A decade of atrial fibrillation ablation

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.

     

Effective contact and outcome after pulmonary vein isolation in novel circular multi-electrode atrial fibrillation ablation

Introduction

Pulmonary vein (PV) reconnection is frequently the cause of recurrence of atrial fibrillation (AF) after ablation. The second-generation gold multi-electrode ablation (Gold-MEA) catheter has a new design possibly resulting in improved lesion formation compared with its predecessor. We aimed to determine the association between effective radiofrequency applications with the Gold-MEA catheter and outcome after AF ablation.

Methods

50 consecutive patients with paroxysmal AF underwent Gold-MEA (PVAC GOLD^TM, Medtronic Inc.) ablation. The Gold-MEA catheter was navigated to the PV ostium by fluoroscopy. Duty-cycled radiofrequency ablations were performed at all PV ostia. Lesions were considered transmural when electrode temperature was >50 °C and power >3 W for >30 seconds. After the ablation procedure, patients visited the outpatient clinic at 3?month intervals including 24-hour Holter ECGs.

Results

Mean age was 56 years. All PVs were acutely isolated with the Gold-MEA catheter. Procedure time was 111 ± 22 minutes, ablation time was 24 ± 6.7 minutes and fluoroscopy time was 20 ± 8.1 minutes. No procedure-related complications were observed. One year after ablation, 60?% of patients were still free of arrhythmia recurrences after a single PV isolation attempt. The number of transmural lesions was associated with arrhythmia-free survival: 25.0?% in <72 transmural lesions, 64.3?% in 72–108 transmural lesions and 71.4?% in >108 transmural lesions (p = 0.029).

Conclusion

PV isolation can be performed successfully with the Gold-MEA catheter, with a favourable safety profile. Transmurality of lesions was associated with ablation success and may improve AF ablation success.

     

Long-term monitoring for patients after surgical ablation of atrial fibrillation: are all devices the same?

In recent years, the nonmedical management of atrial fibrillation (AF) has rapidly evolved, with more options available to address the arrhythmia. Determining the successful return of sinus rhythm and the medical management after ablation requires the selection of the correct diagnostic method. In May 2007, the Heart Rhythm Society in conjunction with the Society for Thoracic Surgeons, the European Heart Rhythm Association, and the European Cardiac Arrhythmia Society identified the need for programs to adopt a consistent method of follow-up and monitoring. Choosing the right monitor for the determination of the success, postsurgical ablation that meets the Heart Rhythm Society guidelines for monitoring especially for asymptomatic patients is imperative. Therefore, we reviewed the current devices available to assist practitioners in determining which monitor best meets their needs The criteria selected to perform the review include (1) ease of use for patients (compliance), (2) ability of the monitor to perform internal analysis, (3) the monitor has >24 hours of storage capability, and (4) external support. Our selection criteria revealed six cardiac rhythm monitors currently available for use. This review compared the different arrhythmia monitors from an established monitoring program perspective to assist practitioners in choosing a monitor that meets their practice needs for determining the return to sinus rhythm postsurgical ablation.     

Expression of TGFβ1 in pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs

The development of pulmonary vein stenosis has recently been described after radiofrequency ablation (RF) to treat atrial fibrillation (AF). The purpose of this study was to examine expression of TGFβ1 in pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs. About 28 mongrel dogs were randomly assigned to the sham-operated group (n = 7), the AF group (n = 7), AF + RF group (n = 7), and RF group (n = 7). In AF or AF + RF groups, dogs underwent chronic pulmonary vein (PV) pacing to induce sustained AF. RF application was applied around the PVs until electrical activity was eliminated. Histological assessment of pulmonary veins was performed using hematoxylin and eosin staining; TGFβ1 gene expression in pulmonary veins was examined by RT-PCR analysis; expression of TGFβ1 protein in pulmonary veins was assessed by Western blot analysis. Rapid pacing from the left superior pulmonary vein (LSPV) induced sustained AF in AF group and AF + RF group. Pulmonary vein ablation terminated the chronic atrial fibrillation in dogs. Histological examination revealed necrotic tissues in various stages of collagen replacement, intimal thickening, and cartilaginous metaplasia with chondroblasts and chondroclasts. Compared with sham-operated and AF group, TGFβ1 gene and protein expressions was increased in AF + RF or RF groups. It was concluded that TGFβ1 might be associated with pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs. Shufeng Li and Hongli Li contributed equally to the work.     

Impact of the third generation cryoballoon on atrial fibrillation ablation: An useful tool?

Background

Third-generation cryoballoon (CB3) is characterized by a 40% shorter distal tip designed to increase the rate of pulmonary veins real-time signal recording in order to measure time necessary to isolate veins, the “Time to effect” (TTE). Few data are currently available on clinical follow up of CB3 treated patients.

Repeat ablation for paroxysmal atrial fibrillation – Does adenosine play a role in predicting pulmonary vein reconnection patterns?

Background

Pulmonary vein (PV) reconduction after PV isolation (PVI) unmasked by adenosine is associated with a higher risk for paroxysmal atrial fibrillation (PAF) recurrence. It is unknown if the reconnected PVs after adenosine testing and immediate re-ablation can predict reconnection and reconnection patterns of PVs at repeat procedures. We assessed reconnection of PVs with and without dormant-conduction (DC) during the first and the repeat procedure.

Efficacy and safety of catheter ablation for atrial fibrillation in congenital heart disease – A systematic review and meta-analysis

BackgroundPrevalence of atrial fibrillation (AF) in patients with congenital heart disease (CHD) is on the rise. Anti-arrhythmic drugs are usually the first line of treatment in CHD, however, it is often ineffective and poorly tolerated. We aimed to perform a systematic review to assess the efficacy and safety of catheter ablation for AF in CHD.MethodsWe performed a comprehensive search on catheter ablation for atrial fibrillation in congenital heart disease up until July 2019 through several electronic databases.ResultsAblation of AF in patients with CHD had a modest 12 months AF freedom ranging from 32.8% to 63%, which can be increased by subsequent/repeat ablation. The complexity of CHD appears to have a significant effect on a study but not in others. Catheter ablation in ASD and persistent left superior vena cava had a high success rate. Overall, catheter ablation is safe whichever the type of CHD is.ConclusionCatheter ablation for AF in CHD had modest efficacy that can be increased by subsequent/repeat ablation and it also has an excellent safety profile. Ablation in complex CHD could also have similar efficacy, however, it is preferably done by experts in a high volume tertiary center.     

Learning curves in atrial fibrillation ablation – A comparison between second generation cryoballoon and contact force sensing radiofrequency catheters

ObjectiveTo examine the learning curves of atrial fibrillation (AF) ablation comparing the cryoballoon (CB) and radiofrequency (RF) catheters.MethodsWe performed a retrospective data analysis from the initiation of AF ablation program in our center. For CB ablation, a second generation 28 mm balloon was utilized and for RF ablation.ResultsA total of 100 consecutive patients (50 in each group) have been enrolled in the study (male 74%, mean age 58.9 ± 10 years, paroxysmal AF 85%). The mean procedure time was shorter for CB (116.6 ± 39.8 min) than RF group (191.8 ± 101.1 min) (p < 0.001). There was no difference in the mean fluoroscopy time, 24.2 ± 10.6 min in RF and 22.4 ± 11.7 min in CB group, (p = 0.422). Seven major complications occurred during the study; 5 in RF group (10%) and 2 in CB group (4%) (p = 0.436). After the mean follow up of 14.5 ± 2.4 months, 15 patients in RF group (30%) and 11 in CB group (26%) experienced AF recurrences (P = 0.300).ConclusionWhen starting a new AF ablation program, our results suggest that CB significantly shortens procedure while fluoroscopy time and clinical outcomes are comparable to RF ablation.     

Comparison between surgical and catheter based ablation in atrial fibrillation,should surgical based ablation be implemented as first line? - A meta-analysis of studies

IntroductionAblation remains a modality of choice in select patients with Atrial fibrillation (AF). Which is done via a surgical or catheter-based approach.ObjectiveThis meta-analysis aimed to compare the efficacy of Surgical and Catheter ablation in the management of AF.MethodsElectronic search on PubMed (MEDLINE), EBSCO, EuropePMC, Clinicaltrials.gov, and Google Scholar was done. Studies comparing the use of surgical or catheter ablation in patients with AF were included. The Primary outcome of interest was Arrhythmia free patients at 12 months post-ablation.ResultsEight studies (744 patients) reported a statistically significant difference in Arrhythmia recurrence rate between surgical and catheter-based ablation. The pooled hazard ratio was chosen to compare the risk of AF recurrence between these groups with pooled Hazard ratio comparing surgical to catheter approach of 0.40 [0.35,0.45], p < 0.001 favoring surgical approach; low heterogeneity I² 22%, p = 0.25. Meta-analyses were also performed on procedural time, length of stay and major adverse events.ConclusionThe increased rate of adverse effects and length of hospitalization impedes the implementation of surgical ablation as primary ablation method of AF in general. However, the result of our meta-analysis shows the promising result of surgical ablation compared to catheter-based ablation.     

Safety and feasibility of atrial fibrillation ablation using Amigo® system versus manual approach: A pilot study

Background

The Amigo^® Remote Catheter System is a relatively new robotic system for catheter navigation. This study compared feasibility and safety using Amigo (RCM) versus manual catheter manipulation (MCM) to treat paroxysmal atrial fibrillation (PAF). Contact force (CF) and force-time integral (FTI) values obtained during pulmonary vein isolation (PVI) ablation were compared.

Cryoablation in persistent atrial fibrillation – a critical appraisal

Ablation of atrial fibrillation is an established treatment for the management of patients with paroxysmal and persistent atrial fibrillation. The complex pathophysiology of persistent atrial fibrillation has fuelled the concept of adjunctive substrate modification on top of pulmonary vein isolation. However, recent studies have failed to demonstrate additive benefit from complex ablation approaches, thus supporting that standalone pulmonary vein isolation may prove sufficient, at least as the initial ablation strategy in persistent atrial fibrillation. In this premise, the new-generation cryoballoon is an attractive option in this demanding subgroup of patients due to its reliable efficacy in achieving pulmonary vein isolation combined with collateral debulking of the neighbouring atrial myocardium. In this review, we present a critical appraisal of the role of cryoablation in patients with persistent atrial fibrillation, discussing related technical considerations and existing scientific evidence.     

A new predictor for the onset of atrial fibrillation?

In this issue of the Netherlands Heart Journal, the results of a substudy of the PREVEND trial are published.1 This prospective registry of presumably healthy citizens of Groningen aims to establish the association between microalbuminuria and the emergence of renal and cardiovascular diseases.2 This general population based long-term study extends the series of previous large-scale epidemiological trials conducted in the Netherlands. We recall among them the 1970 Vlagtwedde study for epidemiological cardiology and ischaemic heart disease, the 1982 Zutphen study of diet and cardiovascular diseases, the 1997 Maastricht study of circulatory arrest and sudden death, the 1998 Amsterdam study of out-of-hospital cardiac arrest and the 1999 Rotterdam study of prolonged QT interval and mortality.     

Left atrial enlargement and clinical considerations in patients with or without a residual interatrial shunt after closure of the left atrial appendage with the WATCHMAN™-device

Background

Interventional closure of the left atrial appendage (LAA) in patients with non-valvular atrial fibrillation, high thromboembolic and bleeding risk or bleeding history is an alternative therapeutic strategy to oral anticoagulation. It is not known if the exclusion of the LAA from the blood circulation affects the left atrial volume (LAV) and consequently its prognostic value or the circulatory performance of the heart in humans.

Methods

We aimed to prospectively assess potential changes in baseline LAV, left ventricular ejection fraction (LVEF), NT-proBNP-level and the covered distance in the 6-min walk-test 6 weeks and 6 months after LAA closure with the WATCHMAN? device. We used serial 3-dimensional transthoracic and transesophageal echocardiography to assess LAV, residual interatrial shunt and device performance in 58 consecutive patients with successful LAA closure.

Results

Accurate 3D–echocardiographic data for LAV measurements were evaluable for 51 (91%) patients. Maximum LAV (LAVmax) at baseline was 102.8?±?30.8 ml and increased significantly to 107.7?±?32.8 ml after 6 weeks (p?<?0.01) and 113.5?±?34.2 ml after 6 months (p?<?0.01). Minimal LAV (LAVmin) increased from 76.9?±?29.5 ml at baseline to 81.8?±?30.2 ml after 45 days (p?<?0.01) and 82.1?±?33.3 ml after 6 months (p?<?0.01). Similarly, their indexes to BSA (LAVImax and LAVImin) increased significantly, as well. Patients without a residual left-to-right interatrial shunt showed a significantly higher increase in LAVmax or LAVmin. Baseline LVEF, NT-proBNP-level or the distance covered at the 6-min walk test did not significantly change 6 weeks or 6 months after LAA closure.

Conclusions

LAVmax and LAVmin increase significantly after interventional LAA closure. LA enlargement does not correlate with clinical progression of heart failure. Persistent left-to-right interatrial shunt counteracts the LA enlargement. A reduced LA compliance after exclusion of the LAA from the blood circulation with consecutive increase in LA pressure may be a potential cause of LA enlargement and warrants further investigation.

Trial registration

German Clinical Trials Register ID: DRKS00010768; Registration Date 07.07.2016.

     

Studies of abnormalities of the lower esophageal sphincter during esophageal emptying based on a fully coupled bolus–esophageal–gastric model

The aim of this work was to develop a fully coupled bolus–esophageal–gastric model based on the immersed boundary–finite element method to study the process of esophageal emptying across the esophagogastric junction (EGJ). The model included an esophageal segment, an ellipsoid-shaped stomach, a bolus, and a simple model of the passive and active sphincteric functions of the lower esophageal sphincter (LES). We conducted three sets of case studies: (1) the effect of a non-relaxing LES; (2) the influence of the tissue anisotropy in the form of asymmetrical right- and left-sided compliance of the LES segment; and (3) the influence of LES and gastric wall stiffness on bulge formation of the distal esophageal wall. We found that a non-relaxing LES caused sustained high wall stress along the LES segment and obstruction of bolus emptying. From the simulations of tissue anisotropy, we found that the weaker side (i.e., more compliant) of the LES segment sustained greater deformation, greater wall shear stress, and a greater high-pressure load during bolus transit. In the third set of studies, we found that a right-sided bulge in the esophageal wall tends to develop during esophageal emptying when LES stiffness was decreased or gastric wall stiffness was increased. Hence, the bulge may be partly due to the asymmetric configuration of the gastric wall with respect to the esophageal tube. Together, the observations from these simulations provide insight into the genesis of epiphrenic diverticula, a complication observed with esophageal motility disorders. Future work, with additional layers of complexity to the model, will delve into the mechanics of gastroesophageal reflux and the effects of hiatus hernia on EGJ function.     

Antithrombotic management of patients with atrial fibrillation—Dutch anticoagulant initiatives anno 2020

In recent years, as more and more experience has been gained with prescribing direct oral anticoagulants (DOACs), new research initiatives have emerged in the Netherlands to improve the safety and appropriateness of DOAC treatment for stroke prevention in patients with atrial fibrillation (AF). These initiatives address several contemporary unresolved issues, such as inappropriate dosing, non-adherence and the long-term management of DOAC treatment. Dutch initiatives have also contributed to the development and improvement of risk prediction models. Although fewer bleeding complications (notably intracranial bleeding) are in general seen with DOACs in comparison with vitamin K antagonists, to successfully identify patients with high bleeding risk and to tailor anticoagulant treatment accordingly to mitigate this increased bleeding risk, is one of the research aims of recent and future years. This review highlights contributions from the Netherlands that aim to address these unresolved issues regarding the anticoagulant management in AF in daily practice, and provides a narrative overview of contemporary stroke and bleeding risk assessment strategies.