Publications by authors named "Mario Talajic"

184 Publications

Variant Re-interpretation in Survivors of Cardiac Arrest with Preserved Ejection Fraction (CASPER Registry) by Clinicians and Clinical Commercial Laboratories.

Circ Genom Precis Med 2021 May 7. Epub 2021 May 7.

Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.

- Following an unexplained cardiac arrest, clinical genetic testing is increasingly becoming standard of care. Periodic review of variant classification is required, as re-interpretation can change the diagnosis, prognosis, and management of patients and their relatives. - This study aimed to develop and validate a standardized algorithm to facilitate clinical application of the 2015 American College of Medical Genetics and Association for Molecular Pathology (ACMG-AMP) guidelines for the interpretation of genetic variants. The algorithm was applied to genetic results in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER), to assess the rate of variant re-classification over time. Variant classifications were then compared to the classifications of two commercial laboratories to determine the rate and identify sources of variant interpretation discordance. - Thirty-one percent of participants (40/131) had at least one genetic variant with a clinically significant reclassification over time. Variants of uncertain significance were more likely to be downgraded (73%) to benign than upgraded to pathogenic (27%, p= 0.03). For the second part of the study, 50% (70/139) of variants had discrepant interpretations (excluding benign variants), provided by at least one team. - Periodic review of genetic variant classification is a key component of follow-up care given rapidly changing information in the field. There is potential for clinical care gaps with discrepant variant interpretations, based in the interpretation and application of current guidelines. The development of gene and disease specific guidelines and algorithms may provide an opportunity to further standardize variant interpretation reporting in the future.
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http://dx.doi.org/10.1161/CIRCGEN.120.003235DOI Listing
May 2021

Shared genetic pathways contribute to risk of hypertrophic and dilated cardiomyopathies with opposite directions of effect.

Nat Genet 2021 02 25;53(2):128-134. Epub 2021 Jan 25.

Department of Epidemiology and Biostatistics, Imperial College London, London, UK.

The heart muscle diseases hypertrophic (HCM) and dilated (DCM) cardiomyopathies are leading causes of sudden death and heart failure in young, otherwise healthy, individuals. We conducted genome-wide association studies and multi-trait analyses in HCM (1,733 cases), DCM (5,521 cases) and nine left ventricular (LV) traits (19,260 UK Biobank participants with structurally normal hearts). We identified 16 loci associated with HCM, 13 with DCM and 23 with LV traits. We show strong genetic correlations between LV traits and cardiomyopathies, with opposing effects in HCM and DCM. Two-sample Mendelian randomization supports a causal association linking increased LV contractility with HCM risk. A polygenic risk score explains a significant portion of phenotypic variability in carriers of HCM-causing rare variants. Our findings thus provide evidence that polygenic risk score may account for variability in Mendelian diseases. More broadly, we provide insights into how genetic pathways may lead to distinct disorders through opposing genetic effects.
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http://dx.doi.org/10.1038/s41588-020-00762-2DOI Listing
February 2021

A randomized ablation-based atrial fibrillation rhythm control versus rate control trial in patients with heart failure and high burden atrial fibrillation: The RAFT-AF trial rationale and design.

Am Heart J 2021 04 17;234:90-100. Epub 2021 Jan 17.

Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.

Heart failure (HF) and atrial fibrillation (AF) are 2 cardiac conditions that are increasing in prevalence and incidence. The 2 conditions frequently coexist, and are associated with increased morbidity and mortality. Catheter ablation of AF has been successfully performed in patients with HF, with an improvement in HF and AF, when compared to amiodarone, but further data is required to compare this to rate control. OBJECTIVES: The primary objective is to determine whether AF treated by catheter ablation, with or without antiarrhythmic drugs reduces all-cause mortality and hospitalizations for HF as compared with rate control in patients with HF and a high burden AF. METHODS: This is a multi-center prospective randomized open blinded endpoint (PROBE) study. Patients with NYHA class II-III HF (HF with reduced ejection fraction (<35%) or HF with preserved ejection fraction), and high burden AF are included in the trial. Patients are randomized to either rate control or catheter ablation-based AF rhythm control in a 1:1 ratio. Patients in the rate control group receive optimal HF therapy and rate control measures to achieve a resting hazard ratio (HR) < 80 bpm and 6-minute walk HR < 110 bpm. Patients randomized to catheter ablation-based AF rhythm control group receive optimal HF therapy and one or more aggressive catheter ablation, which include PV antral ablation and LA substrate ablation with or without adjunctive antiarrhythmic drug. The primary outcome is a composite of all-cause mortality and hospitalization for heart failure defined as an admission to a health care facility. The sample size is 600. Enrolment has been completed.
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http://dx.doi.org/10.1016/j.ahj.2021.01.012DOI Listing
April 2021

The Hearts in Rhythm Organization: A Canadian National Cardiogenetics Network.

CJC Open 2020 Nov 29;2(6):652-662. Epub 2020 May 29.

Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.

Background: The Hearts in Rhythm Organization (HiRO) is a team of Canadian inherited heart rhythm and cardiomyopathy experts, genetic counsellors, nurses, researchers, patients, and families dedicated to the detection of inherited arrhythmias and cardiomyopathies, provision of best therapies, and protection from the tragedy of sudden cardiac arrest.

Methods: Recently, existing disease-specific registries were merged into the expanded National HiRO Registry, creating a single common data set for patients and families with inherited conditions that put them at risk for sudden death in Canada. Eligible patients are invited to participate in the registry and optional biobank from 20 specialized cardiogenetics clinics across Canada.

Results: Currently, there are 4700 participants enrolled in the National HiRO Registry, with an average of 593 participants enrolled annually over the past 5 years. The capacity to enable knowledge translation of research findings is built into HiRO's organizational infrastructure, with 3 additional working groups (HiRO Clinical Care Committee, HiRO Active Communities Committee, and HiRO Annual Symposium Committee), supporting the organization's current goals and priorities as set alongside patient partners.

Conclusion: The National HiRO Registry aims to be an integrated research platform to which researchers can pose novel research questions leading to a better understanding, detection, and clinical care of those living with inherited heart rhythm and cardiomyopathy conditions and ultimately to prevent sudden cardiac death.
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http://dx.doi.org/10.1016/j.cjco.2020.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710951PMC
November 2020

Sudden Cardiac Death Prediction in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Collaboration.

Circ Arrhythm Electrophysiol 2021 Jan 9;14(1):e008509. Epub 2020 Dec 9.

Department of Medicine, Division of Cardiology (J.C.-T., W.W., A.B., C.T., B.M., S.C., J.E.C., D.P.J., H.T., H.C., C.A.J.), Johns Hopkins Hospital, Baltimore, MD.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with ventricular arrhythmias (VA) and sudden cardiac death (SCD). A model was recently developed to predict incident sustained VA in patients with ARVC. However, since this outcome may overestimate the risk for SCD, we aimed to specifically predict life-threatening VA (LTVA) as a closer surrogate for SCD.

Methods: We assembled a retrospective cohort of definite ARVC cases from 15 centers in North America and Europe. Association of 8 prespecified clinical predictors with LTVA (SCD, aborted SCD, sustained, or implantable cardioverter-defibrillator treated ventricular tachycardia >250 beats per minute) in follow-up was assessed by Cox regression with backward selection. Candidate variables included age, sex, prior sustained VA (≥30s, hemodynamically unstable, or implantable cardioverter-defibrillator treated ventricular tachycardia; or aborted SCD), syncope, 24-hour premature ventricular complexes count, the number of anterior and inferior leads with T-wave inversion, left and right ventricular ejection fraction. The resulting model was internally validated using bootstrapping.

Results: A total of 864 patients with definite ARVC (40±16 years; 53% male) were included. Over 5.75 years (interquartile range, 2.77-10.58) of follow-up, 93 (10.8%) patients experienced LTVA including 15 with SCD/aborted SCD (1.7%). Of the 8 prespecified clinical predictors, only 4 (younger age, male sex, premature ventricular complex count, and number of leads with T-wave inversion) were associated with LTVA. Notably, prior sustained VA did not predict subsequent LTVA (=0.850). A model including only these 4 predictors had an optimism-corrected C-index of 0.74 (95% CI, 0.69-0.80) and calibration slope of 0.95 (95% CI, 0.94-0.98) indicating minimal over-optimism.

Conclusions: LTVA events in patients with ARVC can be predicted by a novel simple prediction model using only 4 clinical predictors. Prior sustained VA and the extent of functional heart disease are not associated with subsequent LTVA events.
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http://dx.doi.org/10.1161/CIRCEP.120.008509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7834666PMC
January 2021

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation.

Can J Cardiol 2020 12 22;36(12):1847-1948. Epub 2020 Oct 22.

Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada.

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.
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http://dx.doi.org/10.1016/j.cjca.2020.09.001DOI Listing
December 2020

Hein Wellens and Electrical Stimulation of the Heart in The Netherlands: The Canadian Contingent.

Can J Cardiol 2021 Feb 7;37(2):180-181. Epub 2020 Nov 7.

Institut universitaire de cardiologie et de pneumologie de Québec, Québec City, Québec, Canada.

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http://dx.doi.org/10.1016/j.cjca.2020.10.016DOI Listing
February 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

Missense variants in the spectrin repeat domain of DSP are associated with arrhythmogenic cardiomyopathy: A family report and systematic review.

Am J Med Genet A 2020 10 18;182(10):2359-2368. Epub 2020 Aug 18.

Cardiovascular Genetics Center, Montreal Heart Institute and Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.

Rare loss of function variants in DSP, which codes for the desmosomal protein desmoplakin, have been implicated in dilated and arrhythmogenic right ventricular cardiomyopathies. We present a family with arrhythmogenic cardiomyopathy associated with a novel missense variant in DSP (NM_004415.4): c.877G>A, p.(Glu293Lys). The phenotype is characterized by predominant involvement of the left ventricle with systolic dysfunction, fibrosis, and life-threatening arrhythmias. We performed a systematic review of literature collecting all cardiomyopathy cases with rare missense variants in DSP. We demonstrate that the distribution of missense variants across the protein domains in cardiomyopathy cases differs from that in gnomAD (p = .04), with a case enrichment of rare missense variants in the spectrin repeat domain (36/78 [46%] in cases vs. 449/1495 [30%] in gnomAD; p = .004). Our findings highlight the predominance of cardiac arrhythmia and left ventricular involvement in desmoplakin cardiomyopathy and pinpoint to a potential mutation hotspot in DSP thereby facilitating missense variant interpretation in the diagnostic setting.
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http://dx.doi.org/10.1002/ajmg.a.61799DOI Listing
October 2020

Infections Associated with Resterilized Pacemakers and Defibrillators.

N Engl J Med 2020 05;382(19):1823-1831

From the Montreal Heart Institute, Université de Montréal, Montreal (T.F.K., M.-A.L., C.V., R.C., D.R., M.T., M.D., B.T., P.G.G., L.R., K.D., B.M., R.T., J.C.-T., L.M., P.K.); Instituto Nacional de Cardiologia, Ignacio Chavez, Mexico City (S.N.); the Dominican Institute of Cardiology, Santo Domingo, Dominican Republic (F.V.B.); Clínicas Médicas las Américas, Guatemala City, Guatemala (F.S.O.); and Cardiología Hospital General del Sur, Choluteca (N.E.L.O.), and Instituto Nacional Cardiopulmonar (G.S.M.) and Medicina Interna-Programación de Marcapaso Definitivo, Instituto Nacional Cardiopulmonar, Tegucigalpa (C.A.C.) - all in Honduras.

Background: Access to pacemakers and defibrillators is problematic in places with limited resources. Resterilization and reuse of implantable cardiac devices obtained post mortem from patients in wealthier nations have been undertaken, but uncertainty around the risk of infection is a concern.

Methods: A multinational program was initiated in 1983 to provide tested and resterilized pacemakers and defibrillators to underserved nations; a prospective registry was established in 2003. Patients who received reused devices in this program were matched in a 1:3 ratio with control patients who received new devices implanted in Canada. The primary outcome was infection or device-related death, with mortality from other causes modeled as a competing risk.

Results: Resterilized devices were implanted in 1051 patients (mean [±SD] age, 63.2±18.5 years; 43.6% women) in Mexico (36.0%), the Dominican Republic (28.1%), Guatemala (26.6%), and Honduras (9.3%). Overall, 85% received pacemakers and 15% received defibrillators, with one (55.5%), two (38.8%), or three (5.7%) leads. Baseline characteristics did not differ between these patients and the 3153 matched control patients. At 2 years of follow-up, infections had occurred in 21 patients (2.0%) with reused devices and in 38 (1.2%) with new devices (hazard ratio, 1.66; 95% confidence interval, 0.97 to 2.83; P = 0.06); there were no device-related deaths. The most common implicated pathogens were and .

Conclusions: Among patients in underserved countries who received a resterilized and reused pacemaker or defibrillator, the incidence of infection or device-related death at 2 years was 2.0%, an incidence that did not differ significantly from that seen among matched control patients with new devices in Canada.
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http://dx.doi.org/10.1056/NEJMoa1813876DOI Listing
May 2020

Risk stratification for ventricular arrhythmias and sudden cardiac death in arrhythmogenic right ventricular cardiomyopathy: an update.

Expert Rev Cardiovasc Ther 2019 Sep 21;17(9):645-651. Epub 2019 Aug 21.

Department of Medicine, Montreal Heart Institute , Montreal , Quebec , Canada.

: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined disease associated with a significant risk of ventricular arrhythmias and sudden cardiac death (SCD). Implantable cardioverter-defibrillators (ICDs) are the only effective preventive measure. Over the past 30 years, much effort has been invested in determining predictors of adverse arrhythmic events in these patients. : This review summarizes available evidence on risk stratification for ARVC, with an emphasis on recent research findings. While efforts are ongoing to define risk predictors, several recent publications have synthetized and built on this knowledge base. A recently published meta-analysis has clarified the strongest predictors of ventricular arrhythmias in ARVC, which vary depending on the population included. Three management guidelines/expert consensus documents have integrated the previously described risk predictors into proposed ICD recommendations. Furthermore, a risk prediction model has allowed the integration of multiple risk factors to provide individualized risk prediction and to inform shared-decision making regarding ICD implantation. : Over the past few years, knowledge of risk prediction in ARVC has been consolidated and refined. Further improvements may be made by the considering additional predictors such as exercise and by targeting more specific surrogate outcomes for SCD.
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http://dx.doi.org/10.1080/14779072.2019.1657831DOI Listing
September 2019

Blinded Randomized Trial of Anticoagulation to Prevent Ischemic Stroke and Neurocognitive Impairment in Atrial Fibrillation (BRAIN-AF): Methods and Design.

Can J Cardiol 2019 08 7;35(8):1069-1077. Epub 2019 May 7.

Department of Medicine, Université de Montréal, Montréal, Québec, Canada.

Background: Compelling evidence showing a link between atrial fibrillation (AF) and cognitive decline and dementia is accumulating.

Methods: Blinded Randomized Trial of Anticoagulation to Prevent Ischemic Stroke and Neurocognitive Impairment in Atrial Fibrillation (BRAIN-AF) is a prospective, multicentric, double-blind, randomized-controlled trial, recruiting patients with nonvalvular AF and a low risk of stroke. Patients with a high risk of bleeding will be excluded from the study. Participants will be randomized to receive either rivaroxaban (15 mg daily) or standard of care (placebo in patients without vascular disease or acetylsalicylic acid 100 mg daily in patients with vascular disease).

Results: The primary outcome is the composite of stroke, transient ischemic attack, and cognitive decline (defined by a decrease in the Montreal Cognitive Assessment score ≥ 3 at any follow-up visit after baseline). Approximately 3250 patients will be enrolled in approximately 130 clinical sites until 609 adjudicated primary outcome events have occurred.

Conclusions: BRAIN-AF determines whether oral anticoagulation therapy with rivaroxaban compared with standard of care reduces the risk of stroke, transient ischemic attack, or cognitive decline in patients with nonvalvular AF and a low risk of stroke.
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http://dx.doi.org/10.1016/j.cjca.2019.04.022DOI Listing
August 2019

Comparison of Ajmaline and Procainamide Provocation Tests in the Diagnosis of Brugada Syndrome.

JACC Clin Electrophysiol 2019 04 27;5(4):504-512. Epub 2019 Mar 27.

Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

Objectives: The authors studied the response rates and relative sensitivity of the most common agents used in the sodium-channel blocker (SCB) challenge.

Background: A type 1 Brugada electrocardiographic pattern precipitated by an SCB challenge confers a diagnosis of Brugada syndrome.

Methods: Patients undergoing an SCB challenge were prospectively enrolled across Canada and the United Kingdom. Patients with no prior cardiac arrest and family histories of sudden cardiac death or Brugada syndrome were included.

Results: Four hundred twenty-five subjects underwent SCB challenge (ajmaline, n = 331 [78%]; procainamide, n = 94 [22%]), with a mean age of 39 ± 15 years (54% men). Baseline non-type 1 Brugada ST-segment elevation was present in 10%. A total of 154 patients (36%) underwent signal-averaged electrocardiography, with 41% having late potentials. Positive results were seen more often with ajmaline than procainamide infusion (26% vs. 4%, p < 0.001). On multivariate analysis, baseline non-type 1 Brugada ST-segment elevation (odds ratio [OR]: 6.92; 95% confidence interval [CI]: 3.15 to 15.2; p < 0.001) and ajmaline use (OR: 8.76; 95% CI: 2.62 to 29.2; p < 0.001) were independent predictors of positive results to SCB challenge. In the subgroup undergoing signal-averaged electrocardiography, non-type 1 Brugada ST-segment elevation (OR: 9.28; 95% CI: 2.22 to 38.8; p = 0.002), late potentials on signal-averaged electrocardiography (OR: 4.32; 95% CI: 1.50 to 12.5; p = 0.007), and ajmaline use (OR: 12.0; 95% CI: 2.45 to 59.1; p = 0.002) were strong predictors of SCB outcome.

Conclusions: The outcome of SCB challenge was significantly affected by the drug used, with ajmaline more likely to provoke a type 1 Brugada electrocardiographic pattern compared with procainamide. Patients undergoing SCB challenge may have contrasting results depending on the drug used, with potential clinical, psychosocial, and socioeconomic implications.
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http://dx.doi.org/10.1016/j.jacep.2019.01.026DOI Listing
April 2019

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy.

Eur Heart J 2019 06;40(23):1850-1858

Department of Genetics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands.

Aims: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients.

Methods And Results: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.6% reduction of ICD placements with the same proportion of protected patients (P < 0.001).

Conclusion: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).
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http://dx.doi.org/10.1093/eurheartj/ehz103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6568197PMC
June 2019

Early Repolarization Pattern Inheritance in the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER).

JACC Clin Electrophysiol 2018 11 29;4(11):1473-1479. Epub 2018 Aug 29.

University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

Objectives: This study explored early repolarization (ER) pattern inheritance between survivors of unexplained cardiac arrest (UCA) and their first-degree relatives.

Background: ER is considered a factor that confers an increased risk of sudden death. A monogenic explanation for ER is seldom evident after cascade screening.

Methods: UCA survivors and their first-degree relatives enrolled in the CASPER (Cardiac Arrest Survivors With Preserved Ejection Fraction Registry) were included in the study. ER was defined and characterized according to accepted criteria. Logistic regression was performed to explore the association between ER status in the UCA survivor and first-degree relative groups based on the presence of an ER pattern in their related family members after adjusting for age, sex, and ethnicity.

Results: A total of 289 patients from 14 Canadian sites were studied (age: 43.0 ± 15.9 years; 148 women), and 945 electrocardiograms were analyzed. Seventy-five patients had the ER pattern. There was a significantly higher prevalence of the ER pattern in UCA survivors who had first-degree relatives with the ER pattern (adjusted odds ratio: 5.79; 95% confidence intervals [CIs]: 1.79 to 18.7). There was also a nonsignificant higher prevalence of the ER pattern in first-degree relatives of UCA survivors with the ER pattern (OR: 2.43; 95% CI: 0.70 to 8.43). The highest prevalence of the ER pattern was seen in first-degree relatives of UCA survivors with ER syndrome (29%).

Conclusions: The ER pattern appeared to be more common among UCA survivors and first-degree relatives whose related family members had similar changes on electrocardiography, which suggested that genetically complex factors contribute to electrocardiographic patterns that predispose to cardiac arrest.
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http://dx.doi.org/10.1016/j.jacep.2018.07.001DOI Listing
November 2018

2018 Focused Update of the Canadian Cardiovascular Society Guidelines for the Management of Atrial Fibrillation.

Can J Cardiol 2018 11;34(11):1371-1392

Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada. Electronic address:

The Canadian Cardiovascular Society (CCS) Atrial Fibrillation Guidelines Committee provides periodic reviews of new data to produce focused updates that address clinically important advances in atrial fibrillation (AF) management. This 2018 Focused Update addresses: (1) anticoagulation in the context of cardioversion of AF; (2) the management of antithrombotic therapy for patients with AF in the context of coronary artery disease; (3) investigation and management of subclinical AF; (4) the use of antidotes for the reversal of non-vitamin K antagonist oral anticoagulants; (5) acute pharmacological cardioversion of AF; (6) catheter ablation for AF, including patients with concomitant AF and heart failure; and (7) an integrated approach to the patient with AF and modifiable cardiovascular risk factors. The recommendations were developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) standards. Individual studies and literature were reviewed for quality and bias; the literature review process and evidence tables are included as Supplementary Material and are available on the CCS Web site. Details of the updated recommendations are presented, along with their background and rationale. This document is linked to an updated summary of all CCS AF guidelines recommendations, from 2010 to the present 2018 Focused Update, which is provided in the Supplementary Material.
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http://dx.doi.org/10.1016/j.cjca.2018.08.026DOI Listing
November 2018

Biomarkers and arrhythmia recurrence following radiofrequency ablation of atrial fibrillation.

J Int Med Res 2018 Dec 4;46(12):5183-5194. Epub 2018 Sep 4.

1 Division of Cardiology, Geneva University Hospitals, Geneva, Switzerland.

Objective: Atrial fibrillation (AF) is the most common cardiac arrhythmia, and radiofrequency catheter ablation of AF (RCAAF) has become increasingly popular. Cardiac stress and inflammation have been associated with AF. This study was performed to determine whether the pre- or post-AF ablation levels of high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are predictive of AF recurrence.

Methods: This multicenter prospective cohort study involved patients undergoing RCAAF in Switzerland and Canada. The primary endpoint was the recurrence of AF or atrial flutter at 6 months.

Results: Of 202 patients, 195 completed follow-up (age, 57.5 ± 9 years; mean left ventricular ejection fraction, 62%; mean left atrial size, 19.4 cm). Patients with AF recurrence had larger atrial surfaces and longer total RCAAF times. Both the pre-ablation hs-CRP level and 1-day post-RCAAF NT-proBNP level were significantly associated with an increased risk of recurrence.

Conclusions: The pre-ablation hs-CRP level and immediate post-ablation NT-proBNP level were markers for atrial arrhythmia recurrence after RCAAF. This confirms growing evidence of the role of inflammation in the pathogenesis of AF. These biomarkers appear to be promising stratification tools for selection and management of patients undergoing RCAAF.
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http://dx.doi.org/10.1177/0300060518793807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6300961PMC
December 2018

Quinidine effective for the management of ventricular and atrial arrhythmias associated with Brugada syndrome.

HeartRhythm Case Rep 2018 Jul 30;4(7):270-272. Epub 2018 Apr 30.

Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.

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http://dx.doi.org/10.1016/j.hrcr.2018.01.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050440PMC
July 2018

Atrial fibrillation in young patients.

Expert Rev Cardiovasc Ther 2018 Jul 2;16(7):489-500. Epub 2018 Jul 2.

a Electrophysiology Service , Montreal Heart Institute, Université de Montréal , Montreal , Canada.

Introduction: Atrial fibrillation (AF) is the most frequent arrhythmia worldwide. While mostly seen in elderly, it can also affect young adults (≤ 45 years of age), older adolescent, and children. Areas covered: The aim of this review is to provide an overview of the current management of AF in young patients. Specific issues arise over diagnostic workup as well as antiarrhythmic and anticoagulation therapies. The future management and diagnostic strategies are also discussed. Expert commentary: Management of AF in the young adult is largely extrapolated from adult studies and guidelines. In this population, AF could reveal a genetic pathology (e.g. Brugada, Long QT or Short QT syndromes) or be the initial presentation of a cardiomyopathy. Therefore, thorough workup in the young population to eliminate potential malignant pathology.
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http://dx.doi.org/10.1080/14779072.2018.1490644DOI Listing
July 2018

Rationale, design, and preliminary results of the Quebec Warfarin Cohort Study.

Clin Cardiol 2018 May 15;41(5):576-585. Epub 2018 May 15.

Université de Montréal Beaulieu-Saucier Pharmacogenomics Centre, Montreal, Quebec, Canada.

Over- and undercoagulation with warfarin are associated with hemorrhagic and thromboembolic events, respectively. Genetic and clinical factors affect warfarin response, and the causes of this variability remain unclear. We present descriptive statistics and test for predictors of poor anticoagulation control. The Quebec Warfarin Cohort (QWC) comprises 1059 new warfarin users, with prospective follow-up using telephone questionnaires every 3 months for 1 year, and using healthcare administrative databases (RAMQ and Med-Echo) for 5 years prior to cohort entry and up to 10 years following active patient participation. Genetic material was collected, and genotyping of CYP2C9 and VKORC1 genes was conducted. Measured outcomes included the percentage of time patients spent within therapeutic range, anticoagulation control, warfarin dose, bleeding, and thromboembolic events. We report baseline characteristics and outcomes after 1 year of follow-up. Poor anticoagulation control was defined as time in therapeutic range <60% in the 3- to 12-month interval. Participants had a mean age of 71 years, and 62% were men. The most common indication for warfarin was atrial fibrillation (87%). Mean time in therapeutic range was 56% (±25%) in the 3 months following warfarin initiation, and 70% (±21%) in the 3- to 12-month interval. During follow-up, the rate of stroke or systemic embolism was 1.8 events per 100 person-years; for major bleeding events, 3.3 events per 100 person-years. Independent predictors of poor anticoagulation control were chronic kidney disease, heart failure, dyslipidemia, and age. The QWC represents a good research cohort to investigate clinical and genetic factors in a warfarin-anticoagulated population.
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http://dx.doi.org/10.1002/clc.22948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6490141PMC
May 2018

Reducing radiation exposure during procedures performed in the electrophysiology laboratory.

J Cardiovasc Electrophysiol 2018 02 17;29(2):308-315. Epub 2017 Nov 17.

Electrophysiology Service, Montreal Heart Institute and the Department of Medicine, Université de Montréal, Montréal, Canada.

Introduction: Expert societies recently published strong recommendations to reduce the exposure of patients and staff to ionizing radiation (IR) during interventional and electrophysiology (EP) procedures. However, adherence to these guidelines remains difficult and the impact of implementing such recommendations is poorly characterized.

Methods And Results: We conducted a single-center cohort study to quantify radiation exposure over time in three EP laboratories at the Montreal Heart Institute during 5,546 consecutive procedures from 2012 to 2015 by 11 primary operators. Overall, 2,618 (47.2%) procedures were catheter-based and 2,928 (52.8%) were device interventions. Interventions to reduce radiation exposure included educational initiatives to raise awareness (i.e., limiting cine acquisition, patient position, table height), slower frame rate, lower radiation dose per pulse, collimation, and integration with 3-D mapping systems and/or MediGuide technology. An 85% reduction in IR exposure was observed from 2012 to 2015, with the mean dose-area-product (DAP) decreasing from 7.65 ± 0.05 Gy·cm to 1.15 ± 0.04 Gy·cm (P < 0.001). This was true for catheter-based procedures (mean DAP 16.99 ± 0.08 to 2.00 ± 0.06 Gy·cm , P < 0.001) and device interventions (mean DAP 4.18 ± 0.06 to 0.64 ± 0.05 Gy·cm , P < 0.001). The median effective dose of IR recorded per quarter by 282 cervical dosimeters on EP staff decreased from 0.57 (IQR 0.18, 1.03) mSv in 2012 to 0.00 (IQR 0.00, 0.19) mSv in 2015, P < 0.001.

Conclusion: Enforcing good clinical practices with simple measures and low-dose fluoroscopy settings are highly effective in reducing IR exposure in the EP lab. These promising results should encourage other EP labs to adopt similar protective measures.
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http://dx.doi.org/10.1111/jce.13373DOI Listing
February 2018

Characterization of a Human Induced Pluripotent Stem Cell-Derived Cardiomyocyte Model for the Study of Variant Pathogenicity: Validation of a Mutation.

Circ Cardiovasc Genet 2017 Oct;10(5)

From the Research Center (R.G., N.E.K., M.-A.C., C.B., A.A., N.E., G.B., L.V., L.R., F.L., B.M., L.R., P.G., M.T., C.F., J.D.R.) and Cardiovascular Genetics Center (L. Robb, L. Rivard, M.T.), Montreal Heart Institute, Quebec, Canada; and Department of Medicine (R.G., M.-A.C., B.M., L.R., M.T., J.D.R.) and Faculty of Pharmacy (N.E.K., C.F.), Université de Montréal, Quebec, Canada.

Background: Long-QT syndrome is a potentially fatal condition for which 30% of patients are without a genetically confirmed diagnosis. Rapid identification of causal mutations is thus a priority to avoid at-risk situations that can lead to fatal cardiac events. Massively parallel sequencing technologies are useful for the identification of sequence variants; however, electrophysiological testing of newly identified variants is crucial to demonstrate causality. Long-QT syndrome could, therefore, benefit from having a standardized platform for functional characterization of candidate variants in the physiological context of human cardiomyocytes.

Methods And Results: Using a variant in Kir2.1 (Gly52Val) revealed by whole-exome sequencing in a patient presenting with symptoms of long-QT syndrome as a proof of principle, we demonstrated that commercially available human induced pluripotent stem cell-derived cardiomyocytes are a powerful model for screening variants involved in genetic cardiac diseases. Immunohistochemistry experiments and whole-cell current recordings in human embryonic kidney cells expressing the wild-type or the mutant Kir2.1 demonstrated that Kir2.1-52V alters channel cellular trafficking and fails to form a functional channel. Using human induced pluripotent stem cell-derived cardiomyocytes, we not only confirmed these results but also further demonstrated that Kir2.1-52V is associated with a dramatic prolongation of action potential duration with evidence of arrhythmic activity, parameters which could not have been studied using human embryonic kidney cells.

Conclusions: Our study confirms the pathogenicity of Kir2.1-52V in 1 patient with long-QT syndrome and also supports the use of isogenic human induced pluripotent stem cell-derived cardiomyocytes as a physiologically relevant model for the screening of variants of unknown function.
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http://dx.doi.org/10.1161/CIRCGENETICS.117.001755DOI Listing
October 2017

Loss-of-Function Variants: True Monogenic Culprits of Long-QT Syndrome or Proarrhythmic Variants Requiring Secondary Provocation?

Circ Arrhythm Electrophysiol 2017 Aug;10(8)

For author affiliations, please see the Appendix.

Background: Insight into type 6 long-QT syndrome (LQT6), stemming from mutations in the -encoded voltage-gated channel β-subunit, is limited. We sought to further characterize its clinical phenotype.

Methods And Results: Individuals with reported pathogenic mutations identified during arrhythmia evaluation were collected from inherited arrhythmia clinics and the Rochester long-QT syndrome (LQTS) registry. Previously reported LQT6 cases were identified through a search of the MEDLINE database. Clinical features were assessed, while reported mutations were evaluated for genotype-phenotype segregation and classified according to the contemporary American College of Medical Genetics guidelines. Twenty-seven probands possessed reported pathogenic mutations, while a MEDLINE search identified 17 additional LQT6 cases providing clinical and genetic data. Sixteen probands had normal resting QTc values and only developed QT prolongation and malignant arrhythmias after exposure to QT-prolonging stressors, 10 had other LQTS pathogenic mutations, and 10 did not have an LQTS phenotype. Although the remaining 8 subjects had an LQTS phenotype, evidence suggested that the variant was not the underlying culprit. The collective frequency of variants implicated in LQT6 in the Exome Aggregation Consortium database was 1.4%, in comparison with a 0.0005% estimated clinical prevalence for LQT6.

Conclusions: On the basis of clinical phenotype, the high allelic frequencies of LQT6 mutations in the Exome Aggregation Consortium database, and absence of previous documentation of genotype-phenotype segregation, our findings suggest that many variants, and perhaps all, have been erroneously designated as LQTS-causative mutations. Instead, variants may confer proarrhythmic susceptibility when provoked by additional environmental/acquired or genetic factors, or both.
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http://dx.doi.org/10.1161/CIRCEP.117.005282DOI Listing
August 2017

Risk of arrhythmic events in drug-induced Brugada syndrome.

Heart Rhythm 2017 10 27;14(10):1434-1435. Epub 2017 Jun 27.

Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Cardiovascular Genetics Center, Montreal Heart Institute, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montreal, Quebec, Canada. Electronic address:

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http://dx.doi.org/10.1016/j.hrthm.2017.06.033DOI Listing
October 2017

Use of Evidence-Based Therapy for Cardiovascular Risk Factors in Canadian Outpatients With Atrial Fibrillation: From the Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation (FREEDOM AF) and Co-ordinated National Network to Engage Physicians in the Care and Treatment of Patients With Atrial Fibrillation (CONNECT AF).

Am J Cardiol 2017 Aug 1;120(4):582-587. Epub 2017 Jun 1.

Canadian Heart Research Centre, Toronto, Ontario, Canada; Division of Cardiology, Terrence Donnelly Heart Centre, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address:

Using data collected from 2 national atrial fibrillation (AF) primary care physician chart audits (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation [FREEDOM AF] and Co-ordinated National Network to Engage Physicians in the Care and Treatment of Patients With Atrial Fibrillation [CONNECT AF]), we evaluated the frequency of, and factors associated with, the use of cardiovascular (CV) evidence-based therapies in Canadian AF outpatients with at least 1 CV risk factor or co-morbidity. Of the 11,264 patients enrolled, 9,495 (84.3%) were eligible for one or more CV evidence-based therapies. The proportions of patients with AF receiving all eligible guideline-recommended therapies were 40.8% of patients with coronary artery disease, 48.9% of patients with diabetes mellitus, 40.2% of patients with heart failure, 96.7% of patients with hypertension, and 55.1% of patients with peripheral arterial disease. Factors that were independently associated with nonreceipt of all indicated evidence-based therapies included sinus rhythm rather than AF at baseline and liver disease. In conclusion, although most Canadian outpatients with AF have CV risk factors or co-morbidities, a substantial portion of these patients did not receive all guideline-recommended therapies. These findings suggest that there is an opportunity to improve the quality of care for patients with AF in Canada.
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http://dx.doi.org/10.1016/j.amjcard.2017.05.027DOI Listing
August 2017

Genetic Testing in the Evaluation of Unexplained Cardiac Arrest: From the CASPER (Cardiac Arrest Survivors With Preserved Ejection Fraction Registry).

Circ Cardiovasc Genet 2017 Jun;10(3)

Background: Unexplained cardiac arrest may be because of an inherited arrhythmia syndrome. The role of genetic testing in cardiac arrest survivors without a definite clinical phenotype is unclear.

Methods And Results: The CASPER (Cardiac Arrest Survivors with Preserved Ejection Fraction Registry) is a large registry of cardiac arrest survivors where initial assessment reveals normal coronary arteries, left ventricular function, and resting ECG. Of 375 cardiac arrest survivors in CASPER from 2006 to 2015, 174 underwent genetic testing. Patients were classified as phenotype-positive (n=72) or phenotype-negative (n=102). Genetic testing was performed at treating physicians' discretion in line with contemporary guidelines and availability. All genetic variants identified from original laboratory reports were reassessed by the investigators in line with modern criteria. Pathogenic variants were identified in 29 (17%) patients (60% channelopathy-associated and 40% cardiomyopathy-associated genes) and 70 variants of unknown significance were identified in 32 (18%) patients. Prior syncope (odds ratio, 4.0; 95% confidence interval, 1.6-9.7) and a family history of sudden death (odds ratio, 3.2; 95% confidence interval, 1.1-9.4) were independently associated with the presence of a pathogenic variant. In phenotype-negative patients, broad multiphenotype genetic testing led to higher yields (21% versus 8%; =0.04) but was associated with more variants of unknown significance (55% versus 5%; <0.01).

Conclusions: Genetic testing identifies a pathogenic variant in a significant proportion of unexplained cardiac arrest survivors. Prior syncope and family history of sudden death are predictors of a positive genetic test. Both arrhythmia and cardiomyopathy genes are implicated. Broad, multiphenotype testing revealed the highest frequency of pathogenic variants in phenotype-negative patients.

Clinical Trial Registration: https://www.clinicaltrials.gov. Unique Identifier: NCT00292032.
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http://dx.doi.org/10.1161/CIRCGENETICS.116.001686DOI Listing
June 2017

Focal Transcatheter Cryoablation: Is a Four-Minute Application Still Required?

J Cardiovasc Electrophysiol 2017 May 3;28(5):559-563. Epub 2017 Apr 3.

Electrophysiology Service and Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Canada.

Introduction: The standard 4-minute application time for transcatheter cryoablation was determined in the 1990s when the system employed less potent chlorofluorocarbon refrigerants. The current refrigerant, nitrous oxide, generates substantially colder temperatures, with a faster cooling rate.

Methods And Results: We conducted a preclinical study on 32 mongrel dogs with stratified randomization of right atrial, right ventricular, and left ventricular chambers to 2-minute versus 4-minute application times using 8-mm electrode tip cryocatheters (Freezor Max, Medtronic CryoCath LP, Montreal, Canada). Animals were sacrificed one month after the procedure. Three-dimensional morphometric analyses were conducted in a blinded fashion. A total of 193 identified ablation lesions were processed for histological analyses, 102 with 2-minute applications and 91 with 4-minute applications. Ablation lesion surface area (167.8 ± 21.6 mm vs. 194.3 ± 22.6 mm , P = 0.40), maximum depth (4.4 ± 0.2 mm vs. 4.5 ± 0.2 mm, P = 0.71), and volume (125.7 ± 69.5 mm vs. 141.0 ± 83.5 mm , P = 0.25) were similar between groups. Overall, 90.2% of ablation lesions in the right atrium were transmural, 45.6% in the right ventricle, and 2.4% in the left ventricle, with no differences between 2-minute and 4-minute application times (P = 0.55). Thrombus was detected on the endocardial surface of 0.0% and 3.3% of ablation lesions created with 2-minute and 4-minute application times, respectively (P = 0.10).

Conclusion: Single 2-minute and 4-minute application times result in catheter ablation lesions of similar size using the modern cryoablation system with nitrous oxide as a refrigerant. While these findings suggest the potential to reduce the standard 4-minute application time, further studies are required to compare clinical efficacy.
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http://dx.doi.org/10.1111/jce.13193DOI Listing
May 2017

Progression of paroxysmal to persistent atrial fibrillation: 10-year follow-up in the Canadian Registry of Atrial Fibrillation.

Heart Rhythm 2017 06 21;14(6):801-807. Epub 2017 Feb 21.

University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

Background: Progression from paroxysmal to persistent atrial fibrillation (AF) has important clinical implications and is relevant to the management of patients with AF.

Objective: The purpose of this study was to define the long-term rate of progression from paroxysmal to persistent AF and the relevant clinical variables.

Methods: The Canadian Registry of Atrial Fibrillation enrolled patients after a first electrocardiographic diagnosis of paroxysmal AF. Associations between baseline characteristics and clinical outcomes were evaluated using a multivariable Cox proportional hazard model and a competing risk model accounting for death as a competing risk, where appropriate.

Results: We enrolled 755 patients (61.7% men) aged between 14 and 91 years (mean age 61.2 ± 14.2 years). The median follow-up was 6.35 years (interquartile range 2.93-10.04 years), with a rate of progression to persistent AF at 1, 5, and 10 years was 8.6%, 24.3%, and 36.3%, respectively. All-cause mortality was 30.3% at 10 years. Factors associated with AF progression were increasing age (hazard ratio [HR] 1.40; 95% confidence interval [CI] 1.23-1.60, for each 10-year increment), mitral regurgitation (HR 1.87; 95% CI 1.28-2.73), left atrial dilatation (HR 3.01; 95% CI 2.03-4.47), aortic stenosis (HR 2.40; 95% CI 1.05-5.48), and left ventricular hypertrophy (HR .47; 95% CI 1.04-2.08). Factors associated with a lower rate of progression were a faster heart rate during AF (HR 0.94; 95% CI 0.92-0.96 per 5-beat/min increment) and angina (HR 0.54; 95% CI 0.38-0.77). After accounting for death as a competing risk, left ventricular hypertrophy and aortic stenosis were no longer significant.

Conclusion: Within 10 years of presenting with paroxysmal AF, >50% of patients will progress to persistent AF or be dead. Increasing age, mitral regurgitation, aortic stenosis, left ventricular hypertrophy, and left atrial dilatation were associated with progression to persistent AF.
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http://dx.doi.org/10.1016/j.hrthm.2017.01.038DOI Listing
June 2017

Decreased Mortality With Beta-Blockers in Patients With Heart Failure and Coexisting Atrial Fibrillation: An AF-CHF Substudy.

JACC Heart Fail 2017 02 11;5(2):99-106. Epub 2017 Jan 11.

Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada; Montreal Health Innovations Coordinating Center, Université de Montréal, Montreal, Quebec, Canada. Electronic address:

Objectives: The impact of beta-blockers on mortality and hospitalizations was assessed in the largest randomized trial of patients with both atrial fibrillation (AF) and heart failure with a reduced ejection fraction (HFrEF): the Atrial Fibrillation-Congestive Heart Failure trial.

Background: Although beta-blockers are the cornerstone of therapy for HFrEF, a recent patient-level meta-analysis cast doubt on their efficacy in patients with coexisting AF.

Methods: From a total of 1,376 subjects randomized in the AF-CHF trial, those without beta-blockers at baseline were propensity matched to a maximum of 2 exposed patients. All absolute standardized differences after matching were ≤10%. Primary analyses respected the intention-to-treat principle. In on-treatment sensitivity analyses, beta-blocker status was modeled as a time-dependent covariate.

Results: Baseline characteristics were comparable among the matched cohorts (mean age 70 ± 11 years, 81% male, and mean left ventricular ejection fraction 27 ± 6%). During a median follow-up of 37 months, beta-blockers were associated with significantly lower all-cause mortality (hazard ratio [HR]: 0.721, 95% confidence interval [CI]: 0.549 to 0.945; p = 0.0180) but not hospitalizations (HR: 0.886; 95% CI: 0.715 to 1.100; p = 0.2232). Similar results were obtained in sensitivity analyses that modeled beta-blockers as a time-dependent variable (HR: 0.668 for all-cause mortality; 95% CI: 0.511 to 0.874; p = 0.0032; HR: 0.814 for hospitalizations; 95% CI: 0.653 to 1.014; p = 0.0658). There were no significant interactions between beta-blockers and patterns (i.e., persistent vs. paroxysmal) or burden of AF with respect to mortality or hospitalizations.

Conclusions: In propensity-matched analyses, beta-blockers were associated with significantly lower mortality but not hospitalizations in patients with HFrEF and AF, irrespective of the pattern or burden of AF. These results support current evidence-based recommendations for beta-blockers in patients with HFrEF, whether or not they have associated AF.
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http://dx.doi.org/10.1016/j.jchf.2016.10.015DOI Listing
February 2017