Publications by authors named "Louis Blier"

22 Publications

  • Page 1 of 1

Twiddler Syndrome without Lead Dislodgment Discovered by Remote Monitoring.

Case Rep Cardiol 2021 6;2021:8816524. Epub 2021 Feb 6.

Department of Cardiology, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec, Canada.

Twiddler syndrome is an uncommon yet dangerous phenomenon usually resulting in lead displacement with loss of capture of cardiac implantable electronic devices. In this case report, we present an interesting case of Twiddler syndrome without lead dislodgment which was detected by an alert triggered by an increase in impedance on remote monitoring.
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http://dx.doi.org/10.1155/2021/8816524DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884166PMC
February 2021

Ventricular Arrhythmia in Septal and Apical Hypertrophic Cardiomyopathy: The French-Canadian Experience.

Front Cardiovasc Med 2020 22;7:548564. Epub 2020 Oct 22.

Division of Cardiology, Multidisciplinary Cardiovascular Department, Institut Universitaire de Cardiologie et Pneumologie de Québec (IUCPQ-UL), Université Laval, Québec City, QC, Canada.

Apical hypertrophic cardiomyopathy (aHCM) is thought to have a more benign clinical course compared to septal HCM (sHCM), but most data have been derived from Asian cohorts. Comparative data on clinical outcome in Caucasian aHCM cohorts are scarce, and the results are conflicting. The aim of this study was to estimate the prevalence and outcome of aHCM in French-Canadians of Caucasian descent. We conducted a retrospective, single-center cohort study. The primary endpoint was a composite of documented sustained ventricular arrhythmia (VA), appropriate ICD therapy, arrhythmogenic syncope, cardiac arrest, or all-cause mortality. A total of 301 HCM patients (65% males) were enrolled including 80/301 (27%) with aHCM and 221/301 (73%) with sHCM. Maximal wall thickness was similar in both groups. Left ventricular apical aneurysm was significantly more common in aHCM (10 vs. 0.5%; < 0.001). The proportion of patients with myocardial fibrosis ≥ 15% of the left ventricular mass was similar between aHCM and sHCM (21 vs. 24%; = 0.68). Secondary prevention ICDs were more often implanted in aHCM patients (16 vs. 7%; = 0.02). The primary endpoint occurred in 26% of aHCM and 10.4% of sHCM patients ( = 0.001) and was driven by an increased incidence of sustained VA (10 vs. 2.3%; = 0.01). Multivariate analysis identified apical aneurysm and a phenotype of aHCM as independent predictors of the primary endpoint and the occurrence of sustained ventricular tachycardia. Unexplained syncope and a family history of sudden cardiac death were additional predictors for sustained VA. Apical HCM was associated with an increased risk of ventricular arrhythmia even when excluding patients with apical aneurysm. The phenotype of apical HCM is much more common in French-Canadians (27%) of Caucasian descent compared to other Caucasian HCM populations. Apical HCM in French-Canadians is associated with an increased risk for ventricular arrhythmia.
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http://dx.doi.org/10.3389/fcvm.2020.548564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7642600PMC
October 2020

Findings of remote monitoring of implantable cardioverter defibrillators during the COVID-19 pandemic.

Pacing Clin Electrophysiol 2020 11 26;43(11):1366-1372. Epub 2020 Oct 26.

Department of Cardiology, Quebec Heart and Lung Institute, Laval University, Quebec City, Quebec, Canada.

Background: Monitoring of cardiac implantable electronic devices was highly impacted by the COVID-19 pandemic considering the high volume of in-person visits for regular follow-up. Recent recommendations highlight the important role of remote monitoring to prevent exposure to the virus. This study compared remote monitoring of implantable cardioverter defibrillators (ICDs) in patients whose in-person annual visit was substituted for a remote monitoring session with patients who were already scheduled for a remote monitoring session.

Methods: This was a cross-sectional observational study of 329 consecutive patients between 20 March and 24 April 2020. Group 1 included 131 patients whose in-person annual visit was substituted for a remote monitoring session. Group 2 included 198 patients who underwent a remote monitoring session as scheduled in their usual device follow-up. The time interval since the last in-person visit was 13.3 ± 3.2 months in group 1 and 5.9 ± 1.7 months in group 2 (P < .01).

Results: In group 1, 15 patients (11.5%) experienced a clinical event compared to 15 patients (7.6%) in group 2 (P = .25). Nineteen patients (14.5%) required a physician intervention in group 1 compared to 19 patients (9.6%) in group 2 (P = .22). Two patients (1.5%) in group 1 and four patients (2.0%) in group 2 required an early in-person follow-up visit during the pandemic (P > .99).

Conclusion: Remote monitoring of ICDs is useful to identify clinical events and allows physicians to treat patients appropriately during the COVID-19 pandemic regardless of the time interval since their last in-person visit. It reduces significantly in-person visit for regular follow-up.
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http://dx.doi.org/10.1111/pace.14086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7675613PMC
November 2020

Driving Restrictions and Early Arrhythmias in Patients Receiving a Primary-Prevention Implantable Cardioverter-Defibrillator (DREAM-ICD) Study.

Can J Cardiol 2020 Aug 28;36(8):1269-1277. Epub 2020 May 28.

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

Background: Current guidelines recommend 4 weeks of private driving restriction after implantation of a primary-prevention implantable cardioverter-defibrillator (ICD). These driving restrictions result in significant inconvenience and social implications. Advances in medical treatment and ICD programming have lowered the overall rate of device therapies. The objective of this study was to assess the incidence of ICD therapies at 30, 60, and 180 days after implantation.

Methods: Driving Restrictions and Early Arrhythmias in Patients Receiving a Primary-Prevention Implantable Cardioverter-Defibrillator (DREAM-ICD) was a retrospective cohort study conducted at 2 Canadian university centres enrolling patients with new implantation of a primary-prevention ICD. Device programming was standardised according to current guidelines. A total of 803 patients were enrolled.

Results: The cumulative rates of appropriate ICD therapies at 30, 60, and 180 days were 0.12%, 0.50%, and 0.75%, respectively. There was no syncope during the first 6 months. The median duration to the first appropriate ICD therapy was 208 (range 23-1109) days after implantation. The rate of inappropriate ICD therapies at 30 days was only 0.2%. Overall, < 13.6% of all appropriate ICD therapies occurred within the first 6 months after implantation.

Conclusions: The rate of appropriate ICD therapies within the first 30 days after device insertion is extremely low in contemporary primary prevention cohorts with guideline-concordant device programming. There was no increased risk for ventricular arrhythmia early after ICD insertion. The results of DREAM-ICD suggest the need for a revision of the existing driving restrictions for primary-prevention ICD recipients.
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http://dx.doi.org/10.1016/j.cjca.2020.05.029DOI Listing
August 2020

A Novel Wearable Device for Continuous Ambulatory ECG Recording: Proof of Concept and Assessment of Signal Quality.

Biosensors (Basel) 2019 Jan 21;9(1). Epub 2019 Jan 21.

Electrophysiology Division, Institut Universitaire de cardiologie et de pneumologie de Québec, Québec, G1V 4G5, QC, Canada.

Diagnosis of arrhythmic disorders is challenging because of their short-lasting, intermittent character. Conventional technologies of noninvasive ambulatory rhythm monitoring are limited by modest sensitivity. We present a novel form of wearable electrocardiogram (ECG) sensors providing an alternative tool for long-term rhythm monitoring with the potential of increased sensitivity to detect intermittent or subclinical arrhythmia. The objective was to assess the signal quality and R-R coverage of a wearable ECG sensor system compared to a standard 3-lead Holter. In this phase-1 trial, healthy individuals underwent 24-h simultaneous rhythm monitoring using the OMsignal system together with a 3-lead Holter recording. The OMsignal system consists of a garment (bra or shirt) with integrated sensors recording a single-lead ECG and an acquisition module for data storage and processing. Head-to-head signal quality was assessed regarding adequate P-QRS-T distinction and was performed by three electrophysiologists blinded to the recording technology. The accuracy of signal coverage was assessed using Bland-Altman analysis. Fifteen individuals underwent simultaneous 24-h recording. Signal quality and accuracy of the OMgaments was equivalent to Holter-monitoring (84% vs 93% electrophysiologists rating, = 0.06). Signal coverage of R-R intervals showed a very close overlay between the OMsignal system and Holter signals, mean difference in heart rate of 2 5 bpm. The noise level of OMgarments was comparable to Holter recording. OMgarments provide high signal quality for adequate rhythm analysis, representing a promising novel technology for long-term non-invasive ECG monitoring.
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http://dx.doi.org/10.3390/bios9010017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6468449PMC
January 2019

Validation of a novel single lead ambulatory ECG monitor - Cardiostat™ - Compared to a standard ECG Holter monitoring.

J Electrocardiol 2019 Mar - Apr;53:57-63. Epub 2018 Dec 19.

IUCPQ - Institut Universitaire de Cardiologie et de Pneumologie de Québec, Canada.

Background: Cardiostat™ is a single lead ambulatory ECG monitor. Recording is made through 2 electrodes positioned in a lead 1-like configuration. We first validated its accuracy for atrial fibrillation detection compared to a 12-lead ECG. In the second phase of the study, arrhythmia detection accuracy was compared between Cardiostat™ ambulatory ECG and a standard 24 h Holter ECG monitoring.

Method/results: Phase one of the study included patients undergoing cardioversion for atrial fibrillation (AF) or atrial flutter. Cardiostat™ tracings were compared with standard 12-lead ECG. In the second phase, patients undergoing 24 h ambulatory Holter ECG monitoring for control or suspicion of atrial fibrillation (AF) were included. Simultaneous Holter monitoring and Cardiostat™ ECG recordings were performed. Tracings were analysed and compared. Two hundred twelve monitoring were compared. AF was diagnosed in 73 patients. Agreement between Cardiostat™ ECG and standard Holter monitoring was 99% for AF detection with kappa = 0.99. Kappa correlation for atrial flutter detection was only moderate at 0.51. AF burden was similar in both recordings. Noise hindered analysis in a greater proportion with Cardiostat™ compared to Holter ambulatory ECG (8.5 vs 3.8%).

Conclusion: Cardiostat™ ambulatory ECG device showed excellent correlation with the standard Holter ECG monitoring for AF detection. Holter monitoring was however superior to discriminate premature atrial and ventricular beats and to qualify the morphology of PVCs since it has more vectors for analysis. Added value of Cardiostat™ includes longer monitoring duration, less cumbersome installation and water resistance.
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http://dx.doi.org/10.1016/j.jelectrocard.2018.12.011DOI Listing
July 2020

Clinical performance of different DF-4 implantable cardioverter defibrillator leads.

Pacing Clin Electrophysiol 2018 Jun 1. Epub 2018 Jun 1.

Department of Cardiology, Institut universitaire de cardiologie et pneumologie de Québec, Quebec, QC, Canada.

Introduction: Implantable cardioverter-defibrillator (ICD) DF-4 connectors have been introduced to facilitate defibrillator lead connection and to reduce the size of device header. There are limited data regarding the overall performance of those leads and no comparison between different ICD DF-4 leads.

Methods: This is a cohort study of consecutive patients implanted with ICD DF-4 lead system at one University Centre between October 2010 and February 2015. A historical control group of patients with ICD DF-1 lead implantation was used for comparison. The following ICD DF-4 leads were evaluated: St. Jude Medical Durata 7122Q (St. Jude Medical, St. Paul, MN, USA), Medtronic Sprint Quattro Secure 6935 M (Medtronic Inc., Minneapolis, MN, USA), Boston Scientific Endotak Reliance 4-Site 0293 (Boston Scientific, Marlborough, MA, USA), and Boston Scientific Reliance 4-Front 0693. This study evaluated the acute and mid-term performances of those leads as well as complications.

Results: A total of 812 patients (age 63 ± 12 years, 80% male, left ventricular ejection fraction 31 ± 12%) underwent implantation of an ICD DF-4 lead. Acute and follow-up R-wave sensing and threshold were excellent. Compared to implantation, intrinsic R waves were higher at follow-up for Boston Scientific and Medtronic leads, and pacing lead impedances were lower for all leads at first follow-up (P < 0.001). The number of lead dislodgement or failure was similar between all leads. The estimated lead survival rates at 3 years were 95.6% for Boston Scientific Endotak 4-Site, 97.1% for Boston Scientific 4-Front, 97.7% for Medtronic Sprint Quattro, and 97.5% for St. Jude Durata (P  =  0.553).

Conclusion: All ICD DF-4 leads had excellent acute and mid-term electrical performances. Longer follow-up will be necessary to confirm their sustained performance.
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http://dx.doi.org/10.1111/pace.13400DOI Listing
June 2018

Cost Effectiveness of Ventricular Tachycardia Ablation Versus Escalation of Antiarrhythmic Drug Therapy: The VANISH Trial.

JACC Clin Electrophysiol 2018 05 28;4(5):660-668. Epub 2018 Mar 28.

Department of Medicine, Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Canada. Electronic address:

Objectives: This analysis uses the data from the randomized controlled trial to assess the cost effectiveness of catheter ablation (n = 132) versus escalated antiarrhythmic therapy (n = 127).

Background: For survivors of myocardial infarction with implantable cardioverter-defibrillator shocks despite antiarrhythmic drugs, the VANISH (Ventricular Tachycardia Ablation Versus Escalated Antiarrhythmic Drug Therapy in Ischemic Heart Disease) trial demonstrated improved clinical outcomes with catheter ablation compared with more aggressive antiarrhythmic pharmacotherapy.

Methods: Health care resource use and quality-of-life data were used to determine the cost effectiveness of catheter ablation. Published references were used to estimate costs (in 2015 Canadian dollars). The analysis was over 3 years, with a 5% discount rate. Adjustment was made for censoring and baseline utilities.

Results: Ablation resulted in greater quality-adjusted life-years (QALYs) than escalated drug therapy did (1.63 vs. 1.49; difference: 0.14; 95% confidence interval [CI]: -0.20 to 0.46) and higher cost ($65,126 vs. $60,269; difference: $4,857; 95% CI: -$19,757 to $27,106); with an incremental cost per QALY gained for ablation versus escalated drug therapy of $34,057 primarily due to the initial costs of ablation, which were partially offset by the costs of subsequent ablations and adverse outcomes in the escalated drug therapy arm. For patients with amiodarone-refractory ventricular tachycardia, ablation dominated escalated drug therapy, with greater QALYs (1.48 vs. 1.26; difference: 0.22; 95% CI: -0.19 to 0.59) and lower costs ($67,614 vs. $68,383; difference: -$769; 95% CI: -$35,330 to $27,092). For those with sotalol-refractory ventricular tachycardia, ablation resulted in similar QALYs (1.90 vs. 1.90; difference: -0.00; 95% CI: -0.59 to 0.62) and higher costs ($60,455 vs. $45,033; difference: $15,422; 95% CI: -$10,968 to $48,555).

Conclusions: For the total trial population, results are suggestive that ablation is cost effective compared with escalation of drug therapy. This result was only manifest for the subgroup of patients whose qualifying arrhythmia occurred despite amiodarone.
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http://dx.doi.org/10.1016/j.jacep.2018.01.007DOI Listing
May 2018

Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs.

N Engl J Med 2016 Jul 5;375(2):111-21. Epub 2016 May 5.

From the Department of Medicine, QEII Health Sciences Centre and Dalhousie University, Halifax, NS (J.L.S., R.P.), University of Ottawa Heart Institute, Ottawa (G.A.W., P.B.N.), Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC (L.B., J.-F.S.), Institut de Cardiologie de Montréal (B.T., L.R.), McGill University Health Center and Hôpital Sacré-Coeur de Montréal (V.E.), and Centre Hospitalier de L'Universite de Montréal (J.-M.R.), Montreal, Western University, London, ON (L.G., P.L.-S., A.S.L.T.), the Division of Cardiology, Royal Columbian Hospital, New Westminster, BC (S.K.T.), Royal Jubilee Hospital, Victoria, BC (L.D.S.), Libin Cardiovascular Institute of Alberta, Calgary (G.D.V.), Population Health Research Institute, Hamilton, ON (J.S.H.), Kingston General Hospital, Kingston, ON (D.R.), and Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC (J.-F.R.) - all in Canada; and the Cardiovascular Division, Brigham and Women's Hospital, Boston (W.G.S.).

Background: Recurrent ventricular tachycardia among survivors of myocardial infarction with an implantable cardioverter-defibrillator (ICD) is frequent despite antiarrhythmic drug therapy. The most effective approach to management of this problem is uncertain.

Methods: We conducted a multicenter, randomized, controlled trial involving patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite the use of antiarrhythmic drugs. Patients were randomly assigned to receive either catheter ablation (ablation group) with continuation of baseline antiarrhythmic medications or escalated antiarrhythmic drug therapy (escalated-therapy group). In the escalated-therapy group, amiodarone was initiated if another agent had been used previously. The dose of amiodarone was increased if it had been less than 300 mg per day or mexiletine was added if the dose was already at least 300 mg per day. The primary outcome was a composite of death, three or more documented episodes of ventricular tachycardia within 24 hours (ventricular tachycardia storm), or appropriate ICD shock.

Results: Of the 259 patients who were enrolled, 132 were assigned to the ablation group and 127 to the escalated-therapy group. During a mean (±SD) of 27.9±17.1 months of follow-up, the primary outcome occurred in 59.1% of patients in the ablation group and 68.5% of those in the escalated-therapy group (hazard ratio in the ablation group, 0.72; 95% confidence interval, 0.53 to 0.98; P=0.04). There was no significant between-group difference in mortality. There were two cardiac perforations and three cases of major bleeding in the ablation group and two deaths from pulmonary toxic effects and one from hepatic dysfunction in the escalated-therapy group.

Conclusions: In patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite antiarrhythmic drug therapy, there was a significantly lower rate of the composite primary outcome of death, ventricular tachycardia storm, or appropriate ICD shock among patients undergoing catheter ablation than among those receiving an escalation in antiarrhythmic drug therapy. (Funded by the Canadian Institutes of Health Research and others; VANISH ClinicalTrials.gov number, NCT00905853.).
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http://dx.doi.org/10.1056/NEJMoa1513614DOI Listing
July 2016

Extra-anatomic Course of a Right Ventricular Pacing Lead: Clinical Implications.

Can J Cardiol 2016 06 17;32(6):830.e5-6. Epub 2015 Jul 17.

Electrophysiology Division, Institut universitaire de cardiologie et de pneumologie de Québec, Laval University, Québec City, Québec, Canada.

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http://dx.doi.org/10.1016/j.cjca.2015.06.036DOI Listing
June 2016

Longitudinal follow-up of Riata leads reveals high annual incidence of new conductor externalization and electrical failure.

J Interv Card Electrophysiol 2014 Dec 16;41(3):217-22. Epub 2014 Nov 16.

Institut universitaire de cardiologie et pneumologie de Québec (IUCPQ), Division of electrophysiology, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada,

Background And Purpose: Riata(TM) defibrillation leads are susceptible to conductor externalization. The point prevalence of insulation defect in Riata(TM) leads is up to 33 %, but prospective data concerning incidence of new lead abnormalities are lacking. The purpose of our study was to determine the annual incidence of new conductor externalizations and electrical lead failure.

Methods: A prospective observational study was conducted at a single tertiary center. One hundred forty-one patients were followed over 12 months. A posterior-anterior (PA)/lateral chest x-ray (CXR) with zooming was performed at baseline and at 12 months to screen for conductor externalization. Electrical abnormalities and clinical outcome were also assessed.

Results: The overall incidence of new insulation defects was 8.5 % at 12 months. High-risk leads for new conductor externalization were lead models 1580, 1582, and 1590 with an annual rate of 11.9, 11.1, and 10 %, respectively. New conductor externalizations were three times more common in 8 Fr leads compared to 7 Fr leads. The overall incidence of new electrical dysfunction was 6.4 % at 12 months. Electrical dysfunction was significantly higher in abnormal leads (25 % [3/12], 4.7 % [6/129]; p = 0.03) and mostly driven by high ventricular pacing thresholds. There was no difference in inappropriate shock or failure of high-voltage therapy.

Conclusion: The annual incidence of new insulation defects in Riata(TM) leads is much higher than previously reported. Lead models 1580, 1582, and 1590 are at highest risk for new conductor externalization. Electrical dysfunction in Riata(TM) leads is also much higher than reported and is associated with conductor externalization.
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http://dx.doi.org/10.1007/s10840-014-9951-6DOI Listing
December 2014

PA/Lateral chest X-ray is equivalent to cine-fluoroscopy for the detection of conductor externalization in defibrillation leads.

Pacing Clin Electrophysiol 2015 Jan 16;38(1):77-83. Epub 2014 Sep 16.

Division of Electrophysiology, Institut universitaire de cardiologie et pneumologie de Québec (IUCPQ), Québec, Canada.

Background: Riata™ and Riata ST defibrillation leads (St. Jude Medical, Sylmar, CA, USA) are susceptible to insulation defects with conductor externalization. Cine-fluoroscopy is considered to be the gold standard for the documentation of insulation defects, but similar detection rates have been reported for posterior-anterior (PA)/lateral chest x-ray (CXR) with zooming.

Objective: Prospective single-center study to assess the diagnostic equivalence of a PA/lateral CXR with zooming for the detection of Riata insulation defects in a direct comparison to cine-fluoroscopy.

Methods: Seventy-eight consecutive patients underwent 3-view cine-fluoroscopy and a PA/lateral CXR. All CXRs and cine-fluoroscopy images were reviewed by blinded electrophysiologists and staff radiologists.

Results: Forty-four of 78 patients had an abnormal cine-fluoroscopy (56%). The diagnostic correlation between PA/lateral CXR and cine-fluoroscopy was excellent (κ = 0.90; 95% confidence interval 0.80-1.00). PA/lateral CXR was equivalent to cine-fluoroscopy for the detection of conductor externalization showing a sensitivity of 97.7% and a specificity of 91.2%. The mean radiation effective dose of CXR was significantly lower compared to cine-fluoroscopy (0.09 millisievert [mSV] vs 0.85 ± 0.47 mSv; P < 0.001). Also, CXR was significantly less expensive.

Conclusion: PA/lateral CXR with zooming is equivalent to cine-fluoroscopy for the detection of Riata insulation defects and should be considered as the preferred screening method.
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http://dx.doi.org/10.1111/pace.12504DOI Listing
January 2015

Detection of high incidence of Riata lead breaches by systematic postero-anterior and lateral chest X-ray in a large cohort.

Europace 2013 Mar 1;15(3):402-8. Epub 2012 Nov 1.

Division of Electrophysiology, Quebec Heart and Lung Institute, Affiliated to Laval University, 2725, Chemin Sainte-Foy, Quebec G1V 4G5, Canada.

Aims: Insulation breaches with externalization of conductor cables have been described for St-Jude Medical Riata™ defibrillation leads. Published data on the incidence of Riata lead abnormalities are quite heterogeneous. The objective of this study was to estimate systematically the prevalence of lead abnormalities using a postero-anterior (PA) and lateral chest X-ray (CXR).

Methods And Results: From 2002 to 2008, 552 Riata defibrillation leads were implanted at our centre. We evaluated patients for potential insulation breaches. A PA and lateral CXR was obtained. Chest X-rays were reviewed by two electrophysiologists using a zooming function with magnification up to factor 7.5 and were classified as normal or abnormal for the presence of conductor externalization. A total of 284 patients were included. Riata lead models were 1570, 1580, 1582, 1590, 1592, 7000, 7002, and 7022. The total frequency of radiological lead defects was 24.3%. Insulation breaches occurred at zones of major lead curvature. Mean maximal spacing between extruding lead components was 3.6 ± 1.9 mm (range 2.0-12.4). Abnormal CXRs were more frequent in 8F leads (31.4% vs. 6.3%; P < 0.001). Most defects occurred with lead models 1582 (41.2%) and 1580 (31.4%). Mean time since implantation was longer in abnormal leads (6.7 vs. 5.9 years; P < 0.001). Abnormal leads had higher pacing thresholds (1.1 ± 0.8 V vs. 0.9 ± 0.4 V; P = 0.02).

Conclusion: The incidence of insulation breach in Riata leads is much higher than quoted by the manufacturer or reported by most of the literature. A PA and lateral CXR with zooming appears adequate to identify lead breaches when reviewed by an electrophysiologist. Riata lead breaches without electrical abnormalities present a management dilemma and will require further studies.
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http://dx.doi.org/10.1093/europace/eus339DOI Listing
March 2013

Usefulness of fluorine-18 positron emission tomography/computed tomography for identification of cardiovascular implantable electronic device infections.

J Am Coll Cardiol 2012 May;59(18):1616-25

Department of Medicine, Division of Cardiology, Institut universitaire de cardiologie et pneumologie de Québec, 2725 chemin Sainte-Foy, Québec City, Quebec, Canada.

Objectives: This study evaluated the usefulness of fluorodesoxyglucose marked by fluorine-18 ((18)F-FDG) positron emission tomography (PET) and computed tomography (CT) in patients with suspected cardiovascular implantable electronic device (CIED) infection.

Background: CIED infection is sometimes challenging to diagnose. Because extraction is associated with significant morbidity/mortality, new imaging modalities to confirm the infection and its dissemination would be of clinical value.

Methods: Three groups were compared. In Group A, 42 patients with suspected CIED infection underwent (18)F-FDG PET/CT. Positive PET/CT was defined as abnormal uptake along cardiac devices. Group B included 12 patients without infection who underwent PET/CT 4 to 8 weeks post-implant. Group C included 12 patients implanted for >6 months without infection who underwent PET/CT for another indication. Semi-quantitative ratio (SQR) was obtained from the ratio between maximal uptake and lung parenchyma uptake.

Results: In Group A, 32 of 42 patients with suspected CIED infection had positive PET/CT. Twenty-four patients with positive PET/CT underwent extraction with excellent correlation. In 7 patients with positive PET/CT, 6 were treated as superficial infection with clinical resolution. One patient with positive PET/CT but negative leukocyte scan was considered false positive due to Dacron pouch. Ten patients with negative-PET/CT were treated with antibiotics and none has relapsed at 12.9 ± 1.9 months. In Group B, patients had mild uptake seen at the level of the connector. There was no abnormal uptake in Group C patients. Median SQR was significantly higher in Group A (A = 2.02 vs. B = 1.08 vs. C = 0.57; p < 0.001).

Conclusions: PET/CT is useful in differentiating between CIED infection and recent post-implant changes. It may guide appropriate therapy.
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http://dx.doi.org/10.1016/j.jacc.2011.11.059DOI Listing
May 2012

Prospective comparison between conventional transseptal puncture and transseptal needle puncture with radiofrequency energy.

J Interv Card Electrophysiol 2011 Sep 19;31(3):237-42. Epub 2011 Apr 19.

Institut Universitaire de Cardiologie et Pneumologie de Québec, Quebec, QC, Canada.

Purpose: Patients undergoing left atrial ablation require transseptal puncture, which can be challenging, even for experienced physicians. This study compared the efficacy and safety of radiofrequency (RF) energy transseptal punctures to conventional approach.

Methods: Patients requiring transseptal puncture for left atrial access were included using either conventional approach or the NRG™ RF transseptal needle as first attempt. Procedure time for transseptal access, fluoroscopy time, crossover, and safety of both techniques were compared.

Results: A total of 241 transseptal punctures were performed in 148 consecutive patients (114 men, 54 ± 10 years, left atrial volume 32 ± 10 ml/m(2)) who underwent 157 procedures with left atrial access, mainly for atrial fibrillation. It was a repeat transseptal procedure in 49 patients. Procedures were guided by transesophageal echocardiography. RF transseptal puncture was planned in 119 procedures. RF was delivered in 98 procedures (82%) for 139/187 punctures: 48 punctures did not require RF, including 25 punctures performed by exposing the needle tip, 22 through patent foramen ovale, and 1 RF delivery failure by the generator. Average time for RF transseptal was 4.8 ± 2.8 min compared to 7.5 ± 8.5 min for conventional approach (p = 0.045). Fluoroscopy time was 1.8 ± 1.3 min for RF transseptal and 2.9 ± 2.8 min for standard approach (p = 0.043). Four patients required crossover to RF transseptal needle in the conventional group (p = 0.003). One tamponade occurred at the end of procedure in a patient using the RF needle, and one interatrial septum dissection with aortic root hematoma occurred in the conventional group.

Conclusions: Transseptal needle puncture using RF energy can be performed safely and quickly under imaging guidance.
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http://dx.doi.org/10.1007/s10840-011-9564-2DOI Listing
September 2011

Recommendations for the use of genetic testing in the clinical evaluation of inherited cardiac arrhythmias associated with sudden cardiac death: Canadian Cardiovascular Society/Canadian Heart Rhythm Society joint position paper.

Can J Cardiol 2011 Mar-Apr;27(2):232-45

Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.

The era of gene discovery and molecular medicine has had a significant impact on clinical practice. Knowledge of specific genetic findings causative for or associated with human disease may enhance diagnostic accuracy and influence treatment decisions. In cardiovascular disease, gene discovery for inherited arrhythmia syndromes has advanced most rapidly. The arrhythmia specialist is often confronted with the challenge of diagnosing and managing genetic arrhythmia syndromes. There is now a clear need for guidelines on the appropriate use of genetic testing for the most common genetic conditions associated with a risk of sudden cardiac death. This document represents the first ever published recommendations outlining the role of genetic testing in various clinical scenarios, the specific genes to be considered for testing, and the utility of test results in the management of patients and their families.
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http://dx.doi.org/10.1016/j.cjca.2010.12.078DOI Listing
June 2011

Contractile reserve assessed using dobutamine echocardiography predicts left ventricular reverse remodeling after cardiac resynchronization therapy: prospective validation in patients with left ventricular dyssynchrony.

Echocardiography 2010 Jul 25;27(6):668-76. Epub 2010 Mar 25.

Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Cardiology, Quebec, Quebec, Canada.

Background: The presence of viable myocardium may predict response to cardiac resynchronization therapy (CRT). The aim of this study is to evaluate in patients with left ventricular (LV) dyssynchrony whether response to CRT is related to myocardial viability in the region of the pacing lead.

Methods: Forty-nine consecutive patients with advanced heart failure, LV ejection fraction < 35%, QRS duration > 120 ms and intraventricular asynchronism > or = 50 ms were included. Dobutamine stress echocardiography was performed within the week before CRT implantation. Resting echocardiography was performed 6 months after CRT implantation. Viability in the region of LV pacing lead was defined as the presence of viability in two contiguous segments. Response to CRT was defined by evidence of reverse LV remodeling (> or =15% reduction in LV end-systolic volume).

Results: Thirty-one patients (63%) were identified as responders at follow-up. The average of viable segments was 5.9 +/- 2 in responders and 3.2 +/- 3 in nonresponders (P = 0.0003). Viability in the region of the pacing lead had a sensitivity of 94%, a specificity of 67%, a positive predictive value of 83%, and a negative predictive value of 86% for the prediction of response to CRT.

Conclusions: In patients with LV dyssynchrony, reverse remodeling after CRT requires viability in the region of the pacing lead. This simple method using echocardiography dobutamine for the evaluation of local viability (i.e., viability in two contiguous segments) may be useful to the clinician in choosing the best LV lead positioning.
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http://dx.doi.org/10.1111/j.1540-8175.2009.01106.xDOI Listing
July 2010

Usefulness and limitation of dobutamine stress echocardiography to predict acute response to cardiac resynchronization therapy.

Echocardiography 2010 Jan 31;27(1):50-7. Epub 2009 Aug 31.

Department of Cardiology, Institut de Cardiologie de Québec, Hôpital Laval, Québec, Canada.

Background: It has been hypothesized that a long-term response to cardiac resynchronization therapy (CRT) could correlate with myocardial viability in patients with left ventricular (LV) dysfunction. Contractile reserve and viability in the region of the pacing lead have not been investigated in regard to acute response after CRT.

Methods: Fifty-one consecutive patients with advanced heart failure, LV ejection fraction 120 ms, and intraventricular asynchronism >or= 50 ms were prospectively included. The week before CRT implantation, the presence of viability was evaluated using dobutamine stress echocardiography. Acute responders were defined as a >or=15% increase in LV stroke volume.

Results: The average of viable segments was 5.8 +/- 1.9 in responders and 3.9 +/- 3 in nonresponders (P = 0.03). Viability in the region of the pacing lead had an excellent sensitivity (96%), but a low specificity (56%) to predict acute response to CRT. Mitral regurgitation (MR) was reduced in 21 patients (84%) with acute response. The presence of MR was a poor predictor of response (sensibility 93% and specificity 17%). However, combining the presence of MR and viability in the region of the pacing lead yields a sensibility (89%) and a specificity (70%) to predict acute response to CRT.

Conclusion: Myocardial viability is an important factor influencing acute hemodynamic response to CRT. In acute responders, significant MR reduction is frequent. The combined presence of MR and viability in the region of the pacing lead predicts acute response to CRT with the best accuracy.
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http://dx.doi.org/10.1111/j.1540-8175.2009.00962.xDOI Listing
January 2010

Impact of AV conduction disorders on SafeR mode performance.

Pacing Clin Electrophysiol 2009 Mar;32 Suppl 1:S231-5

Montreal Heart Institute, Montreal, Quebec, Canada.

Purpose: CAN-SAVE R is a Canadian multicenter study that compares the effects of a new pacing mode algorithm designed to minimize right ventricular (V) pacing versus DDD mode with a long atrioventricular (AV) delay in a general population of pacemaker (PM) recipients.

Study Participants: Patients with permanent atrial fibrillation (AF) or high-degree AV block (AVB) were excluded. We present preliminary data collected in 208 patients (mean age=71 +/- 11 years, 68% men), for the 2-month baseline period during which all PM were programmed in the new pacing mode. The pacing indications were sinus node disease (SND) without AVB in 39%, AVB without SND in 30%, SND and AVB in 16%, and miscellaneous in 15% of patients.

Results: The mean percent V pacing in the overall population was 9.5 +/- 23.8% (range=0-100%, median <1%), ranging between 0.5 +/- 1.5% (median=0) in patients without AVB and 18.7 +/- 31.2% in patients (median = 1) with AVB. Adverse events potentially related to the new pacing mode were observed in two patients with AVB.

Conclusions: A new pacing mode was effective and safe in a general population of PM recipients without permanent AVB and was associated with an overall <1% median V pacing. CAN-SAVE R will compare the long-term effects of the new pacing mode with DDD with a long AV delay on clinical outcomes and cardiac function.
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http://dx.doi.org/10.1111/j.1540-8159.2008.02293.xDOI Listing
March 2009

The Brugada syndrome in Canada: a unique French-Canadian experience.

Can J Cardiol 2007 Oct;23 Suppl B:71B-75B

Institut Universitaire de Cardiologie et Pneumologie de l'Université Laval, Laval Hospital, Sainte-Foy, Quebec.

Unlabelled: The Brugada syndrome (BS) is a clinical entity involving cardiac sodium channelopathy, typical electrocardiogram (ECG) changes and predisposition to ventricular arrhythmia. This syndrome is mainly recognized by specialized cardiologists and electrophysiologists. Data regarding BS largely come from multicentre registries or Asian countries. The present report describes the Quebec Heart Institute experience, including the clinical characteristics and prognosis of native French-Canadian subjects with the Brugada-type ECG pattern.

Methods And Results: BS has been diagnosed in 35 patients (mean age 51 +/- 12 years) at the Quebec Heart Institute since 2001. Patients were referred from primary care physicians for ECG abnormalities, syncope or ventricular arrhythmia, or were diagnosed incidentally on an ECG obtained for other purposes. The abnormal ECG was recognized after a syncopal spell in four patients and during family screening in four patients. All of the others were incidental findings following a routine ECG. No patient had a family history of sudden cardiac death at younger than 45 years of age. In this population, right bundle branch block pattern with more than 2 mm ST segment elevation in leads V1 to V3 was recorded spontaneously in 25 patients and was induced by sodium blockers in 10 patients. The sodium channel blocker test was performed in 21 patients and was positive in 18 patients (86%). An electrophysiological study was performed in 20 of 35 patients, during which ventricular fibrillation was induced in five patients; three of the five patients were previously asymptomatic. An implantable cardioverter-defibrillator was implanted in six of 35 patients (17%), including three of four patients with a history of syncope. A loop recorder was implanted in three patients. After a mean follow-up of 36 +/- 18 months, one patient died from a noncardiac cause and one patient (with a history of syncope) received an appropriate shock from his implantable cardioverter-defibrillator. No event occurred in the asymptomatic population.

Conclusions: BS is present in the French-Canadian population and is probably under-recognized. Long-term prognosis of individuals with BS, especially in sporadic, asymptomatic cases, needs to be clarified.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2794469PMC
http://dx.doi.org/10.1016/s0828-282x(07)71014-0DOI Listing
October 2007

Catheter ablation for cardiac arrhythmias: a 14-year experience with 5330 consecutive patients at the Quebec Heart Institute, Laval Hospital.

Can J Cardiol 2007 Oct;23 Suppl B:67B-70B

Institut Universitaire de Cardiologie et de Pneumologie, Hopital Laval, Sainte-Foy, Quebec.

Background: Catheter ablation is a curative treatment with excellent success and minimal complication rates for patients with supraventricular or ventricular arrhythmias.

Methods: The acute outcomes and complications of all catheter ablation procedures for supraventricular and ventricular arrhythmias performed at the Quebec Heart Institute (Sainte-Foy, Quebec) during a 14-year period from January 1, 1993, to December 31, 2006, were prospectively assessed. The ablation procedures were classified according to the arrhythmias induced using standard electrophysiological techniques and definitions. Immediate success and complication rates were prospectively included in the database.

Results: A total of 5330 patients had catheter ablation performed at the Institute during the period assessed. The mean (+/- SD) age of patients was 50 +/- 18 years (range four to 97 years), and 2340 patients (44%) were men. Most of the patients were younger than 75 years (group 1), and 487 (9%) were 75 years of age and older (group 2). Indications for ablations were as follows: atrioventricular nodal re-entry tachycardia (AVNRT) in 2263 patients, accessory pathways in 1147 patients, atrioventricular node ablation in 803 patients, typical atrial flutter in 377 patients and atrial tachycardia in 160 patients; 580 patients had other ablation procedures. The overall success rates were 81% for atrial tachycardia, 92% for accessory pathways or flutter, and 99% for AVNRT or atrioventricular node ablation. There was no difference in the success rates of the younger (group 1) and older (group 2) patients. Seventy-seven patients (1.4%) had complications, including 11 major events (myocardial infarction in one patient, pulmonary embolism in three patients and permanent pacemaker in seven patients). In patients undergoing AVNRT ablation, two had a permanent pacemaker implanted immediately after the procedure and three had a permanent pacemaker implanted at follow-up.

Conclusions: The results confirm that radiofrequency ablation is safe and effective, supporting ablation therapy as a first-line therapy for the majority of patients with cardiac arrhythmias.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2794475PMC
http://dx.doi.org/10.1016/s0828-282x(07)71013-9DOI Listing
October 2007

Usefulness of transesophageal echocardiography in the isolation of pulmonary veins in the treatment of atrial fibrillation.

Pacing Clin Electrophysiol 2007 Jan;30 Suppl 1:S116-9

Institut Universitaire de cardiologie et pneumologie de l'Université Laval, Laval Hospital, Quebec City, Quebec, Canada.

Background: New imaging strategies for atrial fibrillation (AF) ablation should enhance the safety of this technique. The role of transesophageal echocardiography (TEE) in this setting has not been prospectively evaluated.

Methods: Under general anesthesia, 85 patients underwent TEE-guided AF ablation. A hybrid technique was performed with circular pulmonary veins (PV) lesions and antrum and ostial electrical isolation guided by TEE. TEE excluded left atrial (LA) thrombus, guided transseptal puncture and catheter positioning, and helped to identify PV ostia and their velocities. The TEE probe localized the esophagus, its temperature (T degrees ) and micro bubbles formation.

Results: Overall, one patient had a LA clot. The esophagus was located close to left PV in 38%, the right PV in 28%, midline in 17% and with an oblique course in 17% of patients. Right and left superior PV velocities were detected in 100%, left inferior PV in 88% and right inferior PV in 82% of patients. Microbubbles were detected in 9 patients (11%). Elevation of TEE T degrees occurred in 14 patients (16%) and was regularly observed when lesions were applied over the TEE probe shadow, in close proximity to the posterior wall. Two major complications (1 tamponade, 1 PV laceration) occurred and were detected early by TEE.

Conclusions: TEE offers advantages compared to a map-guided only approach. It is a reliable tool to assess esophagus T degrees and localization, guide transseptal puncture, delineate the PV ostia, and monitor complications.
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http://dx.doi.org/10.1111/j.1540-8159.2007.00619.xDOI Listing
January 2007