Publications by authors named "Paul Novak"

53 Publications

Association Between Quality of Life and Procedural Outcome After Catheter Ablation for Atrial Fibrillation: A Secondary Analysis of a Randomized Clinical Trial.

JAMA Netw Open 2020 12 1;3(12):e2025473. Epub 2020 Dec 1.

Department of Cardiology, Southlake Regional Health Centre, University of Toronto, Newmarket, Ontario, Canada.

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 < .001). Significant improvements in mean (SD) PCS (68.3 [20.7] to 82.5 [18.6]) and MCS (35.3 [8.6] to 37.5 [7.6]) occurred 18 months after ablation (P < .05 for both). Significant QOL improvement occurred in all 3 study arms and regardless of AF recurrence, defined as AF episodes lasting more than 30 seconds: for no recurrence, mean (SD) PCS increased from 66.5 (20.9) to 79.1 (19.4) and MCS from 35.3 (8.7) to 37.7 (7.7); for recurrence, mean (SD) PCS increased from 70.2 (20.4) to 86.4 (16.8) and MCS from 35.3 (8.6) to 37.1 (7.4) (P < .05 for all). When outcome was defined by AF burden reduction, in patients with less than 70% reduction in AF burden, the increase in PCS was significantly less than in those with greater than 70% reduction, and only 3 of 8 subscales showed significant improvement.

Conclusions And Relevance: In this secondary analysis, decreases in AF burden after ablation for AF were significantly associated with improvements in QOL. Quality of life changes were significantly associated with the percentage of AF burden reduction after ablation.

Trial Registration: ClinicalTrials.gov Identifier: NCT01203748.
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http://dx.doi.org/10.1001/jamanetworkopen.2020.25473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7718606PMC
December 2020

Cryoablation or Drug Therapy for Initial Treatment of Atrial Fibrillation.

N Engl J Med 2021 01 16;384(4):305-315. Epub 2020 Nov 16.

From Vancouver General Hospital (J.G.A., M.B.), the University of British Columbia (J.G.A., M.W.D., M.B., S.L.), and the Centre for Cardiovascular Innovation (J.G.A., M.W.D.), Vancouver, Montreal Heart Institute, Université de Montréal (J.G.A., L.M.) and McGill University Health Centre (V.E.), Montreal, the University of Ottawa Heart Institute, Ottawa (G.A.W.), Université Laval, Quebec, QC (J.C.), Université de Sherbrooke, Sherbrooke, QC (J.-F.R.), Rouge Valley Centenary Hospital, Scarborough, ON (D.Y.), Western University, London, ON (A.S.), Southlake Regional Health Centre, University of Toronto, Newmarket, ON (Y.K., A.V.), Libin Cardiovascular Institute, University of Calgary, Calgary, AB (C.M.), St. Mary's General Hospital, Kitchener, ON (U.J.), Royal Jubilee Hospital, Victoria, BC (P.N.), Royal Alexandra Hospital, Edmonton, AB (E.L.), McMaster University, Hamilton, ON (G.A.), St. Michael's Hospital, University of Toronto, Toronto (P.A.), Dalhousie University, Halifax, NS (J.S.), and the University of Saskatchewan, Saskatoon, SK (S.W.) - all in Canada.

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 more effective in maintaining sinus rhythm.

Methods: We randomly assigned 303 patients with symptomatic, paroxysmal, untreated atrial fibrillation to undergo catheter ablation with a cryothermy balloon or to receive antiarrhythmic drug therapy for initial rhythm control. All the patients received an implantable cardiac monitoring device to detect atrial tachyarrhythmia. The follow-up period was 12 months. The primary end point was the first documented recurrence of any atrial tachyarrhythmia (atrial fibrillation, atrial flutter, or atrial tachycardia) between 91 and 365 days after catheter ablation or the initiation of an antiarrhythmic drug. The secondary end points included freedom from symptomatic arrhythmia, the atrial fibrillation burden, and quality of life.

Results: At 1 year, a recurrence of atrial tachyarrhythmia had occurred in 66 of 154 patients (42.9%) assigned to undergo ablation and in 101 of 149 patients (67.8%) assigned to receive antiarrhythmic drugs (hazard ratio, 0.48; 95% confidence interval [CI], 0.35 to 0.66; P<0.001). Symptomatic atrial tachyarrhythmia had recurred in 11.0% of the patients who underwent ablation and in 26.2% of those who received antiarrhythmic drugs (hazard ratio, 0.39; 95% CI, 0.22 to 0.68). The median percentage of time in atrial fibrillation was 0% (interquartile range, 0 to 0.08) with ablation and 0.13% (interquartile range, 0 to 1.60) with antiarrhythmic drugs. Serious adverse events occurred in 5 patients (3.2%) who underwent ablation and in 6 patients (4.0%) who received antiarrhythmic drugs.

Conclusions: Among patients receiving initial treatment for symptomatic, paroxysmal atrial fibrillation, there was a significantly lower rate of atrial fibrillation recurrence with catheter cryoballoon ablation than with antiarrhythmic drug therapy, as assessed by continuous cardiac rhythm monitoring. (Funded by the Cardiac Arrhythmia Network of Canada and others; EARLY-AF ClinicalTrials.gov number, NCT02825979.).
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http://dx.doi.org/10.1056/NEJMoa2029980DOI Listing
January 2021

Pulmonary Vein Stenosis After Atrial Fibrillation Ablation: Insights From the ADVICE Trial.

Can J Cardiol 2020 12 3;36(12):1965-1974. Epub 2020 Nov 3.

Montreal Health Innovations Coordinating Center (MHICC), Montreal, Quebec, Canada.

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.
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http://dx.doi.org/10.1016/j.cjca.2020.10.013DOI Listing
December 2020

Quality of Life and Health Care Utilization in the CIRCA-DOSE Study.

JACC Clin Electrophysiol 2020 08;6(8):935-944

Montreal Heart Institute, Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; Montreal Health Innovations Coordinating Centre, Montreal, Québec, Canada.

Objectives: This study evaluated the impact of contact force-guided radiofrequency ablation versus cryoballoon ablation on quality of life and health care utilization.

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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).
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http://dx.doi.org/10.1016/j.jacep.2020.04.017DOI Listing
August 2020

Repeat Atrial Fibrillation Ablation Procedures in the CIRCA-DOSE Study.

Circ Arrhythm Electrophysiol 2020 09 23;13(9):e008480. Epub 2020 Jul 23.

Department of Medicine, University of British Columbia, Vancouver, Canada (C.C.C., M.W.D., J.G.A.).

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http://dx.doi.org/10.1161/CIRCEP.120.008480DOI Listing
September 2020

Association of Atrial Fibrillation Episode Duration With Arrhythmia Recurrence Following Ablation: A Secondary Analysis of a Randomized Clinical Trial.

JAMA Netw Open 2020 07 1;3(7):e208748. Epub 2020 Jul 1.

Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Quebec, Canada.

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 < .001; 24 hours vs >7 days: HR, 0.23; 95% CI, 0.09-0.55; P < .001). Patients with preablation AF episodes limited to less than 24 continuous hours had a significantly lower median (interquartile range) postablation AF burden (0% [0%-0.1%]) compared with those with AF preablation episodes lasting 2-7 days (0.1% [0%-1.0%]; P = .003) and those with AF preablation episodes lasting more than 7 days (1.0% [0%-5.4%]; P = .008). There was no significant difference in arrhythmia recurrence or AF burden between the 3 groups with a baseline AF episode duration of longer than 24 hours.

Conclusions And Relevance: In this study, patients with AF episodes limited to less than 24 continuous hours had a significantly lower incidence of arrhythmia recurrence following AF ablation. This suggests that current guidelines for classification of AF may not reflect clinical outcomes.

Trial Registration: ClinicalTrials.gov Identifier: NCT01913522.
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http://dx.doi.org/10.1001/jamanetworkopen.2020.8748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333024PMC
July 2020

Cryoballoon ablation of pulmonary veins for persistent atrial fibrillation: Results from the multicenter STOP Persistent AF trial.

Heart Rhythm 2020 11 24;17(11):1841-1847. Epub 2020 Jun 24.

Johns Hopkins Medical Institutions, Baltimore, Maryland. Electronic address:

Background: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation to treat patients with symptomatic drug-refractory atrial fibrillation (AF).

Objective: The purpose of this study was to assess the safety and efficacy of PVI using the cryoballoon catheter to treat patients with persistent AF.

Methods: 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 episodes <6 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 at >40% and <13% 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.

Results: 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).

Conclusion: 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 episodes <6 months.
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http://dx.doi.org/10.1016/j.hrthm.2020.06.020DOI Listing
November 2020

Efficacy and Safety of Same-Day Discharge for Atrial Fibrillation Ablation.

JACC Clin Electrophysiol 2020 06 29;6(6):609-619. Epub 2020 Apr 29.

Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.

Objectives: The purpose of this study was to evaluate the efficacy, health care utilization, and safety of a same-day discharge protocol.

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.
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http://dx.doi.org/10.1016/j.jacep.2020.02.009DOI Listing
June 2020

Cryoballoon or Radiofrequency Ablation for Atrial Fibrillation Assessed by Continuous Monitoring: A Randomized Clinical Trial.

Circulation 2019 11 21;140(22):1779-1788. Epub 2019 Oct 21.

Montreal Heart Institute, Department of Medicine, Université de Montréal, Montreal, Canada (J.G.A., M.D., L.M., P.K.).

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 (=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 (=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 (=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 (=0.24). The CF-RF group had a significantly longer procedure duration but significantly shorter fluoroscopy exposure (<0.001 vs cryoballoon groups).

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.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.119.042622DOI Listing
November 2019

Sustained quality-of-life improvement post-cryoballoon ablation in patients with paroxysmal atrial fibrillation: Results from the STOP-AF Post-Approval Study.

Heart Rhythm 2020 03 10;17(3):485-491. Epub 2019 Oct 10.

Northwestern University, Chicago, Illinois.

Background: 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.

Objective: The purpose of this study was to evaluate the effects of cryoballoon ablation on long-term QoL.

Methods: 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.

Results: 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).

Conclusion: 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.
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http://dx.doi.org/10.1016/j.hrthm.2019.10.014DOI Listing
March 2020

Optimum lesion set and predictors of outcome in persistent atrial fibrillation ablation: a meta-regression analysis.

Europace 2019 Aug;21(8):1176-1184

International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, London, UK.

Aims: Ablation 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.
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http://dx.doi.org/10.1093/europace/euz108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6680367PMC
August 2019

Copper-containing glass ceramic with high antimicrobial efficacy.

Nat Commun 2019 04 30;10(1):1979. Epub 2019 Apr 30.

Corning Incorporated, Corning, NY, 14831, USA.

Hospital acquired infections (HAIs) and the emergence of antibiotic resistant strains are major threats to human health. Copper is well known for its high antimicrobial efficacy, including the ability to kill superbugs and the notorious ESKAPE group of pathogens. We sought a material that maintains the antimicrobial efficacy of copper while minimizing the downsides - cost, appearance and metallic properties - that limit application. Here we describe a copper-glass ceramic powder as an additive for antimicrobial surfaces; its mechanism is based on the controlled release of copper (I) ions (Cu) from cuprite nanocrystals that form in situ in the water labile phase of the biphasic glass ceramic. Latex paints containing copper-glass ceramic powder exhibit ≥99.9% reduction in S. aureus, P. aeruginosa, K. aerogenes and E. Coli colony counts when evaluated by the US EPA test method for efficacy of copper-alloy surfaces as sanitizer, approaching that of benchmark metallic copper.
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http://dx.doi.org/10.1038/s41467-019-09946-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6491652PMC
April 2019

Long-Term Outcomes After Ablation for Paroxysmal Atrial Fibrillation Using the Second-Generation Cryoballoon: Final Results From STOP AF Post-Approval Study.

JACC Clin Electrophysiol 2019 03 26;5(3):306-314. Epub 2018 Dec 26.

Massachusetts General Hospital, Boston, Massachusetts.

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).
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http://dx.doi.org/10.1016/j.jacep.2018.11.006DOI Listing
March 2019

Outcomes of paroxysmal atrial fibrillation ablation studies are affected more by study design and patient mix than ablation technique.

J Cardiovasc Electrophysiol 2018 11 30;29(11):1471-1479. Epub 2018 Oct 30.

Department of Medicine, Royal Jubilee Hospital, Victoria, Canada.

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 < 0.001) or in patients who had implantable loop recorders (by 21%; P = 0.006), rather than those with the less thorough periodic Holter monitoring.

Conclusions: Outcomes of AF ablation studies involving PVI are not affected by the technologies used to produce PVI. Neither do adjunctive lesion sets change the outcome. Achieving high success rates in these studies appears to be dependent more on patient mix and on the thoroughness of AF detection protocols. These should be carefully considered when quoting the success rates of AF ablation procedures that are derived from such studies.
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http://dx.doi.org/10.1111/jce.13745DOI Listing
November 2018

Intracardiac ablation for atrioventricular nodal reentry tachycardia using a 6 mm distal electrode cryoablation catheter: Prospective, multicenter, North American study (ICY-AVNRT STUDY).

J Cardiovasc Electrophysiol 2018 01 10;29(1):167-176. Epub 2017 Nov 10.

Baylor Heart and Vascular Institute, Dallas, TX, USA.

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 U.S. 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. Note that 397 subjects met enrollment criteria after the EP study and received cryoablation. Mean ablation procedure duration (including a waiting period) was 89 ± 40 minutes, and mean fluoroscopy time was 4.8 ± 5.9 minutes. Isoproterenol was administered before cryoablation in 53% and after the last lesion in 85% of cases. Acute procedural success was realized in 95% (378 of 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.
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http://dx.doi.org/10.1111/jce.13367DOI Listing
January 2018

Contact force sensing for ablation of persistent atrial fibrillation: A randomized, multicenter trial.

Heart Rhythm 2018 02 10;15(2):201-208. Epub 2017 Oct 10.

Southlake Regional Health Centre, Newmarket, Ontario, Canada. Electronic address:

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 <.001).

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.
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http://dx.doi.org/10.1016/j.hrthm.2017.10.010DOI Listing
February 2018

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.

BMJ Open 2017 Oct 5;7(10):e017970. Epub 2017 Oct 5.

Department of Medicine, Montreal Heart Institute, Université de Montréal, British Columbia, Canada.

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.
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http://dx.doi.org/10.1136/bmjopen-2017-017970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5639989PMC
October 2017

Effect of Aggressive Blood Pressure Control on the Recurrence of Atrial Fibrillation After Catheter Ablation: A Randomized, Open-Label Clinical Trial (SMAC-AF [Substrate Modification With Aggressive Blood Pressure Control]).

Circulation 2017 May 22;135(19):1788-1798. Epub 2017 Feb 22.

From Queen Elizabeth II Health Sciences Center and Dalhousie University, Halifax, Nova Scotia, Canada (R.P., J.L.S., C.G., M.G.); University of Ottawa Heart Institute, Ontario, Canada, (G.A.W.); Population Health Research Institute, Hamilton, Ontario, Canada (J.S.H.); Montreal Heart Institute, Quebec, Canada (J.-C.T., L.R.); Centre Hospitalier de L'Universite de Montreal, Quebec, Canada (I.G.); Centre Hospitalier Universitaire de Sherbrooke, Quebec, Canada (J.-F.R.); University of Western Ontario, London, Canada (L.G., A.S.L.T.); Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Canada (I.N.); Royal Jubilee Hospital, Victoria, British Columbia, Canada (P.N.); Ottawa Heart Institute, Ontario, Canada (D.B.); University Health Network, Toronto, Ontario, Canada (A.H.); Libin Cardiovascular Institute of Alberta, Calgary, Canada (S.B.W.); and St. Michael's Hospital, Toronto, Ontario, Canada (I.M.).

Background: Radiofrequency catheter ablation for atrial fibrillation has become an important therapy for AF; however, recurrence rates remain high. We proposed to determine whether aggressive blood pressure (BP) lowering prevents recurrent atrial fibrillation (AF) after catheter ablation in patients with AF and a high symptom burden.

Methods: We randomly assigned 184 patients with AF and a BP >130/80 mm Hg to aggressive BP (target <120/80 mm Hg) or standard BP (target <140/90 mm Hg) treatment before their scheduled AF catheter ablation. The primary outcome was symptomatic recurrence of AF/atrial tachycardia/atrial flutter lasting >30 seconds, determined 3 months beyond catheter ablation by a blinded end-point evaluation.

Results: The median follow-up was 14 months. At 6 months, the mean systolic BP was 123.2±13.2 mm Hg in the aggressive BP treatment group versus 135.4±15.7 mm Hg (<0.001) in the standard treatment group. The primary outcome occurred in 106 patients, 54 (61.4%) in the aggressive BP treatment group compared with 52 (61.2%) in the standard treatment group (hazard ratio=0.94; 95% confidence interval, 0.65-1.38; =0.763). In the prespecified subgroup analysis of the influence of age, patients ≥61 years of age had a lower primary outcome event rate with aggressive BP (hazard ratio=0.58; 95% confidence interval, 0.34-0.97; =0.013). There was a higher rate of hypotension requiring medication adjustment in the aggressive BP group (26% versus 0%).

Conclusions: In this study, this duration of aggressive BP treatment did not reduce atrial arrhythmia recurrence after catheter ablation for AF but resulted in more hypotension.

Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00438113.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.116.026230DOI Listing
May 2017

Impact of acute atrial fibrillation termination and prolongation of atrial fibrillation cycle length on the outcome of ablation of persistent atrial fibrillation: A substudy of the STAR AF II trial.

Heart Rhythm 2017 04 21;14(4):476-483. Epub 2016 Dec 21.

Southlake Regional Health Centre, Newmarket, Ontario, Canada. Electronic address:

Background: 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.

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.
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http://dx.doi.org/10.1016/j.hrthm.2016.12.033DOI Listing
April 2017

Atrioventricular Nodal Non Re-Entrant Tachycardia (AVNNT).

Heart Lung Circ 2017 May 30;26(5):524-525. Epub 2016 Aug 30.

Royal Jubilee Hospital, Victoria, BC, Canada; Victoria Cardiac Arrhythmia Trials (VCAT), Victoria BC, Canada.

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http://dx.doi.org/10.1016/j.hlc.2016.07.014DOI Listing
May 2017

Redefining the Blanking Period After Catheter Ablation for Paroxysmal Atrial Fibrillation: Insights From the ADVICE (Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination) Trial.

Circ Arrhythm Electrophysiol 2016 08;9(8)

For the author affiliations, please see the Appendix.

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<0.0001). Receiver operating curve analyses revealed a strong correlation between the timing of ER and late recurrence (area under the curve 0.82, P<0.0001). Corresponding hazard ratios for ER during the first, second, and third months were 1.84, 4.45, and 9.64, respectively.

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.
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http://dx.doi.org/10.1161/CIRCEP.115.003909DOI Listing
August 2016

Ejectable loop recorders?

Heart Rhythm 2016 10 31;13(10):2105. Epub 2016 May 31.

Royal Jubilee Hospital and Victoria Cardiac Arrhythmia Trials, Victoria, British Columbia, Canada.

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http://dx.doi.org/10.1016/j.hrthm.2016.05.027DOI Listing
October 2016

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

Lancet 2015 Aug 23;386(9994):672-9. Epub 2015 Jul 23.

Montreal Heart Institute and Montreal Health Innovations Coordinating Centre, Department of Medicine, Université de Montréal, Montreal, QC, Canada.

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

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

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

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

Funding: Canadian Institutes of Health Research, St Jude Medical, Biosense-Webster, and M Lachapelle (Montreal Heart Institute Foundation).
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http://dx.doi.org/10.1016/S0140-6736(15)60026-5DOI Listing
August 2015

Approaches to catheter ablation for persistent atrial fibrillation.

N Engl J Med 2015 May;372(19):1812-22

From Southlake Regional Health Centre, Newmarket, ON (A.V.), Montreal Heart Institute, Montreal (L.M.), McMaster University, Hamilton, ON (C.A.M.), and Royal Jubilee Hospital, Victoria, BC (P.N.) - all in Canada; Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China (C.J.); John Radcliffe Hospital, Oxford, United Kingdom (T.R.B.); Haukeland University Hospital, Bergen, Norway (J.C.); the German Heart Center, Munich (I.D.), and Charité Campus Virchow-Klinikum, Berlin (W.H.) - both in Germany; Ospedale M. Bufalini, Cesena (R.M.), Presidio Ospedaliero Pineta Grande, Castel Volturno (S.N.), and Ospedale Santa Croce e Carle, Cuneo (E.M.) - all in Italy; Hollywood Private Hospital, Perth, WA (R.W.), and the University of Adelaide and Royal Adelaide Hospital, Adelaide, SA (P.S.) - all in Australia; and Clinique Pasteur Toulouse, Toulouse, France (J.-P.A.).

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

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

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

Conclusions: Among patients with persistent atrial fibrillation, we found no reduction in the rate of recurrent atrial fibrillation when either linear ablation or ablation of complex fractionated electrograms was performed in addition to pulmonary-vein isolation. (Funded by St. Jude Medical; ClinicalTrials.gov number, NCT01203748.).
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http://dx.doi.org/10.1056/NEJMoa1408288DOI Listing
May 2015

Charting a course for cardiac electrophysiology training in Canada: the vital role of fellows in advanced cardiovascular care.

Can J Cardiol 2013 Nov;29(11):1527-30

Royal Jubilee Hospital, Victoria, British Columbia, Canada. Electronic address:

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.
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http://dx.doi.org/10.1016/j.cjca.2013.08.019DOI Listing
November 2013

Relationship of quality of life with procedural success of atrial fibrillation (AF) ablation and postablation AF burden: substudy of the STAR AF randomized trial.

Can J Cardiol 2013 Oct 26;29(10):1211-7. Epub 2013 Aug 26.

Ospedale Regionale di Treviso, Treviso, Italy.

Background: The Substrate and Trigger Ablation for Reduction of Atrial Fibrillation (STAR AF) trial compared 3 strategies for ablation of high-burden paroxysmal/persistent atrial fibrillation (AF): complex fractionated electrogram ablation (CFE), pulmonary vein isolation (PVI), or a combined approach (PVI with CFE). This subanalysis aimed to identify the effect on quality of life (QOL) conferred by ablation strategy, AF recurrence, and type of AF.

Methods: The STAR AF study (n = 100) found 88%, 68%, and 38% freedom from AF > 30 seconds at 12 months for PVI with CFE, PVI, and CFE approaches, respectively (P = 0.001). QOL was measured before ablation and at 12 months after ablation using the Short-Form Health Survey (SF-36) scale. Transformed scores were calculated for each of the 8 subscales of the SF-36, and also converted to physical health and mental health component scores.

Results: There was a significant improvement in physical health (24%) and mental health (19%) component scores from baseline to 12 months after ablation (P < 0.05 for both). Significant QOL improvements were seen for all 3 ablation strategies despite differences in outcome. QOL measurements also improved regardless of AF recurrence, except in patients with an AF burden in the highest quartile (median 27.2 hours per month). AF recurrence independently predicted aggregate QOL score.

Conclusions: QOL after AF ablation improves regardless of procedural outcome. QOL scores were only negatively affected in patients with a high symptomatic burden of arrhythmia recurrence suggesting that significant reduction in AF burden can improve QOL without total elimination of AF.
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http://dx.doi.org/10.1016/j.cjca.2013.06.006DOI Listing
October 2013

Discerning the incidence of symptomatic and asymptomatic episodes of atrial fibrillation before and after catheter ablation (DISCERN AF): a prospective, multicenter study.

JAMA Intern Med 2013 Jan;173(2):149-56

Department of Cardiology, Southlake Regional Health Centre, 105-712 Davis Dr, Newmarket, ON L3Y 8C3, Canada.

Background: The DISCERN AF study (Discerning Symptomatic and Asymptomatic Episodes Pre and Post Radiofrequency Ablation of Atrial Fibrillation) monitored atrial fibrillation (AF) using an implantable cardiac monitor (ICM) to assess the incidence and predictors of asymptomatic AF before and after catheter ablation.

Methods: Patients with symptomatic AF underwent implantation of an ICM with an automated AF detection algorithm 3 months before and 18 months after ablation. Patients kept a standardized diary to record symptoms of arrhythmia, and ICM data were downloaded every 3 months. All episodes were blindly adjudicated and correlated with the diary. Asymptomatic recurrences were ICM episodes of 2 minutes or longer with no associated diary symptoms.

Results: Fifty patients had 2355 ICM episodes. Of these, 69.0% were true AF/atrial flutter (AFL)/atrial tachycardia (AT); 16.0%, sinus with extrasystoles; 11.0%, artifact; and 4.0%, sinus arrhythmia. Total AF/AFL/AT burden was reduced by 86% from a mean (SD) of 2.0 (0.5) h/d per patient before to 0.3 (0.2) h/d per patient after ablation (P < .001), and 56.0% of all episodes were asymptomatic. The ratio of asymptomatic to symptomatic AF episodes increased after ablation from 1.1 to 3.7 (P = .002). By symptoms alone, 29 of 50 patients (58%) were free of AF/AFL/AT after ablation compared with 23 of 50 (46%) using ICM-detected AF/AFL/AT recurrence. Asymptomatic episodes were more likely AFL/AT and were significantly shorter and slower, with lower heart rate variability. However, the postablation state was the strongest independent predictor of asymptomatic AF.

Conclusions: The ratio of asymptomatic to symptomatic AF episodes increased from 1.1 before to 3.7 after ablation. Postablation state is the strongest predictor of asymptomatic AF. Symptoms alone underestimate postablation AF burden, with 12% of patients having asymptomatic recurrences only.

Trial Registration: clinicaltrials.gov Identifier: NCT00745706.
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http://dx.doi.org/10.1001/jamainternmed.2013.1561DOI Listing
January 2013
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