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Verma A.,Southlake Regional Health Center | Jiang C.-Y.,Zhejiang University | Betts T.R.,John Radcliffe Hospital | Chen J.,University of Bergen | And 11 more authors.
New England Journal of Medicine | Year: 2015

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. Copyright © 2015 Massachusetts Medical Society.


Morillo C.A.,Hamilton Health Sciences | Verma A.,Southlake Regional Health Center | Connolly S.J.,Hamilton Health Sciences | Nair G.M.,Ottawa Heart Institute | And 5 more authors.
JAMA - Journal of the American Medical Association | Year: 2014

IMPORTANCE: Atrial fibrillation (AF) is the most common rhythm disorder seen in clinical practice. Antiarrhythmic drugs are effective for reduction of recurrence in patients with symptomatic paroxysmal AF. Radiofrequency ablation is an accepted therapy in patients for whom antiarrhythmic drugs have failed; however, its role as a first-line therapy needs further investigation. OBJECTIVE: To compare radiofrequency ablation with antiarrhythmic drugs (standard therapy) in treating patients with paroxysmal AF as a first-line therapy. DESIGN, SETTING, AND PATIENTS: A randomized clinical trial involving 127 treatment-naive patients with paroxysmal AF were randomized at 16 centers in Europe and North America to received either antiarrhythmic therapy or ablation. The first patient was enrolled July 27, 2006; the last patient, January 29, 2010. The last follow-up was February 16, 2012. INTERVENTIONS: Sixty-one patients in the antiarrhythmic drug group and 66 in the radiofrequency ablation group were followed up for 24 months. MAIN OUTCOMES AND MEASURES: The time to the first documented atrial tachyarrhythmia of more than 30 seconds (symptomatic or asymptomatic AF, atrial flutter, or atrial tachycardia), detected by either scheduled or unscheduled electrocardiogram, Holter, transtelephonic monitor, or rhythm strip, was the primary outcome. Secondary outcomes included symptomatic recurrences of atrial tachyarrhythmias and quality of life measures assessed by the EQ-5D tool. RESULTS: Forty-four patients (72.1%) in the antiarrhythmic group and in 36 patients (54.5%) in the ablation group experienced the primary efficacy outcome (hazard ratio [HR], 0.56 [95% CI, 0.35-0.90]; P = .02). For the secondary outcomes, 59% in the drug group and 47% in the ablation group experienced the first recurrence of symptomatic AF, atrial flutter, atrial tachycardia (HR, 0.56 [95% CI, 0.33-0.95]; P = .03). No deaths or strokes were reported in either group; 4 cases of cardiac tamponade were reported in the ablation group. In the standard treatment group, 26 patients (43%) underwent ablation after 1-year. Quality of life was moderately impaired at baseline in both groups and improved at the 1 year follow-up. However, improvement was not significantly different among groups. CONCLUSIONS AND RELEVANCE: Among patients with paroxysmal AF without previous antiarrhythmic drug treatment, radiofrequency ablation compared with antiarrhythmic drugs resulted in a lower rate of recurrent atrial tachyarrhythmias at 2 years. However, recurrence was frequent in both groups. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00392054 Copyright 2014 American Medical Association. All rights reserved.


Mohareb M.M.,University of Toronto | Qiu F.,Institute for Clinical Evaluative science | Cantor W.J.,Southlake Regional Health Center | Kingsbury K.J.,Care Network | And 2 more authors.
Annals of Internal Medicine | Year: 2015

Background: The use of invasive coronary angiography in stable ischemic heart disease (IHD) varies widely. Objective: To validate the 2012 appropriate use criteria for diagnostic catheterization by examining the relationship between the appropriateness of cardiac catheterization in patients with suspected stable IHD and the proportion of patients with obstructive coronary artery disease (CAD) and subsequent revascularization. Design: Population-based, observational, multicenter cohort study. Setting: The Cardiac Care Network, a registry of all patients having elective angiography at 18 hospitals in Ontario, Canada, between 1 October 2008 and 30 September 2011. Patients: Persons without prior coronary revascularization or myocardial infarction who had angiography for suspected stable CAD. Measurements: Appropriateness scores were ascertained by using data collected at the time of the index angiography and were categorized as appropriate, inappropriate, or uncertain. Results: Among the final cohort of 48 336 patients, 58.2% of angiographic studies were classified as appropriate, 10.8% were classified as inappropriate, and 31.0% were classified as uncertain. Overall, 45.5% of patients had obstructive CAD. In patients with appropriate indications for angiography, 52.9% had obstructive CAD, with 40.0% undergoing revascularization. In those with inappropriate indications, 30.9% had obstructive CAD and 18.9% underwent revascularization; in those with uncertain indications, 36.7% had obstructive CAD and 25.9% had revascularization. Although more patients with appropriate indications had obstructive CAD and underwent revascularization (P < 0.001), a substantial proportion of those with inappropriate or uncertain indications had important coronary disease. Limitation: Data were not available on whether symptoms were atypical. Conclusion: Despite the association between appropriateness category and obstructive CAD, this study raises concerns about the ability of the appropriate use criteria to guide clinical decision making. Primary Funding Source: Canadian Institutes of Health © 2015 American College of Physicians.


Verma A.,Southlake Regional Health Center | Debruyne P.,Imelda Ziekenhuis | Nardi S.,Pineta Grande Hospital | Deneke T.,Herz und Gefass Klinik | And 4 more authors.
Circulation: Arrhythmia and Electrophysiology | Year: 2013

Background: This prospective, multicenter study sought to evaluate the incidence of asymptomatic cerebral emboli (ACE) during ablation of atrial fibrillation (AF) using a multielectrode radiofrequency (MER) system when specific procedural changes were applied. Methods and Results: Sixty subjects (age 60±10 years; 87% paroxysmal; CHADS2 score, 0.6±0.7) undergoing AF ablation with a circular MER catheter were studied. Three procedural changes were specified: (1) ablation was performed under therapeutic vitamin K antagonist and heparin to maintain activated clotting time >350 seconds; (2) submerged loading of the catheter into the introducer before sheath insertion to minimize air ingress; and (3) either the distal or proximal electrode of the circular MER catheter was deactivated to prevent inadvertent bipolar radiofrequency interaction. MRI was performed <7 days preablation and 2 days postablation. Subjects with new cerebral findings after ablation underwent repeat MRI after 1 month. An acute ACE lesion was defined by a new hyperintensity on diffusion-weighted and fluidattenuated inversion recovery cerebral MRI sequences. Neurological function was evaluated at baseline, postablation, and 1 month. All target pulmonary veins were isolated. In 60% (36/60) of patients, pre-existing cerebral lesions were seen on the preprocedure MRI (8 lesions per subject; interquartile range, 3-22). New postprocedural ACE occurred in only 1/60 patients (incidence, 1.7%; 95% confidence interval, 0.04-8.9), which was no longer visible on MRI after 1 month. Conclusions: Applying procedural changes to MER ablation significantly reduces the ACE incidence to 1.7%, which is on the low end of reported ACE rates of any technology. © 2013 American Heart Association, Inc.


Alsahli M.,Southlake Regional Health Center | Alsahli M.,Kings College | Gerich J.E.,University of Rochester
Endocrinology and Metabolism Clinics of North America | Year: 2013

Hypoglycemia remains a common problem for patients with diabetes and is associated with substantial morbidity and mortality. This article summarizes our current knowledge of the epidemiology, pathogenesis, risk factors, and complications of hypoglycemia in patients with diabetes and discusses prevention and treatment strategies. © 2013 Elsevier Inc.

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