Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial

Association of P wave duration index with atrial fibrillation recurrence after cryoballoon catheter ablation

AIM

We aimed to investigate the relationship between the recurrence of AF and P wave duration index (PWDI) in patients with nonvalvular PAF.

METHODS

We included 114 patients who underwent cryoballoon catheter ablation with the diagnosis of paroxysmal atrial fibrillation (PAF) (55 male, 59 female; mean age 55.5±10,9years). PWDI was calculated by dividing the Pwd by the PR interval in DII lead of 12‑lead ECG. Patients had regular follow-up visits with 12-lead ECG, medical history and clinical evaluation. 24h Holter ECG monitoring had been recorded at least 12months after ablation.

RESULTS

AF recurrence was detected in 24 patients after 1year. Patients were divided into two groups according to the AF recurrence. All parameters were compared between the two groups. Age, DM, HT frequency, ACEI-ARB use, CHA2DS2VASc and HAS-BLED score, HsCRP, LA diameter, LA volume, LA volume index, Pwd and PWDI were related to AF recurrence. In binary logistic regression analysis, PWDI (OR=1.143, p=0.001) and HT (OR=0.194, p=0.020) were found to be independent parameters for predicting AF recurrence. Every 0,01 unit increase in PWDI was found to be associated with 14.3% increase in the risk of AF recurrence. The cut-off value of PWDI obtained by ROC curve analysis was 59,9 for prediction of AF recurrence (sensitivity: 75.0%, specificity: 69.0%). The area under the curve (AUC) was 0.760 (p<0.001).

CONCLUSION

Increased PWDI may help to identify those patients in whom electrical remodeling has already occurred and who will get less benefit from cryoablation.

Integrating new approaches to atrial fibrillation management: the 6th AFNET/EHRA Consensus Conference

There are major challenges ahead for clinicians treating patients with atrial fibrillation (AF). The population with AF is expected to expand considerably and yet, apart from anticoagulation, therapies used in AF have not been shown to consistently impact on mortality or reduce adverse cardiovascular events. New approaches to AF management, including the use of novel technologies and structured, integrated care, have the potential to enhance clinical phenotyping or result in better treatment selection and stratified therapy. Here, we report the outcomes of the 6th Consensus Conference of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new approaches to screening and diagnosis, enhancing integration of AF care, developing clinical pathways for treating complex patients, improving stroke prevention strategies, and better patient selection for heart rate and rhythm control. Ultimately, these approaches can lead to better outcomes for patients with AF.

Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF): study protocol for a randomised controlled trial

BACKGROUND

Atrial fibrillation is the commonest arrhythmia which raises the risk of heart failure, thromboembolic stroke, morbidity and death. Pharmacological treatments of this condition are focused on heart rate control, rhythm control and reduction in risk of stroke. Selective ablation of cardiac tissues resulting in isolation of areas causing atrial fibrillation is another treatment strategy which can be delivered by two minimally invasive interventions: percutaneous catheter ablation and thoracoscopic surgical ablation. The main purpose of this trial is to compare the effectiveness and safety of these two interventions.

METHODS/DESIGN

Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF) is a prospective, multi-centre, randomised controlled trial within three NHS tertiary cardiovascular centres specialising in treatment of atrial fibrillation. Eligible adults (n = 120) with symptomatic, long-standing, persistent atrial fibrillation will be randomly allocated to either catheter ablation or thoracoscopic ablation in a 1:1 ratio. Pre-determined lesion sets will be delivered in each treatment arm with confirmation of appropriate conduction block. All patients will have an implantable loop recorder (ILR) inserted subcutaneously immediately following ablation to enable continuous heart rhythm monitoring for at least 12 months. The devices will be programmed to detect episodes of atrial fibrillation and atrial tachycardia ≥ 30 s in duration. The patients will be followed for 12 months, completing appropriate clinical assessments and questionnaires every 3 months. The ILR data will be wirelessly transmitted daily and evaluated every month for the duration of the follow-up. The primary endpoint in the study is freedom from atrial fibrillation and atrial tachycardia at the end of the follow-up period.

DISCUSSION

The CASA-AF Trial is a National Institute for Health Research-funded study that will provide first-class evidence on the comparative efficacy, safety and cost-effectiveness of thoracoscopic surgical ablation and conventional percutaneous catheter ablation for long-standing persistent atrial fibrillation. In addition, the results of the trial will provide information on the effects on patients' quality of life.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN18250790 . Registered on 24 April 2015.

Successful External Cardioversion via Fluoroscopic Electrode Positioning in Patients with Enlarged Trans-Thoracic Diameter

BACKGROUND Atrial fibrillation is the most common cardiac arrhythmia. It increases the risk of stroke by at least five-fold and is associated with higher risk for mortality and morbidity. Therefore, prompt diagnosis and treatment is crucial. In addition to anti-coagulation therapy, electrical and pharmacological cardioversion to restore sinus rhythm remains the standard of care. The most common and effective method for electrical cardioversion is achieved with placement of electrodes in the anteroposterior position. CASE REPORT We present three cases of patients with initial unsuccessful cardioversion attempts for persistent atrial fibrillation. These patients had elevated body mass indices and large trans-thoracic diameters. Their initial external cardioversion via the conventional method was not successful for restoration of sinus rhythm. This failure may have been attributed to their body habitus. To ensure that the current would traverse through the atrial tissue, the electrode pads were applied using fluoroscopic guidance for adequate myocardial depolarization. CONCLUSIONS Optimal fluoroscopic placement of the electrode pads during external cardioversion procedure increases the odds of successful restoration of sinus rhythm when compared to the conventional method.

Bayesian adaptive trials for rare cardiovascular conditions

Escalating costs of cardiovascular trials are limiting medical innovations, prompting the development of more efficient and flexible study designs. The Bayesian paradigm offers a framework conducive to adaptive trial methodologies and is well suited for the study of small populations. Bayesian adaptive trials provide a statistical structure for combining prior information with accumulating data to compute probabilities of unknown quantities of interest. Adaptive design features are useful in modifying randomization schemes, adjusting sample sizes and providing continuous surveillance to guide decisions on dropping study arms or premature trial interruption. Advantages include greater efficiency, minimization of risks, inclusion of knowledge as it is generated, cost savings and more intuitive interpretability. Extensive high-level computations are facilitated by an expanding armamentarium of available tools.

Intra-Atrial Dyssynchrony During Sinus Rhythm Predicts Recurrence After the First Catheter Ablation for Atrial Fibrillation

OBJECTIVES

The purpose of this study was to evaluate the usefulness of intra-atrial dyssynchrony as a marker of underlying left atrial (LA) remodeling to predict recurrence after the first atrial fibrillation (AF) ablation.

BACKGROUND

Catheter ablation for AF remains far from curative with relatively high recurrence rates. One of the causes of recurrence is poor patient selection out of a diverse patient population with different degrees of LA remodeling.

METHODS

We included 208 patients with a history of AF (59.4 ± 10.0 years of age; 26.0% nonparoxysmal AF) referred for catheter ablation of AF who underwent pre-ablation cardiac magnetic resonance in sinus rhythm. Clinical follow-up was 20 ± 6 months. Using tissue tracking cardiac magnetic resonance, we measured the LA longitudinal strain in each of 12 equal-length segments in 2- and 4-chamber views. We defined intra-atrial dyssynchrony as the standard deviation of the time to the peak longitudinal strain corrected by the cycle length (SD-time to peak strain [TPS], %).

RESULTS

Patients with AF recurrence after ablation (n = 101) had significantly higher SD-TPS than those without (n = 107; 3.9% vs. 2.2%; p < 0.001). Multivariable cox analysis showed that SD-TPS was associated with recurrence after adjusting for clinical risk factors, AF type, LA structure and function, and fibrosis (p < 0.001). Furthermore, receiver-operating characteristics analysis showed SD-TPS improved prediction of recurrence better than clinical risk factors, LA structure and function, and fibrosis.

CONCLUSIONS

Intra-atrial dyssynchrony during sinus rhythm is an independent predictor of recurrence after the first catheter ablation of paroxysmal or persistent AF. Assessment of intra-atrial dyssynchrony may improve ablation outcomes by refining patient selection.

The absence of effect of ganglionated plexi ablation on heart rate variability parameters in patients after thoracoscopic ablation for atrial fibrillation

Background

Hybrid ablation [thoracoscopic ablation (TA) of atrial fibrillation (AF) followed by catheter ablation (CA)] is an increasingly common method of the treatment for patients with AF. The aim of this study was to assess the response to ganglionated plexi (GP) ablation in patients with a previous TA (i.e., to assess whether TA had resulted in damage to the GP. Heart rate variability (HRV) was used as a marker of the autonomic response.

Methods

Twenty AF patients underwent pulmonary vein isolation (PVI) plus GP ablation (GP group) and 18 AF patients underwent CA including GP ablation as a part of hybrid ablation (i.e., all patients had undergone a previous TA; Hybrid group). In each group, a 5 min electrocardiogram (ECG) obtained before and after the CA were analyzed. Time and frequency domain parameters were evaluated.

Results

Vagal responses (VR) during CA were observed in 12 (60%) patients in the GP group; however, in the Hybrid group, VR was not observed in any of the patients during CA. The change in normalized power in the low frequency (LF) component and the ratio between the LF and high frequency (LF/HF ratio) components of the HRV spectra, before and after ablation, were statistically significant in the GP group (3.3±2.6 before vs. 1.8±1.9 after ablation) but unchanged, before or after CA, in the Hybrid group.

Conclusions

GP ablation in patients subsequent to TA has a little influence on HRV parameters, which could be explained by GP damage during the preceding TA.

Gender and AF: Differences and Disparities

AF is the most common clinical arrhythmia encountered. A wealth of evidence has improved our ability to diagnose and effectively treat AF. An intriguing aspect of this common disease – gender-based differences – is well recognized, but poorly understood. In this brief review, we will explore the accumulating evidence suggesting a gender-based disparity in the prevalence, pathogenesis and management of AF.

New migraine with visual disturbance after cryoballoon ablation of atrial fibrillation

We report the case of a 58-year-old woman who developed a headache and visual disturbances after a cryoballoon ablation procedure for atrial fibrillation at our institution. She presented to the emergency department four days post ablation and was admitted the hospital for overnight observation. Serial neurological examinations and neuroimaging were unremarkable for stroke or transient ischemic attack. The patient had some brief transient visual changes which resolved completely after several days, with no further clinical sequelae. She followed up in the outpatient neuro-ophthalmology clinic and had a normal visual field examination. She was given a diagnosis of new onset migraine with visual aura.

Radiofrequency Ablation of Atrial Fibrillation in Patients with Ebstein's Anomaly: A Two-Case Report

Ebstein's anomaly (EA) is a rare congenital heart disease characterized by “atrialization” of the right ventricle, due to apical displacement of the tricuspid leaflets into the right ventricle. Patients with EA may develop all kinds of supraventricular arrhythmias requiring radiofrequency ablation. Atrial fibrillation (Afib) is a common arrhythmia in EA patients, and results in debilitating symptoms that often require surgical treatment. This is a follow-up report of 2 patients with EA undergoing radiofrequency ablation for Afib. The first patient underwent pulmonary vein isolation (PVI) and the ablation of a concomitant atrioventricular nodal reentrant tachycardia. The second patient was also treated with a PVI and a redo PVI 8 months later. Both patients remain in sinus rhythm 8 months on. Radiofrequency ablation is the therapy of choice for patients with pharmacological refractory Afib, but it is not common in patients with EA.

The Short and Long-Term Efficacy of Pulmonary Vein Isolation as a Sole Treatment Strategy for Paroxysmal Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background:

Pulmonary vein isolation (PVI) is an accepted treatment strategy for catheter ablation (CA) of paroxysmal atrial fibrillation (PAF). In this study, we aimed to assess the short, mid- and long-term outcome of PVI as a sole treatment strategy for PAF.

Methods:

Six bibliographic electronic databases were searched to identify all published relevant stud-ies until December 14, 2015. Search of the scientific literature was performed for studies describing outcomes with mean follow-up > 24 months after PAF ablation. Only articles with 1, 3 or 5-year fol-low up were included, from the same group of investigators.

Results:

Of the 2398 references reviewed for eligibility, 13 articles (enrolling a total of 1774 patients) were included in the final analysis. Pooled analysis showed that the 12- and 62 -month success rate of a single CA procedure was 78% (95% CI 0.76% to 0.855) and 59% (95% CI 0.56% to 0.64%), re-spectively. The results did not differ by type of CA performed. Major complications mentioned in the enrolled studies were cerebrovascular event, pericardial tamponade and PV stenosis.

Conclusion:

There is a progressive and significant decline in freedom from AF between 1, 3 and 5-year after successful PVI in patients with PAF. Our analysis suggests that a high short-time success rate after PVI does not necessarily result in high chronic success rate.

Clinical outcomes of radiofrequency catheter ablation of atrial fibrillation in octogenarians-10-year experience of a one high-volume center

BACKGROUND

Prevalence of atrial fibrillation (AF) increases with age. Radiofrequency catheter ablation (RFCA) is an established treatment option superior to antiarrhythmics (AAs). In this study, we investigated safety and efficacy of RFCA of AF in octogenarians.

METHODS

From our database, we extracted procedural and follow-up data for patients ≥ 80 years with symptomatic AF undergoing RFCA and compared this population to RFCA patients ≤ 50 years. All patients underwent pulmonary vein isolation (PVI) supplemented by linear lesions in PVI-nonresponders. Arrhythmia-free survival was assessed using seven day Holter every three months post procedure. All patients completed their 12 months follow-up.

RESULTS

Fifty patients aged ≥ 80 years (80.5 ± 1.6 years) were compared to 259 patients aged ≤ 50 years (43.5 ± 5.5 years). The RFCA complication rate did not vary between groups. No differences in procedural characteristics were seen after being analyzed by type of AF. Among patients with paroxysmal AF, 71.4% octogenarian vs. 84.7% young patients was free of any arrhythmia, without AAs, after single procedure. For non-paroxysmal AF, arrhythmia-free survival without AAs, was considerably lower (58.6% octogenarians vs. 81.2% younger patients, P = 0.023). If AAs were used, arrhythmia-free survival for paroxysmal AF increased to 90.5% and 92.1% in octogenarians and younger patients, respectively; and in non-paroxysmal AF it increased to 79.3% vs. 88.4%.

CONCLUSIONS

RFCA is a safe and effective strategy to achieve normal sinus rhythm in a highly selected group of octogenarians. Paroxysmal AF ablation in octogenarians has similar clinical effectiveness as that seen in much younger patients. Non-paroxysmal AF ablation has lower, but still reasonable clinical effectiveness.

Randomised clinical trial of cryoballoon versus irrigated radio frequency catheter ablation for atrial fibrillation-the effect of double short versus standard exposure cryoablation duration during pulmonary vein isolation (CIRCA-DOSE): methods and rationale

INTRODUCTION

Pulmonary vein isolation (PVI) is an effective therapy for paroxysmal atrial fibrillation (AF), but it has limitations. The two most significant recent advances have centred on the integration of real-time quantitative assessment of catheter contact force into focal radio frequency (RF) ablation catheters and the development of dedicated ablation tools capable of achieving PVI with a single ablation lesion (Arctic Front cryoballoon, Medtronic, Minneapolis, MN, USA). Although each of these holds promise for improving the clinical success of catheter ablation of AF, there has not been a rigorous comparison of these advanced ablation technologies. Moreover, the optimal duration of cryoablation (freezing time) has not been determined.

METHODS AND ANALYSIS

Patients undergoing an initial PVI procedure for paroxysmal AF will be recruited. Patients will be randomised 1:1:1 between contact-force irrigated RF ablation, short duration cryoballoon ablation (2 min applications) and standard duration cryoballoon ablation (4 min applications). The primary outcome is time to first documented AF recurrence on implantable loop recorder. With a sample size of 111 per group and a two-sided 0.025 significance level (to account for the two main comparisons), the study will have 80% power (using a log-rank test) to detect a difference of 20% between contact force RF catheter ablation and either of the two cryoballoon ablation groups. Factoring in a 4% loss to follow-up, 116 patients per group should be randomised and followed for a year (total study population of 348).

ETHICS AND DISSEMINATION

The study was approved by the University of British Columbia Office of Research (Services) Ethics Clinical Research Ethics Board. Results of the study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT01913522; Pre-results.

Identification and Ablation of Dormant Conduction in Atrial Fibrillation Using Adenosine

BACKGROUND

Ablation is used for treatment of atrial fibrillation (AF) but recurrence is common. Dormant conduction is hypothesized to be responsible for these recurrences, and the role of adenosine in identification and ablation of these pathways is controversial with conflicting results on AF recurrence.

MATERIALS AND METHODS

We conducted a meta-analysis for studies evaluating AF ablation and adenosine use. Included in the meta-analysis were human studies that compared ablation using adenosine or adenosine triphosphate (ATP) and reported freedom from AF in patients beyond a minimum follow-up of 6 months.

RESULTS

Our analysis suggests that the use of adenosine leads to a decrease in recurrence of AF compared to the cohort which did not utilize adenosine. Subgroup analysis showed no difference in the recurrence of AF with the modality used for ablation (cryoablation vs. radiofrequency ablation) or with the preparation of adenosine used (ATP vs. adenosine). There was a significant benefit in delayed administration of ATP over early administration. Pooling results of only randomized control trials did not show any significant difference in AF recurrence.

CONCLUSIONS

Adenosine-guided identification and ablation of dormant pathways may lead to a decrease in recurrence of AF.

Three-year outcomes and reconnection patterns after initial contact force guided pulmonary vein isolation for paroxysmal atrial fibrillation

BACKGROUND AND OBJECTIVE

Contact force (CF) sensing is a novel technology used for catheter ablation of atrial fibrillation (AF). We compared the single procedure success of CF-guided pulmonary vein isolation (PVI) with that of non-CF guided PVI during a 3-year (1,095 days) follow up period and analyzed the pattern of pulmonary vein (PV) reconnection.

METHODS

A cohort of 167 subjects (68 CF vs. 99 non-CF) with paroxysmal AF were included in the study. Atrial arrhythmia (AA) recurrence was defined as documented AF, atrial flutter, or atrial tachycardia lasting >30 seconds and occurring after 90 days.

RESULTS

Subjects in the CF group showed a statistically nonsignificant improvement in AA free survival compared to those in the non-CF group (66.2% vs. 51.5%; P value: 0.06). A greater propensity for reconnection was noted around the right-sided PVs compared to left-sided PVs related in both catheter ablation groups. For example, in the CF group 36% of right-sided segments reconnected compared to 16% of left-sided segments (P value <0.01).

CONCLUSIONS

A greater propensity for reconnection was noted around the right sided PV segments in both the CF and non-CF groups. The explanation for this finding was related to greater catheter instability around the right sided veins. Further research is needed to explore the utility of a "real-time" composite indicator that includes RF energy, CF and catheter stability in predicting transmural lesion formation during catheter ablation.

Comparison of health-related quality of life in patients with atrial fibrillation treated with catheter ablation or antiarrhythmic drug therapy: a systematic review and meta-analysis protocol

INTRODUCTION

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia and causes patients considerable burden; symptoms such as palpitations and dyspnoea are common, leading to frequent emergency room visits. Patients with AF report reduced health-related quality of life (HQOL) compared with the general population; thus, treatments focus on the restoration of sinus rhythm to improve symptoms. Catheter ablation (CA) is a primary treatment strategy to treat AF-related burden in select patient populations; however, repeat procedures are often needed, there is a risk of major complications and the procedure is quite costly in comparison to medical therapy. As the outcomes after CA are mixed, an updated review that synthesises the available literature, on outcomes that matter to patients, is needed so that patients and their healthcare providers can make quality treatment decisions. The purpose of this review protocol is to extend previous findings by systematically analysing randomised controlled trials (RCTs) of CA in patients with AF and using meta-analytic techniques to identify the benefits and risks of CA with respect to HQOL and AF-related symptoms.

METHODS AND ANALYSIS

We will include all RCTs that compare CA with antiarrhythmic drugs, or radiofrequency CA with cryoballoon CA, in patients with paroxysmal or persistent AF. To locate studies we will perform comprehensive electronic database searches from database inception to 4 April 2017, with no language restrictions. We will conduct a quantitative synthesis of the effect of CA on HQOL as well as AF-related symptoms and the number of CA procedures needed for success, using meta-analytic techniques.

ETHICS AND DISSEMINATION

No ethical issues are foreseen and ethical approval is not required given that this is a protocol. The findings of the study will be reported at national and international conferences, and in a peer-reviewed journal using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

TRIAL REGISTRATION NUMBER

In accordance with the guidelines, our systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 6 March 2017 and was last updated on 6 March 2017 (registration number CRD42017057427).

PROTOCOL AMENDMENTS

Any protocol amendments will be documented on the International Prospective Register of Systematic Reviews (PROSPERO) and in the final manuscript and indicated as such.

Atriobronchial Fistula Complicated by Septic Cerebral Air Emboli After Pulmonary Vein Ablation

OBJECTIVE

To describe a case of an infected atriobronchial fistula as a late complication after pulmonary vein ablation, leading to septic air emboli and requiring urgent cardiac surgery.

DATA SOURCES

Clinical observation.

STUDY SELECTION

Case report.

DATA EXTRACTION

Relevant clinical information. PubMed was searched for relevant literature.

DATA SYNTHESIS

Given its high success and low complication rate, pulmonary vein isolation is expected to be increasingly performed worldwide. Despite its success, some of its rare complications are potentially devastating and are difficult to diagnose early. In this report, we present the case of a 32-year-old woman, who was readmitted to hospital 2 months after pulmonary vein ablation. The clinical picture resembled meningococcemia with spreading petechiae on legs and arms raising concern for Waterhouse-Friderichsen syndrome. Further echocardiographic investigation led to the discovery of massive amounts of intracardiac air which demanded urgent lung isolation and sternotomy. Intraoperatively a small infected left atrial perforation was oversewn and a fistula to the right main bronchus was closed by means of an autologous pericardial patch. One month later, still revalidating, she could be discharged home with only minor neurologic sequelae.

CONCLUSIONS

Clinicians should be aware of the dramatic complications of invasive antiarrhythmic procedures and their atypical and late presentations. Better preprocedural appreciation of cardiac wall thickness, early echocardiographic diagnosis, and swift referral for cardiac surgery might impact outcome dramatically.

Catheter Ablation of Atrial Fibrillation: An Overview for Clinicians

Catheter ablation (CA) of atrial fibrillation (AF) is currently one of the most commonly performed electrophysiology procedures. Ablation of paroxysmal AF is based on the elimination of triggers by pulmonary vein isolation (PVI), while different strategies for additional AF substrate modification on top of PVI have been proposed for ablation of persistent AF. Nowadays, various technologies for AF ablation are available. The radiofrequency point-by-point ablation navigated by electro-anatomical mapping system and cryo-balloon technology are comparable in terms of the efficacy and safety of the PVI procedure. Long-term success of AF ablation including multiple procedures varies from 50 to 80%. Arrhythmia recurrences commonly occur, mostly due to PV reconnection. The recurrences are particularly common in patients with non-paroxysmal AF, dilated left atrium and the "early recurrence" of AF within the first 2-3 post-procedural months. In addition, this complex procedure can be accompanied by serious complications, such as cardiac tamponade, stroke, atrio-esophageal fistula and PV stenosis. Therefore, CA represents a second-line treatment option after a trial of antiarrhythmic drug(s). Good candidates for the procedure are relatively younger patients with symptomatic and frequent episodes of AF, with no significant structural heart disease and no significant left atrial enlargement. Randomized trials demonstrated the superiority of ablation compared to antiarrhythmic drugs in terms of improving the quality of life and symptoms in AF patients. However, nonrandomized studies reported additional clinical benefits from ablation over drug therapy in selected AF patients, such as the reduction of the mortality and stroke rates and the recovery of tachyarrhythmia-induced cardiomyopathy. Future research should enable the creation of more durable ablative lesions and the selection of the optimal lesion set in each patient according to the degree of atrial remodeling. This could provide better long-term CA success and expand indications for the procedure, especially among the patients with non-paroxysmal AF.

Atrio-Esophageal Fistula: A Case Series and Literature Review

Case series

Patient: Male, 72 • Male, 29 • Male, 75

Final Diagnosis: Atrio-esophageal fistula

Symptoms: Altered mental state • chest pain • fever • melena

Medication: —

Clinical Procedure: —

Specialty: Critical Care Medicine

Persistent atrial fibrillation vs paroxysmal atrial fibrillation: differences in management

INTRODUCTION

Atrial fibrillation (AF) is the most common human arrhythmia. AF is a progressive disease, initially being nonsustained and induced by trigger activity, and progressing towards persistent AF through alteration of the atrial myocardial substrate. Treatment of AF aims to decrease the risk of stroke and improve the quality of life, by preventing recurrences (rhythm control) or controlling the heart rate during AF (rate control). In the last 20 years, catheter-based and, less frequently, surgical and hybrid ablation techniques have proven more successful compared with drug therapy in achieving rhythm control in patients with AF. However, the efficiency of ablation techniques varies greatly, being highest in paroxysmal and lowest in long-term persistent AF. Areas covered: In this review, we discuss the fundamental differences between paroxysmal and persistent AF and the potential impact of those differences on patient management, emphasizing the available therapeutic strategies to achieve rhythm control. Expert commentary: Treatment to prevent AF recurrences is suboptimal, particularly in patients with persistent AF. Emerging technologies, such as documentation of atrial fibrosis using magnetic resonance imaging and documentation of electrical substrate using advanced electrocardiographic imaging techniques are likely to provide valuable insights about patient-specific tailoring of treatments.

The quest for durable lesions in catheter ablation of atrial fibrillation - technological advances in radiofrequency catheters and balloon devices

INTRODUCTION

Atrial fibrillation is the most common cardiac arrhythmia and represents a growing clinical, social and economic challenge. Catheter ablation for symptomatic atrial fibrillation has evolved from an experimental procedure into a widespread therapy and offers a safe and effective treatment option. A prerequisite for durable PVI are transmural and contiguous circumferential lesions around the pulmonary veins. However, electrical reconnection of initially isolated pulmonary veins remains a primary concern and is a dominant factor for arrhythmia recurrence during long-term follow up. Areas covered: This article discusses the physiology of lesion formation using radiofrequency-, cryo- or laser- energy for pulmonary vein isolation and provides a detailed review of recent technological advancements in the field of radiofrequency catheters and balloon devices. Finally, future directions and upcoming developments for the interventional treatment of atrial fibrillation are discussed. Expert commentary: Durable conduction block across deployed myocardial lesions is mandatory not only for PVI but for any other cardiac ablation strategy as well. A major improvement urgently expected is the intraprocedural real-time distinction of durable lesions from interposed gaps with only transiently impaired electrical conduction. Furthermore, a simplification of ablation tools used for PVI is required to reduce the high technical complexity of the procedure.

A decade of atrial fibrillation ablation : Shifts in patient characteristics and procedural outcomes

Background

Over the past decade, radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) has evolved into a frequently performed procedure. The aim of this study was to monitor changes in patient characteristics, procedural characteristics, outcomes and complications over the past 10 years.

Methods

All consecutive patients who underwent primary RFCA treatment of AF in the University Medical Center Utrecht from 2005–2015 were included. In all patients, the primary ablation strategy was pulmonary vein (PV) antrum isolation without additional substrate modification. Baseline patient and procedure characteristics, and 1‑year follow-up data of 975 patients were prospectively collected.

Results

In 2005, 73.4% of patients suffered from paroxysmal AF, which decreased to 45.3% in 2014. Mean age increased from 54 ± 9 to 61 ± 10 years and CHA₂DS₂-VASc score ≥2 from 18 to 40.6%. History of AF decreased significantly from 7 to 4 years. Mean procedure duration was 237 ± 53 min in 2005 and 163 ± 41 min in 2014. Fluoroscopy time significantly decreased from 41 ± 17 to 19 ± 8 min and total radiation exposure from 465 (263–687) to 210 (118–376) mGy. One-year success remained similar (2005: 55.6%, 2014: 54.8%), as did the amount of PV reconnection observed during redo procedures. Due to a marked reduction in vascular complications and moderate PV stenosis, the total complication rate decreased significantly.

Conclusion

Over the past decade, AF ablation has increasingly been performed in older patients with persistent AF and more comorbidity. Moreover, it has been performed earlier after AF diagnosis. Although several performance parameters, such as procedure duration and complication rate, improved, 1‑year single procedure success remained unchanged.

Ablation as targeted perturbation to rewire communication network of persistent atrial fibrillation

Persistent atrial fibrillation (AF) can be viewed as disintegrated patterns of information transmission by action potential across the communication network consisting of nodes linked by functional connectivity. To test the hypothesis that ablation of persistent AF is associated with improvement in both local and global connectivity within the communication networks, we analyzed multi-electrode basket catheter electrograms of 22 consecutive patients (63.5 ± 9.7 years, 78% male) during persistent AF before and after the focal impulse and rotor modulation-guided ablation. Eight patients (36%) developed recurrence within 6 months after ablation. We defined communication networks of AF by nodes (cardiac tissue adjacent to each electrode) and edges (mutual information between pairs of nodes). To evaluate patient-specific parameters of communication, thresholds of mutual information were applied to preserve 10% to 30% of the strongest edges. There was no significant difference in network parameters between both atria at baseline. Ablation effectively rewired the communication network of persistent AF to improve the overall connectivity. In addition, successful ablation improved local connectivity by increasing the average clustering coefficient, and also improved global connectivity by decreasing the characteristic path length. As a result, successful ablation improved the efficiency and robustness of the communication network by increasing the small-world index. These changes were not observed in patients with AF recurrence. Furthermore, a significant increase in the small-world index after ablation was associated with synchronization of the rhythm by acute AF termination. In conclusion, successful ablation rewires communication networks during persistent AF, making it more robust, efficient, and easier to synchronize. Quantitative analysis of communication networks provides not only a mechanistic insight that AF may be sustained by spatially localized sources and global connectivity, but also patient-specific metrics that could serve as a valid endpoint for therapeutic interventions.

[Not Available]

Zusammenfassung. Zusammenfassung: Das Vorhofflimmern ist die häufigste supraventrikuläre Rhythmusstörung und entwickelt sich typischerweise bei Patienten mit kardiovaskulären Risikofaktoren oder einer zugrunde liegenden Kardiopathie. Die Bandbreite an Symptomen ist sehr weit und reicht von vollkommen asymptomatischen Patienten bis zur schweren Herzinsuffizienz. Eine korrekte Dokumentation mittels EKG ist unabdingbar für die Diagnose. Für jeden Patienten mit Vorhofflimmern ist eine komplette internistisch-kardiologische Abklärung indiziert. Von zentraler Bedeutung in der Behandlung ist die Thromboembolie-Prophylaxe bei Patienten mit einem erhöhten Risiko für einen Schlaganfall, dies unabhängig von der übrigen Therapie des Vorhofflimmerns. Beim Letzteren ist neben der antiarrhythmischen Therapie die Kontrolle der kardiovaskulären Risikofaktoren sowie die Behandlung einer allfällig vorhandenen Herzinsuffizienz entscheidend. Neben der medikamentösen Rhythmuskontrolle hat sich die Ablationsbehandlung als effektive und sichere alternative Therapieoption etabliert.

Comparison of Direct Current Synchronized Cardioversion to Ibutilide-Guided Catheter Ablation for Long-Term Sinus Rhythm Maintenance After Isolated Pulmonary Vein Isolation of Persistent Atrial Fibrillation

Use of the antiarrhythmic ibutilide after isolated pulmonary vein isolation (PVI) might distinguish atrial remodeling severity and cases requiring further substrate modification, thereby improving efficacy of persistent atrial fibrillation (AF) treatment. Ninety-six consecutive patients with persistent AF were randomized after PVI to either direct current synchronized cardioversion (DCC group, n = 48) or 1 mg of intravenous ibutilide (ibutilide group, n = 48) followed by no further intervention if AF converted to sinus rhythm (SR) within 30 minutes (ibutilide conversion subgroup) or by complex fractionated atrial electrogram (CFAE) ablation until SR recovery or complete CFAE elimination (ibutilide nonconversion subgroup). With similarly distributed baseline characteristics and no serious postablation complications, the primary end point of 12-month SR maintenance rate after PVI was significantly higher for ibutilide versus the DCC group before (75% vs 56%; p = 0.042) or after (83% vs 60%; p = 0.011) reablation at physician's discretion for recurrence beyond 3 months after PVI. After ibutilide administration, 21 of 48 patients (44%) converted to SR at 17 ± 8 minutes (mean ± SD); those in the ibutilide nonconversion subgroup had larger atrial size (47 ± 4 vs 45 ± 4; p = 0.025) and CFAE area (29 ± 8 vs 12 ± 5; p = 0.001) and longer AF duration (27 ± 6 vs 21 ± 10; p = 0.026). Among ibutilide conversion and nonconversion subgroups and DCC group, procedure, ablation, and x-ray exposure times differed significantly, as did 12-month SR maintenance rate before (81% vs 70% vs 56%; p = 0.043) or after reablation (86% vs 81% vs 60%; p = 0.042). In conclusion, in persistent AF treatment, ibutilide-guided ablation after PVI yields higher 1-year SR maintenance rate than PVI only.

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.

Use of three-dimensional computed tomography overlay for real-time cryoballoon ablation in atrial fibrillation reduces radiation dose and contrast dye

AIMS

Cryoballoon pulmonary vein (PV) isolation in patients with atrial fibrillation has proven to be effective in short-term and long-term follow-up. To visualise the PV anatomy, pre-ablation contrast pulmonary venography is commonly performed. Three-dimensional (3D) computed tomography (CT) overlay is a new technique creating a live 3D image of the left atrium by integrating a previously obtained CT scan during fluoroscopy. To evaluate the benefits of 3D CT overlay during cryoballoon ablation, we studied the use of 3D CT overlay versus contrast pulmonary venography in a randomised fashion in patients with paroxysmal atrial fibrillation undergoing cryoballoon PV isolation.

METHODS AND RESULTS

Between October 2012 and June 2013, 30 patients accepted for PV isolation were randomised to cryoballoon PV isolation using either 3D CT overlay or contrast pulmonary venography. All patients underwent a pre-procedural cardiac CT for evaluation of the anatomy of the left atrium (LA) and the PVs. In the 3D CT overlay group, a 3D reconstruction of the LA and PVs was made. An overlay of the CT reconstruction was then projected over live fluoroscopy. Patients in the contrast pulmonary venography group received significantly more contrast agent (77.1 ± 21.2 cc vs 40.1 ± 17.6 cc, p < 0.001) and radiation (43.0 ± 21.9 Gy.cm2 vs 28.41 ± 11.7 Gy.cm2, p = 0.04) than subjects in the 3D CT overlay group. There was no difference in total procedure time, fluoroscopy time and the amount of cryoapplications between the two groups.

CONCLUSION

The use of 3D CT overlay decreases radiation and contrast dye exposure and can assist in guiding cryoballoon-based PV isolation.

Pulmonary Vein Isolation Alone Versus Additional Linear Ablation in Patients With Persistent Atrial Fibrillation Converted to Paroxysmal Type With Antiarrhythmic Drug Therapy

Background—

Atrial fibrillation (AF) type can vary depending on condition and timing, and some patients who initially present with persistent AF may be changed to paroxysmal AF after antiarrhythmic drug medication and cardioversion. We investigated whether circumferential pulmonary vein isolation (CPVI) alone is an effective rhythm control strategy in patients with persistent AF to paroxysmal AF.

Methods and Results—

We enrolled 113 patients with persistent AF to paroxysmal AF (male 75%, 60.4±10.1 years old) who underwent catheter ablation for nonvalvular AF at 3 tertiary hospitals. The participants were randomly assigned to 2 groups: CPVI alone (n=59) or CPVI plus linear ablation (CPVI+Line; posterior box+anterior line, n=54). Compared with the CPVI+Line, CPVI alone required shorter procedure (187.2±58.0 versus 211.2±63.9 min; P =0.043) and ablation times (4922.1±1110.5 versus 6205.7±1425.2 s; P <0.001) without difference in procedure-related major complication (3% versus 2%; P =0.611). Antiarrhythmic drug utility rates after ablation were not different between the 2 groups (22% versus 30%; P =0.356). Overall, AF-free survival (log-rank; P =0.206) and AF and antiarrhythmic drug–free survival (log-rank; P =0.321) were not different between groups.

Conclusions—

CPVI alone is an effective rhythm control strategy with a shorter procedure time in persistent AF patients converted to paroxysmal AF compared with CPVI with linear ablation.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02176616.

Contact force technology integrated with 3D navigation system for atrial fibrillation ablation: improving results?

INTRODUCTION

Pulmonary veins isolation (PVI) by radiofrequency (RF) ablation is currently an established treatment for symptomatic, drug-resistant paroxysmal atrial fibrillation. Although the effectiveness of the therapy has been clearly demonstrated, success rate after a single procedure is still sub-optimal. The main reason for recurrences after PVI is electrical pulmonary vein-atrium reconnection. In order to increase the likelihood of permanent PVI, the creation of a transmural, durable lesion is mandatory. The main determinants of lesion size and transmurality are power, stability, duration and contact-force during RF application. In recent times, catheters with contact-force sensors have been developed and released for clinical use. Areas covered: The present review summarizes rational and clinical evidences for efficacy and safety of contact force (CF) technology integrated into 3D navigation systems for AF ablation. Expert commentary Although CF technology has a strong rational, clinical data on the superior safety and efficacy of CF technology over traditional non-CF catheters are still conflicting. The reason for that is very likely to rely on the lack of definite data on how to optimize CF parameters and how to integrate CF data with power, duration of RF applications and information on catheter stability.

Synergistic Effect of Dofetilide and Mexiletine on Prevention of Atrial Fibrillation

Background

Although atrial fibrillation (AF) is the most common abnormal heart rhythm and its prevalence continues to rise, there is a marked paucity of effective and safe antiarrhythmic drugs for AF. This study was done to test whether combined use of dofetilide and mexiletine exhibits not only a synergistic effect on AF suppression but also a safer profile in drug‐induced ventricular proarrhythmias.

Methods and Results

The effects of dofetilide plus mexiletine on atrial effective refractory period (ERP), AF inducibility, QT, and QT‐related ventricular arrhythmias were studied using the isolated arterially perfused rabbit atrial and ventricular wedge preparations. Dofetilide or mexiletine alone mildly to moderately prolonged atrial ERP, but their combined use produced a markedly rate‐dependent increase in atrial ERP. Dofetilide (3 nmol/L) plus mexiletine (10 μmol/L) increased the ERP by 28.2% from 72.2±5.7 to 92.8±5.9 ms (n=9, P<0.01) at a pacing rate of 0.5 Hz and by 94.5% from 91.7±5.2 to 178.3±12.0 ms (n=9, P<0.01) at 3.3 Hz. Dofetilide plus mexiletine strongly suppressed AF inducibility. On the other hand, dofetilide at 10 nmol/L produced marked QT and T_p‐e prolongation, steeper QT‐BCL and T_p‐e‐BCL slopes, and induced early afterdepolarizations and torsade de pointes in the ventricular wedges. Mexiletine at 10 μmol/L reduced dofetilide‐induced QT and T_p‐e prolongation, QT‐BCL and T_p‐e‐BCL slopes, and abolished early afterdepolarizations and torsade de pointes.

Conclusions

In rabbits, combined use of dofetilide and mexiletine not only synergistically increases atrial ERP and effectively suppresses AF inducibility, but also markedly reduces QT liability and torsade de pointes risk posed by dofetilide alone.

Cryoballoon versus Radiofrequency Ablation for Atrial Fibrillation: A Meta-analysis of 16 Clinical Trials

Introduction: We aimed to study the procedural characteristics, efficacy and safety of cryoballoon ablation (CBA) versus radiofrequency ablation (RFA) for catheter ablation of paroxysmal atrial fibrillation (AF). Methods: A systematic literature search was performed using PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials to clinical trials comparing CBA and RFA for AF. Outcomes were evaluated for efficacy, procedure characteristics and safety. For each study, odd ratio (OR) and 95% confidence intervals (CIs) were calculated for endpoints for both approaches. Results: We analyzed a total of 9,957 participants (3,369 in the CBA and 6,588 in RFA group) enrolled in 16 clinical trials. No significant difference was observed between CBA and RFA with regards to freedom from atrial arrhythmia at 12-months, recurrent atrial arrhythmias or repeat catheter ablation. CBA group had a significantly higher transient phrenic nerve injury (OR 14.19, 95% CI: 6.92-29.10; p<0.001) and persistent phrenic nerve injury (OR 4.62, 95% CI: 1.97-10.81; p<0.001); and a significantly lower pericardial effusion/cardiac tamponade (OR 0.43, 95% CI: 0.26-0.72; p=0.001), and groin site complications (OR 0.60, 95% CI: 0.38-0.93; p=0.02). No significant difference was observed in overall complications, stroke/thromboembolic events, major bleeding, and minor bleeding. Conclusion: CBA was non-inferior to RFA for catheter ablation of paroxysmal AF. RF ablation was associated with a higher groin complications and pericardial effusion/cardiac tamponade, whereas CBA was associated with higher rates of transient and persistent phrenic nerve injury.

Pressure-Guided cryoablation of pulmonary veins in atrial fibrillation: A fast and effective strategy

BACKGROUND

Cryoballoon ablation of atrial fibrillation (AF) involves successful electrical pulmonary vein isolation (PVI). Pulmonary vein (PV) ostial occlusion with cryoballoon is classically assessed using PV angiography. A pressure-guided technique to assess ostial occlusion has been evaluated in small cohorts with mixed results. We evaluated the efficacy of this pressure-guided PVI technique and its impact on reducing contrast and fluoroscopy time as compared to the traditional approach.

METHODS

We evaluated patients with paroxysmal AF, who underwent cryoballoon PVI. Patients prior to January 20th, 2013 underwent confirmation of PV occlusion by angiography only. Patients ablated after this time had PV occlusion initially determined by pressure monitoring and further confirmed by contrast injection into the PV in most cases (Pressure-guided PVI). Differences in the volume of contrast used and fluoroscopy time were evaluated.

RESULTS

46 patients had pressure-guided PVI and29 patients had occlusion of PV confirmed by angiography alone. Pressure-guided PVI was 99.5% successful in ablating AF, which was non-inferior to traditional method of PV isolation. This technique used an average of 8cc of contrast and 21.5min of fluoroscopy time, which was significantly less than the contrast amount used, and fluoroscopy time with angiographic isolation of PV.

CONCLUSION

Pressure-guided PVI is an effective method for cryoablation of AF. This method not only significantly reduces the volume of contrast used but also decreases the fluoroscopy without compromising the success of PVI.