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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.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.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.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.

Atrial fibrillation is a chronic, progressive disorder, and persistent forms of atrial fibrillation are associated with increased risks of thromboembolism and heart failure. Catheter ablation as initial therapy may modify the pathogenic mechanism of atrial fibrillation and alter progression to persistent atrial fibrillation.We report the 3-year follow-up of patients with paroxysmal, untreated atrial fibrillation who were enrolled in a trial in which they had been randomly assigned to undergo initial rhythm-control therapy with cryoballoon ablation or to receive antiarrhythmic drug therapy. All the patients had implantable loop recorders placed at the time of trial entry, and evaluation was conducted by means of downloaded daily recordings and in-person visits every 6 months. Data regarding the first episode of persistent atrial fibrillation (lasting ≥7 days or lasting 48 hours to 7 days but requiring cardioversion for termination), recurrent atrial tachyarrhythmia (defined as atrial fibrillation, flutter, or tachycardia lasting ≥30 seconds), the burden of atrial fibrillation (percentage of time in atrial fibrillation), quality-of-life metrics, health care utilization, and safety were collected.A total of 303 patients were enrolled, with 154 patients assigned to undergo initial rhythm-control therapy with cryoballoon ablation and 149 assigned to receive antiarrhythmic drug therapy. Over 36 months of follow-up, 3 patients (1.9%) in the ablation group had an episode of persistent atrial fibrillation, as compared with 11 patients (7.4%) in the antiarrhythmic drug group (hazard ratio, 0.25; 95% confidence interval [CI], 0.09 to 0.70). Recurrent atrial tachyarrhythmia occurred in 87 patients in the ablation group (56.5%) and in 115 in the antiarrhythmic drug group (77.2%) (hazard ratio, 0.51; 95% CI, 0.38 to 0.67). The median percentage of time in atrial fibrillation was 0.00% (interquartile range, 0.00 to 0.12) in the ablation group and 0.24% (interquartile range, 0.01 to 0.94) in the antiarrhythmic drug group. At 3 years, 8 patients (5.2%) in the ablation group and 25 (16.8%) in the antiarrhythmic drug group had been hospitalized (relative risk, 0.31; 95% CI, 0.14 to 0.66). Serious adverse events occurred in 7 patients (4.5%) in the ablation group and in 15 (10.1%) in the antiarrhythmic drug group.Initial treatment of paroxysmal atrial fibrillation with catheter cryoballoon ablation was associated with a lower incidence of persistent atrial fibrillation or recurrent atrial tachyarrhythmia over 3 years of follow-up than initial use of antiarrhythmic drugs. (Funded by the Cardiac Arrhythmia Network of Canada and others; EARLY-AF ClinicalTrials.gov number, NCT02825979.).

Background Guidelines recommend a trial of one or more antiarrhythmic drugs before catheter ablation is considered in patients with atrial fibrillation. However, first-line ablation may be...

Gas-phase solar receivers can operate over a wider temperature range than receivers which use conventional liquid heat transfer media. However, due to their relatively poor heat transfer performance, gas-phase receivers require substantially more heat transfer area and/or higher flow rates to extract the same amount of heat which leads to more complicated designs (e.g. a porous-media absorber with small feature/pore size) and decreased reliability (e.g. internal temperature gradients and higher thermal stresses). Detailed numerical modelling techniques can help elucidate the fundamental heat and mass transfer mechanisms/interactions in such to help mitigate these risks and to create innovative, high-performance, designs. To collate the research efforts towards gas-phase receiver modelling, this paper systematically reviews—and critically compares—the latest numerical studies of various high-temperature gas-phase receiver designs. It was found that, from a numerical point of view, gas-phase receivers can be categorised by whether they contain a porous medium or not. This categorisation is crucial, because it dictates the numerical techniques needed to capture the underlying phenomena. It was also found that no standardised performance metrics are reported for gas-phase receivers. This study suggests that a holistic figure of merit, such as the one developed by Lenert et al. (2012), be adopted in this field to merge all performance criteria for comparative evaluation. Overall, the present review is expected to serve as a guide for the development/enhancement of receiver designs based on linking best practices in simulation/modelling with the key features and limitations of gas-phase receivers.

Pulmonary vein isolation by catheter ablation is a class IA indication for the treatment of symptomatic, drug-refractory, paroxysmal atrial fibrillation (PAF). Quality of life (QoL) has been identified as a clinically meaningful endpoint but has not been comprehensively evaluated to date.The purpose of this study was to evaluate the effects of cryoballoon ablation on long-term QoL.As part of the STOP-AF Post-Approval Study, QoL was assessed using the Short Form-12 Health Survey (SF-12) along with evaluation of arrhythmia-related symptoms through 36 months. A multivariate linear mixed effects regression was used to determine the association between atrial fibrillation symptoms and QoL scores, and univariate linear regressions were used to assess predictors of 36-month change in QoL scores.Three hundred thirty-five subjects fully completed SF-12 forms at baseline, with 319, 308, 291, and 278 subjects completing surveys at the subsequent follow-up visits. Both physical and mental composite scores increased significantly from baseline (P.001), and all arrhythmia symptoms significantly decreased from baseline (P.001), with 62.0% of subjects reporting no symptoms at 6 months compared to 5.7% at baseline (P.001). Presence of dyspnea and fatigue at baseline were univariate predictors of physical QoL improvement (P = .045 and 0.0497, respectively), whereas each year of age and each year of PAF duration were predictors of a decrease in mental QoL (P = .014 and .04, respectively).Cryoballoon ablation for treatment of PAF results in a significant, and sustained, QoL improvement. The observed improvement in physical and mental health likely may be mediated by a reduction in symptom and arrhythmia burden.

Background: Atrial fibrillation (AF) and heart failure (HF) frequently coexist and can be challenging to treat. Pharmacologically based rhythm control of AF has not proven to be superior to rate control. Ablation-based rhythm control was compared with rate control to evaluate if clinical outcomes in patients with HF and AF could be improved. Methods: This was a multicenter, open-label trial with blinded outcome evaluation using a central adjudication committee. Patients with high-burden paroxysmal (>4 episodes in 6 months) or persistent (duration Results: From December 1, 2011, to January 20, 2018, 411 patients were randomly assigned to ablation-based rhythm control (n=214) or rate control (n=197). The primary outcome occurred in 50 (23.4%) patients in the ablation-based rhythm-control group and 64 (32.5%) patients in the rate-control group (hazard ratio, 0.71 [95% CI, 0.49–1.03]; P =0.066). Left ventricular ejection fraction increased in the ablation-based group (10.1±1.2% versus 3.8±1.2%, P =0.017), 6-minute walk distance improved (44.9±9.1 m versus 27.5±9.7 m, P =0.025), and NT-proBNP demonstrated a decrease (mean change –77.1% versus –39.2%, P P =0.0036), as did the AF Effect on Quality of Life score (least-squares mean difference of 6.2 [95% CI, 1.7–10.7]; P =0.0005). Serious adverse events were observed in 50% of patients in both treatment groups. Conclusions: In patients with high-burden AF and HF, there was no statistical difference in all-cause mortality or HF events with ablation-based rhythm control versus rate control; however, there was a nonsignificant trend for improved outcomes with ablation-based rhythm control over rate control. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01420393.

ImportanceRecurrent atrial fibrillation (AF) commonly occurs after catheter ablation and is associated with patient morbidity and health care costs.ObjectiveTo evaluate the superiority of an augmented double wide-area circumferential ablation (WACA) compared with a standard single WACA in preventing recurrent atrial arrhythmias (AA) (atrial tachycardia, atrial flutter, or atrial fibrillation [AF]) in patients with paroxysmal AF.Design, Setting, and ParticipantsThis was a pragmatic, multicenter, prospective, randomized, open, blinded end point superiority clinical trial conducted at 10 university-affiliated centers in Canada. The trial enrolled patients 18 years and older with symptomatic paroxysmal AF from March 2015 to May 2017. Analysis took place between January and April 2022. Analyses were intention to treat.InterventionsPatients were randomized (1:1) to receive radiofrequency catheter ablation for pulmonary vein isolation with either a standard single WACA or an augmented double WACA.Main Outcomes and MeasuresThe primary outcome was AA recurrence between 91 and 365 days postablation. Patients underwent 42 days of ambulatory electrocardiography monitoring after ablation. Secondary outcomes included need for repeated catheter ablation and procedural and safety variables.ResultsOf 398 patients, 195 were randomized to the single WACA (control) arm (mean [SD] age, 60.6 [9.3] years; 65 [33.3%] female) and 203 to the double WACA (experimental) arm (mean [SD] age, 61.5 [9.3] years; 66 [32.5%] female). Overall, 52 patients (26.7%) in the single WACA arm and 50 patients (24.6%) in the double WACA arm had recurrent AA at 1 year (relative risk, 0.92; 95% CI, 0.66-1.29; P = .64). Twenty patients (10.3%) in the single WACA arm and 15 patients (7.4%) in the double WACA arm underwent repeated catheter ablation (relative risk, 0.72; 95% CI, 0.38-1.36). Adjudicated serious adverse events occurred in 13 patients (6.7%) in the single WACA arm and 14 patients (6.9%) in the double WACA arm.Conclusions and RelevanceIn this randomized clinical trial of patients with paroxysmal AF, additional ablation by performing a double ablation lesion set did not result in improved freedom from recurrent AA compared with a standard single ablation set.Trial RegistrationClinicalTrials.gov Identifier: NCT02150902

Recurrence of atrial fibrillation (AF) after a pulmonary vein isolation procedure is often due to electrical reconnection of the pulmonary veins. Repeat ablation procedures may improve freedom from AF but are associated with increased risks and health care costs. A novel ablation strategy in which patients receive "augmented" ablation lesions has the potential to reduce the risk of AF recurrence.The Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence (AWARE) Trial was designed to evaluate whether an augmented wide-area circumferential antral (WACA) ablation strategy will result in fewer atrial arrhythmia recurrences in patients with symptomatic paroxysmal AF, compared with a conventional WACA strategy.The AWARE trial was a multicenter, prospective, randomized, open, blinded endpoint trial that has completed recruitment (ClinicalTrials.gov NCT02150902). Patients were randomly assigned (1:1) to either the control arm (single WACAlesion set) or the interventional arm (augmented- double WACA lesion set performed after the initial WACA). The primary outcome was atrial tachyarrhythmia (AA; atrial tachycardia [AT], atrial flutter [AFl] or AF) recurrence between days 91 and 365 post catheter ablation. Patient follow-up included 14-day continuous ambulatory ECG monitoring at 3, 6, and 12 months after catheter ablation. Three questionnaires were administered during the trial- the EuroQuol-5D (EQ-5D) quality of life scale, the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale, and a patient satisfaction scale.The AWARE trial was designed to evaluate whether a novel approach to catheter ablation reduced the risk of AA recurrence in patients with symptomatic paroxysmal AF.

Background: Advanced generation ablation technologies have been developed to achieve more effective pulmonary vein isolation (PVI) and minimize arrhythmia recurrence after atrial fibrillation (AF) ablation. Methods: We randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force–guided radiofrequency ablation (CF-RF; n=115), 4-minute cryoballoon ablation (Cryo-4; n=115), or 2-minute cryoballoon ablation (Cryo-2; n=116). Follow-up was 12 months. The primary outcome was time to first documented recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) between days 91 and 365 after ablation or a repeat ablation procedure at any time. Secondary end points included freedom from symptomatic arrhythmia and AF burden. All patients received an implantable loop recorder. Results: One-year freedom from atrial tachyarrhythmia defined by continuous rhythm monitoring was 53.9%, 52.2%, and 51.7% with CF-RF, Cryo-4, and Cryo-2, respectively ( P =0.87). One-year freedom from symptomatic atrial tachyarrhythmia defined by continuous rhythm monitoring was 79.1%, 78.2%, and 73.3% with CF-RF, Cryo-4, and Cryo-2, respectively ( P =0.26). Compared with the monitoring period before ablation, AF burden was reduced by a median of 99.3% (interquartile range, 67.8%–100.0%) with CF-RF, 99.9% (interquartile range, 65.3%–100.0%) with Cryo-4, and 98.4% (interquartile range, 56.2%–100.0%) with Cryo-2 ( P =0.36). Serious adverse events occurred in 3 patients (2.6%) in the CF-RF group, 6 patients (5.3%) in the Cryo-4 group, and 7 patients (6.0%) in the Cryo-2 group, with no significant difference between groups ( P =0.24). The CF-RF group had a significantly longer procedure duration but significantly shorter fluoroscopy exposure ( P Conclusions: In this multicenter, randomized, single-blinded trial, CF-RF and 2 different regimens of cryoballoon ablation resulted in no difference in 1-year efficacy, which was 53% by time to first recurrence but >98% burden reduction as assessed by continuous cardiac rhythm monitoring. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01913522.

Objectives STOP AF PAS (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study) is the first prospective, multicenter, 3-year study in North America to assess long-term safety and effectiveness of the cryoballoon for treatment of patients with drug-refractory symptomatic pAF. Background The STOP AF PAS was required by the U.S. Food and Drug Administration at the time of approval of the first-generation cryoballoon for the treatment of paroxysmal atrial fibrillation (pAF). The second-generation cryoballoon (CB2) was commercially released shortly after this trial was initiated. Methods The study was nonrandomized. Enrollment was completed with 344 eligible patients undergoing pulmonary vein isolation (PVI) using the CB2. Procedure-related safety and freedom from AF and symptomatic atrial flutter/atrial tachycardia through 3 years were determined. Documented atrial arrhythmias ≥30 s were considered treatment failures. Results Acute PVI was achieved in 99.3% (1,341 of 1,350) of veins. Mean follow-up was 34 ± 7 months. The rate of major complications was 5.8%, including a 3.2% rate of phrenic nerve injury, which resolved in all but 1 patient by 36 months. At 36 months, 11.7% of patients were prescribed antiarrhythmic agents, inclusive of “pill-in-the-pocket” administration. Freedom from AF was 81.6% at 12 months, 73.8% at 24 months, and 68.1% at 36 months. Freedom from AF and symptomatic atrial flutter/atrial tachycardia was 79.0% at 12 months, 70.8% at 24 months, and 64.1% at 36 months. Freedom from a repeat ablation procedure was 80.9% at 36 months. Conclusions PVI using the CB2 was an effective treatment for patients with pAF, with freedom from all atrial arrhythmias of 64% at 36 months. (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study [STOP AF PAS]; NCT01456949)

IMPORTANCE: Patients with atrial fibrillation (AF) have impaired health-related quality of life primarily owing to symptoms related to AF episodes; however, quality of life can be influenced by AF therapies, AF complications, the frequency of follow-up visits and hospitalizations, illness perceptions, and patient factors, such as anxiety or depression. OBJECTIVE: To determine the association between change in AF burden and quality of life in the year following ablation. DESIGN, SETTING, AND PARTICIPANTS: The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration [CIRCA-DOSE] study), which took place at 8 Canadian centers. Between September 2014 and July 2017, 346 patients older than 18 years with symptomatic, primarily low-burden AF refractory to antiarrhythmic therapy referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation and were followed up with up to December 2018. Data were analyzed from April 2020 to June 2021. INTERVENTIONS: Patients were randomized 1:1:1 to contact force–guided radiofrequency ablation, 4-minute cryoballoon ablation, or 2-minute cryoballoon ablation. The exposure in the present analysis is the absolute difference in AF burden prior to ablation and 12 months following ablation, as evaluated by the Atrial Fibrillation Effect on Quality of Life (AFEQT) Score. MAIN OUTCOMES AND MEASURES: Absolute difference in quality of life from baseline to 12 months postablation. RESULTS: Of 346 included patients, 231 (66.7%) were male, and the median (interquartile range) age was 60 (52-66) years. A total of 328 patients (94.8%) had paroxysmal AF. The median (interquartile range) preablation AF burden was 2.0% (0.1-11.9), and the AF burden decreased to 0% at 12 months postablation. At 12 months, a 1-point improvement in AFEQT score was observed for every absolute reduction in daily AF burden of 15.8 minutes (95% CI, 7.2-24.4; P

BACKGROUND The STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation 2) was a multicenter, randomized trial which randomized patients to pulmonary vein isolation (PVI) alone, PVI plus complex fractionated electrograms (CFE), or PVI plus linear ablation (roof line and mitral line). The study failed to show any additional benefit of additional substrate ablation (CFE or lines) in addition to PVI. However, complete block of linear ablations or total elimination of CFE was not achieved in all patients in the adjuvant ablation arms and this could explain why these additive ablation strategies did not improve outcome. We sought to determine whether completeness of adjuvant linear or CFE ablation affected the outcome of these additive ablation strategies when combined with PVI. METHODS AND RESULTS In STAR AF II, 549 patients were randomized 1:4:4 to PVI alone, PVI plus lines, and PVI plus CFE. In this substudy, outcomes of patients with complete linear block and without complete linear block in the PVI + lines group and outcomes for patients with all CFE regions successfully ablated and without all of them ablated in the PVI + CFE are analysed. Of the 243 patients in the PVI plus lines group who received both mitral and roof lines, bidirectional block across both lines was achieved in 179 (74%) but was not achieved in 65 (26%). At 18 months follow-up, AF recurrence occurred in 107 of 179 patients (59.8%) with complete block conduction block across lines and in 40 of 64 patients (62.5%) without complete block (p=0.89) (Figure 1). Even after 2 procedures, AF recurred in 51.9% of patients with complete linear block and 46% of patients without complete block (p=0.09). Of the 207 patients in the PVI plus CFE group who actually underwent CFE ablation, 188 (91%) had elimination of all CFE sites while all CFE were not eliminated in 19 (9%). At 18 months follow-up, AF recurrence occurred in 117 of 188 patients (62.2%) with all the CFE ablated and in 11 of 19 patients (57.9%) without all CFE ablated (p=0.47) (Figure 1). After 2 procedures, AF recurrence occurred in 56.7% of patients with all CFE ablated and 68.0% of patients without all CFE ablated (p=0.29). CONCLUSION PVI combined with both linear and CFE ablation did not result in less AF recurrence compared to PVI alone even after more than one procedure regardless of how well empiric linear or CFE ablation is performed.

Sergio Conti, Chen-yang Jiang, Timothy R. Betts, Jian Chen, Isabel Deisenhofer, Roberto Mantovan ... et al.

BACKGROUND: Pulmonary vein (PV) stenosis is a complication of atrial fibrillation (AF) ablation. The incidence of PV stenosis after routine post-ablation imaging remains unclear and is limited to single-centre studies. Our objective was to determine the incidence and predictors of PV stenosis following circumferential radiofrequency ablation in the multicentre Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) trial. METHODS: Patients with symptomatic AF underwent circumferential radiofrequency ablation in one of 13 trial centres. Computed tomographic (CTA) or magnetic resonance (MRA) angiography was performed before ablation and 90 days after ablation. Two blinded reviewers measured PV diameters and areas. PVs with stenosis were classified as severe (> 70%), moderate (50%-70%), or mild (< 50%). Predictors of PV stenosis were identified by means of multivariable logistic regression. RESULTS: A total of 197 patients (median age 59.5 years, 29.4% women) were included in this substudy. PV stenosis was identified in 41 patients (20.8%) and 47 (8.2%) of 573 ablated PVs. PV stenosis was classified as mild in 42 PVs (7.3%) and moderate in 5 PVs (0.9%). No PVs had severe stenosis. Both cross-sectional area and diameter yielded similar classifications for severity of PV stenosis. Diabetes was associated with a statistically significant increased risk of PV stenosis (OR 4.91, 95% CI 1.45-16.66). CONCLUSIONS: In the first systematic multicentre evaluation of post-ablation PV stenosis, no patient acquired severe PV stenosis. Although the results are encouraging for the safety of AF ablation, 20.8% of patients had mild or moderate PV stenosis, in which the long-term effects are unknown.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation to treat patients with symptomatic drug-refractory atrial fibrillation (AF).The purpose of this study was to assess the safety and efficacy of PVI using the cryoballoon catheter to treat patients with persistent AF.STOP Persistent AF (ClinicalTrials.gov Identifier: NCT03012841) was a prospective, multicenter, single-arm, Food and Drug Administration-regulated trial designed to evaluate the safety and efficacy of PVI-only cryoballoon ablation for drug-refractory persistent AF (continuous episodes6 months). The primary efficacy endpoint was 12-month freedom from ≥30 seconds of AF, atrial flutter (AFL), or atrial tachycardia (AT) after a 90-day blanking period. The prespecified performance goals were set at40% and13% for the primary efficacy and safety endpoints, respectively. Secondary endpoints assessed quality of life using the AFEQT (Atrial Fibrillation Effect on Quality of Life) and SF (Short Form)-12 questionnaires.Of 186 total enrollments, 165 subjects (70% male; age 65 ± 9 years; left atrial diameter 4.2 ± 0.6 cm; body mass index 31 ± 6) were treated at 25 sites in the United States, Canada, and Japan. Total procedural, left atrial dwell, and fluoroscopy times were 121 ± 46 minutes, 102 ± 41 minutes, and 19 ± 16 minutes, respectively. At 12 months, the primary efficacy endpoint was 54.8% (95% confidence [CI] 46.7%-62.1%) freedom from AF, AFL, or AT. There was 1 primary safety event, translating to a rate of 0.6% (95% CI 0.1%-4.4%). AFEQT and SF-12 assessments demonstrated significant improvements from baseline to 12 months postablation (P.001).The STOP Persistent AF trial demonstrated cryoballoon ablation to be safe and effective in treating patients with drug-refractory persistent AF characterized by continuous AF episodes6 months.

OBJECTIVE We tested whether ablation methodology and study design can explain the varying outcomes in terms of atrial fibrillation (AF)-free survival at 1 year. BACKGROUND There have been numerous paroxysmal AF ablation trials, which are heterogeneous in their use of different ablation techniques and study design. A useful approach to understanding how these factors influence outcome is to dismantle the trials into individual arms and reconstitute them as a large meta-regression. METHODS Data were collected from 66 studies (6941 patients). With freedom from AF as the dependent variable, we performed meta-regression using the individual study arm as the unit. RESULTS Success rates did not change regardless of the technique used to produce pulmonary vein isolation (PVI). Neither was adjunctive lesion sets associated with any improvement in outcome. Studies that included more males and fewer hypertensive patients were found more likely to report better outcomes. The electrocardiography method selected to assess outcome also plays an important role. Outcomes were worse in studies that used regular telemonitoring (by 23%; P

Background Impact of contact force sensing (CFS) on ablation of persistent atrial fibrillation (PeAF) is unknown. Objective The purpose of the TOUCH AF (Therapeutic Outcomes Using Contact force Handling during Ablation of Persistent Atrial Fibrillation) randomized trial was to compare CFS-guided ablation to a CFS-blinded strategy. Methods Patients (n = 128) undergoing first-time ablation for persistent AF were randomized to a CFS-guided vs CFS-blinded strategy. In the CFS-guided procedure, operators visualized real-time force data. In the blinded procedure, force data were hidden. Wide antral pulmonary vein isolation plus a roof line were performed. Patients were followed at 3, 6, 9, and 12 months with clinical visit, ECG, and 48-hour Holter monitoring. The primary endpoint was cumulative radiofrequency (RF) time for all procedures. Atrial arrhythmia >30 seconds after 3 months was a recurrence. Results PeAF was continuous for 26 weeks (interquartile range [IQR] 13–52), and left atrial size was 45 ± 5 mm. Force in the CFS-blinded and CFS-guided arms was 12 g [IQR 6–20] and 14 g [IQR 9–20] ( P = .10), respectively. Total RF time did not differ between CFS-guided and CFS-blinded groups (49 ± 14 min vs 50 ± 20 min, respectively; P = .70). Single procedure freedom from atrial arrhythmia was 60% in the CFS-guided arm and 63% in the CFS-blinded arm off drugs. Lesions with gaps were associated with significantly less force (11.4 g [IQR 6–19] vs 13.2 g [IQR 8–20], respectively; P = .0007) and less force-time integral (174 gs [IQR 91–330] vs 210 gs [IQR 113–388], respectively; P Conclusion CFS-guided ablation resulted in no difference to RF time or 12-month outcome. Lower force/force-time integral was associated with significantly more gaps.

Controversy exists about the impact of acute atrial fibrillation (AF) termination and prolongation of atrial fibrillation cycle length (AFCL) during ablation on long-term procedural outcome.The purpose of this study was to analyze the influence of AF termination and AFCL prolongation on freedom from AF in patients from the STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial-Part II) trial.Acute changes in AFCL and AF termination were collected during the index procedure of the STAR AF II trial and compared to recurrence of AF at 18 months. Recurrence was assessed by ECG, Holter (3, 6, 9, 12, 18 months), and weekly transtelephonic ECG monitoring for 18 months.AF terminated in 8% of the pulmonary vein isolation (PVI) arm, 45% in the PVI+complex electrogram arm, and 22% of the PVI+linear ablation arm (P.001), but freedom from AF did not differ among the 3 groups (P = .15). Freedom from AF was significantly higher in patients who presented to the laboratory in sinus rhythm (SR) compared to those without AF termination (63% vs 44%, P = .007). Patients with AF termination had an intermediate outcome (53%) that was not significantly different from those in SR (P = .84) or those who did not terminate (P = .08). AF termination was a univariable predictor of success (P = .007), but by multivariable analysis, presence of early SR was the strongest predictor of success (hazard ratio 0.67, P = .004). Prolongation of AFCL was not predictive of 18-month freedom from AF.Acute AF termination and prolongation in AFCL did not consistently predict 18-month freedom from AF. Presence of SR before or early during the ablation was the strongest predictor of better outcome.

This study evaluated the impact of contact force-guided radiofrequency ablation versus cryoballoon ablation on quality of life and health care utilization.Traditional outcome parameters, such as arrhythmia-free survival, are insufficient to evaluate the clinical impact of atrial fibrillation (AF), as it fails to the capture patient- and health system-level differences in treatment approaches.The CIRCA-DOSE (Cryoballoon Vs. Contact-Force Atrial Fibrillation Ablation) study randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force-guided radiofrequency or cryoballoon ablation. Health-related quality-of-life (HRQOL) was assessed at baseline, and at 6 and 12 months post-ablation using a disease-specific and generic HRQOL instruments. Health care utilization (hospitalization, emergency department visits, and cardioversion) and antiarrhythmic drug use for the 12 months preceding ablation was compared with the 12 months following ablation.Disease-specific and generic HRQOL was moderately to severely impaired at baseline and improved significantly at 6 and 12 months of follow-up (median improvement in AFEQT [Atrial Fibrillation Effect on QualiTy of Life] score 32.4 [interquartile range: 17.7 to 48.9]). When compared with the 12 months pre-ablation, the proportion and absolute number of cardioversions decreased significantly (41.1% vs. 10.1% of patients, 137 vs. 35 events; p 0.0001). Similar significant reductions in emergency department visits (66.7% vs. 25.1% of patients, 224 vs. 87 events; p 0.0001), and hospitalizations (25.5% vs. 14.5% of patients, 86 vs. 50 events; p 0.001) were observed. There were no significant differences between randomized groups.In this multicenter randomized trial, catheter ablation with advanced-generation technologies resulted in a significant improvement in HRQOL and a significant reduction in health care utilization in the year following AF ablation. (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation [CIRCA-DOSE]; NCT01913522).

The purpose of this study was to evaluate the efficacy, health care utilization, and safety of a same-day discharge protocol.Catheter ablation of atrial fibrillation (AF) is the most common ablation performed. Increasing volumes of AF ablation are placing demands on hospital resources. In response, our institutions developed a same-day discharge protocol for AF ablation.This was a multicenter cohort study of all patients undergoing AF ablation from 2010 to 2014 at 2 major centers. The primary efficacy outcome was the proportion of successful same-day discharges. The primary health care utilization outcome was 30-day hospital readmission for any reason. The primary safety outcome was a composite of 30-day death, stroke/transient ischemic attack or embolism, or bleeding requiring hospitalization.A total of 3,054 patients underwent AF ablation from 2010 to 2014 and met inclusion criteria. Same-day discharge was achieved in 79.2% (2,418 of 3,054). Hospital readmission at 30 days was 7.7% for the same-day discharge group, 10.2% for those who remained in the hospital overnight without complications (p = 0.055 for comparison with same-day discharge), and 19.5% (p 0.001) for those who remained in the hospital with procedural complications (7.7%). Complication rates from discharge to 30 days (excluding immediate procedural complications) were 0.37% for the same-day discharge group, 0.36% (p = 0.999) for those kept overnight without complications, and 2.5% (p = 0.044) for those with initial procedural complications.Same-day discharge after AF ablation is feasible in the majority of patients with use of a standardized protocol. This approach was not associated with higher hospital readmission or complication rates after discharge.

AimsAblation of persistent atrial fibrillation (PsAF) has been performed by many techniques with varying success rates. This may be due to ablation techniques, patient demographics, comorbidities, and trial design. We conducted a meta-regression of studies of PsAF ablation to elucidate the factors affecting atrial fibrillation (AF) recurrence.Methods and results Databases were searched for prospective studies of PsAF ablation. A meta-regression was performed. Fifty-eight studies (6767 patients) were included. Complex fractionated atrial electrogram (CFAE) ablation reduced freedom from AF by 8.9% [95% confidence interval (CI) −15 to −2.3, P = 0.009). Left atrial appendage [LAA isolation (three study arms)] increased freedom from AF by 39.5% (95% CI 9.1–78.4, P = 0.008). Posterior wall isolation (PWI) (eight study arms) increased freedom from AF by 19.4% (95% CI 3.3–38.1, P = 0.017). Linear ablation or ganglionated plexi ablation resulted in no significant effect on freedom from AF. More extensive ablation increased intraprocedural AF termination; however, intraprocedural AF termination was not associated with improved outcomes. Increased left atrial diameter was associated with a reduction in freedom from AF by 4% (95% CI −6.8% to −1.1%, P = 0.007) for every 1 mm increase in diameter.Conclusion Linear ablation, PWI, and CFAE ablation improves intraprocedural AF termination, but such termination does not predict better long-term outcomes. Study arms including PWI or LAA isolation in the lesion set were associated with improved outcomes in terms of freedom from AF; however, further randomized trials are required before these can be routinely recommended. Left atrial size is the most important marker of AF chronicity influencing outcomes.

Background The BRUISE CONTROL trial (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial) demonstrated that a strategy of continued warfarin during cardiac implantable electronic device surgery was safe and reduced the incidence of clinically significant pocket hematoma (CSH). CSH was defined as a post-procedure hematoma requiring further surgery and/or resulting in prolongation of hospitalization of at least 24 h, and/or requiring interruption of anticoagulation. Previous studies have inconsistently associated hematoma with the subsequent development of device infection; reasons include the retrospective nature of many studies, lack of endpoint adjudication, and differing subjective definitions of hematoma. Objectives The BRUISE CONTROL INFECTION (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial Extended Follow-Up for Infection) prospectively examined the association between CSH and subsequent device infection. Methods The study included 659 patients with a primary outcome of device-related infection requiring hospitalization, defined as 1 or more of the following: pocket infection; endocarditis; and bloodstream infection. Outcomes were verified by a blinded adjudication committee. Multivariable analysis was performed to identify predictors of infection. Results The overall 1-year device-related infection rate was 2.4% (16 of 659). Infection occurred in 11% of patients (7 of 66) with previous CSH and in 1.5% (9 of 593) without CSH. CSH was the only independent predictor and was associated with a >7-fold increased risk of infection (hazard ratio: 7.7; 95% confidence interval: 2.9 to 20.5; p Conclusions CSH is associated with a significantly increased risk of infection requiring hospitalization within 1 year following cardiac implantable electronic device surgery. Strategies aimed at reducing hematomas may decrease the long-term risk of infection. (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial [BRUISE CONTROL]; NCT00800137 )

IMPORTANCE: Catheter ablation is effective in reducing atrial fibrillation (AF), but the association of ablation for AF with quality of life is unclear. OBJECTIVE: To evaluate whether the procedural outcome of ablation for AF is associated with quality of life (QOL) measures. DESIGN, SETTING, AND PARTICIPANTS: This was a prespecified secondary analysis of the Substrate and Trigger Ablation for Reduction of Atrial Fibrillation–Part II (STAR AF II) prospective randomized clinical trial, which compared 3 strategies for ablation of persistent AF. This analysis included 549 of the 589 patients enrolled in the trial who underwent ablation. Enrollment occurred at 35 centers in Europe, Canada, Australia, China, and Korea from November 2010 to July 2012. Data for the current study were analyzed on December 11, 2019. INTERVENTIONS: Patients underwent AF ablation with 1 of 3 ablation strategies: (1) pulmonary vein isolation (PVI), (2) PVI plus complex fractionated electrograms, or (3) PVI plus linear lesions. MAIN OUTCOMES AND MEASURES: Quality of life was assessed at baseline and at 6, 12, and 18 months after ablation for AF using the 36-Item Short Form Health Survey and the EuroQol Health-Related Quality of Life 5-Dimension 3-Level questionnaire. Scores were also converted to a physical health component score (PCS) and a mental health component score (MCS). Individual AF burden was calculated by the total time with AF from Holter monitors and the percentage of transtelephonic monitor recordings showing AF. RESULTS: Among the 549 patients included in this secondary analysis, QOL was assessed in 466 (85%) at baseline and at 6, 12, and 18 months after ablation for AF. The mean (SD) age of the study population was 60 (9) years; 434 (79%) individuals were men, and 417 (76%) had continuous AF for 6 months or more before ablation. The AF burden significantly decreased from a mean (SD) of 82% (36%) before ablation to 6.6% (23%) after ablation (P

Key Points Question What is the association between preablation atrial fibrillation (AF) episode duration and arrhythmia recurrence outcomes following AF ablation? Findings In this prespecified subanalysis of a randomized clinical trial of 346 patients with symptomatic AF undergoing catheter ablation, patients with AF episodes limited to less than 24 continuous hours had a significantly lower rate of recurrence following an ablation procedure. Arrhythmia recurrence and AF burden after ablation did not differ between patients with persistent AF (episodes lasting >7 days) and those with paroxysmal AF (episodes lasting 24 to 48 hours or 2 to 7 days). Meaning The findings of this study suggest that the contemporary definition of paroxysmal AF does not reflect post-AF ablation arrhythmia outcomes., This secondary analysis of a randomized clinical trial evaluates the association of baseline atrial fibrillation episode duration with post–atrial fibrillation ablation arrhythmia outcomes., Importance Contemporary guidelines recommend that atrial fibrillation (AF) be classified based on episode duration, with these categories forming the basis of therapeutic recommendations. While pragmatic, these classifications are not based on pathophysiologic processes and may not reflect clinical outcomes. Objective To evaluate the association of baseline AF episode duration with post-AF ablation arrhythmia outcomes. Design, Setting, and Participants The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (the Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration [CIRCA-DOSE] study), which took place at 8 Canadian centers. Between September 2014 and July 2017, 346 patients older than 18 years with symptomatic AF referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation. Data analysis was performed in September 2019. Exposure Before ablation, patients were classified based on their longest AF episode. Ablation consisted of circumferential pulmonary vein isolation using standard techniques. Main Outcomes and Measures Time to first recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) following ablation and AF burden (percentage of time in AF) on preablation and postablation continuous rhythm monitoring. Results The study included 346 patients (mean [SD] age, 59 [10] years; 231 [67.7%] men). Overall, 263 patients (76.0%) had AF episode duration of less than 24 hours; 25 (7.2%), 24 to 48 hours; 40 (11.7%), 2 to 7 days; and 18 (5.2%), more than 7 days. Documented recurrence of any atrial tachyarrhythmia following ablation was significantly lower in patients with baseline AF episode duration of less than 24 continuous hours compared with those with longer AF episodes (24 hours vs 24-48 hours: hazard ratio [HR], 0.41; 95% CI, 0.21-0.80; P = .009; 24 hours vs 2-7 days: HR, 0.25; 95% CI, 0.14-0.45; P 7 days: HR, 0.23; 95% CI, 0.09-0.55; P

Current guidelines recommend pulmonary vein isolation (PVI) as the cornerstone of atrial fibrillation (AF) ablation, including persistent AF (PerAF). Multiple examinations support cryoablation for paroxysmal AF, however, there are limited evaluations in PerAF patients. The STOP PERSISTENT AF study

BackgroundCatheter 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. MethodsWe 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. ResultsProcedure time was significantly shorter for pulmonary-vein isolation alone than for the other two procedures (P

Introduction Radiofrequency (RF) ablation is effective for slow pathway ablation, but carries a risk of inadvertent AV block requiring permanent pacing. By comparison, cryoablation with a 4 mm distal electrode catheter has not been reported to cause permanent AV block but has been shown to be less effective than RF ablation. We sought to define the safety and efficacy of a 6 mm distal electrode cryoablation catheter for slow pathway ablation in patients with atrioventricular nodal reentry tachycardia (AVNRT). Methods and results Twenty-six US and eight Canadian centers participated in the study. Patients with supraventricular tachycardia (SVT) thought likely to be AVNRT were enrolled. If AVNRT was inducible and confirmed to be the clinical SVT, then the slow pathway was targeted with a cryoablation catheter using a standardized protocol of best practices. Acute success was defined as inducibility of no more than one echo beat after cryoablation. Primary efficacy was defined as acute success and the absence of documented recurrent AVNRT over 6 months of follow-up. Primary safety was a composite of serious procedure-related adverse events and/or device-related complications. 397 subjects met enrollment criteria after the EP study and received cryoablation. Mean ablation procedure duration (including a waiting period) was 89 ± 40 min, and mean fluoroscopy time was 4.8 ± 5.9 min. Isoproterenol was administered before cryoablation in 53% and after the last lesion in 85% of cases. Acute procedural success was realized in 95% (378/397) of subjects. No subject received a permanent pacemaker due to AV block. The slow pathway could not be ablated in 19 subjects, including: 12 due to inefficacy, 2 due to transient AV block, and 5 due to both inefficacy and transient AV block. RF ablation was used in the same procedure in 11 of 19 failed subjects, and was ineffective in 3 subjects. Among the group with acute success, 10 subjects (2.7%) had documented recurrent AVNRT over the 6-month follow-up period, and all occurred within 3 months of the index cryoablation. Serious procedure-related adverse events occurred in 4 subjects (1.0%), including one each: tamponade, pulmonary embolism, femoral vein hemorrhage, and diagnostic EP catheter knotting. None of these serious adverse events were related to use of the cryoablation catheter. Overall, 93% of subjects had successful slow pathway ablation at 6 months with the study cryoablation catheter. Conclusions Cryoablation for AVNRT using a focal 6 mm catheter was safe and effective. It resulted in a low risk of recurrence over 6 months of follow-up with no incidence of AV block requiring permanent pacing. This article is protected by copyright. All rights reserved

Canadian electrophysiology (EP) fellowship programs have evolved in an ad hoc fashion over 30 years. This evolution has occurred in many fields in medicine and is natural when innovators and pioneers attract research fellows who help change the status quo from predominantly research to a predominantly clinical application and focus. Fellows not only push their supervisors and their centres into new areas of inquiry but also function at the most advanced level to encourage and teach junior trainees and to provide examples of excellence to residents, medical students, and other health professionals. Funding for fellows has never been provided in the traditional way through the Ministry of Health or the Ministry of Advanced Education. Each Canadian centre has over the years found novel ways to fund fellowship programs, and many centres have used value-adds from procurement programs. These sources of funding are eroding as provincial government agencies are beginning to assume procurement responsibilities and local flexibility to fund fellowships is lost. In particular, provincial government agencies feel that valuable financial resources should be restricted to Canadian trainees only, despite the international consensus that fellowship is an essential time for advanced trainees to travel abroad to acquire a broad a range of experience, learn new techniques and approaches, make lifelong research connections, and hopefully return home with these skills and expertise. This article summarizes the long history of EP fellowship training in Canada, as well as EP fellowship experiences at home and abroad by Canadian electrophysiologists, in an attempt to contextualize these new realities.

© 2016 Elsevier Ltd The issue of safety and longevity of engineering assets is of increasing importance because of their impact when disasters happen. This paper addresses a literature gap by examining the role of workplace relationships in employees' safety behaviour, and builds on the Resilience Engineering (RE) framework by examining some organisational culture factors affecting how employees behave. A Social Exchange framework is used to examine the impact of supervisor-employee relationships, employee commitment to safety practices, and the type of maintenance culture upon employees’ commitment to safety and safety outcomes. Survey data from 284 technical and engineering employees in engineering asset management organisations within Australia were analyzed using Structural Equation Modelling (SEM). Effective employee relationships with management and a proactive maintenance culture were associated with employee commitment to safety culture and safety outcomes. The findings provide empirical support for embedding an effective organisational culture focused on a proactive maintenance approach, along with ensuring employees are committed to safety processes, to ensure safety outcomes and also asset longevity. One study contribution is that good safety outcomes do not develop in a vacuum; instead they are built on effective workplace relationships. Therefore, SET helps to explain the forming of effective safety culture.

Heart, Lung and Circulation - In Press.Proof corrected by the author Available online since mercredi 19 octobre 2016

Early Recurrence in STAR-AF. Background: Early recurrences of atrial tachyarrhythmias (ERAT) are common after atrial fibrillation (AF) ablation, and predict late recurrences (LR). We sought to determine the impact of different ablation strategies on ERAT and LR. Methods and Results: The STAR-AF trial randomized 100 patients with paroxysmal or persistent AF to ablation of complex fractionated electrograms (CFAE) alone, pulmonary vein isolation (PVI) alone, or combined PVI + CFAE. Patients were followed for 12 months. ERAT was defined as any recurrence of AF, atrial tachycardia, or flutter (AT/AFL) >30 seconds during the first 3 months of follow-up. LR was defined as any recurrence of AF/AT/AFL >30 seconds 3–12 months post. Forty-nine patients experienced ERAT. The index ablation strategy was the only independent predictor of ERAT on multivariate analysis (HR 2.24 PVI vs PVI + CFAE; and HR 2.65 CFAE vs PVI + CFAE). Fifty-two patients experienced LR. The presence of ERAT (HR 3.23), the use of antiarrhythmic drug (AAD) in the first 3 months postablation (HR 2.85), and the index ablation strategy were independently associated with LR (HR 3.42 PVI vs PVI + CFAE; HR 4.72 CFAE vs PVI + CFAE). Thirty-five of 49 (71%) patients with ERAT and 17 (33%) of 51 patients without ERAT had LR (P < 0.0001). Among patients with ERAT, increased left atrium size (HR 1.08), the use of AAD in the first 3 months postablation (HR 2.86) and the index ablation strategy were independently associated with LR (HR 4.77 PVI vs PVI + CFAE; HR 4.45 CFAE vs PVI + CFAE). Conclusion: ERAT is common following AF ablation and is strongly associated with LR. Although CFAE ablation alone results in higher rates of early and LR, the addition of CFAE to PVI results in increased long-term success without an increase in ERAT. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1295-1301, December 2012)

Pulmonary vein (PV) isolation (PVI) has emerged as an effective therapy for paroxysmal atrial fibrillation (AF). However, AF recurs in up to 50% of patients, generally because of recovery of PV conduction. Adenosine given during the initial procedure may reveal dormant PV conduction, thereby identifying the need for additional ablation, leading to improved outcomes. The Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) study is a prospective multicentre randomized trial assessing the impact of adenosine-guided PVI in preventing AF recurrences.Patients undergoing a first PVI procedure for paroxysmal AF will be recruited. After standard PVI is completed, all patients will receive intravenous adenosine in an attempt to unmask dormant conduction. If dormant conduction is elicited, patients will be randomized to no further ablation (control group) or additional adenosine-guided ablation until dormant conduction is abolished. If no dormant conduction is revealed, randomly selected patients will be followed in a registry. The primary outcome is time to first documented symptomatic AF recurrence. Assuming that dormant conduction is present in 50% of patients post PVI and symptomatic AF recurs in 45% of controls, 244 patients with dormant conduction will be required to obtain90% power to detect a difference of 20%. Thus, a total of 488 patients will be enrolled and followed for 12 months.The ADVICE trial will assess whether a PVI strategy incorporating elimination of dormant conduction unmasked by intravenous adenosine will decrease the rate of recurrent symptomatic AF compared with standard PVI.

Although pulmonary vein isolation (PVI) is the cornerstone for catheter ablation of atrial fibrillation (AF), it is not known if additional ablation would improve outcomes, particularly for persistent AF [(1,2)][1]. Recently, the multicenter randomized STAR AF II (The Substrate and Trigger Ablation

Hospitalization due to heart failure (HF) exacerbation represents a major burden in health care and portends a poor long-term prognosis for patients. As a result, there is considerable interest to develop novel tools and strategies to better detect onset of volume overload, as HF hospitalizations may be reduced if appropriate interventions can be promptly delivered. One such innovation is the use of device-based diagnostic parameters in HF patients with implantable cardioverter defibrillators (ICD) and/or cardiac resynchronization therapy (CRT) devices. These diagnostic algorithms can effectively monitor and detect changes in patients' HF status, as well as predict one's risk of HF hospitalization. This paper will review the role of these device diagnostics parameters in the assessment and management of HF patients in ambulatory settings. In addition, the integration of these novel algorithms in existing HF disease management models will be discussed.

Background: Although the incidence of atrial fibrillation (AF) progressively increases with age, the vast majority of AF ablation is done in middle-aged patients. We evaluated the feasibility and safety of catheter ablation in patients older than 65years of age with paroxysmal and persistent AF. Methods: Out of a total of 230 consecutive AF ablation procedures, 45 patients were older than 65years of age and underwent 53 procedures. The ablation strategy consisted of wide-area circumferential lines around both ipsilateral pulmonary veins using a three-dimensional mapping system. Results: The mean age was 69 ± 3.5years (35 males). The mean duration for AF was 8.7 ± 6.5years. Thirty-nine had paroxysmal and six persistent AF despite use of 1.38 ± 0.77 antiarrhythmic drugs. All patients had a structurally normal heart. Eleven had systemic hypertension. Mean procedure time was 187 ± 33min. Acute procedural success rate with abolition of all pulmonary vein potentials was achieved in all patients. Pericardial tamponade requiring percutaneous drainage occurred in one (1.9%) patient. There were no cardioembolic events. Among the 43 patients whose clinical outcome was assessed at 6months, 34 (79%) had a significant reduction (>90%) of the total symptomatic AF burden, compared to pre-ablation, with a complete lack of symptomatic AF in 32 (74%) patients. The success rate was higher for patients with paroxysmal versus persistent AF (81 vs. 67%). Six patients (11%) underwent repeat procedures. Conclusions: Catheter ablation is a safe and effective treatment for patients over the age of 65years with symptomatic, drug-refractory AF. Therefore, patients should not be excluded from undergoing AF catheter ablation on the basis of age alone

Aims This multicentre, randomized trial compared three strategies of AF ablation: ablation of complex fractionated electrograms (CFE) alone, pulmonary vein isolation (PVI) alone, and combined PVI + CFE ablation, using standardized automated mapping software. Methods and results Patients with drug-refractory, high-burden paroxysmal (episodes >6 h, >4 in 6 months) or persistent atrial fibrillation (AF) were enrolled at eight centres. Patients (n = 100) were randomized to one of three arms. For CFE alone (n = 34), spontaneous/induced AF was mapped using validated, automated CFE software and all sites 30 s at 1 year. Patients (age 57 ± 10 years, LA size 42 ± 6 mm) were 35% persistent AF. In CFE, ablation terminated AF in 68%. Only 0.4 PVs per patient were isolated as a result of CFE. In PVI, 94% had all four PVs successfully isolated. In PVI + CFE, 94% had all four PVs isolated, 76% had inducible AF with additional CFE ablation, with 73% termination of AF. There were significantly more repeat procedures in the CFE arm (47%) vs. PVI (31%) or PVI + CFE (15%) (P = 0.01). After one procedure, PVI + CFE had a significantly higher freedom from AF (74%) compared with PVI (48%) and CFE (29%) (P = 0.004). After two procedures, PVI + CFE still had the highest success (88%) compared with PVI (68%) and CFE (38%) (P = 0.001). Ninety-six percent of these patients were off anti-arrhythmics. Complications were two tamponades, no PV stenosis, and no mortality. Conclusion In high-burden paroxysmal/persistent AF, PVI + CFE has the highest freedom from AF vs. PVI or CFE alone after one or two procedures. Complex fractionated electrogram alone has the lowest one and two procedure success rates with a higher incidence of repeat procedures. ClinicalTrials.gov identifier number NCT00367757.

Background Cryoablation is increasingly used to treat atrioventricular nodal reentrant tachycardia (AVNRT). It is unknown whether larger electrode-tip cryocatheters improve outcomes without compromising safety. Objective This study sought to compare acute and long-term success with 4-mm versus 6-mm electrode-tip cryocatheters for AVNRT. Methods We conducted a 2-group cohort study on 289 patients, age 45.5 ± 15.9 years (76.8% female), who underwent transcatheter cryoablation as a first-time procedure for AVNRT with 4-mm (N = 152) or 6-mm (N = 137) electrode-tip catheters. Results Acute procedural success was achieved in 90.7% (95% confidence interval 86.9% to 93.7%) with no difference between the 2 electrode-tip sizes. A shorter fluoroscopy time (16.1 ± 11.3 versus 20.3 ± 14.9 minutes, P = .0096) and trend toward briefer procedural duration (166.6 ± 49.1 versus 173.5 ± 53.0 minutes, P = NS) were noted with 6-mm electrode tips. Transient AV block occurred in 5.2%, with complete recovery in 4.4 ± 2.6 seconds. Over a median follow-up of 155 days, recurrences were less common with 6-mm electrode tips. Actuarial event-free survival rates at 1, 3, 6, and 12 months with 6-mm versus 4-mm electrode-tip cryocatheters were 96.7%, 93.4%, 91.9%, and 88.5% versus 89.9%, 87.0%, 84.1%, and 77.1%, respectively, with no recurrence thereafter (P = .0457). In multivariate analyses adjusting for baseline imbalances and medical therapy postablation, cryoablation with a 4-mm-tip catheter incurred a 2.5-fold increased risk of recurrence (hazard ratio 2.5, 95% confidence interval 1.0 to 6.1, P = .0420). Conclusion In patients with AVNRT, cryoablation with 6-mm electrode-tip catheters is safe and is associated with fewer recurrences on long-term follow-up compared with 4-mm electrode-tip cryocatheters.

Aims Predictors of recurrence following transcatheter cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) are currently unknown. Our objective was to explore predictors of recurrence postcryoablation for AVNRT, including the impact of procedural endpoints such as complete elimination of slow pathway conduction vs. persistent dual atrioventricular (AV) nodal physiology with or without echo beats. Methods and results A single center cohort study was performed on patients undergoing a first cryoablation procedure for AVNRT between May 1999 and December 2004. Cryoablation for AVNRT was attempted in 185 consecutive patients (79.2% female), age 43.1 + 15.2 years. Acute success was achieved in 170 (91.9%) patients with 4.4+ 3.5 cryoapplications and a total procedural duration of 2.8+ 0.8 h. Complete elimination of slow pathway conduction was noted in 47.6% of acutely successful interventions, absence of AV nodal echoes despite dual AV nodal physiology in 8.8%, and presence of echoes but no inducible AVNRT on and off isoproterenol in 43.5%. Actuarial recurrence-free survival following acutely successful cryoablation at 1, 3, 6, 12, and 24 months was 94.8, 93.1, 91.7, 90.8, and 90.8%, respectively. Independent predictors of recurrence were younger age (P ¼ 0.0045) and valvular heart disease (P ¼ 0.0186). The achieved procedural endpoint did not modulate recurrence rates. Eight patients (4.3%) experienced transient third degree AV block; none required permanent pacing. Conclusions As a cryoablation procedural outcome for AVNRT, persistent dual AV nodal physiology with or without echo beats is not associated with higher recurrence rates than complete elimination of dual AV nodal physiology if AVNRT remains non-inducible on and off isoproterenol.

Background— Early recurrences (ERs) of atrial tachyarrhythmia are common after catheter ablation of atrial fibrillation. A 3-month blanking period is recommended by current guidelines. This study sought to investigate the significance of ER during the first 3 months post ablation in predicting late recurrences and determine whether it varies according to timing. Methods and Results— A total of 401 patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation were followed for 12 months with transtelephonic monitoring in the ADVICE (Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination) trial. Patients with atrial tachyarrhythmia ≥30 s within the 3-month blanking period were stratified according to the timing of ER. A total of 179 patients (44.6%) experienced their last episode of ER during the first (n=53), second (n=44), or third (n=82) month of the 3-month blanking period. One-year freedom from symptomatic atrial tachyarrhythmia was 77.2% in patients without ER compared with 62.6%, 36.4%, and 7.8% in patients with ER 1, 2, and 3 months post ablation, respectively ( P P Conclusions— This study validates the use of a blanking period after catheter ablation for paroxysmal atrial fibrillation but calls into question the 90-day cut-off value. In particular, >90% of patients with ER during the third month post ablation experience late recurrence by 1 year. However, pending further study, repeat ablation before 90 days cannot be routinely advocated. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01058980.

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.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.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; p0·0001) and a hazard ratio of 0·44 (95% CI 0·31-0·64; p0·0001). 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.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.Canadian Institutes of Health Research, St Jude Medical, Biosense-Webster, and M Lachapelle (Montreal Heart Institute Foundation).

An increase in the prevalence of both atrial fibrillation and congestive heart failure is occurring in part because of the demographic shift toward an aging population. These two clinical entities often coexist in the same patient, resulting in the worsening of symptoms and prognosis, rendering their management even more challenging. A large clinical trial is currently examining whether a rhythm-control strategy is superior to a rate-control strategy in patients with congestive heart failure. New nonpharmacologic therapies such as pulmonary vein isolation are undergoing clinical investigation and may also alter the management of these patients. At present, therapy for atrial fibrillation in patients with congestive heart failure should aim first at controlling heart rate to provide symptomatic relief; then sinus rhythm should be restored if symptoms persist or if congestive heart failure worsens. For a more definitive approach in managing these patients, the authors await further clinical trial data.