External electrical and pharmacological cardioversion for atrial fibrillation, atrial flutter or atrial tachycardias: a network meta-analysis

BACKGROUND

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Cardioversion is a rhythm control strategy to restore normal/sinus rhythm, and can be achieved through drugs (pharmacological) or a synchronised electric shock (electrical cardioversion).

OBJECTIVES

To assess the efficacy and safety of pharmacological and electrical cardioversion for atrial fibrillation (AF), atrial flutter and atrial tachycardias.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Conference Proceedings Citation Index-Science (CPCI-S) and three trials registers (ClinicalTrials.gov, WHO ICTRP and ISRCTN) on 14 February 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) at the individual patient level. Patient populations were aged ≥ 18 years with AF of any type and duration, atrial flutter or other sustained related atrial arrhythmias, not occurring as a result of reversible causes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology to collect data and performed a network meta-analysis using the standard frequentist graph-theoretical approach using the netmeta package in R. We used GRADE to assess the quality of the evidence which we presented in our summary of findings with a judgement on certainty. We calculated differences using risk ratios (RR) and 95% confidence intervals (CI) as well as ranking treatments using a P value. We assessed clinical and statistical heterogeneity and split the networks for the primary outcome and acute procedural success, due to concerns about violating the transitivity assumption.

MAIN RESULTS

We included 112 RCTs (139 records), from which we pooled data from 15,968 patients. The average age ranged from 47 to 72 years and the proportion of male patients ranged from 38% to 92%. Seventy-nine trials were considered to be at high risk of bias for at least one domain, 32 had no high risk of bias domains, but had at least one domain classified as uncertain risk, and one study was considered at low risk for all domains. For paroxysmal AF (35 trials), when compared to placebo, anteroapical (AA)/anteroposterior (AP) biphasic truncated exponential waveform (BTE) cardioversion (RR: 2.42; 95% CI 1.65 to 3.56), quinidine (RR: 2.23; 95% CI 1.49 to 3.34), ibutilide (RR: 2.00; 95% CI 1.28 to 3.12), propafenone (RR: 1.98; 95% CI 1.67 to 2.34), amiodarone (RR: 1.69; 95% CI 1.42 to 2.02), sotalol (RR: 1.58; 95% CI 1.08 to 2.31) and procainamide (RR: 1.49; 95% CI 1.13 to 1.97) likely result in a large increase in maintenance of sinus rhythm until hospital discharge or end of study follow-up (certainty of evidence: moderate). The effect size was larger for AA/AP incremental and was progressively smaller for the subsequent interventions. Despite low certainty of evidence, antazoline may result in a large increase (RR: 28.60; 95% CI 1.77 to 461.30) in this outcome. Similarly, low-certainty evidence suggests a large increase in this outcome for flecainide (RR: 2.17; 95% CI 1.68 to 2.79), vernakalant (RR: 2.13; 95% CI 1.52 to 2.99), and magnesium (RR: 1.73; 95% CI 0.79 to 3.79). For persistent AF (26 trials), one network was created for electrical cardioversion and showed that, when compared to AP BTE incremental energy with patches, AP BTE maximum energy with patches (RR 1.35, 95% CI 1.17 to 1.55) likely results in a large increase, and active compression AP BTE incremental energy with patches (RR: 1.14, 95% CI 1.00 to 1.131) likely results in an increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: high). Use of AP BTE incremental with paddles (RR: 1.03, 95% CI 0.98 to 1.09; certainty of evidence: low) may lead to a slight increase, and AP MDS Incremental paddles (RR: 0.95, 95% CI 0.86 to 1.05; certainty of evidence: low) may lead to a slight decrease in efficacy. On the other hand, AP MDS incremental energy using patches (RR: 0.78, 95% CI 0.70 to 0.87), AA RBW incremental energy with patches (RR: 0.76, 95% CI 0.66 to 0.88), AP RBW incremental energy with patches (RR: 0.76, 95% CI 0.68 to 0.86), AA MDS incremental energy with patches (RR: 0.76, 95% CI 0.67 to 0.86) and AA MDS incremental energy with paddles (RR: 0.68, 95% CI 0.53 to 0.83) probably result in a decrease in this outcome when compared to AP BTE incremental energy with patches (certainty of evidence: moderate). The network for pharmacological cardioversion showed that bepridil (RR: 2.29, 95% CI 1.26 to 4.17) and quindine (RR: 1.53, (95% CI 1.01 to 2.32) probably result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up when compared to amiodarone (certainty of evidence: moderate). Dofetilide (RR: 0.79, 95% CI 0.56 to 1.44), sotalol (RR: 0.89, 95% CI 0.67 to 1.18), propafenone (RR: 0.79, 95% CI 0.50 to 1.25) and pilsicainide (RR: 0.39, 95% CI 0.02 to 7.01) may result in a reduction in this outcome when compared to amiodarone, but the certainty of evidence is low. For atrial flutter (14 trials), a network could be created only for antiarrhythmic drugs. Using placebo as the common comparator, ibutilide (RR: 21.45, 95% CI 4.41 to 104.37), propafenone (RR: 7.15, 95% CI 1.27 to 40.10), dofetilide (RR: 6.43, 95% CI 1.38 to 29.91), and sotalol (RR: 6.39, 95% CI 1.03 to 39.78) probably result in a large increase in the maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: moderate), and procainamide (RR: 4.29, 95% CI 0.63 to 29.03), flecainide (RR 3.57, 95% CI 0.24 to 52.30) and vernakalant (RR: 1.18, 95% CI 0.05 to 27.37) may result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: low). All tested electrical cardioversion strategies for atrial flutter had very high efficacy (97.9% to 100%). The rate of mortality (14 deaths) and stroke or systemic embolism (3 events) at 30 days was extremely low. Data on quality of life were scarce and of uncertain clinical significance. No information was available regarding heart failure readmissions. Data on duration of hospitalisation was scarce, of low quality, and could not be pooled.

AUTHORS' CONCLUSIONS

Despite the low quality of evidence, this systematic review provides important information on electrical and pharmacological strategies to help patients and physicians deal with AF and atrial flutter. In the assessment of the patient comorbidity profile, antiarrhythmic drug onset of action and side effect profile versus the need for a physician with experience in sedation, or anaesthetics support for electrical cardioversion are key aspects when choosing the cardioversion method.

Characterization of electropharmacological profile of an anti-atrial fibrillatory drug vernakalant along with potential risk toward torsade de pointes: Translational studies using isoflurane-anesthetized dogs and isolated rat aortic preparations

We simultaneously assessed electropharmacological effects of anti-atrial fibrillatory drug vernakalant and its potential risk toward torsade de pointes. Vernakalant hydrochloride in doses of 0.3 and 3 mg/kg/10 min was intravenously administered to isoflurane-anesthetized beagle dogs without (n = 5) and with (n = 4) α-adrenoceptor blockade. Its vascular effect was analyzed using the rat aortae (n = 12). Vernakalant increased total peripheral vascular resistance and preload to left ventricle, leading to transient elevation of mean blood pressure indirectly via non-adrenergic pathway. Vernakalant suppressed sinus automaticity, ventricular contractility and intra-atrial/atrioventricular nodal/intraventricular conductions, and decreased cardiac output. Moreover, vernakalant prolonged atrial/ventricular effective refractory period by 53/55 ms, respectively, whereas it delayed ventricular repolarization in a reverse frequency-dependent manner. The extent of prolongation in early/late ventricular repolarization and electrically vulnerable period was 26/32 and 9 ms, respectively when QT-interval prolongation was the greatest. We compared them with those of known anti-atrial fibrillatory drugs; ranolazine, amiodarone, dronedarone, dl-sotalol and bepridil. The magnitude of vernakalant to alter those variables was the greater among those drugs except that the atrial selectivity was the lesser of those. Thus, vernakalant is expected to be efficacious against atrial fibrillation, but caution should be excised on its use for patients having labile ventricular function and repolarization.

Effectiveness and Safety Profiles of Vernakalant for Cardioversion of acute-onset Atrial Fibrillation: A Systematic Review and Meta-analysis

PURPOSE

Pharmacologic cardioversion is an effective clinical strategy for fibrillation. Vernakalant is a novel drug used to treat atrial fibrillation (AF). This study aimed to evaluate the efficacy- and tolerability-related data on vernakalant from clinical trials.

METHODS

Literature from PubMed and the Cochrane Library was systematically reviewed, and 139 eligible studies were found after specific key words were identified. Twelve randomized clinical trials discussing vernakalant cardioversion in patients with AF were chosen for the meta-analysis after scrutiny. Ten of the 12 trials used placebo while two reported data on active and established drugs to compare the effects of vernakalant. Three of the 12 trials included relevant clinical states in addition to AF.

FINDINGS

In this meta-analysis of data from 12 studies (2365 patients, 887 events), the rate of cardioversion from AF to sinus rhythm (SR) was significantly greater with vernakalant compared with placebo and active comparators (risk ratio = 5.60; 95% CI, 2.83-11.09; I² test for heterogeneity, 92%). Tolerability-related data revealed that dysgeusia, paresthesia, atrial flutter, and hypotension were major adverse events that occurred with vernakalant use, but the data were not clinically significant compared to placebo and active drug (risk ratio = 1.13; 95% CI, 0.86-1.47). Eleven deaths were reported in 4 trials, with vernakalant directly implicated in two deaths. Vernakalant was well tolerated and effective in patients with rapid-onset AF.

IMPLICATIONS

Vernakalant appears to be a good choice when AF is manifested postoperatively or exists with ischemic heart disease and valvular states. Tolerability-related data are promising, but a specific trial may be required to identify the causes of the deaths considered unrelated to vernakalant use. (Clin Ther. 2023;45:XXX-XXX) © 2023 Elsevier Inc.

Antiarrhythmic Drug Therapy in the Treatment of Acute and Chronic Atrial Flutter

In the present article, we will focus on the pharmacologic treatment of atrial flutter aimed either at restoring/maintaining sinus rhythm or controlling the ventricular response during tachyarrhythmia. To provide a comprehensive description we will start discussing the electroanatomic substrate underlying the development of atrial flutter and the complex relationship with atrial fibrillation. We will then describe the available drugs for the treatment of atrial flutter on the bases of their electrophysiological effects and data from available clinical studies. We will conclude by discussing the general principles of rhythm and rate control treatment during atrial flutter.

Body Weight Counts—Cardioversion with Vernakalant or Ibutilide at the Emergency Department

Aim: Medication for the pharmacological cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) is applied either in a fixed dose or adapted to body weight. Individual body weight might be a relevant confounder for anti-arrhythmic treatment success. Therefore, the aim of this study was to elucidate the impact of body weight on pharmacological cardioversion success, comparing weight adapted (Vernakalant) and fixed dose (Ibutilide) pharmacotherapeutic cardioversion regimes. Methods: Within this prospective observational trial, a total of 316 episodes of AF and AFL were enrolled. Patients were stratified in either a Vernakalant (n = 181) or Ibutilide (n = 135) treatment arm, based on the chosen regime, for direct comparison of treatment efficacy. Results: Conversion to sinus rhythm was achieved in 76.3% of all cases. Of note, there was no difference comparing the Vernakalant and Ibutilide treatment arms (Vernakalant 76.2% vs. Ibutilide 76.3%; p = 0.991). Within the whole study population, decreasing conversion rates with increasing body weight (adjusted odds ratio (OR) = 0.69 (0.51–0.94); p = 0.018) were observed. An independent effect of body weight within the Ibutilide treatment arm was noted, which remained stable after adjustment for potential confounders (adjusted OR = 0.55 (0.38–0.92), p = 0.022. Conclusion: Both, the Vernakalant and Ibutilide treatment arms showed comparable rates of treatment success in pharmacotherapeutic cardioversion of AF and AFL. Of utmost importance, we observed that the fixed dose of Ibutilide—as compared to the weight-adapted dose of Vernakalant—showed a reduced treatment success with increasing body weight.

Worldwide trends in oral anticoagulant use in patients with atrial fibrillation from 2010 to 2018: a systematic review and meta-analysis

AIMS

Non-vitamin K antagonist oral anticoagulants (NOACs) are effective and safe alternatives compared with vitamin K antagonists (VKAs) for thromboembolic prevention in atrial fibrillation (AF), while antiplatelets are no longer recommended. However, to which extent NOAC introduction and guideline updates have increased OAC use in AF, is unclear. Therefore, worldwide trends in real-life prescribing of OACs, NOACs, VKAs, and antiplatelet monotherapy in AF patients were investigated.

METHODS AND RESULTS

Using PubMed and Embase, observational nationwide cohort studies on annual prevalent and/or incident OAC use in non-selected AF patients since 2010 were included. A meta-analysis of single proportions was performed. Twenty-one studies were included assessing prevalent and incident use among 9 758 637 and 197 483 OAC-eligible AF patients, respectively. Worldwide prevalence and incidence of OAC users increased from 0.42 [95% confidence interval (CI) 0.22-0.65] and 0.43 (95% CI 0.37-0.49) in 2010 to 0.78 (95% CI 0.77-0.78) and 0.75 (95% CI 0.74-0.76) in 2018, respectively. Prevalent and incident NOAC users increased globally from 0 in 2010 to 0.45 (95% CI 0.45-0.46) and 0.68 (95% CI 0.67-0.69) in 2018, respectively, whereas prevalent and incident VKA use decreased from 0.42 (95% CI 0.22-0.65) and 0.42 (95% CI 0.36-0.49) in 2010 to 0.32 (95% CI 0.32-0.32) and 0.06 (95% CI 0.06-0.07) in 2018, respectively. Prevalent antiplatelet monotherapy use decreased from 0.37 (95% CI 0.32-0.42) in 2010 to 0.09 (95% CI 0.09-0.10) in 2018.

CONCLUSION

The proportion of OAC users worldwide almost doubled following NOAC introduction. As one-quarter of OAC-eligible AF subjects were not anticoagulated and 9% were only treated with antiplatelets in 2018, there is still room for improvement.

Long-term outcome of left atrial appendage occlusion with multiple devices

BACKGROUND

To evaluate long-term efficacy of left atrial appendage occlusion with multiple devices.

METHODS

All consecutive patients who underwent left atrial appendage occlusion (LAAO) with a follow-up of at least 4 years, were included in this single center, retrospective registry. No specific exclusion criteria were applied. LAA occlusion was performed with the Watchman, Watchman FLX, Amplatzer Cardiac plug or Amplatzer Amulet occluder devices.

RESULTS

A total of 224 consecutive patients underwent LAAO occlusion. Mean age was 72.5 ± 9.0 years. A history of stroke was present in 29%, TIA in 8.5% and a previous episode of bleeding in 64.7% of patients. In 63% there was a contraindication to oral anticoagulants. The average CHADS-VASc was 4.0 ± 1.6 and the average HAS-BLED was 3.4 ± 1.3. There was a reduction of strokes of 72.9%, thromboembolic events of 59.7% and major bleeding events of 70.9% compared to historic data. During follow-up, 48.3% of the ischemic and major bleeding events occurred within the first year. The annual mortality rate of 7.5 deaths/ 100 patients years. There were no significant differences in terms of outcome between the devices used and there were no late events associated with any device. The main antithrombotic regimen in the long term was with single antiplatelet therapy and the second one was no therapy.

CONCLUSION

LAAO is a safe and effective procedure, that reduces ischemic and bleeding events in the long-term, regardless of the type of device used, in AF patients at high risk of ischemic stroke and major bleeding, without the need of anticoagulation.

Systematic Review and Meta-analysis Appraising Efficacy and Safety of Vernakalant for Cardioversion of Recent-Onset Atrial Fibrillation

Vernakalant is a novel, relatively atrial-selective antiarrhythmic agent. Despite its good efficacy profile and rapid onset of action, there was still controversial evidence regarding vernakalant-related adverse events. We searched PubMed and Embase for studies that compared intravenous vernakalant with placebo or antiarrhythmic agents in patients with recent-onset atrial fibrillation (AF) lasting no more than 7 days. Efficacy and safety outcomes were the treatment-induced cardioversion rate within 90 minutes and adverse events after first exposure to study drug respectively. Nine randomized controlled trials enrolling 1296 patients were analyzed. Quantitative synthesis showed that vernakalant was superior to placebo for cardioversion of recent-onset AF within 90 minutes [49.7% vs. 6.2%, risk ratio (RR) 8.13, 95% confidence interval (CI) 5.35-12.36, P < 0.00001], and it did not achieve statistical significance in cardioversion when vernakalant was compared with ibutilide (62.4% vs. 47.3%, RR 1.32, 95% CI 1.00-1.73, P = 0.05). As for safety assessment, no significant differences were found in occurring serious adverse events (9.9% vs. 10.4%, RR 0.91, 95% CI 0.67-1.25, P = 0.57) and hypotension (5.3% vs. 3.3%, RR 1.53, 95% CI 0.86-2.73, P = 0.15) between vernakalant and comparator (either placebo, ibutilide, or amiodarone). There were trends that patients receiving vernakalant experienced more drug discontinuation (2.5% vs. 1.0%, RR 2.21, 95% CI 0.96-5.11, P = 0.06) and less any ventricular tachycardia (6.1% vs. 8.1%, RR 0.70, 95% CI 0.49-1.00, P = 0.05) than those receiving comparator, but the differences were not statistically significant. Furthermore, vernakalant was associated with a higher risk of bradycardia in comparison with comparator (6.3% vs. 1.1%, RR 4.04, 95% CI 1.67-9.75, P = 0.002). Vernakalant is effective in converting recent-onset AF to sinus rhythm rapidly, while significantly more bradycardia events are related to vernakalant in our meta-analysis.

Vernakalant for cardioversion of recent-onset atrial fibrillation: a systematic review and meta-analysis

AIMS

To evaluate the efficacy and safety of vernakalant for the cardioversion of atrial fibrillation (AF).

METHODS AND RESULTS

We reviewed the literature for randomized trials that compared vernakalant to another drug or placebo in patients with AF of onset ≤7 days. We used a random-effects model to combine quantitative data and rated the quality of evidence using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation). From 441 total citations in MEDLINE, EMBASE, and CENTRAL (December 2018), we identified nine trials evaluating 1358 participants. Six trials compared vernakalant to placebo, two trials compared vernakalant to ibutilide, and one trial compared vernakalant to amiodarone. We found significant methodological bias in four trials. For conversion within 90 min, vernakalant was superior to placebo [50% conversion, risk ratio (RR) 5.15; 95% confidence interval (CI); 2.24-11.84, I2 = 91%], whereas we found no significant difference in conversion when vernakalant was compared with an active drug (56% vs. 24% conversion, RR 2.40; 95% CI 0.76-7.58, I2 = 94). Sinus rhythm was maintained at 24 h in 85% (95% CI 80-88%) of patients who converted acutely with vernakalant. Overall, we judged the quality of evidence for efficacy to be low based on inconsistency and suspected publication bias. There was no significant difference in the risk of significant adverse events between vernakalant and comparator (RR 0.95; 95% CI 0.70-1.28, I2 = 0, moderate quality evidence). Vernakalant is safe and effective for rapid and durable restoration of sinus rhythm in patients with recent-onset AF.

CONCLUSION

Vernakalant should be a first line option for the pharmacological cardioversion of patients with haemodynamically stable recent-onset AF without severe structural heart disease.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Vernakalant hydrochloride for the treatment of atrial fibrillation: evaluation of its place in clinical practice

Vernakalant is an intravenous anti-arrhythmic drug available in Europe, Canada and some countries in Asia for the restoration of sinus rhythm in acute onset atrial fibrillation. Currently, it is not available in USA because the US FDA have ongoing concerns about its safety. Vernakalant has a unique pharmacological profile of multi-ion channel activity and atrial-specificity that distinguishes it from other anti-arrhythmic drugs. This is thought to enhance efficacy but there are concerns of adverse events stemming from its diverse pharmacology. This ambiguity has prompted a review of the available clinical evidence on efficacy and safety to help re-evaluate its place in clinical practice.

Hemodynamic effects of Vernakalant in cardio-surgical ICU-patients treated for recent-onset postoperative atrial fibrillation

Postoperative atrial fibrillation (POAF) is one of the most frequent complications after cardiothoracic surgery and a predictor for postoperative mortality and prolonged ICU-stay. Current guidelines suggest the multi-channel inhibitor Vernakalant as a treatment option for rhythm control. However, rare cases of severe hypotension and cardiogenic shock following drug administration have been reported. To elucidate the impact of Vernakalant on hemodynamics, we included ten ICU patients developing POAF after elective cardiac surgery, all of them awake and breathing spontaneously, in this prospective trial. Patients received the recommended dosage of Vernakalant and were clinically observed and monitored (heart rate, invasive blood pressure, pulse oximetry, central venous pressure) in 1-minute-intervals for 20 minutes before- and 120 minutes after the first dose of Vernakalant. The median time from the end of surgery until occurrence of POAF amounted up to 52.8 [45.9–77.4] hours, it took 3.5 [1.2–10.1] hours from occurrence of POAF until the first application of Vernakalant. All patients received catecholamine support with epinephrine that was held steady and not dynamic throughout the observational phase. We noted stable hemodynamic conditions, with a trend towards a reduction in heart rate throughout the 120 minutes after drug administration. In 7 patients (70%), conversion to sustained sinus rhythm (SR) occurred within 8.0 minutes [6.0–9.0]. No serious adverse events (SAEs) were noted during the observation period. In this prospective trial in ICU-patients showing POAF after cardiac surgery, intravenous Vernakalant did not induce clinically relevant negative effects on patients’ hemodynamics but resulted in conversion to sustained SR after a median of 8.0 minutes in 7 out of ten patients.

Effectiveness and Safety of Apixaban Compared With Rivaroxaban for Patients With Atrial Fibrillation in Routine Practice: A Cohort Study

Background

Apixaban and rivaroxaban are the most commonly prescribed direct oral anticoagulants for adults with atrial fibrillation, but head-to-head data comparing their safety and effectiveness are lacking.

Objective

To compare the safety and effectiveness of apixaban versus rivaroxaban for patients with nonvalvular atrial fibrillation.

Design

New-user, active-comparator, retrospective cohort study.

Setting

A U.S. nationwide commercial health care claims database from 28 December 2012 to 1 January 2019.

Patients

Adults newly prescribed apixaban (n = 59 172) or rivaroxaban (n = 40 706).

Measurements

The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial hemorrhage or gastrointestinal bleeding.

Results

39 351 patients newly prescribed apixaban were propensity score matched to 39 351 patients newly prescribed rivaroxaban. Mean age was 69 years, 40% of patients were women, and mean follow-up was 288 days for new apixaban users and 291 days for new rivaroxaban users. The incidence rate of ischemic stroke or systemic embolism was 6.6 per 1000 person-years for adults prescribed apixaban compared with 8.0 per 1000 person-years for those prescribed rivaroxaban (hazard ratio [HR], 0.82 [95% CI, 0.68 to 0.98]; rate difference, 1.4 fewer events per 1000 person-years [CI, 0.0 to 2.7]). Adults prescribed apixaban also had a lower rate of gastrointestinal bleeding or intracranial hemorrhage (12.9 per 1000 person-years) compared with those prescribed rivaroxaban (21.9 per 1000 person-years), corresponding to an HR of 0.58 (CI, 0.52 to 0.66) and a rate difference of 9.0 fewer events per 1000 person-years (CI, 6.9 to 11.1).

Limitation

Unmeasured confounding, incomplete laboratory data.

Conclusion

In routine care, adults with atrial fibrillation prescribed apixaban had a lower rate of both ischemic stroke or systemic embolism and bleeding compared with those prescribed rivaroxaban.

Primary Funding Source

Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital.

Serum microRNA in patients undergoing atrial fibrillation ablation

MicroRNAs mediate posttranscriptional gene regulation. The aim of the study was to find a microRNA predictor of successful atrial fibrillation (AF) ablation. A total of 109 patients undergoing first-time AF ablation were included. Nineteen patients were selected to undergo serum microRNA sequencing (study group). The sequencing data were used to select several microRNAs that correlated with 12-month recurrences after AF ablation. Those microRNAs were validated by digital droplet PCR in samples from remaining 90 patients. All patients underwent pulmonary vein isolation (RF ablation, contact force catheter, electroanatomical system). The endpoint of the study was the 12-month AF recurrence rate; the overall recurrence rate was 42.5%. In total, levels of 34 miRNAs were significantly different in sera from patients with AF recurrence compared to patients without AF recurrence. Six microRNAs (miR-183-5p, miR-182-5p, miR-32-5p, miR-107, miR-574-3p, and miR-144-3p) were validated in the whole group. Data from the validation group did not confirm the observations from the study group, as no significant differences were found between miRNAs serum levels in patients with and without recurrences 12 months after AF ablation.

Current Anticoagulant Usage Patterns and Determinants in Korean Patients with Nonvalvular Atrial Fibrillation

PURPOSE

Stroke prevention in patients with atrial fibrillation (AF) is influenced by many factors. Using a contemporary registry, we evaluated variables associated with the use of warfarin or direct oral anticoagulants (OACs).

MATERIALS AND METHODS

In the prospective multicenter CODE-AF registry, 10529 patients with AF were evaluated. Multivariate analyses were performed to identify variables associated with the use of anticoagulants.

RESULTS

The mean age of the patients was 66.9±14.4 years, and 64.9% were men. The mean CHA₂DS₂-VASc and HAS-BLED scores were 2.6±1.7 and 1.8±1.1, respectively. In patients with high stroke risk (CHA₂DS₂-VASc ≥2), OACs were used in 83.2%, including direct OAC in 68.8%. The most important factors for non-OAC treatment were end-stage renal disease [odds ratio (OR) 0.27; 95% confidence interval (CI): 0.19-0.40], myocardial infarct (OR 0.53; 95% CI: 0.40-0.72), and major bleeding (OR 0.57; 95% CI: 0.39-0.84). Female sex (OR 1.40; 95% CI: 1.21-1.61), cancer (OR 1.78; 95% CI: 1.38-2.29), and smoking (OR 1.60; 95% CI: 1.15-2.24) were factors favoring direct OAC use over warfarin. Among patients receiving OACs, the rate of combined antiplatelet agents was 7.8%. However, 73.6% of patients did not have any indication for a combination of antiplatelet agents.

CONCLUSION

Renal disease and history of valvular heart disease were associated with warfarin use, while cancer and smoking status were associated with direct OAC use in high stroke risk patients. The combination of antiplatelet agents with OAC was prescribed in 73.6% of patients without definite indications recommended by guidelines.

A Novel Loss-of-Function Variant in the Chloride Ion Channel Gene Clcn2 Associates with Atrial Fibrillation

Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Its pathogenesis is complex and poorly understood. Whole exome sequencing of Danish families with AF revealed a novel four nucleotide deletion c.1041_1044del in CLCN2 shared by affected individuals. We aimed to investigate the role of genetic variation of CLCN2 encoding the inwardly rectifying chloride channel ClC-2 as a risk factor for the development of familiar AF. The effect of the CLCN2 variant was evaluated by electrophysiological recordings on transiently transfected cells. We used quantitative PCR to assess CLCN2 mRNA expression levels in human atrial and ventricular tissue samples. The nucleotide deletion CLCN2 c.1041_1044del results in a frame-shift and premature stop codon. The truncated ClC-2 p.V347fs channel does not conduct current. Co-expression with wild-type ClC-2, imitating the heterozygote state of the patients, resulted in a 50% reduction in macroscopic current, suggesting an inability of truncated ClC-2 protein to form channel complexes with wild type channel subunits. Quantitative PCR experiments using human heart tissue from healthy donors demonstrated that CLCN2 is expressed across all four heart chambers. Our genetic and functional data points to a possible link between loss of ClC-2 function and an increased risk of developing AF.

Mortality risk in atrial fibrillation: the role of aspirin, vitamin K and non-vitamin K antagonists

Background As an alternative to vitamin K antagonist and low-dose aspirin (< 325 mg), non-vitamin K oral anticoagulants are available for the prevention of stroke in patients with atrial fibrillation. However, the mortality risk associated with these drugs in daily practice remains unclear. Objective To evaluate the risk of all-cause mortality associated with non-Vitamin K antagonist oral anticoagulants, vitamin K antagonists or aspirin in patients with atrial fibrillation. Setting A cohort study conducted among atrial fibrillation patients using the UK Clinical Practice Research Datalink (March 2008-October 2014). Method New users of vitamin K antagonists, non vitamin K oral anticoagulants, low-dose aspirin, or combination therapy were followed from the date of first prescription to the date of death, as recorded in the UK datalink. Cox proportional hazard models estimated the hazard ratio (HR) of all-cause mortality for users of NOACs, aspirin, or combination use, as compared to vitamin K antagonist. Analyses were adjusted for confounders. Main outcome measure All-cause mortality. Results We identified 31,497 patients. Non vitamin K antocoagulant use (adjusted HR [aHR] = 1.42; 95% Confidence Interval [CI] 1.18-1.71) and aspirin use (aHR = 1.64; 95% CI 1.57-1.77) were both significantly associated with a higher mortality risk than use of vitamin K antagonists. The higher mortality risk for the non vitamin K anticoagulant use was observed in men (aHR = 1.72; 95% CI 1.25-2.36), but not in women (aHR = 1.28; 95% CI 0.92-1.79. Compared to  vitamin K antagonists, mortality risk associated with the non vitamin K anticoagulants and aspirin use was significantly increased in patients with higher stroke risk (CHA₂DS₂-VASc > 2). Conclusion Non vitamin K oral anticoagulants are  associated with a higher risk on all-cause mortality, particularly in men and in patients with higher stroke risk.

The effect of cardiac rehabilitation at 4 weeks postoperatively on quality of life in patients treated with totally thoracoscopic ablation

There is a lack of evidence on the effect of exercise-based cardiac rehabilitation (EBCR) in patients treated with total thoracoscopic ablation (TTA) for atrial fibrillation (AF). Our study investigated the efficacy and safety of postoperative exercise intervention in patients recovering from TTA. Twenty-four patients participated in the study, and were divided into the two groups, exercise group (EG) (n=12) and control group (n= 12). Patients in EG performed the exercise intervention including the aerobic and resistance exercise program twice a week for 8 weeks, which was used as a hospital-based cardiac rehabilitation for the out-patient. A cardiopulmonary exercise test was administered to evaluate aerobic exercise capacity, and qualitative aspect of patient’s life was assessed using the Short Form 36 questionnaires to compare pre and postoperative wellness of patient’s life. Although there was an increase of VO_2peak (peak oxygen uptake) after exercise intervention, no significant improvement was found (P=0.055). Two of 4 physical health scores (role-physical, P=0.013 and general health, P=0.05) and three of four mental health scores (vitality, P=0.027, social function, P=0.016, and mental health, P=0.003) were significantly improved after 8 weeks of EBCR. Each summarized scale in the physical (P=0.022) and mental (P= 0.004) survey section was also significantly improved in postoperative assessment compared to the preoperative one. In this context, we concluded that EBCR initiated at the time point of 4th week after TTA operation can guarantee the secure postoperative physical activity, and the 8 weeks of EBCR can effectively improve the quality of life in AF Patients.

Clinical outcomes of catheter ablation of paroxysmal atrial fibrillation in very young population compared to older population: a prospective study

Background

Data on procedural characteristics and clinical outcome of catheter ablation of atrial fibrillation (AF) in adults younger than 35 years has not been sufficiently addressed. The aim is to assess procedural characteristics and clinical outcome of catheter ablation of paroxysmal atrial fibrillation in young adults in comparison to older adults.

Results

Seventy-six consecutive patients with symptomatic paroxysmal AF underwent pulmonary vein isolation (PVI) at Ain Shams University Hospitals from 2013 till 2016. They were divided into the two groups, young population group (mean age 31.6 ± 4.2 years, 77% men) and older population group (mean age 49 ± 8.4 years, 74% men). Clinical data before and during the procedure were recorded. Follow-up was based on outpatient visits including 24 h Holter, ECG at 3, 6, and, 12 months post single ablation procedure. Recurrence was defined as any AF/atrial tachycardia episode > 30 s following a 3-month blanking period. Body mass index, CHA2DS2-VASc score, and left atrial volume were higher in the older population group [P values 0.019, < 0.001, and 0.001, respectively]. The presence of low-voltage areas was found only in 22% of the older population group and not in the younger group [P 0.02]. All patients were followed up for 1 year; 1-year arrhythmia-free survival after a single procedure was 83.3% (25/30) and 78.3% (36/46) in the older group [P 0.75]. No complications were recorded in both groups. Redo AF ablation were done for four patients in the old group and one patient in the young group.

Conclusions

Catheter ablation of AF in very young adults is associated with higher 1-year success rates but comparable to success rates in older populations. AF ablation for PAF is effective in very young adults.

Stroke Risk in Atrial Fibrillation: Beyond the CHA2DS2-VASc Score

PURPOSE OF REVIEW

Stroke prevention is the cornerstone of atrial fibrillation (AF) management and the anticoagulation decision is currently based on CHA₂DS₂-VASc risk score. We discuss several novel risk factors besides those included in CHA₂DS₂-VASc score and alternative models for stroke prediction.

RECENT FINDINGS

Several clinical markers including obstructive sleep apnea and renal failure, laboratory markers like brain natriuretic peptide, imaging criteria including left atrial appendage morphology, spontaneous echo contrast, and coronary artery calcium score may predict stroke in AF patients. Addition of African American ethnicity to CHA₂DS₂-VASc score also improves stroke prediction in AF. Finally, novel models including TIMI-AF score, ATRIA score, and GARFIELD-AF scores have potential roles in risk stratification for stroke. While CHA₂DS₂-VASc score is the currently recommended risk stratification model for stroke prediction in AF, use of additional clinical, laboratory, imaging markers, ethnicity, and novel stroke prediction models may further assist in decision to anticoagulate the AF patient for stroke prevention.

2018 Focused Update of the Canadian Cardiovascular Society Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) Atrial Fibrillation Guidelines Committee provides periodic reviews of new data to produce focused updates that address clinically important advances in atrial fibrillation (AF) management. This 2018 Focused Update addresses: (1) anticoagulation in the context of cardioversion of AF; (2) the management of antithrombotic therapy for patients with AF in the context of coronary artery disease; (3) investigation and management of subclinical AF; (4) the use of antidotes for the reversal of non-vitamin K antagonist oral anticoagulants; (5) acute pharmacological cardioversion of AF; (6) catheter ablation for AF, including patients with concomitant AF and heart failure; and (7) an integrated approach to the patient with AF and modifiable cardiovascular risk factors. The recommendations were developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) standards. Individual studies and literature were reviewed for quality and bias; the literature review process and evidence tables are included as Supplementary Material and are available on the CCS Web site. Details of the updated recommendations are presented, along with their background and rationale. This document is linked to an updated summary of all CCS AF guidelines recommendations, from 2010 to the present 2018 Focused Update, which is provided in the Supplementary Material.

Vernakalant in Atrial Fibrillation: A Relatively New Weapon in the Armamentarium Against an Old Enemy

Atrial fibrillation is the most common sustained cardiac arrhythmia, and its prevalence is increasing with age; also it is associated with significant morbidity and mortality. Rhythm control is advised in recent-onset atrial fibrillation, and in highly symptomatic patients, also in young and active individuals. Moreover, rhythm control is associated with lower incidence of progression to permanent atrial fibrillation. Vernakalant is a relatively new anti-arrhythmic drug that showed efficacy and safety in recent-onset atrial fibrillation. Vernakalant is indicated in atrial fibrillation (⩽7 days) in patients with no heart disease (class I, level A) or in patients with mild or moderate structural heart disease (class IIb, level B). Moreover, Vernakalant may be considered for recent-onset atrial fibrillation (⩽3 days) post cardiac surgery (class IIb, level B). Although it is mainly indicated in patients with recent-onset atrial fibrillation and with no structural heart disease, it can be given in moderate stable cardiac disease as alternative to Amiodarone. Similarly to electrical cardioversion, pharmacological cardioversion requires a minimal evaluation and cardioversion should be included in a comprehensive management strategy for better outcome.

Effectiveness and Safety of Off-Label Dose-Reduced Direct Oral Anticoagulants in Atrial Fibrillation

BACKGROUND

Direct oral anticoagulants (DOACs) reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation but may result in serious bleeding complications. Off-label dose-reduced use of DOACs to mitigate bleeding is common in routine clinical practice although data about its consequences on patient outcomes are limited. Therefore, our objective was to evaluate the effectiveness and safety of off-label dose-reduced vs per-label standard-dose DOAC treatment.

METHODS

The study cohort included newly diagnosed patients with nonvalvular atrial fibrillation that had initiated DOAC therapy between 2011 and 2017 in Clalit Health Services (Tel Aviv, Israel). Effectiveness was defined as the composite outcome of all-cause mortality, stroke, or myocardial infarction. The safety outcome was defined as bleeding events requiring hospitalization. Patients were followed until March 30, 2018 or until occurrence of an outcome event. Hazard ratios (HR) were adjusted for 21 variables, including comorbidities, concomitant medications, and socioeconomic factors, using multivariate regression.

RESULTS

A total of 8425 patients met the study criteria; 5140 (61%) patients were treated with DOACs at per-label dosing and 3285 (39%) patients were treated with off-label dose-reduced DOAC. Off-label dose-reduced treatment was associated with a higher rate of the composite effectiveness outcome: adjusted HR 1.57 (95% confidence interval, 1.34-1.83; P < .001) and a higher rate of bleeding: adjusted HR 1.63 (95% confidence interval, 1.14-2.34; P = .008).

CONCLUSIONS

Almost 4 of 10 patients were treated with off-label dose-reduced DOAC, which was associated with reduced effectiveness without a safety benefit. Compliance with per-label dosage may significantly improve outcomes of this population.

Introducing Vernakalant into Clinical Practice

Vernakalant is an antiarrhythmic drug licensed for the pharmacological cardioversion of recent onset AF. Randomised clinical trials, backed up by real-world experience, have confirmed its efficacy at restoring sinus rhythm. Vernakalant can be administered simply with a short time to action, facilitating early discharge from hospital in selected patients in place of electrical cardioversion. The authors explore the data behind vernakalant and discuss how it can be introduced into clinical practice.

Efficacy and safety of intravenous vernakalant for the rapid conversion of recent-onset atrial fibrillation: A meta-analysis

BACKGROUND

Atrial fibrillation is a common cardiac arrhythmia with increasing prevalence in the aging population. It is a major cause of emergency department visits worldwide. Vernakalant, a relatively new antiarrhythmic drug with selectively preferential effects on the atrial tissue is currently used in many European countries for the termination of recent-onset atrial fibrillation. Presently, the drug is still not approved by the United States Food and Drug Administration due to safety concerns. We evaluate the efficacy and safety of vernakalant for the conversion of recent-onset atrial fibrillation or atrial flutter into normal sinus rhythm (NSR).

METHODS

PubMed/MEDLINE (1993-2017), the Cochrane Central Register of Controlled Trials (2000-2017), and reference lists of relevant articles were searched for randomized controlled trials (RCTs) comparing vernakalant to a control drug and extracted subsequently.

RESULTS

Nine RCTs were identified and included in the meta-analysis. Pooled analysis of events extracted for a total of 1421 patients with recent-onset atrial fibrillation showed a statistically significant increase in cardioversion within 90 minutes from drug infusion (Relative Risk [RR], 6.61; 95% Confidence Interval [CI], 2.78 - 15.71; p < .00001). In terms of adverse events, vernakalant was considered safe in comparison to control drugs (RR, 0.80; 95% CI, 0.61-1.05; p = .11).

CONCLUSION

Vernakalant is effective for rapid conversion of recent-onset atrial fibrillation into NSR. However, although it showed a safe profile in terms of side effects in this analysis, we are still hesitant about this conclusion and few safety issues should be addressed within specific patients' subgroups.

Impact of chronic kidney disease on Watchman implantation: experience with 300 consecutive left atrial appendage closures at a single center

The prevalence of chronic kidney disease (CKD) is high in patients with atrial fibrillation (AF). Left atrial appendage closure (LAAC) has been recognized as an efficient alternative to oral anticoagulation for the prevention of thromboembolic events in patients with non-valvular AF (NVAF); however, the long-term safety and efficacy of LAAC in patients with CKD remain unclear. This study was designed to provide data regarding the safety and efficacy of LAAC in NVAF patients with CKD. A real-world analysis of the safety and efficacy of LAAC was performed on a cohort of 300 NVAF patients with or without CKD who underwent LAAC using the Watchman (WM) device at our center. The patients with CKD (n = 151) were significantly older (77.0 ± 7.2 vs. 73.2 ± 7.8 years, respectively, P < 0.0001) and had a higher CHA2DS2-VASc score (4.3 ± 1.5 vs. 3.4 ± 1.4, respectively, P < 0.0001) and HAS-BLED score (4.0 ± 1.0 vs. 3.0 ± 1.0, respectively, P < 0.0001) than the patients without CKD (n = 149). However, there were no differences between groups with respect to the device implant success rate (98.7 vs. 97.3%, respectively, P = 0.446) or severe periprocedural complications within 7 days. The patients were followed up for 637 ± 398 days, and all patients received repeat transesophageal echocardiography (TEE). Thirteen (4.3%) device-related thrombi, 3 (1.0%) ischemic strokes, and 19 (6.3%) non-procedural major bleeding cases were documented, and there were no differences in these complications between groups. The observed rate of all thromboembolic events by Kaplan–Meier analysis decreased by 68.8% (CKD) and 48.6% (non-CKD); moreover, the observed annual rate of bleeding was reduced by 57.5% (CKD) and 11.4% (non-CKD). Our results indicate that LAAC with the WM device is safe and effective in preventing stroke in NVAF patients with and without CKD.

Emerging pharmacotherapies for the treatment of atrial fibrillation

INTRODUCTION

The main aim of current research on the field of atrial fibrillation (AF) treatment is to find new antiarrhythmic drugs with less side effects. Areas covered: Dronedarone and vernakalant showed promising result in term of efficacy and safety in selected patients. Ranolazine and colchicine are obtaining a role as a potential antiarrhythmic drug. Ivabradine is used in experimental studies for the rate control of AF. Moreover, new compounds (vanoxerine, moxonidine, budiodarone) are still under investigation. Monoclonal antibodies or selective antagonist of potassium channel are under investigation for long term maintenance of sinus rhythm. Clinical evidence and new pharmacological investigation on new drugs will be accurately reviewed in this article. Expert opinion: Dronedarone use is not recommended in patients with symptomatic heart failure (HF), NYHA class III-IV, depressed ventricular function and permanent AF, especially in patients assuming a concomitant therapy with digoxin. Vernakalant had superior efficacy than amiodarone, flecainide and propafenone in single studies and similar efficacy to direct current cardioversion. Several of the developing drugs examined in this paper show an interesting potential, in particular the research on selective ionic channel inhibition and on compounds which reduce the inflammation state, especially after ablation or surgery.

Comparison of calibrated chromogenic anti-Xa assay and PT tests with LC-MS/MS for the therapeutic monitoring of patients treated with rivaroxaban

Possibilities to monitor rivaroxaban therapy could be useful in certain circumstances. Prothrombin time (PT) or chromogenic anti-Xa assays such as the Biophen Direct Factor Xa Inhibitor® (DiXaI) have been proposed to estimate rivaroxaban concentrations but are mainly based on in vitro studies. The study aim was to compare PT and Biophen DiXaI® measurements with liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurements in plasma samples from patients treated with Xarelto®. Fifty-two plasma samples were included. PT was performed using Innovin® and Triniclot PT Excel S®. Biophen DiXaI® was performed according to instructions from the manufacturer. The rivaroxaban plasma concentration ranged between 0 and 485 ng/ml as measured by LC-MS/MS. The limits of quantification were 30 ng/ml and 5 ng/ml for Biophen DiXaI® and LC-MS/MS, respectively. The linear correlation between Biophen DiXaI® and LC-MS/ MS analyses was high for all rivaroxaban concentrations (r2 = 0.95). For concentrations ≤100 ng/ml, r2-value was 0.83. The Bland-Altman analysis showed a mean difference of −16 ng/ml (SD: 25 ng/ml). The PT methods did not correlate well with plasma concentrations measured by LC-MS/MS (r2 ≈ 0.60). In conclusion, the important interindividual variability and the poor correlation with LC-MS/MS preclude the use of PT to estimate rivaroxaban concentrations. Thanks to its small inter-individual variability and good agreement with LC-MS/ MS measurements, we recommend the use of Biophen DiXaI® assays to estimate concentrations of rivaroxaban >30 ng/ml. Quantification of low rivaroxaban levels (<30 ng/ml) requires the LC-MS/MS method.

Validation of the SAMe-TT2R2 score in a nationwide population of nonvalvular atrial fibrillation patients on vitamin K antagonists

The SAMe-TT2R2 score has been proposed to identify patients with non valvular atrial fibrillation (AF) who maintain a high average time in therapeutic range (TTR) on vitamin K antagonists treatment (VKA). This score has been validated in several studies, either monocentric or including very selected populations in a specialised setting. Our objective was to validate this score in a nationwide cohort of AF patients. From November 2013 to March 2014 we included in this study the first 10 patients with AF on VKA consecutively seen in 120 outpatient cardiology clinics in Spain. The SAMe-TT2R2 score was calculated for each patient and TTR in the preceding six months was estimated by Rosendaal method. A total of 1,056 patients were recruited (mean age 73.6 ± 9.8 years, 42 % female). Mean value of TTR was 63.8 ± 25.9 % (median 66.8 %, interquartile range 45.6 %-85.4 %). We found a progressive decline in mean TTR from a score of 0 (67.5 % ± 24.6 %) to4 (52.7 ± 28.7 %, p< 0.01). The score was able to discriminate which patients had a good anticoagulation control (TTR65 %) with a C-statistic of 0.57 (95 %CI 0.53–0.60, p< 0.0005). A SAMe-TT2R2 score of 0–1 was associated with a good anticoagulation control with a sensitivity, specificity, positive and negative predictive values of 64 %, 48 %, 58 % and 54 %, respectively; and the odds ratio of having a TTR< 65 % if the score was2 was 1.64 (95 % confidence interval 1.33–1.95, p< 0.001). In conclusion, in this nationwide population with AF on VKA, the SAMe-TT2R2 score had a significant, although moderate, ability to identify patients with a good anticoagulation control.

Comparison of calibrated dilute thrombin time and aPTT tests with LC-MS/MS for the therapeutic monitoring of patients treated with dabigatran etexilate

Ways to monitor dabigatran etexilate (DE) therapy would be useful in certain situations. Functional assays such as aPTT or Hemoclot® Thrombin Inhibitor (HTI) have been proposed to evaluate dabigatran concentrations, but previous findings are based on in vitro studies and results must be confirmed in clinical samples. The aim of this study was to compare aPTT and HTI measurements with liquid chromatography- tandem mass spectrometry (LC-MS/MS) measurements of dabigatran in plasma samples from DE treated patients. Seventy-one plasma samples were included. aPTT was performed using STA-CKPrest® and SynthASil®. HTI was performed according to instructions from the manufacturer. The LC-MS/MS method utilised dabigatran- d3 as internal standard. The plasma concentration range was 0 to 645 ng/ml as measured by LC-MS/MS. Overall, the HTI and LC-MS/ MS analyses correlated well (r2=0.97). The Bland-Altman analysis showed a mean difference of 9 ng/ml (SD: 20 ng/ml). However, the HTI performed poorly at concentrations <50 ng/ml. LC-MS/MS was sensitive (limit of quantification 1.1 ng/ml) and specific for dabigatran. The aPTT methods did not correlate well with plasma concentrations measured by LC-MS/MS (r2 = 0.59 with SynthASil® and 0.50 with STACKPrest ®). In conclusion, the poor sensitivity, the important inter-individual variability, and the poor correlation with LC-MS/MS preclude the use of aPTT to estimate dabigatran concentrations. Due to its small inter-individual variability and good agreement with LC-MS/MS measurements, we recommend the use of HTI assays to rather accurately estimate concentrations of dabigatran <50 ng/ml. Quantification of lower dabigatran levels in DE-treated patients requires the “reference” LC-MS/MS method.

D-dimer and factor VIIa in atrial fibrillation – prognostic values for cardiovascular events and effects of anticoagulation therapy

Coagulation markers may improve monitoring the risk of stroke and bleeding in patients with atrial fibrillation (AF) during anticoagulant treatment. We examined baseline levels of D-dimer and their association with stroke, cardiovascular death and major bleeding in 6,202 AF patients randomised to dabigatran or warfarin in the RE-LY trial. The effects of treatment on serial levels of D-dimer and coagulation factor (F) VIIa in 2,567 patients were also analysed. Baseline D-dimer levels were related to the rate of stroke/systemic embolism (SEE) with 0.64 % in the lowest quartile (Q1, as reference) (D-dimer < 298 μg/l), 1.38 % Q2 (D-dimer 298–473 μg/l), 1.71 % Q3 (D-dimer 474–822 μg/l) and 2.00 % in Q4 (D-dimer > 822 μg/l) (p=0.0007). Similar associations were shown for cardiovascular death and major bleeding. Addition of baseline D-dimer to established clinical risk factors improved prediction of stroke/SEE, cardiovascular death and major bleeding (C-index increased from 0.66 to 0.68, 0.71 to 0.73 and 0.66 to 0.67, respectively). Dabigatran provided a greater reduction of D-dimer levels than warfarin regardless of baseline anticoagulant treatment. Ontreatment levels of FVIIa were markedly reduced by warfarin (median 12.1–13.8 mU/ml) but significantly higher with dabigatran (median 39.4–49.0 mU/ml) at all-time points. Dabigatran is associated with greater reduction in D-dimer without the pronounced reduction of FVIIa seen with warfarin. These different effects on the coagulation system might explain the better efficacy and less intracranial bleeding observed with dabigatran compared with warfarin.

Clinical Trial Registration: NCT00262600 (www.clinicaltrials.gov).

Supplementary Material to this article is available online at www.thrombosis-online.com.

Vernakalant is superior to ibutilide for achieving sinus rhythm in patients with recent-onset atrial fibrillation: a randomized controlled trial at the emergency department

Aims

Ibutilide is a rapid-acting antiarrhythmic drug with worldwide use for conversion of recent-onset atrial fibrillation. Vernakalant, approved in the EU in 2010, is likewise used intravenously, with proven efficacy and safety compared with placebo and amiodarone in randomized clinical trials. The aim of our study was to compare the time to conversion and the conversion rate within 90 min in patients with recent-onset atrial fibrillation treated with vernakalant or ibutilide.

Methods and Results

A randomized controlled trial registered at clinicaltrials.gov (NCT01447862) was performed in 100 patients with recent-onset atrial fibrillation treated at the emergency department of a tertiary care hospital. Patients received up to two short infusions of vernakalant (n = 49; 3 mg/kg followed by 2 mg/kg if necessary) or ibutilide (n = 51; 1 mg followed by another 1 mg if necessary) according to the manufacturer's instructions. Clinical and laboratory variables, adverse events, conversion rates, and time to conversion were recorded. Time to conversion of AF to sinus rhythm was significantly shorter in the vernakalant group compared with the ibutilide group (median time: 10 vs. 26 min, P = 0.01), and likewise the conversion success within 90 min was significantly higher in the vernakalant group (69 vs. 43%, log-rank P = 0.002). No serious adverse events occurred.

Conclusion

Vernakalant was superior to ibutilide in converting recent-onset atrial fibrillation to sinus rhythm in the emergency department setting.

Does von Willebrand factor improve the predictive ability of current risk stratification scores in patients with atrial fibrillation?

Von Willebrand factor (vWF) is a biomarker of endothelial dysfunction. We investigated its role on prognosis in anticoagulated atrial fibrillation (AF) patients and determined whether its addition to clinical risk stratification schemes improved event-risk prediction. Consecutive outpatients with non-valvular AF were recruited and rates of thrombotic/cardiovascular events, major bleeding and mortality were recorded. The effect of vWF on prognosis was calculated using a Cox regression model. Improvements in predictive accuracy over current scores were determined by calculating the integrated discrimination improvement (IDI), net reclassification improvement (NRI), comparison of receiver-operator characteristic (ROC) curves and Decision Curve Analysis (DCA). 1215 patients (49% males, age 76 (71–81) years) were included. Follow-up was almost 7 years. Significant associations were found between vWF and cardiovascular events, stroke, mortality and bleeding. Based on IDI and NRI, addition of vWF to CHA₂DS₂-VASc statistically improved its predictive value, but c-indexes were not significantly different. For major bleeding, the addition of vWF to HAS-BLED improved the c-index but not IDI or NRI. DCA showed minimal net benefit. vWF acts as a simple prognostic biomarker in AF and, whilst its addition to current scores statistically improves prediction for some endpoints, absolute changes and impact on clinical decision-making are marginal.

The impact of digoxin on mortality in patients with chronic systolic heart failure: A propensity-matched cohort study

BACKGROUND

Prior Studies showed mixed results in association of digoxin use with all-cause mortality (ACM). The aim of this analysis is to identify the impact of digoxin use on ACM in a contemporary heart failure (HF) cohort treated with guideline based therapy.

METHODS

We included 2298 consecutive patients seen in an HF clinic between 2000 and 2015. Patients were considered to be a digoxin user if he/she received digoxin at any point during the enrollment period in the HF clinic. Patients were matched based on digoxin utility using propensity matching in 2-3:1 fashion. The primary outcome was ACM.

RESULT

Of 2298 patients, 325 digoxin users were matched with 750 non-digoxin users. The Matched cohort did not have differences among demographics and clinical variables except for worse HF symptomatology and increased prevalence of atrial fibrillation. Overall, the prevalence of the use of guideline suggested therapies was 96%. After a median follow-up duration of 4years (IQR 2-6years), digoxin use was associated with increased ACM (21.8% versus 12.9%, unadjusted HR=1.81; 95% CI=1.33 to 2.45; p=0.001). This association remained significant after adjusting for the propensity score, atrial fibrillation, ejection fraction, and New York HF Class (HR=1.74; 95% CI=1.20 to 2.38; p<0.0001).

CONCLUSION

In this analysis of well-treated HF patients, digoxin was associated with increased ACM. Further randomized controlled trials are needed to determine whether digoxin therapy should be used in well-treated HF patients. Until then, routine use of digoxin in clinical practice should be discouraged.

Cost comparison of radiofrequency catheter ablation versus cryoablation for atrial fibrillation in hospitals using both technologies

OBJECTIVE

The objective of this study was to compare the cost of radiofrequency (RF) ablation vs cryoablation (Cryo) for atrial fibrillation (AF).

METHODS

This retrospective cohort study used 2013-2014 records from the Premier Healthcare Database for adults with AF catheter ablation. Exclusions included non-AF ablation, surgical ablation, valve replacement or repair, or cardiac implant. Hospitals were required to perform ≥20 procedures using each technology, with the technology identifiable in at least 90% of cases. The primary endpoint was total variable visit cost, modeled separately for inpatient and outpatient visits, and adjusted for patient and hospital characteristics. Technology was categorized as RF or Cryo, with dual-technology procedures classified as Cryo. The Cryo cohort was further divided into Cryo only and Cryo with RF for sensitivity analyses. A composite adverse event endpoint was also compared.

RESULTS

A total of 1261 RF procedures and 1276 Cryo procedures, of which 500 also used RF, met study criteria. RF patients were slightly older and sicker, and had more cardiovascular disease and additional arrhythmias. Adjusted inpatient costs were $2803 (30.0%) higher for Cryo, and adjusted outpatient costs were $2215 (19.5%) higher. Sensitivity models showed higher costs in both Cryo sub-groups compared with RF. Procedural complication rates were not significantly different between cohorts (p-values: 0.4888 inpatient, 0.5072 outpatient).

CONCLUSION

AF ablation using RF results in significantly lower costs compared with Cryo, despite an RF population with more cardiovascular disease. This saving cannot be attributed to a difference in complication rates.

Role of Calcium-activated Potassium Channels in Atrial Fibrillation Pathophysiology and Therapy

Small-conductance Ca²⁺-activated potassium (SK) channels are relative newcomers within the field of cardiac electrophysiology. In recent years, an increased focus has been given to these channels because they might constitute a relatively atrial-selective target. This review will give a general introduction to SK channels followed by their proposed function in the heart under normal and pathophysiological conditions. It is revealed how antiarrhythmic effects can be obtained by SK channel inhibition in a number of species in situations of atrial fibrillation. On the contrary, the beneficial effects of SK channel inhibition in situations of heart failure are questionable and still needs investigation. The understanding of cardiac SK channels is rapidly increasing these years, and it is hoped that this will clarify whether SK channel inhibition has potential as a new anti–atrial fibrillation principle.

Clinical and economic impact of rivaroxaban on the burden of atrial fibrillation: The case study of Japan

OBJECTIVES

Atrial fibrillation (AF) affects an estimated 1.5 million individuals in Japan, increasing their stroke risk and imposing considerable costs on the Japanese healthcare system. To reduce stroke incidence, guidelines recommend using anticoagulants in moderate-to-high risk non-valvular AF (NVAF) patients; however, many patients receive no treatment, aspirin only, or remain poorly-controlled on vitamin K antagonists (VKAs) due to high VKA discontinuation rates and non-adherence to guidelines. A prevalence-based Markov model was developed to estimate the clinical and budgetary impact of treating these patients with Xarelto(TM) (rivaroxaban, Bayer AG) in Japan.

METHODS

Population, baseline risk of events, and associated management costs were estimated using data from Japanese publications where available. Treatment efficacy and safety were derived from published data and the J-ROCKET AF trial. Drug and physician visit costs were based on data from the Ministry of Health, Labor, and Welfare, the J-ROCKET AF trial, and Japanese clinical guidelines.

RESULTS

This model demonstrates that increased use of rivaroxaban in inadequately-managed NVAF patients could avoid 456 081 non-fatal ischemic strokes (IS) and 76 975 cardiovascular deaths over 10 years in Japan. This clinical benefit offsets the increased incidence of myocardial infarctions and anticoagulant-related bleeding. Decreased event costs could lead to a ¥188.4 billion decrease in net spending over the analysis time horizon.

CONCLUSIONS

Introducing rivaroxaban may decrease the burden of NVAF in Japanese society. From a clinical perspective, the reduction in IS and embolic events outweighs the increased risk of anticoagulant-related bleeding; from an economic perspective, reduced event costs offset drug and physician visit costs, resulting in cost savings.

Non-vitamin K antagonist oral anticoagulation usage according to age among patients with atrial fibrillation: Temporal trends 2011-2015 in Denmark

Among atrial fibrillation (AF) patients, Danish nationwide registries (2011-2015) were used to examine temporal trends of initiation patterns of oral anticoagulation (OAC) treatment according to age. Overall, 43,299 AF patients initiating vitamin K antagonists (VKA) (42%), dabigatran (29%), rivaroxaban (13%), or apixaban (16%) were included with mean age (SD) 72.1 (11.3), 71.5 (11.0), 74.3 (11.1), and 75.3 (11.1) years, respectively. Patients aged ≥85 years comprised 15%. Trend tests showed increase in patients ≥85 years initiating OAC (p < 0.0001). VKA usage decreased from 92% to 24% (p < 0.0001). This decrease was independent of age. Dabigatran was the most common non-VKA OAC (NOAC) (40% users), but usage decreased from 2014 until study end (6%) (p < 0.0001). Apixaban was the most used OAC at study end (41%), in particular among those ≥85 years (44%). Compared with patients aged <65 years, the odds ratios associated with initiating VKA, dabigatran, rivaroxaban, or apixaban for patients aged ≥85 years were 0.81 (95% CI 0.75-0.86), 0.65 (95% CI 0.60-0.70), 1.52 (95% CI 1.38-1.67), and 2.09 (95% CI 1.89-2.30), respectively. In conclusion, substantial increase in NOAC usage has occurred. Increasing age was associated with upstart of rivaroxaban or apixaban with reference to age <65 within the specific agent.

Evaluation of SAMe-TT2R2 score and other clinical factors influencing the quality of anticoagulation therapy in non-valvular atrial fibrillation: a nationwide study in Spain

OBJECTIVE

To assess the major clinical factors affecting the quality of anticoagulation and evaluate the predictive value of the SAMe-TT2R2 score to identify patients who will achieve a high average time in therapeutic range (T.T.R.) with vitamin K antagonist (V.K.A.) treatment.

RESEARCH DESIGN AND METHODS

This observational, cross-sectional, retrospective and nationwide multicenter study included 1524 patients from the primary care setting with non-valvular atrial fibrillation receiving V.K.A. (≥12 months). We performed a bivariate analysis to identify factors individually associated with the T.T.R. and a multiple regression analysis to identify the independent predictive factors. For the validation of the SAMe-TT2R2 score, the receiver operating characteristic (R.O.C.) curve was calculated and the Hosmer-Lemeshow test was used to test calibration.

RESULTS

A total of 94.8% of patients received acenocumarol (4.8% warfarin). A progressive decrease in mean T.T.R. was found when the SAMe-TT2R2 score increased from 0 points (72.1 ± 17.1%) to 4 points (64.1 ± 23.2%), p < 0.001. Other risk scores (CHADS2 and CHA2DS2-VASc, HAS-BLED) were also associated with the mean T.T.R. We found a significant association between low T.T.R. and the following clinical factors: female sex, three or more comorbidities, amiodarone treatment, dietary habits, bleeding history and the intake of ≥7 tablets per day besides V.K.A. (p < 0.01). Regarding SAMe-TT2R2 score validation, the R.O.C. curve showed significant capability, although not high, of discriminating good anticoagulation control (T.T.R. ≥65%) with an area under the curve of 0.562 (95% C.I. 0.533-0.592, p < 0.001) which increased, remaining modest, to 0.594 (95% C.I. 0.564-0.624, p < 0.001) when the factors not included in SAMe-TT2R2 score were added.

CONCLUSION

In this cohort, the SAMe-TT2R2 score had a significant, although modest, ability to assess the likelihood of good international normalized ration (I.N.R.) control, and its predictive value might slightly improve by adding other simple clinical factors. Further research is needed to refine the predictive scales.

Dabigatran approaching the realm of heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a serious, immune mediated complication of exposure to unfractionated or low-molecular-weight heparin. Though rare, it is a condition associated with high morbidity and mortality that requires immediate change to alternative anticoagulants for the prevention of life-threatening thrombosis. The direct thrombin inhibitors lepirudin and argatroban are currently licensed for the treatment of HIT. Dabigatran, a novel oral anticoagulant (NOAC) with a similar mechanism of action and effective use in other indications, has recently been proposed as another therapeutic option in cases of HIT. This review serves as an introduction to using dabigatran for this purpose, detailing the clinical aspects of its administration, evidence of its performance compared to other anticoagulants, and the preliminary reports of HIT successfully treated with dabigatran. As the literature on this develops, it will need to include clinical trials that directly evaluate dabigatran against the other NOACs and current treatment options.

Stroke and thromboembolic event rates in atrial fibrillation according to different guideline treatment thresholds: A nationwide cohort study

Contemporary guidelines suggest anticoagulant treatment decisions in atrial fibrillation (AF) patients to be based on risk stratification for stroke. However, guidelines do not agree on the threshold for treatment initiation. We explored the variation in thromboembolic event rates in a non-anticoagulated AF population, according to different guideline threshold and methodological approaches. AF patients between 1998 and 2014 free from anticoagulant treatment were identified. Event rates for ischemic stroke and ischemic stroke/systemic embolism were explored. The overall ischemic stroke rate was 3.20 per 100 person-years (‘formal rate assessment’). For patients with a CHA₂DS₂-VASc score of 1 the ischemic stroke rate was 0.97 when using a ‘formal rate assessment’, 0.62 when using a ‘conditioning on the future’ approach, and 0.93 when using a ‘censoring approach’. Rates for thromboembolism for the ‘European treatment threshold’ (CHA₂DS₂-VASc score of 1, males only) ranged 1.17 to 1.53. Rates for the ‘U.S. treatment threshold’ (CHA₂DS₂-VASc of 2) ranged from 1.95 to 2.33. Thromboembolic event rates differed markedly in non-anticoagulated AF patients according to the conflicting European and U.S. guideline treatment thresholds. Second, the choice of methodological approach has implications, thus we recommend using the censoring approach for event rate estimation among AF patients not on treatment.

Potassium Channel Remodeling in Heart Disease

Heart disease produces substantial remodeling of K(+) channels that in general promotes arrhythmia occurrence. In the case of ventricular arrhythmias, K(+) channel remodeling contributes to the arrhythmic risk and increases vulnerability to torsades de pointes with K(+) channel inhibiting drugs. Atrial K(+) channel remodeling caused by atrial fibrillation promotes arrhythmia stability and presents opportunities for the development of new drugs targeting atrial inward rectifier K(+) currents. A better understanding of K(+) channel remodeling will help clinicians to appreciate arrhythmia mechanisms and determinants in a variety of clinical situations and to better manage arrhythmia therapy in patients with heart disease.

New anthyarrhythmic drugs for atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia associated with increased mortality and morbidity. Different studies have shown no significant difference between rhythm and rate control strategies in terms of mortality. Moreover, the use of antiarrhythmic drugs is afflicted by cardiac and extracardiac toxicity and related costs of hospitalization. Nevertheless, some patients require a rhythm-control strategy and new anti-AF agents are being sought. Only few novel agents showed promising results in term of efficacy and safety. Dronedarone and vernakalant are two of these compounds, respectively introduced for the chronic and acute rhythm control of AF. This article will review pharmacology and clinical evidence on the use of dronedarone and vernakalant and will mention currently investigated new antiarrhythmic drugs.