Abstract The Canadian Cardiovascular Society (CCS) Atrial Fibrillation (AF) Guidelines Committee provides periodic reviews of new data to produce focused updates that address clinically important ...advances in AF management. This 2016 Focused Update deals with: (1) the management of antithrombotic therapy for AF patients in the context of the various clinical presentations of coronary artery disease; (2) real-life data with non-vitamin K antagonist oral anticoagulants; (3) the use of antidotes for the reversal of non-vitamin K antagonist oral anticoagulants; (4) digoxin as a rate control agent; (5) perioperative anticoagulation management; and (6) AF surgical therapy including the prevention and treatment of AF after cardiac surgery. The recommendations were developed with the same methodology used for the initial 2010 guidelines and the 2012 and 2014 Focused Updates. 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 in the Supplementary Material, and on the CCS Web site. The section on concomitant AF and coronary artery disease was developed in collaboration with the CCS Antiplatelet Guidelines Committee. 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 2016 Focused Update.
Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is associated with PV to left atrium reconduction. Effective lesion creation necessitates adequate contact force between the ...ablation catheter and myocardium.
The purpose of this study was to study the utility of contact force-guided ablation on immediate and long-term outcomes.
Seventy-five patients with highly symptomatic paroxysmal AF underwent wide circumferential PVI using an irrigated-tip radiofrequency catheter. In 25 patients, ablation was guided by real-time contact force measurements (CF group; SmartTouch, Biosense Webster). A control group of 50 patients underwent PVI using a standard nonforce sensing catheter (standard group; ThermoCool, Biosense Webster). After PVI, all patients underwent adenosine testing to unmask dormant conduction. Patients were followed up at 3, 6, and 12 months and by transtelephonic monitoring as well.
Dormant conduction was unmasked and subsequently eliminated in 4 PV pairs (8%; 16% of patients) in the CF group and 35 PV pairs (35%; 52% of patients) in the standard group (P = .0004 per PV pair; P = .0029 per patient). The single-procedure, off-antiarrhythmic drug freedom from recurrent atrial arrhythmias at 1 year was 88% in the CF group vs 66% in the standard group (P = .047). Procedure duration and fluoroscopy time were significantly longer in the CF group (P = .0038 and P = .0001, respectively).
The use of real-time contact force guidance results in a significant reduction in the prevalence of dormant conduction with improved long-term freedom from recurrent arrhythmias. The utility of a contact force-guided approach requires evaluation in a long-term prospective randomized study.
Progression from paroxysmal to persistent atrial fibrillation (AF) has important clinical implications and is relevant to the management of patients with AF.
The purpose of this study was to define ...the long-term rate of progression from paroxysmal to persistent AF and the relevant clinical variables.
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.
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.
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.
Abstract Background Recent trials of fish oil for the prevention of atrial fibrillation (AF) recurrence have provided mixed results. Notable uncertainties in the existing evidence base include the ...roles of high-dose fish oil, inflammation, and oxidative stress in patients with paroxysmal or persistent AF not receiving conventional antiarrhythmic (AA) therapy. Objectives The aim of this study was to evaluate the influence of high-dose fish oil on AF recurrence, inflammation, and oxidative stress parameters. Methods We performed a double-blind, randomized, placebo-controlled, parallel-arm study in 337 patients with symptomatic paroxysmal or persistent AF within 6 months of enrollment. Patients were randomized to fish oil (4 g/day) or placebo and followed, on average, for 271 ± 129 days. Results The primary endpoint was time to first symptomatic or asymptomatic AF recurrence lasting >30 s. Secondary endpoints were high-sensitivity C-reactive protein (hs-CRP) and myeloperoxidase (MPO). The primary endpoint occurred in 64.1% of patients in the fish oil arm and 63.2% of patients in the placebo arm (hazard ratio: 1.10; 95% confidence interval: 0.84 to 1.45; p = 0.48). hs-CRP and MPO were within normal limits at baseline and decreased to a similar degree at 6 months (Δhs-CRP, 11% vs. −11%; ΔMPO, −5% vs. −9% for fish oil vs. placebo, respectively; p value for interaction = NS). Conclusions High-dose fish oil does not reduce AF recurrence in patients with a history of AF not receiving conventional AA therapy. Furthermore, fish oil does not reduce inflammation or oxidative stress markers in this population, which may explain its lack of efficacy. (Multi-center Study to Evaluate the Effect of N-3 Fatty Acids OMEGA-3 on Arrhythmia Recurrence in Atrial Fibrillation AFFORD; NCT01235130 ).
Summary 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).
Abstract The stroke rate in atrial fibrillation is 4.5% per year, with death or permanent disability in over half. The risk of stroke varies from under 1% to over 20% per year, related to the risk ...factors of congestive heart failure, hypertension, age, diabetes, and prior stroke or transient ischemic attack (TIA). Major bleeding with vitamin K antagonists varies from about 1% to over 12% per year and is related to a number of risk factors. The CHADS2 index and the HAS-BLED score are useful schemata for the prediction of stroke and bleeding risks. Vitamin K antagonists reduce the risk of stroke by 64%, aspirin reduces it by 19%, and vitamin K antagonists reduce the risk of stroke by 39% when directly compared with aspirin. Dabigatran is superior to warfarin for stroke prevention and causes no increase in major bleeding. We recommend that all patients with atrial fibrillation or atrial flutter, whether paroxysmal, persistent, or permanent, should be stratified for the risk of stroke and for the risk of bleeding and that most should receive antithrombotic therapy. We make detailed recommendations as to the preferred agents in various types of patients and for the management of antithrombotic therapies in the common clinical settings of cardioversion, concomitant coronary artery disease, surgical or diagnostic procedures with a risk of major bleeding, and the occurrence of stroke or major bleeding. Alternatives to antithrombotic therapies are briefly discussed.
Electrophysiological predictors of atrioventricular (AV) block after transcatheter aortic valve replacement (TAVR) are unknown.
We sought to assess the value of electrophysiology study before and ...after TAVR.
Seventy-five consecutive pacemaker-free patients undergoing TAVR at the Montreal Heart Institute were prospectively studied.
Eleven patients (14.7%) developed AV block during the index hospitalization and 3 (4.0%) after hospital discharge over a median follow-up of 1.4 years (interquartile range 0.6-2.1 years). AV block developed in 5 of 6 patients with preprocedural right bundle branch block (83.3%), 8 of 30 patients with new-onset left bundle branch block (LBBB; 26.7%), and 1 of 7 patients with preexisting LBBB (14.3%). In multivariate analysis that considered all patients, the delta-HV interval (HV interval after TAVR minus HV interval before TAVR) was the only factor independently associated with AV block. In the subgroup of patients with new-onset LBBB, the postprocedural HV interval was strongly associated with AV block. By receiver operating characteristic analysis, a delta-HV interval of ≥13 ms predicted AV block with 100.0% sensitivity and 84.4% specificity and an HV interval of ≥65 ms predicted AV block with 83.3% sensitivity and 81.6% specificity. In multivariate analysis, the HV interval after TAVR (hazard ratio 1.073 per ms; 95% confidence interval 1.029-1.119; P = .001) was also independently associated with all-cause mortality.
A prolonged delta-HV interval (≥13 ms) is strongly associated with AV block after TAVR. In patients with new-onset LBBB after TAVR, a postprocedural HV interval of ≥65 ms is likewise predictive of AV block.
Pacemakers and defibrillators were explanted post mortem in Canada, tested and resterilized, and implanted in patients in underserved countries. The incidence of infection at 2 years among patients ...with reused devices was not significantly different from that among matched control patients who received new devices.
Abstract The goals of atrial fibrillation (AF) and atrial flutter (AFL) arrhythmia management are to alleviate patient symptoms, improve patient quality of life, and minimize the morbidity associated ...with AF and AFL. Arrhythmia management usually commences with drugs to slow the ventricular rate. The addition of class I or class III antiarrhythmic drugs for restoration or maintenance of sinus rhythm is largely determined by patient symptoms and preferences. For rate control, treatment of persistent or permanent AF and AFL should aim for a resting heart rate of <100 beats per minute. Beta-blockers or nondihydropyridine calcium channel blockers are the initial therapy for rate control of AF and AFL in most patients without a history of myocardial infarction or left ventricular dysfunction. Digoxin is not recommended as monotherapy for rate control in active patients. Digoxin and dronedarone may be used in combination with other agents to optimize rate control. The first-choice antiarrhythmic drug for maintenance of sinus rhythm in patients with non structural heart disease can be any one of dronedarone, flecainide, propafenone, or sotalol. In patients with abnormal ventricular function but left ventricular ejection fraction >35%, dronedarone, sotalol, or amiodarone is recommended. In patients with left ventricular ejection fraction <35%, amiodarone is the only drug usually recommended. Intermittent antiarrhythmic drug therapy (“pill in the pocket”) may be considered in symptomatic patients with infrequent, longer-lasting episodes of AF or AFL as an alternative to daily antiarrhythmic therapy. Referral for ablation of AF may be considered for patients who remain symptomatic after adequate trials of antiarrhythmic drug therapy and in whom a rhythm control strategy remains desired.
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