Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: Catheter Ablation for Atrial Fibrillation/Atrial Flutter

Efficacy and safety of radiofrequency ablation versus cryoballoon ablation for persistent atrial fibrillation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Persistent Atrial Fibrillation (PeAF) is a challenging case for rhythm control modalities. Catheter ablation is the mainstay in PeAF management; however, data regarding the comparative safety and efficacy of cryoballoon ablation (CBA) versus radiofrequency ablation (RFA) for PeAF is still limited. We aim to compare the safety and efficacy of CBA versus RFA for PeAF ablation.

METHODS

We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through October 2023. RevMan version 5.4 software was used to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI).

PROSPERO ID

CRD42023480314.

RESULTS

Three RCTs with 400 patients were included. There was no significant difference between RFA and CBA regarding AF recurrence (RR: 0.77, 95% CI [0.50, 1.20], P = 0.25), atrial tachycardia or atrial flutter recurrence (RR: 0.54, 95% CI [0.11, 2.76], P = 0.46), and any arrhythmia recurrence (RR: 0.96, 95% CI [0.70, 1.31], P = 0.80). CBA was significantly associated with decreased total procedure duration (MD: - 45.34, 95% CI [- 62.68, - 28.00], P < 0.00001), with no significant difference in fluoroscopy duration (MD: 3.59, 95% CI [- 5.13, 12.31], P = 0.42). Safety parameters were similar in both groups, including the incidence of any complications, phrenic nerve palsy (RR: 2.91 with 95% CI [0.31, 27.54], P = 0.35), access site complications (RR: 0.33 with 95% CI [0.05, 2.03], P = 0.23), and pericardial effusion.

CONCLUSIONS

In PeAF catheter ablation, CBA is comparable to RFA in terms of safety and efficacy. Also, CBA is associated with a shorter total procedure duration.

Clinical Characteristics and Rhythm Outcomes in Patients With Atrial Myopathy After Successful Catheter Ablation of Atrial Fibrillation

BACKGROUND

Although successful atrial fibrillation (AF) ablation can maintain sinus rhythm and reduce the left atrial (LA) dimension, blunted LA reverse remodeling can be observed in patients with atrial myopathy. We explored the potential mechanisms and long-term outcomes in patients with blunted LA reverse remodeling after successful AF catheter ablation.

METHODS AND RESULTS

We included 1685 patients who underwent baseline and 1-year follow-up echocardiograms, had a baseline LA dimension ≥40 mm, and did not have a recurrence of AF within a year. The patients were divided into tertile groups according to the delta value of the change in LA dimension on the preprocedure and 1-year postprocedure echocardiography. After propensity score matching for age, sex, AF type, and LA dimension, 1272 patients were finally included in the analyses (424 in each group; the least/blunted, moderate, and the most reverse remodeling group). The patients in the T1 group (blunted LA reverse remodeling) were independently associated with higher left ventricular mass index (odds ratio [OR], 1.014 [95% CI, 1.005-1.022], P=0.001), change in ΔH2FPEF score (heavy, hypertensive, atrial fibrillation, pulmonary hypertension, elder, filling pressure) score (OR, 1.445 [95% CI, 1.121-1.861], P=0.004), ventricular epicardial adipose tissue volume (OR, 1.010 [95% CI, 1.003-1.017], P=0.003), thinner LA wall thickness (OR, 0.461 [95% CI, 0.271-0.785], P=0.004), lower LA voltage (OR, 0.670 [95% CI, 0.499-0.899], P=0.008), and showed higher long-term AF recurrence (log-rank P<0.001) than other groups.

CONCLUSIONS

Blunted LA reverse remodeling after AF catheter ablation, which is suggestive of atrial myopathy, was independently associated with a larger ventricular epicardial adipose tissue volume and worsening of H2FPEF score. Blunted LA reverse remodeling after AF catheter ablation was also an independent predictor for higher recurrences of AF post-1-year AF catheter ablation.

The diagnostic and therapeutic challenge of atrial flutter in children: a case report

BACKGROUND

Palpitations represent a common cause for consultation in the pediatric Emergency Department (ED). Unlike adults, palpitations in children are less frequently dependent from the heart, recognizing other causes.

CASE PRESENTATION

A 11-year-old male came to our pediatric ED for epigastric pain, vomiting and palpitations. During the previous 6 month the patient was affected by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus). Electrocardiogram (ECG) revealed supraventricular tachycardia. Therefore, adenosine was administered unsuccessfully. The administration of adenosine, however, allowed us to make diagnosis of atypical atrial flutter. Multiple attempts at both electrical cardioversion, transesophageal atrial overdrive, and drug monotherapy were unsuccessful in our patient. Consequently, a triple therapy with amiodarone, flecainide, and beta-blocker was gradually designed to control the arrhythmic pattern with the restoration of a left upper atrial rhythm. There was not any evidence of sinus rhythm in the patient clinical history.

CONCLUSIONS

The present study underlines the rarity of this type of dysrhythmia in childhood and the difficulties in diagnosis and management, above all in a patient who has never showed sinus rhythm. Raising awareness of all available treatment options is essential for a better management of dysrhythmia in children.

Cost-effectiveness analysis of digital therapeutics for home-based cardiac rehabilitation for patients with atrial fibrillation after catheter ablation

Background

In recent years, numerous guidelines and expert consensuses have recommended that digital technologies and products, such as digital therapeutics (DTx), be incorporated into cardiac rehabilitation (CR).

Objective

The study aims to compare the cost-effectiveness of DTx for home-based CR (HBCR) with that of the conventional HBCR for patients with atrial fibrillation (AF) after catheter ablation in a real-world clinical setting.

Methods

Based on a single-center, prospective, blinded, randomized, parallel controlled trial of DTx-based HBCR for AF patients after catheter ablation, 100 AF patients undergoing catheter ablation were selected and randomized at a 1:1 ratio into a UC group (conventional HBCR) and DT group (DTx-based HBCR). The intervention lasted for 12 weeks. Medical cost data and clinical efficacy data (VO2max) were acquired from trial data. Effect data (QALYs, anxiety and depression status, health beliefs related to cardiovascular disease, and exercise self-efficacy) were obtained from a patient questionnaire. The cost-effectiveness analysis was conducted to assess the economic benefits of DTx-based HBCR versus conventional HBCR, and the robustness of the results was verified by sensitivity analysis.

Results

In the DT group (n = 49), the mean QALYs increased 0.119 ± 0.09, VO2max increased 9.3 ± 8.0 mL/(min*kg), anxiety, depression, health belief, and exercise self-efficacy had improved, and the total medical cost was 75,080.55 ± 19,746.62 CNY. In the UC group (n = 48), the mean QALYs increased 0.077 ± 0.06, VO2max increased 4.9 ± 6.6 mL/(min*kg), anxiety, depression, health belief, and exercise self-efficacy had improved, and the total medical cost was 73,972.66 ± 16,582.04 CNY. The difference in the medical cost was 1107.89 CNY, and the incremental cost-effectiveness ratio was 33,572.42 CNY/QALY, which was lower than the willingness-to-pay threshold of 85,698 CNY (China's per capita GDP in 2022).

Conclusion

DTx-based HBCR is more effective and cost-effective than conventional HBCR.

Characterization of arrhythmia substrate to ablate persistent atrial fibrillation (COAST-AF): Randomized controlled trial design and rationale

BACKGROUND

Atrial low voltage area (LVA) catheter ablation has emerged as a promising strategy for ablation of persistent atrial fibrillation (AF). It is unclear if catheter ablation of atrial LVA increases treatment success rates in patients with persistent AF.

OBJECTIVE

The primary aim of this trial is to assess the potential benefit of adjunctive catheter ablation of atrial LVA in addition to pulmonary vein isolation (PVI) in patients with persistent AF, when compared to PVI alone. The secondary aims are to evaluate safety outcomes, the quality of life and the healthcare resource utilization.

METHODS/DESIGN

A multicenter, prospective, parallel-group, 2-arm, single-blinded randomized controlled trial is under way (NCT03347227). Patients who are candidates for catheter ablation for persistent AF will be randomly assigned (1:1) to either PVI alone or PVI + atrial LVA ablation. The primary outcome is 18-month documented event rate of atrial arrhythmia (AF, atrial tachycardia or atrial flutter) post catheter ablation. Secondary outcomes include procedure-related complications, freedom from atrial arrhythmia at 12 months, AF burden, need for emergency department visits/hospitalization, need for repeat ablation for atrial arrhythmia, quality of life at 12 and 18 months, ablation time, and procedure duration.

DISCUSSION

Characterization of Arrhythmia Mechanism to Ablate Atrial Fibrillation (COAST-AF) is a multicenter randomized trial evaluating ablation strategies for catheter ablation. We hypothesize that catheter ablation of atrial LVA in addition to PVI will result in higher procedural success rates when compared to PVI alone in patients with persistent AF.

Clinical electrophysiology of the aging heart

INTRODUCTION

Advancements in medical and consumer-grade technologies have made it easier than ever to monitor a patient's heart rhythm and to diagnose arrhythmias. Octogenarians with symptomatic arrhythmias have unique management challenges due to their frailty, complex drug interactions, cognitive impairment, and competing comorbidities. The management decisions are further complicated by the lack of randomized evidence to guide treatment.

AREAS COVERED

A comprehensive literature review was undertaken to outline various tachyarrhythmias and bradyarrhythmias and their management, the role of cardiac implantable electronic devices, cardiac ablations, and specific geriatric arrhythmia considerations as recommended in international guidelines.

EXPERT OPINION

Atrial fibrillation (AF) is arguably the most important arrhythmia in the elderly and is associated with significant morbidity and mortality. Early diagnosis of AF, potentially with smart devices (wearables), has the potential to reduce the incidence of stroke, systemic emboli, and the risk of dementia. Bradyarrhythmias have a high incidence in the elderly as well, often requiring implantation of a permanent pacemaker. Leadless pacemakers implanted directly into the right ventricle are great options for gaining traction in elderly patients.

Rhythm Monitoring Strategy and Arrhythmia Recurrence in Atrial Fibrillation Ablation Trials: A Systematic Review

Background

: The rhythm-monitoring strategy after catheter ablation (CA) for atrial fibrillation (AF) impacts the detection of atrial arrhythmia recurrence and is not well characterized. We performed a systematic review and meta-regression analysis to determine whether the duration and mode of rhythm monitoring after CA affects detection of atrial arrhythmia recurrence.

Methods

Databases were systematically searched for randomized controlled trials of adult patients undergoing first CA for AF from 2007 to 2021. Duration and strategy of rhythm monitoring were extracted. Meta-regression was used to identify any association between duration of monitoring and detection of atrial arrhythmia recurrence. The primary measure of outcome was single-procedure recurrence of atrial arrhythmia.

Results

The search strategy yielded 57 trial arms from 56 randomized controlled trials comprising 5322 patients: 36 arms of patients with paroxysmal AF (PAF), and 21 arms of patients with persistent AF (PeAF) or both PAF/PeAF. Intermittent monitoring was associated with detection of significantly less atrial arrhythmia recurrence than continuous monitoring in PAF arms (31.2% vs 46.9%, P = 0.001), but not in PeAF/PAF-PeAF combined arms (43.3% vs 63.6%, P = 0.12). No significant relationship was seen between the duration of intermittent rhythm monitoring and atrial arrhythmia recurrence detection in either the PAF (P = 0.93) or PeAF/PAF-PeAF combined arms (P = 0.20).

Conclusions

Continuous rhythm monitoring detected higher atrial arrhythmia recurrence rates, compared to intermittent rhythm monitoring, in patients with PAF. The duration of intermittent monitoring did not show a statistically significant relationship to the yield of arrhythmia detection, in near identical cohorts of trial subjects undergoing similar interventions, with clinical and research implications.

Pulmonary vein isolation alone vs. more extensive ablation with defragmentation and linear ablation of persistent atrial fibrillation: the EARNEST-PVI trial

AIMS

Previous studies could not demonstrate any benefit of more intensive ablation in addition to pulmonary vein isolation (PVI) including complex fractionated atrial electrogram (CFAE) and linear ablation for recurrence in the initial catheter ablation of persistent atrial fibrillation (AF). This study aimed to establish the non-inferiority of PVI alone to PVI plus these additional ablation strategies.

METHODS AND RESULTS

Patients with persistent AF who underwent an initial catheter ablation (n = 512, long-standing persistent AF; 128 cases) were randomly assigned in a 1:1 ratio to either PVI alone (PVI-alone group) or PVI plus CFAE and/or linear ablation (PVI-plus group). After excluding 15 cases who did not receive procedures, we analysed 249 and 248 patients, respectively. The primary endpoint was recurrence of AF, atrial flutter, and/or atrial tachycardia, and the non-inferior margin was set at a hazard ratio of 1.43. In the PVI-plus group, 85.1% of patients had linear ablation and 15.3% CFAE ablation. After 12 months, freedom from the primary endpoint occurred in 71.3% of patients in the PVI-alone group and in 78.3% in the PVI-plus group [hazard ratio = 1.56 (95% confidence interval: 1.10-2.24), non-inferior P = 0.3062]. The procedure-related complication rates were 2.0% in the PVI-alone group and 3.6% in the PVI-plus group (P = 0.199).

CONCLUSION

This randomized trial did not establish the non-inferiority of PVI alone to PVI plus linear ablation or CFAE ablation in patients with persistent AF, but implied that the PVI plus strategy was promising to improve the clinical efficacy (NCT03514693).

Left Atrial Wall Stress and the Long-Term Outcome of Catheter Ablation of Atrial Fibrillation: An Artificial Intelligence-Based Prediction of Atrial Wall Stress

Atrial stretch may contribute to the mechanism of atrial fibrillation (AF) recurrence after atrial fibrillation catheter ablation (AFCA). We tested whether the left atrial (LA) wall stress (LAW-stress_[measured]) could be predicted by artificial intelligence (AI) using non-invasive parameters (LAW-stress_[AI]) and whether rhythm outcome after AFCA could be predicted by LAW-stress_[AI] in an independent cohort. Cohort 1 included 2223 patients, and cohort 2 included 658 patients who underwent AFCA. LAW-stress_[measured] was calculated using the Law of Laplace using LA diameter by echocardiography, peak LA pressure measured during procedure, and LA wall thickness measured by customized software (AMBER) using computed tomography. The highest quartile (Q4) LAW-stress_[measured] was predicted and validated by AI using non-invasive clinical parameters, including non-paroxysmal type of AF, age, presence of hypertension, diabetes, vascular disease, and heart failure, left ventricular ejection fraction, and the ratio of the peak mitral flow velocity of the early rapid filling to the early diastolic velocity of the mitral annulus (E/Em). We tested the AF/atrial tachycardia recurrence 3 months after the blanking period after AFCA using the LAW-stress_[measured] and LAW-stress_[AI] in cohort 1 and LAW-stress_[AI] in cohort 2. LAW-stress_[measured] was independently associated with non-paroxysmal AF (p < 0.001), diabetes (p = 0.012), vascular disease (p = 0.002), body mass index (p < 0.001), E/Em (p < 0.001), and mean LA voltage measured by electrogram voltage mapping (p < 0.001). The best-performing AI model had acceptable prediction power for predicting Q4-LAW-stress_[measured] (area under the receiver operating characteristic curve 0.734). During 26.0 (12.0–52.0) months of follow-up, AF recurrence was significantly higher in the Q4-LAW-stress_[measured] group [log-rank p = 0.001, hazard ratio 2.43 (1.21–4.90), p = 0.013] and Q4-LAW-stress_[AI] group (log-rank p = 0.039) in cohort 1. In cohort 2, the Q4-LAW-stress_[AI] group consistently showed worse rhythm outcomes (log-rank p < 0.001). A higher LAW-stress was associated with poorer rhythm outcomes after AFCA. AI was able to predict this complex but useful prognostic parameter using non-invasive parameters with moderate accuracy.

Prevalence of Left Atrial Thrombus in Anticoagulated Patients With Atrial Fibrillation

BACKGROUND

The prevalence of left atrial (LA) thrombus in patients with atrial fibrillation (AF) or atrial flutter (AFL) on guideline-directed anticoagulation is not well known, yet this may inform transesophageal echocardiogram (TEE) use before cardioversion or catheter ablation.

OBJECTIVES

The purpose of this study was to quantify LA thrombus prevalence among patients with AF/AFL on guideline-directed anticoagulation and to identify high-risk subgroups.

METHODS

EMBASE, MEDLINE, and CENTRAL were systematically searched from inception to July 2020 for studies reporting on LA thrombus prevalence among patients with AF/AFL undergoing TEE following at least 3 weeks of continuous therapeutic oral anticoagulation with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). Meta-analysis was performed using random effects models.

RESULTS

Thirty-five studies describing 14,653 patients were identified. The mean-weighted LA thrombus prevalence was 2.73% (95% confidence interval [CI]: 1.95% to 3.80%). LA thrombus prevalence was similar for VKA- and DOAC-treated patients (2.80%; 95% CI: 1.86% to 4.21% vs. 3.12%; 95% CI: 1.92% to 5.03%; p = 0.674). Patients with nonparoxysmal AF/AFL had a 4-fold higher LA thrombus prevalence compared with paroxysmal patients (4.81%; 95% CI: 3.35% to 6.86% vs. 1.03%; 95% CI: 0.52% to 2.03%; p < 0.001). LA thrombus prevalence was higher among patients undergoing cardioversion versus ablation (5.55%; 95% CI: 3.15% to 9.58% vs. 1.65%; 95% CI: 1.07% to 2.53%; p < 0.001). Patients with CHA₂DS₂-VASc scores ≥3 had a higher LA thrombus prevalence compared with patients with scores ≤2 (6.31%; 95% CI: 3.72% to 10.49% vs. 1.06%; 95% CI: 0.45% to 2.49%; p < 0.001).

CONCLUSIONS

LA thrombus prevalence is high in subgroups of anticoagulated patients with AF/AFL, who may benefit from routine pre-procedural TEE use before cardioversion or catheter ablation.

Protective Effects of Intravenous Magnesium Sulfate in Stroke Patients Receiving Amiodarone: A Randomized Controlled Trial

Anti-arrhythmic agents, like amiodarone, interfere at different stages of the ischemic stroke. However, amiodarone was accompanied with immunological pulmonary complications and adverse neurological effects. We hypothesize that magnesium sulfate in combination with amiodarone holds promise for stroke treatment. Thirty-six patients with confirmed diagnosis of ischemic stroke and atrial fibrillation who received bolus amiodarone were randomly assigned to magnesium sulfate every 24 h or similar volume of normal saline (as placebo) for 5 days. Various severity test scores were used to evaluate the symptoms. Routing biochemistry were also measured at days 1 and 5. Treatment with MgSO4 results in a significant reduction in serum levels of NGAL, Hb, T.Bill, IL-6, IL-8, SNSE, S100B, EGF, PAF, CRP and IgG. Also, MgSO4 treatment significantly improved the RASS, Candida, SOFA, NIHSS and APACHE scores. Moreover, reduction of IL-6, IL-8, SNSE, EGF and APACHE score and increase in RASS score were significantly higher in MgSO4 group compared with placebo. Intravenous administration of MgSO4 in amiodarone-treated stroke patients improved the inflammatory, immunological and neurological indicators and reduced disability in ICU-admitted AIS patients, suggesting that this treatment scheme may prevent amiodarone-induced complications in these patients.

Angiotensin II and angiotensin 1-7: which is their role in atrial fibrillation?

Atrial fibrillation (AF) is a significant cause of morbidity and mortality as well as a public health burden considering the high costs of AF-related hospitalizations. Pre-clinical and clinical evidence showed a potential role of the renin angiotensin system (RAS) in the etiopathogenesis of AF. Among RAS mediators, angiotensin II (AII) and angiotensin 1-7 (A1-7) have been mostly investigated in AF. Specifically, the stimulation of the pathway mediated by AII or the inhibition of the pathway mediated by A1-7 may participate in inducing and sustaining AF. In this review, we summarize the evidence showing that both RAS pathways may balance the onset of AF through different biological mechanisms involving inflammation, epicardial adipose tissue (EAT) accumulation, and electrical cardiac remodeling. EAT is a predictor for AF as it may induce its onset through direct (infiltration of epicardial adipocytes into the underlying atrial myocardium) and indirect (release of inflammatory adipokines, the stimulation of oxidative stress, macrophage phenotype switching, and AF triggers) mechanisms. Classic RAS blockers such as angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARB) may prevent AF by affecting the accumulation of the EAT, representing a useful therapeutic strategy for preventing AF especially in patients with heart failure and known left ventricular dysfunction. Further studies are necessary to prove this benefit in patients with other cardiovascular diseases. Finally, the possibility of using the A1-7 or ACE2 analogues, to enlarge current therapeutic options for AF, may represent an important field of research.

Relationship Between Body Mass Index and Incidence of Atrial Fibrillation in Young Japanese Men - The Nishimura Health Survey

BACKGROUND

The associations between body mass index (BMI) and incidence of atrial fibrillation (AF) in young men are scarce, especially in Asian countries, given the differences in BMI between Asians and Western populations.

METHODS AND RESULTS

This study analyzed 17,865 middle-aged Japanese men without AF from a cohort of employees undergoing annual health examinations. AF incidence was evaluated during a follow-up period (median 4.0 years, interquartile range 2.0-7.1 years). Among young men aged 30-49 years, AF incidence was 0.64/1,000 person-years, whereas it was 2.54/1,000 and 7.60/1,000 person-years among men aged 50-59 and ≥60 years, respectively. Multivariable Cox regression analysis among young men revealed age (hazard ratio [HR] 3.28 by 10-years' increase, 95% confidence interval [CI] 1.72-6.25, P<0.001), BMI (BMI-quadratic, HR 1.01, 95% CI 1.00-1.01, P<0.001, BMI-linear, HR 0.95, 95% CI 0.86-1.05, P=0.33), and electrocardiogram (ECG) abnormalities, such as PQ prolongation, supraventricular beat, and p wave abnormality (HR 8.79, 95% CI 3.05-25.32, P<0.001), were significantly associated with AF incidence. There was a reverse J-shaped association between BMI and AF incidence in young men, whereby the presence of ECG abnormality inversely influenced the BMI-incident AF relationship. A linear association between BMI and AF incidence in men aged 50-59 and ≥60 years was present.

CONCLUSIONS

AF incidence displays a reverse J-shaped relationship with BMI in young men, but a linear association in men aged ≥50 years. The paradoxical relationship seen in young men only may reflect atrial electrical or structural abnormalities.

Electrophysiological Characteristics and Outcomes of Radiofrequency Catheter Ablation of Atrial Flutter in Children with or Without Congenital Heart Disease

There are scarce studies on radiofrequency catheter ablation (RFCA) of atrial flutter (AFL) in the pediatric population. This study therefore aimed to investigate the clinical features and RFCA of AFL in children with or without congenital heart disease. Data from 72 consecutive children (44 males; mean age, 6.1 ± 3.8 [0.9-15.0] years; and mean weight, 23.6 ± 13.9 [8.1-72.0] kg) undergoing RFCA for AFL from 2009 to 2019 were retrospectively reviewed. Thirty-three patients had normal cardiac structure and 39 had congenital heart disease (CHD) of whom 29 had undergone surgical repair and developed AFL at a mean of 3.1 ± 2.5 years later. Fifty-nine patients (84%) presented with persistent AFL. Five patients (7%) had cardiac dysfunction with LVEF of 30-48%, which normalized after ablation. Overall, acute success rate of ablation was 99% and recurrence rate was 18% at 0.5-10 years of follow-up. No procedure-related complications were identified. All 33 patients with normal cardiac structure had cavotricuspid isthmus (CTI)-dependent AFL. Among patients who had undergone corrective surgery for CHD, 15 (52%) had CTI-dependent AFL, 4 (14%) had surgical incisional scar reentrant AFL and the remaining 10 (34%) had both CTI-dependent and scar reentrant AFL. Success rate (100% vs. 97%, P = 1.0000) and recurrence rate (21% vs. 16%, P = 0.7008) were similar between patients with and without CHD. Overall, sick sinus syndrome (SSS) was found in 42% (30/72) of patients with AFL, with an incidence of 39% (13/33) among patients with normal cardiac structure and 59% (17/29) among those who underwent surgery for congenital defects. Permanent pacemakers (PM) were implanted in 53% (16/30) of patients with SSS after ablation. RFCA therefore appeared efficacious and safe for treatment of pediatric AFL. The mechanisms underlying AFL after corrective surgery for CHD are complex, including CTI-dependent macro-reentrant, scar reentrant, or a combination of both. SSS is not rare among pediatric AFL cases, with approximately half of patients needing PM implantation.

Catheter Ablation of Low-Voltage Areas for Persistent Atrial Fibrillation: Procedural Outcomes Using High-Density Voltage Mapping

BACKGROUND

Several approaches have been proposed to address the challenge of catheter ablation of persistent atrial fibrillation (AF). However, the optimal ablation strategy is unknown. We sought to evaluate the efficacy of pulmonary vein isolation (PVI) plus low-voltage area (LVA) ablation using contemporary high-density mapping to identify LVA in patients with persistent AF.

METHODS

Consecutive patients accepted for AF catheter ablation were studied. High-density bipolar voltage mapping data were acquired in sinus rhythm using multipolar catheters to detect LVA (defined as bipolar voltage < 0.5 mV). Semiautomated impedance-based software was used to ensure catheter contact during data collection. Patients underwent PVI + LVA ablation (if LVA present).

RESULTS

A total of 145 patients were studied; 95 patients undergoing PVI + LVA ablation were compared with 50 controls treated with PVI only. Average age was 61 ± 10 years, and 80% were male. Baseline characteristics were comparable. Freedom from atrial tachycardia/AF at 18 months was 72% after PVI + LVA ablation vs 58% in controls (P = 0.022). Median procedure duration (273 [240, 342] vs 305 [262, 360] minutes; P = 0.019) and radiofrequency delivery (50 [43, 63] vs 55 [35, 68] minutes; P = 0.39) were longer in the PVI + LVA ablation group. Multivariable analysis showed that the ablation strategy (PVI + LVA) was the only independent predictor of freedom from atrial tachycardia/AF (hazard ratio, 0.53; 95% confidence interval, 0.29-0.96; P = 0.036). There were no adverse safety outcomes associated with LVA ablation.

CONCLUSIONS

An individualized strategy of high-density mapping to assess the atrial substrate followed by PVI combined with LVA ablation is associated with improved outcomes. Adequately powered randomized clinical trials are needed to determine the role of PVI + LVA ablation for persistent AF.

Antithrombotic Treatment after Atrial Fibrillation Ablation

:

Atrial fibrillation is a major cause of debilitating strokes and anticoagulation is an established and indispensable therapy for reducing their rate. Ablation of the arrhythmia has emerged as a putative means of disrupting its natural course by isolating its triggers and modifying its substrate, dependent on the chosen method. An important dilemma lies in the need for continuation of anticoagulation therapy in those previously receiving it following an, apparently, successful intervention, purportedly preventing arrhythmia recurrence with considerably high rates. Current guidance, given scarcity of high-quality data from randomized trials, focuses on established knowledge and recommends anticoagulation continuation based solely on estimated thromboembolic risk. In the present review, it will be attempted to summarize the pathophysiological rationale for maintaining anticoagulation post-successful ablation, along with the latter’s definition, including the two-fold effects of the procedure per se on thrombogenicity. Available evidence pointing to an overall clinical benefit of anticoagulation withdrawal following careful patient assessment will be discussed, including ongoing randomized trials aiming to offer definitive answers. Finally, the proposed mode of post-ablation anticoagulation will be presented, including the emerging, guideline-endorsed, role of direct oral anticoagulants in the field, altering cost/benefit ratio of anticoagulation and potentially affecting the very decision regarding its discontinuation.

Catheter Ablation in the Treatment of Atrial Fibrillation

Catheter ablation (CA) of the pulmonary veins for atrial fibrillation (AF) is growing exponentially and is the most commonly performed electrophysiologic procedure. Initial descriptions focused on CA for paroxysmal AF, and now more recently expanded in application to persistent AF and those with comorbid heart failure. Efforts to improve success have and continue to address issues such as pulmonary vein "reconnection" following ablation through different ablative energy modalities, and the use of a "hybrid" surgical/endocardial combined approach in persistent forms of AF. Technologic advances as well are concurrently seeking to improve safety, particularly regarding the incidence of atrio-esophageal fistula in this seemingly ever-growing ablation population.

Elongation of the high right atrium to coronary sinus conduction time predicts the recurrence of atrial fibrillation after radiofrequency catheter ablation

BACKGROUND

The impact of intra-atrial conduction delay on the recurrence of atrial tachyarrhythmia after radio frequency catheter ablation (RFCA) has not been fully elucidated.

METHODS

We retrospectively analyzed 155 AF patients who were sinus rhythm at the start of RFCA. The conduction time from the onset of the earliest atrial electrogram at the high right atrium (HRA) to the end of the latest electrogram at the coronary sinus (CS) during sinus rhythm was defined as HRA-CS conduction time. Pulmonary vein isolation (PVI) was performed followed by linear roof lesion and complex fractionated atrial electrogram (CFAE) ablation until AF termination. We evaluated atrial tachyarrhythmia recurrence 12 months after RFCA.

RESULTS

The follow-up data were available for 148 patients. The recurrence of atrial tachyarrhythmia was noted in 28 (18.9%) patients. Atrial tachyarrhythmia recurrence patients had longer HRA-CS conduction times (151.3 ± 22.1 ms vs 160.1 ± 32.6 ms, p = .017). The patients were divided into the long or short HRA-CS conduction time group. The Kaplan-Meier analysis revealed that the long HRA-CS conduction time group held a higher risk of atrial tachyarrhythmia recurrence (log-rank test, p = .019). The multivariable Cox hazard analysis revealed that a long HRA-CS conduction time was a significant risk factor for the recurrence of atrial tachyarrhythmia, despite a long AF duration, persistent AF, and larger left atrial diameter (LAD) were not statistically significant.

CONCLUSIONS

The HRA-CS conduction time was the primary influencing factor that predicted the recurrence of atrial tachyarrhythmia after catheter ablation.

Withdrawal of oral anticoagulants 3 months after successful radiofrequency catheter ablation in patients with atrial fibrillation: A meta-analysis

BACKGROUND

The best anticoagulation therapy for atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) remains a challenge.

METHODS

A systematic search of PubMed, Ovid, and Cochrane Library was conducted identifying at clinical trials which evaluated the differences between thromboembolism (TE) and hemorrhage in an off-oral anticoagulants (OACs) treatment group (the observation group) and an on-OACs treatment group (the control group), at 3 months after successful RFCA. Meta-analysis was performed using RevMan 5.3 software, and the fixed effect model was used as a relevant statistical model. χ² test and I² were used to test for the presence of heterogeneity. Subgroup analysis and sensitivity analysis were also performed.

RESULTS

The results showed no significant differences between two groups in TE (relative risk [RR] 0.82, 95% confidence interval [CI], 0.51-1.33, P = 0.42), and only mild heterogeneity (P = 0.22, I²  = 29%). No significant differences in TE between two subgroups were found according to < 3 years and ≥ 3 years follow-up analyses (RR 0.58, 95% CI, 0.26-1.28, P = 0.18; RR 1.00, 95% CI, 0.54-1.85, P = 1.00). Furthermore, there was a lower risk of TE in the observation subgroup (< 60 years) compared to the control group (RR 0.31, 95% CI, 0.12-0.78, P = 0.01). Also, there were no significant differences in TE between two subgroups (≥ 60 years, RR 1.24, 95% CI, 0.67-2.28, P = 0.49). The risk of hemorrhage in the observation group was significantly lower compared to the control group (RR 0.05, 95%CI, 0.02-0.14, P < 0.00001).

CONCLUSIONS

The withdrawal of OACs 3 months after successful radiofrequency catheter ablation for patients with AF may be safe and feasible. It needs to be tested by randomized controlled trial.

Efficacy of adjunctive measures used to assist pulmonary vein isolation for atrial fibrillation: a systematic review

PURPOSE OF REVIEW

Pulmonary vein reconnection leading to recurrence of atrial arrhythmias after pulmonary vein isolation (PVI) for atrial fibrillation remains a significant challenge. A number of adjunctive measures during PVI have been used to attempt to reduce pulmonary vein reconnection and recurrence of atrial arrhythmias. We performed a systematic review of the literature and meta-analysis of studies evaluating the efficacy of adjunctive measures used during PVI in reducing recurrent atrial arrhythmias.

RECENT FINDINGS

Our literature search found four interventions that met the prespecified definition of adjunctive measure: adenosine testing post-PVI, contact force-guided PVI, pacing inexcitability of the ablation line during PVI and additional ablation based on the computed tomography thickness of the pulmonary vein-left atrial appendage ridge. Sixteen studies enrolling 3507 patients met all inclusion and exclusion criteria. PVI performed with adjunctive measures was shown to reduce the 1-year recurrence rate of atrial arrhythmias. The point estimate for the combined relative risk of atrial arrhythmia recurrence was 0.56 [95% confidence interval (CI): 0.43-0.73; P value <0.001] in the PVI with adjunctive measures group.

SUMMARY

PVI for atrial fibrillation assisted by adjunctive measures results in clinically significant reduction of recurrent atrial arrhythmias. Additional research is required to assess the relative efficacy of individual or combined adjunctive strategies used during PVI for atrial fibrillation.

Real-world outcomes, complications, and cost of catheter-based ablation for atrial fibrillation: an update

PURPOSE OF REVIEW

Catheter-based ablation for atrial fibrillation is a useful and effective form of rhythm-control therapy for symptomatic patients. This article reviews the 'real-world' experience on the outcomes, complications, and costs of atrial fibrillation ablation.

RECENT FINDINGS

Currently, real-world outcomes of atrial fibrillation ablation are derived from retrospective analysis of administrative databases or prospective registries from selected centers and patients. The rate of atrial fibrillation recurrence was reported to be as high as 60% and the rate of repeat ablation ranged from ≈10 to 18% within 1 year after ablation. All-cause hospitalizations after atrial fibrillation ablation were frequent, at up to ≈30% within 1 year and with up to half of them related to atrial fibrillation recurrence or repeat procedures. Rates of periprocedural complications were relatively low (≈3%). Female sex was associated with higher risk of complications such as bleeding, vascular injury, and tamponade. Markov models examining the cost-effectiveness of ablation yielded favorable results when success rates of more than 70% were assumed with long time horizons (>5 years).

SUMMARY

The real-world outcomes of atrial fibrillation ablation are sobering. Confirmation of these findings with prospective, population-based, minimally biased studies is needed. There is a critical need to delineate the downstream economic impact of atrial fibrillation ablation on society to justify its continued delivery and growth.

CHA₂DS₂-VASc Score in the Prediction of Ischemic Stroke in Patients after Radiofrequency Catheter Ablation of Typical Atrial Flutter

PURPOSE

Despite undergoing successful catheter ablation of typical atrial flutter (AFL), patients remain at increased risk for ischemic stroke. However, data on risk prediction tools for the development of stroke after AFL ablation are lacking. This study investigates whether CHA₂DS₂-VASc score is useful for predicting ischemic stroke after successful ablation of typical AFL.

MATERIALS AND METHODS

A total of 293 patients (236 men, mean age 56.1±13.5 years) who underwent successful radiofrequency catheter ablation for typical AFL were included in this study. The clinical end point was occurrence of ischemic stroke during follow-up after AFL ablation.

RESULTS

During the follow-up period (60.8±45.9 months), ischemic stroke occurred in 18 (6%) patients at a median of 34 months (interquartile range, 13-65 months). CHA₂DS₂-VASc score [hazard ratio 2.104; 95% confidence interval (CI), 1.624-2.726; p<0.001] was an independent predictor for the occurrence of stroke after AFL ablation. The area under the receiver operating characteristic curve for CHA₂DS₂-VASc score was 0.798 (95% CI, 0.691-0.904). The CHA₂DS₂-VASc score could be used to stratify patients into two groups with different incidences of ischemic stroke (1.6% vs. 14.4%, p<0.001) at a cutoff value of 2.

CONCLUSION

CHA₂DS₂-VASc score is useful in a prediction model for the risk of stroke after catheter ablation of typical AFL.

The Optimal Anti-Coagulation for Enhanced-Risk Patients Post-Catheter Ablation for Atrial Fibrillation (OCEAN) trial

BACKGROUND

The optimal long-term antithrombotic regimen for patients after successful catheter-based atrial fibrillation (AF) ablation is not well defined. Presently, practice variation exists, and the benefits of oral anticoagulation over antiplatelet therapy across the entire spectrum of stroke risk profile remain undefined in the postablation population. To date, there are no randomized trials to inform clinicians on this therapeutic question.

OBJECTIVE

The objective was to assess whether rivaroxaban is superior to acetylsalicylic acid (ASA) in reducing the risk of clinically overt stroke, systemic embolism, or covert stroke among patients without apparent recurrent atrial arrhythmias for at least 1 year after their most recent AF ablation procedure.

METHODS/DESIGN

A prospective, multicenter, open-label, randomized trial with blinded assessment of outcomes is under way (NCT02168829). Atrial fibrillation patients with at least 1 stroke risk factor (as defined by the CHA₂DS₂-VASc score) and without known atrial arrhythmia recurrences for at least 12 months after ablation are randomized to rivaroxaban 15 mg or ASA 75-160 mg daily. The primary outcome is a composite of clinically overt stroke, systemic embolism, and covert stroke based on brain magnetic resonance imaging. Key secondary outcomes include major bleeding outcomes, intracranial hemorrhage, transient ischemic attack, neuropsychological testing, quality of life, and an economic analysis. Subjects will be followed for 3 years. The estimated overall sample size is 1,572 subjects (786 per arm).

DISCUSSION

The OCEAN trial is a multicenter randomized controlled trial evaluating 2 antithrombotic treatment strategies for patients with risk factors for stroke after apparently successful AF ablation. We hypothesize that rivaroxaban will reduce the occurrence of clinically overt stroke, systemic embolism, and covert stroke when compared with ASA alone.

Ablation of long-standing persistent atrial fibrillation

Atrial fibrillation (AF) is the most commonly encountered arrhythmia in the clinical setting affecting nearly 6 million people in United States and the numbers are only expected to rise as the population continues to age. Broadly it is classified into paroxysmal, persistent and longstanding persistent AF. Electrical, structural and autonomic remodeling are some of the diverse pathophysiological mechanisms that contribute to the persistence of AF. Our review article emphasizes particularly on long standing persistent atrial fibrillation (LSPAF) aspect of the disease which poses a great challenge for electrophysiologists. While pulmonary vein isolation (PVI) has been established as a successful ablation strategy for paroxysmal AF, same cannot be said for LSPAF owing to its long duration, complexity of mechanisms, multiple triggers and substrate sites that are responsible for its perpetuation. The article explains different approaches currently being adopted to achieve freedom from atrial arrhythmias. These mainly include ablation techniques chiefly targeting complex fractionated atrial electrograms (CFAE), rotors, linear lesions, scars and even considering hybrid approaches in a few cases while exploring the role of delayed enhancement magnetic resonance imaging (deMRI) in the pre-procedural planning to improve the overall short and long term outcomes of catheter ablation.

Contemporary Atrial Fibrillation Management: A Comparison of the Current AHA/ACC/HRS, CCS, and ESC Guidelines

In this article we compare and contrast the current recommendations, and highlight the important differences, in the American College of Cardiology/American Heart Association/Heart Rhythm Society, European Society of Cardiology, and Canadian Cardiovascular Society atrial fibrillation (AF) guidelines. Although many of the recommendations of the various societies are similar, there are important differences in the methodologies underlying their development and the specific content. Specifically, key differences can be observed in: (1) the definition of nonvalvular AF, which subsequently affects anticoagulation choices and candidacy for non-vitamin K antagonist oral anticoagulants; (2) the symptom score used to guide management decisions and longitudinal patient profiling; (3) the stroke risk stratification algorithm used to determine indications for oral anticoagulant therapy; (4) the role of acetylsalicylic acid in stroke prevention in AF; (5) the antithrombotic regimens used in the context of coronary artery disease, acute coronary syndromes, and percutaneous coronary intervention; (6) the rate control target and medications recommended to achieve the target; and (7) the role of "first-line" catheter ablation, open surgical ablation, and left atrial appendage exclusion.

Where There's Smoke, There's Fire? Significance of Atrial Fibrillation in Young Patients

BACKGROUND

Atrial fibrillation (AF), a disease of the elderly, occasionally occurs at younger age. Pathophysiology of AF in younger patients is diverse, including channelopathies and cardiomyopathies. Data on the significance and complications of AF in young patients are scarce.

HYPOTHESIS

Atrial fibrillation is the first manifestation of cardiovascular disease (CVD) in young patients.

METHODS

From 11 888 patients in a university hospital database, patients age ≤35 years were identified. A composite of stroke/transient ischemic attack, thromboembolic events, major bleeding, and death was the primary endpoint. Stroke/transient ischemic attack, thromboembolic events, major bleeding, death, AF during follow-up, diagnosis of arrhythmia other than AF, and new diagnosis of any CVD were secondary endpoints. Endpoints were compared between patients with and without comorbidities.

RESULTS

We identified 124 patients (29.1± 5 years). Of those, 84 were followed over 48.4 ± 39.8 months. Comorbidities were present in 40.5%. Incidence of the primary endpoint was not different between the groups. Arrhythmias other than AF were more common in patients without comorbidities (36% vs 14.7%; P = 0.032). A supraventricular tachycardia (SVT) was found in 57.1% of patients who underwent electrophysiological testing and was treated with catheter ablation. None of those patients had AF during follow-up.

CONCLUSIONS

Atrial fibrillation occurs in young patients with and without structural heart disease. Young AF patients without comorbidities rarely develop CVD during the first years after diagnosis. Yet, an SVT is found in a high proportion of young AF patients; AF may be first manifestation of SVT. Therefore, young patients should undergo further evaluation for SVT.

Adenosine-guided pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation: an international, multicentre, randomised superiority trial

BACKGROUND

Catheter ablation is increasingly used to manage atrial fibrillation, but arrhythmia recurrences are common. Adenosine might identify pulmonary veins at risk of reconnection by unmasking dormant conduction, and thereby guide additional ablation to improve arrhythmia-free survival. We assessed whether adenosine-guided pulmonary vein isolation could prevent arrhythmia recurrence in patients undergoing radiofrequency catheter ablation for paroxysmal atrial fibrillation.

METHODS

We did this randomised trial at 18 hospitals in Australia, Europe, and North America. We enrolled patients aged older than 18 years who had had at least three symptomatic atrial fibrillation episodes in the past 6 months, and for whom treatment with an antiarrhythmic drug failed. After pulmonary vein isolation, intravenous adenosine was administered. If dormant conduction was present, patients were randomly assigned (1:1) to additional adenosine-guided ablation to abolish dormant conduction or to no further ablation. If no dormant conduction was revealed, randomly selected patients were included in a registry. Patients were masked to treatment allocation and outcomes were assessed by a masked adjudicating committee. Patients were followed up for 1 year. The primary outcome was time to symptomatic atrial tachyarrhythmia after a single procedure in the intention-to-treat population. The trial is registered with ClinicalTrials.gov, number NCT01058980.

FINDINGS

Adenosine unmasked dormant pulmonary vein conduction in 284 (53%) of 534 patients. 102 (69·4%) of 147 patients with additional adenosine-guided ablation were free from symptomatic atrial tachyarrhythmia compared with 58 (42·3%) of 137 patients with no further ablation, corresponding to an absolute risk reduction of 27·1% (95% CI 15·9-38·2; p<0·0001) and a hazard ratio of 0·44 (95% CI 0·31-0·64; p<0·0001). Of 115 patients without dormant pulmonary vein conduction, 64 (55·7%) remained free from symptomatic atrial tachyarrhythmia (p=0·0191 vs dormant conduction with no further ablation). Occurrences of serious adverse events were similar in each group. One death (massive stroke) was deemed probably related to ablation in a patient included in the registry.

INTERPRETATION

Adenosine testing to identify and target dormant pulmonary vein conduction during catheter ablation of atrial fibrillation is a safe and highly effective strategy to improve arrhythmia-free survival in patients with paroxysmal atrial fibrillation. This approach should be considered for incorporation into routine clinical practice.

FUNDING

Canadian Institutes of Health Research, St Jude Medical, Biosense-Webster, and M Lachapelle (Montreal Heart Institute Foundation).

Effect of catheter ablation versus antiarrhythmic drugs on atrial fibrillation: A meta-analysis of randomized controlled trials

The aim of the present study was to compare the health outcomes of catheter ablation therapy against those of antiarrhythmic drugs (AADs) in the management of atrial fibrillation (AF). The effects of catheter ablation and AADs on a number of parameters were compared, including AF recurrence, all-cause mortality, stroke/transient ischemic attack (TIA) and quality of life (QoL). A systematic literature search of PubMed, Embase and the Cochrane Central Register of Controlled Trials was conducted to obtain relevant randomized controlled trials. The relative risks (RRs) and 95% confidence intervals (CIs) of AF recurrence, all-cause mortality and stroke/TIA between catheter ablation and AADs were subsequently calculated. Weighted mean differences (WMDs) and 95% CIs were used to evaluate the QoL between the two therapy groups. In total, 11 randomized trials, which included 1,763 AF patients, were eligible for the meta-analysis. Overall, the results indicated that catheter ablation produces superior outcomes compared with AADs in reducing AF recurrence (RR, 0.47; 95% CI, 0.38-0.58; P<0.001) and improving the QoL (physical component summary: WMD, 2.23; 95% CI, 0.24-4.21; P=0.03; mental component summary: WMD, 2.69; 95% CI, 0.04-5.35; P=0.05). However, no statistically significant difference was identified between the two groups with regard to the incidence of all-cause mortality (RR, 0.87; 95% CI, 0.37-2.06; P=0.76) and stroke/TIA (RR, 1.83; 95% CI, 0.73-4.55; P=0.20). In summary, catheter ablation was demonstrated to markedly reduce AF recurrence and improve QoL when compared with AAD therapy. However, the incidence rates of all-cause mortality and stroke/TIA were comparable between catheter ablation and AAD therapy.

Approaches to catheter ablation for persistent atrial fibrillation

BACKGROUND

Catheter ablation is less successful for persistent atrial fibrillation than for paroxysmal atrial fibrillation. Guidelines suggest that adjuvant substrate modification in addition to pulmonary-vein isolation is required in persistent atrial fibrillation.

METHODS

We randomly assigned 589 patients with persistent atrial fibrillation in a 1:4:4 ratio to ablation with pulmonary-vein isolation alone (67 patients), pulmonary-vein isolation plus ablation of electrograms showing complex fractionated activity (263 patients), or pulmonary-vein isolation plus additional linear ablation across the left atrial roof and mitral valve isthmus (259 patients). The duration of follow-up was 18 months. The primary end point was freedom from any documented recurrence of atrial fibrillation lasting longer than 30 seconds after a single ablation procedure.

RESULTS

Procedure time was significantly shorter for pulmonary-vein isolation alone than for the other two procedures (P<0.001). After 18 months, 59% of patients assigned to pulmonary-vein isolation alone were free from recurrent atrial fibrillation, as compared with 49% of patients assigned to pulmonary-vein isolation plus complex electrogram ablation and 46% of patients assigned to pulmonary-vein isolation plus linear ablation (P=0.15). There were also no significant differences among the three groups for the secondary end points, including freedom from atrial fibrillation after two ablation procedures and freedom from any atrial arrhythmia. Complications included tamponade (three patients), stroke or transient ischemic attack (three patients), and atrioesophageal fistula (one patient).

CONCLUSIONS

Among patients with persistent atrial fibrillation, we found no reduction in the rate of recurrent atrial fibrillation when either linear ablation or ablation of complex fractionated electrograms was performed in addition to pulmonary-vein isolation. (Funded by St. Jude Medical; ClinicalTrials.gov number, NCT01203748.).

Outcomes after ablation for typical atrial flutter (from the Loire Valley Atrial Fibrillation Project)

Similar predisposing factors are found in most types of atrial arrhythmias. The incidence of atrial fibrillation (AF) among patients with atrial flutter is high, suggesting similar outcomes in patients with those arrhythmias. We sought to investigate the long-term outcomes and prognostic factors of patients with AF and/or atrial flutter with contemporary management using radiofrequency ablation. In an academic institution, we retrospectively examined the clinical course of 8,962 consecutive patients admitted to our department with a diagnosis of AF and/or atrial flutter. After a median follow-up of 934 ± 1,134 days, 1,155 deaths and 715 stroke and/thromboembolic (TE) events were recorded. Patients with atrial flutter undergoing cavotricuspid isthmus ablation (n = 875, 37% with a history of AF) had a better survival rate than other patients (hazard ratio [HR] 0.35, 95% confidence interval [CI] 0.25 to 0.49, p <0.0001). Using Cox proportional hazards model and propensity score model, after adjustment for main other confounders, ablation for atrial flutter was significantly associated with a lower risk of all-cause mortality (HR 0.55, 95% CI 0.36 to 0.84, p = 0.006) and stroke and/or TE events (HR 0.53, 95% CI 0.30 to 0.92, p = 0.02). After ablation, there was no significant difference in the risk of TE between patients with a history of AF and those with atrial flutter alone (HR 0.83, 95% CI 0.41 to 1.67, p = 0.59). In conclusion, in patients with atrial tachyarrhythmias, those with atrial flutter with contemporary management who undergo cavotricuspid isthmus radiofrequency ablation independently have a lower risk of stroke and/or TE events and death of any cause, whether a history of AF is present or not.

The Role Of Renin Angiotensin System In Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent arrhythmia and its incidence is on the rise. AF causes significant morbidity and mortality leading to rising AF-related health care costs. There is experimental and clinical evidence from animal and human studies that suggests a role for the renin angiotensin system (RAS) in the etiopathogenesis of AF. This review appraises the current understanding of RAS antagonism, using angiotensin converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB) and aldosterone antagonists (AA), for prevention of AF. RAS antagonism has proven to be effective for primary and secondary prevention of AF in subjects with heart failure and left ventricular (LV) dysfunction.However, most of the evidence for the protective effect of RAS antagonism is from clinical trials that had AF as a secondary outcome or from unspecified post-hoc analyses. The evidence for prevention in subjects without heart failure and with normal LV function is not as clear. RAS antagonism, in the absence of concomitant antiarrhythmic therapy, was not shown to reduce post cardioversion AF recurrences. RAS antagonism in subjects undergoing catheter ablation has also been ineffective in preventing AF recurrences.

Impact of a 4q25 genetic variant in atrial flutter and on the risk of atrial fibrillation after cavotricuspid isthmus ablation

BACKGROUND

The prediction of atrial fibrillation (AF) following catheter ablation of atrial flutter (Afl) would be helpful to facilitate targeted arrhythmia monitoring and anti-coagulation strategies. A single nucleotide polymorphism, rs2200733, is strongly associated with AF. We sought to characterize the association between rs2200733 and prevalent Afl and to determine if the variant could predict AF after cavotricuspid isthmus ablation.

METHODS AND RESULTS

We performed a genetic association study of 295 patients with Afl and/or AF and 469 controls using multivariable logistic regression. The variant was then assessed as a predictor of incident AF after cavotricuspid isthmus ablation in 87 consecutive typical Afl patients with Cox proportional hazards models. The rs2200733 rare allele was associated with an adjusted 2.06-fold increased odds of isolated Afl (95% CI: 1.13-3.76, P = 0.019) and an adjusted 2.79-fold increased odds of a combined phenotype of AF and Afl (95% CI: 1.81-4.28, P < 0.001). Following catheter ablation for Afl, carrier status of rs2200733 failed to predict an increased risk of AF either among all subjects (adjusted HR: 0.94; 95% CI: 0.58-1.53, P = 0.806) or among those with isolated Afl (adjusted HR: 1.29; 95% CI: 0.51-3.26, P = 0.585).

CONCLUSIONS

Our study demonstrates that Afl, whether occurring in isolation or along with AF, is associated with the rs2200733 AF risk allele. Genetic carrier status of rs2200733 failed to predict an increased risk of incident or recurrent AF following catheter ablation for Afl. These findings suggest that the causal mechanism associated with rs2200733 is germane to both AF and Afl.

Discontinuing anticoagulation following successful atrial fibrillation ablation in patients with prior strokes

Purpose

This study was conducted to examine the outcomes in patients with prior stroke/transient ischemic attack (CVA/TIA) after atrial fibrillation (AF) ablation and the feasibility of discontinuing oral anticoagulation (OAC).

Methods

This study examined long-term outcomes following AF ablations in 108 patients with a history of prior thromboembolic CVA/TIA. Because of risks of OAC, we frequently discontinue OAC in these patients after successful ablation. These patients understand the risks/benefits of discontinuing OAC and remain on OAC for a longer time following successful AF ablation, compared to our patients without prior CVA/TIA.

Results

Patient age was 66.2 ± 9.0 years with an average CHADS₂ score = 3.0 ± 0.9 and CHA₂DS₂-VASc score = 4.1 ± 1.4. Following 1.24 ablations, 71 (65.7 %) patients were AF free 2.8 ± 1.6 (median 2.3) years after their last ablation. OAC was discontinued in 55/71 (77.5 %) patients an average of 7.3 months following the final ablation. These 55 patients had 2.2 ± 1.3 (median 1.8) years of follow-up off of OAC. Kaplan–Meier analysis suggests little AF recurrence >1 year following initial or final ablations, suggesting that 1 year post successful ablation may be the appropriate time to consider discontinuing OAC. Thirty-seven patients had AF postablation, and 32/37 (86.5 %) remained on OAC. One patient with a mechanical valve had a stroke despite OAC. Bleeding occurred in 8.3 % of patients on OAC and 0 % of patients off OAC (P = 0.027).

Conclusions

Patients with prior CVA/TIAs, who undergo successful AF ablation, have a low incidence of subsequent thromboembolic events. Most patients who appear AF free postablation may be able to discontinue OAC after successful ablation with a low thromboembolic risk and with a reduced bleeding risk.