having the KCD-6 code I48.1. Patients at high risk of stroke with a congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke (or transient ischemic attack), vascular disease, sex score of ≥2 and at low risk of bleeding with an anticoagulation and risk factors in atrial fibrillation score of ≤4 were included in the study. Oral anticoagulant therapy underutilization was estimated in these patients using anticoagulant underutilization (ACU) scales. Demographic and clinical factors associated with OAC therapy underutilization were investigated using a logistic regression model.

RESULTS

The mean ACU value was calculated as 67.4% between 2011 and 2015. Positive risk factors for ACU were identified as follows: female sex, aspirin utilization, and limited anticoagulant options. Negative risk factors included comorbidities, such as congestive heart failure and valvular heart disease, and a history of stroke or transient ischemic attack.

CONCLUSIONS

Our study demonstrates that two-third of patients with AFL in South Korea failed to obtain adequate stroke prevention treatment, even in the era of direct OAC availability. This tendency was more profound in women or those on aspirin therapy.

Right atrium enlargement predicts clinically significant supraventricular arrhythmia in patients with pulmonary arterial hypertension

BACKGROUND

Right atrial (RA) enlargement is a common finding in patients with pulmonary arterial hypertension (PAH) and an important predictor of mortality, however its relation to the risk of atrial arrhythmias has not been assessed.

OBJECTIVES

To assess whether RA enlargement is associated with supraventricular arrhythmias (SVA) and whether it predicts new clinically significant SVA (csSVA).

METHODS

Patients with PAH were recruited between January 2010 and December 2014 and followed until January 2017. csSVA was diagnosed if it resulted in hospitalization. To assess predictors of new csSVA, only patients without a history of SVA at baseline were analyzed.

RESULTS

Among 97 patients, any SVA was observed in 45 (46.4%) and included permanent atrial fibrillation(AF, n = 8), paroxysmal AF (n = 10), permanent atrial flutter (AFl, n = 1), paroxysmal AFl (n = 2) or other types of supraventricular tachycardia (n = 24). Patients with SVA as compared to patients without SVA were characterized by older age, lower distance in a 6-minute test, higher NT-proBNP, higher RA area index (RAai), left atrial area index, mean right atrial pressure (mRAP) and were more commonly treated with β-blocker. Eighty five patients who were in sinus rhythm at baseline assessment and had no history of significant SVA were observed for 37 ± 19.9 months. During that time csSVA occurred in 15.3%. In univariate models, the occurrence of csSVA were predicted by age, right ventricular ejection fraction, right ventricular end diastolic index, RAai and mRAP, but in multivariate model only RAai remained significant predictor for csSVA (HR of 1.23, 95%CI: 1.11-1.36, p < 0.001). The optimal threshold for RA enlargement as discriminator of csSVA was 21.7 cm2/m2.

CONCLUSIONS

In PAH patients RA enlargement is associated with increased prevalence of SVA. RAai is an independent predictor of hospitalization due to csSVA.

The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter: A systematic review with meta-analysis and Trial Sequential Analysis

Background

Atrial fibrillation and atrial flutter may be managed by either a rhythm control strategy or a rate control strategy but the evidence on the clinical effects of these two intervention strategies is unclear. Our objective was to assess the beneficial and harmful effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter.

Methods

We searched CENTRAL, MEDLINE, Embase, LILACS, Web of Science, BIOSIS, Google Scholar, clinicaltrials.gov, TRIP, EU-CTR, Chi-CTR, and ICTRP for eligible trials comparing any rhythm control strategy with any rate control strategy in patients with atrial fibrillation or atrial flutter published before November 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were stroke and ejection fraction. We performed both random-effects and fixed-effect meta-analysis and chose the most conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. Statistical heterogeneity was assessed by visual inspection of forest plots and by calculating inconsistency (I²) for traditional meta-analyses and diversity (D²) for TSA. Sensitivity analyses and subgroup analyses were conducted to explore the reasons for substantial statistical heterogeneity. We assessed the risk of publication bias in meta-analyses consisting of 10 trials or more with tests for funnel plot asymmetry. We used GRADE to assess the quality of the body of evidence.

Results

25 randomized clinical trials (n = 9354 participants) were included, all of which were at high risk of bias. Meta-analysis showed that rhythm control strategies versus rate control strategies significantly increased the risk of a serious adverse event (risk ratio (RR), 1.10; 95% confidence interval (CI), 1.02 to 1.18; P = 0.02; I² = 12% (95% CI 0.00 to 0.32); 21 trials), but TSA did not confirm this result (TSA-adjusted CI 0.99 to 1.22). The increased risk of a serious adverse event did not seem to be caused by any single component of the composite outcome. Meta-analysis showed that rhythm control strategies versus rate control strategies were associated with better SF-36 physical component score (mean difference (MD), 6.93 points; 95% CI, 2.25 to 11.61; P = 0.004; I² = 95% (95% CI 0.94 to 0.96); 8 trials) and ejection fraction (MD, 4.20%; 95% CI, 0.54 to 7.87; P = 0.02; I² = 79% (95% CI 0.69 to 0.85); 7 trials), but TSA did not confirm these results. Both meta-analysis and TSA showed no significant differences on all-cause mortality, SF-36 mental component score, Minnesota Living with Heart Failure Questionnaire, and stroke.

Conclusions

Rhythm control strategies compared with rate control strategies seem to significantly increase the risk of a serious adverse event in patients with atrial fibrillation. Based on current evidence, it seems that most patients with atrial fibrillation should be treated with a rate control strategy unless there are specific reasons (e.g., patients with unbearable symptoms due to atrial fibrillation or patients who are hemodynamically unstable due to atrial fibrillation) justifying a rhythm control strategy. More randomized trials at low risk of bias and low risk of random errors are needed.

Trial registration

PROSPERO CRD42016051433

Different Implications of Heart Failure, Ischemic Stroke, and Mortality Between Nonvalvular Atrial Fibrillation and Atrial Flutter-a View From a National Cohort Study

BACKGROUND

Atrial flutter (AFL) has been identified to be equivalent to atrial fibrillation (AF) in terms of preventing ischemic stroke, although differences exist in atrial rate, substrate, and electrophysiological mechanisms. This study aimed to investigate differences in clinical outcomes between nonvalvular AF and AFL.

METHODS AND RESULTS

AF and AFL patients without any prescribed anticoagulation were enrolled from a 13-year national cohort database. Under series exclusion criteria, ischemic stroke, heart failure hospitalization, and all-cause mortality were compared between the groups in real-world conditions and after propensity score matching. We identified 175 420 patients in the AF cohort and 6239 patients in the AFL cohort, and the prevalence of most comorbidities and frequency of medications were significantly higher in the AF group than the AFL group. In the real-world setting the AF patients had higher incidence rates of ischemic stroke, heart failure hospitalization, and all-cause mortality than the AFL patients (all P<0.001). After propensity score matching, the incidence rate of ischemic stroke in the AF cohort was 1.63-fold higher than in the AFL cohort (P<0.001), the incidence rate of heart failure hospitalization in the AF cohort was 1.70-fold higher than in the AFL cohort (P<0.001), and the incidence rate of all-cause mortality in the AF cohort was 1.08-fold higher than in the AFL cohort (P=0.002).

CONCLUSIONS

There were differences between AF and AFL in comorbidities and prognosis with regard to ischemic stroke, heart failure hospitalization, and all-cause mortality.

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.

Digoxin versus placebo, no intervention, or other medical interventions for atrial fibrillation and atrial flutter: a protocol for a systematic review with meta-analysis and Trial Sequential Analysis

BACKGROUND

Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillation and atrial flutter have an increased risk of death and morbidities. In the management of atrial fibrillation and atrial flutter, it is often necessary to use medical interventions to lower the heart rate. Lowering the heart rate may theoretically prevent the development of heart failure and tachycardia-mediated cardiomyopathy. The evidence on the benefits and harms of digoxin compared with placebo or with other medical interventions is unclear. This protocol for a systematic review aims at identifying the beneficial and harmful effects of digoxin compared with placebo, no intervention, or with other medical interventions for atrial fibrillation and atrial flutter.

METHODS

This protocol for a systematic review was conducted following the recommendations of Cochrane and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials comparing digoxin with placebo, no intervention, or with other medical interventions. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either at high risk of bias or low risk of bias, and our primary conclusions will be based on trials with low risk of bias. We will perform our meta-analyses of the extracted data using Review Manager 5.3 and Trial Sequential Analysis ver. 0.9.5.5 beta. For both our primary and secondary outcomes, we will create a 'Summary of Findings' table based on GRADE assessments of the quality of the evidence.

DISCUSSION

The results of this systematic review have the potential to benefit millions of patients worldwide as well as healthcare economy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016052935.

The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter: a protocol for a systematic review with meta-analysis and Trial Sequential Analysis

BACKGROUND

Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillation and atrial flutter have an increased risk of death and morbidities. The management of atrial fibrillation and atrial flutter is often based on interventions aiming at either a rhythm control strategy or a rate control strategy. The evidence on the comparable effects of these strategies is unclear. This protocol for a systematic review aims at identifying the best overall treatment strategy for atrial fibrillation and atrial flutter.

METHODS

This protocol for a systematic review was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5 and Trial Sequential Analysis. For both our primary and secondary outcomes, we will create a 'Summary of Findings' table and use GRADE assessment to assess the quality of the evidence.

DISCUSSION

The results of this systematic review have the potential to benefit thousands of patients worldwide as well as healthcare systems and healthcare economy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016051433.

Relationship between smoking and adverse outcomes in patients with atrial fibrillation: A meta-analysis and systematic review

BACKGROUND

Several studies have investigated the impact of smoking on the prognosis of atrial fibrillation (AF), but the results remain controversial. We therefore aimed to estimate the association between smoking and adverse outcomes in patients with AF.

METHODS

We systematically searched the Cochrane Library, PubMed, and Elsevier databases through May 2016 for studies regarding the association between smoking and adverse outcomes in AF patients. Risk ratios [RRs] and 95% confidence intervals [CIs] were abstracted and then pooled using a random-effects model.

RESULTS

A total of 8 cohort studies with 87,373 participants were included in this meta-analysis. Among patients with AF, smoking was associated with increased risks of all-cause death (RR=1.82, 95% CI: 1.33-2.49, P=0.0002) and cardiovascular death (RR=1.54, 95% CI: 1.31-1.81, P<0.00001) but not stroke/thromboembolism (RR=1.19, 95% CI 0.97-1.46; P=0.10). In addition, smoking was associated with an increased risk of major bleeding (RR=1.93, 95% CI 1.08-3.47, P=0.03), even after adjustment for the antithrombotic treatment.

CONCLUSIONS

The published literature demonstrates that smoking is not associated with the risk of stroke/thromboembolism but increases the risks of all-cause death and cardiovascular death in AF patients, as well as the risk of major bleeding in AF patients using anticoagulants.

Relations of Arterial Stiffness and Brachial Flow-Mediated Dilation With New-Onset Atrial Fibrillation: The Framingham Heart Study

The relations of measures of arterial stiffness, pulsatile hemodynamic load, and endothelial dysfunction to atrial fibrillation (AF) remain poorly understood. To better understand the pathophysiology of AF, we examined associations between noninvasive measures of vascular function and new-onset AF. The study sample included participants aged ≥45 years from the Framingham Heart Study offspring and third-generation cohorts. Using Cox proportional hazards regression models, we examined relations between incident AF and tonometry measures of arterial stiffness (carotid-femoral pulse wave velocity), wave reflection (augmentation index), pressure pulsatility (central pulse pressure), endothelial function (flow-mediated dilation), resting brachial arterial diameter, and hyperemic flow. AF developed in 407/5797 participants in the tonometry sample and 270/3921 participants in the endothelial function sample during follow-up (median 7.1 years, maximum 10 years). Higher augmentation index (hazard ratio, 1.16; 95% confidence interval, 1.02-1.32; P=0.02), baseline brachial artery diameter (hazard ratio, 1.20; 95% confidence interval, 1.01-1.43; P=0.04), and lower flow-mediated dilation (hazard ratio, 0.79; 95% confidence interval, 0.63-0.99; P=0.04) were associated with increased risk of incident AF. Central pulse pressure, when adjusted for age, sex, and hypertension (hazard ratio, 1.14; 95% confidence interval, 1.02-1.28; P=0.02) was associated with incident AF. Higher pulsatile load assessed by central pulse pressure and greater apparent wave reflection measured by augmentation index were associated with increased risk of incident AF. Vascular endothelial dysfunction may precede development of AF. These measures may be additional risk factors or markers of subclinical cardiovascular disease associated with increased risk of incident AF.

Urgent Catheter Ablation in Octogenarians with Serious Tachyarrhythmias

BACKGROUND

Urgent catheter ablation is often required for various tachyarrhythmias; however, its efficacy and safety in elderly patients have not been fully elucidated.

METHODS

This study included consecutive octogenarians who underwent urgent radiofrequency catheter ablation (RFCA) for various serious tachyarrhythmias (urgent group, n=28) that were life-threatening, hemodynamically deleterious, or provoking ischemia, and consecutive octogenarians who underwent elective RFCA (control group, n=36). The rate of a successful RFCA, complications, later arrhythmia recurrences, and mortality were compared between the groups.

RESULTS

There was no significant difference in the breakdown of the targeted arrhythmias between the groups, and common-type atrial flutter was most often targeted in both the urgent group (57%) and the elective group (56%). Compared with the control group patients, the patients of the urgent group were older (84±3 vs. 82±2 years P=0.001), with a higher frequency of baseline heart disease (68% vs. 17%, P<0.001) and lower left ventricular ejection fraction (45%±15% vs. 68%±10%, P<0.001). The rates of acute success (100% vs. 100%, P=1.00) and later arrhythmia recurrences (4% vs. 14%, P=0.22) were comparable between the groups. Two patients in the urgent group and 2 in the elective group had procedure-related nonlethal complications (7% vs. 6%, P=1.00): groin hematoma in 2, pressure ulcer in 1, and CO2 narcosis in 1. There were no in-hospital deaths, and mortality during follow-up did not differ between the urgent and elective groups (6.0% vs. 3.9% per year, log-rank P=0.38).

CONCLUSION

Even in octogenarian patients, urgent catheter ablation for serious tachyarrhythmias can be safely performed with a high success rate and acceptable prognosis.