Allan C Skanes

The University of Western Ontario, London, Ontario, Canada

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Publications (248)1075.72 Total impact

  • Lorne J Gula, Allan C Skanes
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    ABSTRACT: It has been almost twenty years since the discovery that pulmonary vein ectopy is largely responsible for initiation of paroxysmal atrial fibrillation (PAF). We have spent the better part of those twenty years seeking effective ways of eliminating pulmonary vein ectopy or its effect on the atrial rhythm. This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 09/2014; · 3.48 Impact Factor
  • Lorne J Gula, Peter Leong-Sit, Allan C Skanes
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; · 4.56 Impact Factor
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    ABSTRACT: Early repolarization (ER) is associated with an increased risk of death from cardiac causes. Recent evidence supports ER's role as a modifier and/or predictor of risk in many cardiac conditions.
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; · 4.56 Impact Factor
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    ABSTRACT: The Integrated Diagnostics (ID) algorithm is an implantable device-based tool that collates data pertaining to heart rhythm, heart rate, intrathoracic fluid status, and activity, producing a risk score that correlates with 30-day risk of heart failure (HF) hospitalization.
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; · 4.56 Impact Factor
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    ABSTRACT: Beta-blockers are the standard of care for the treatment of long QT syndrome (LQTS), and have been shown to reduce recurrent syncope and mortality in patients with type 1 LQTS (LQT1). Although beta-blockers have minimal effect on the resting corrected QT interval, their effect on the dynamics of the non-corrected QT interval is unknown, and may provide insight into their protective effects. Twenty-three patients from eight families with genetically distinct mutations for LQT1 performed exercise stress testing before and after beta-blockade. One hundred and fifty-two QT, QTc, and Tpeak-Tend intervals were measured before starting beta-blockers and compared with those at matched identical cycle lengths following beta-blockade. Beta-blockers demonstrated heart-rate-dependent effects on the QT and QTc intervals. In the slowest heart rate tertile (<90 b.p.m.), beta-blockade increased the QT and QTc intervals (QT: 405 vs. 409 ms; P = 0.06; QTc: 459 vs. 464 ms; P = 0.06). In the fastest heart rate tertile (>100 b.p.m.), the use of beta-blocker was associated with a reduction in both the QT and QTc intervals (QT: 367 vs. 358 ms; P < 0.0001; QTc: 500 vs. 486 ms; P < 0.0001). The Tpeak-Tend interval showed minimal change at slower heart rates (<90 b.p.m.) (93 vs. 87 ms; P = 0.09) and at faster heart rates (>100 b.p.m.) (87 vs. 84 ms; P = NS) following beta-blockade. Beta-blockers have heart-rate-dependent effects on the QT and QTc intervals in LQTS. They appear to increase the QT and QTc intervals at slower heart rates and shorten them at faster heart rates during exercise.
    Europace 05/2014; · 2.77 Impact Factor
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    Circulation 04/2014; 129(16):1688-94. · 15.20 Impact Factor
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    ABSTRACT: Interventional cardiac electrophysiology (EP) has experienced a significant growth in Canada. Our aim is to establish a periodic registry as a nationwide initiative. The registry is designed to collect information regarding EP laboratory infrastructure, human resources, and the spectrum and volumes of EP procedures. Respective administrative staff were contacted electronically. Out of 25 identified Canadian EP centers, 19 centers (76 %) have participated in the registry. Responding centers have access on average to 5.3 lab days per week to perform EP studies/ablations; average lab time per full- and part-time (prorated to 0.5) EP physician is 0.8 day per week. Diagnostic EP studies and radio-frequency ablations are performed in all (19) centers; cryoablation is available in 83 % of centers. Two centers have remote magnetic navigation systems. EnSite NavX is the most widely available 3D mapping system utilized in 15 (83 %) centers, followed by CARTO and intracardiac echo which are each available in 14 (78 %) centers; LocaLisa is actively used in one center. The number of full-time physicians ranges between 0 and 7, with a mean of 3.5 full-time physicians per center. The ratio of staff to trainees is 1.6:1. A total of 8,041 EP procedures are performed in the 19 centers per annum. On an annual average, 104 procedures per one operator and 159 procedures per trainee are performed. This registry provides contemporary information on invasive EP lab resources and procedures in Canada. It also demonstrates that Canadian EP procedural intensities of practice and training are comparable to international standards.
    Journal of Interventional Cardiac Electrophysiology 04/2014; · 1.39 Impact Factor
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    ABSTRACT: Provocative testing with sodium channel blockers is advocated for the evaluation of unexplained cardiac arrest (UCA) with the primary purpose of unmasking the typical ECG features of Brugada syndrome. The CASPER registry systematically assesses subjects with UCA or a family history of sudden death (FHSD). To determine the clinical yield of procainamide infusion in a national registry of subjects with either UCA or a FHSD. Subjects with either UCA or a FHSD without evidence of a Brugada pattern at baseline underwent procainamide testing (15 mg/kg to a maximum of 1 g at 50 mg/min). A test was considered positive for Brugada pattern if there was an increase in ST elevation >1 mm or if there was >1 mm of new ST elevation in leads V1 and/or V2. Genetic testing was performed on the basis of phenotype detection. Procainamide testing was performed in 174 subjects (age 46.8±15.4 years; 47% female). Testing provoked a Brugada pattern in 12 subjects (6.9%), 5 of whom had no ST abnormalities at baseline. No subjects with a negative procainamide challenge were subsequently diagnosed with Brugada syndrome. Genetic testing was conducted in 10 of the 12 subjects with a provoked Brugada pattern, and was positive for a mutation in the SCN5A gene in 1. Irrespective of the baseline ECG, procainamide testing provoked a Brugada pattern in a significant proportion of subjects with UCA or a FHSD, thereby facilitating a diagnosis of Brugada syndrome, and is recommended in the workup of UCA.
    Heart rhythm: the official journal of the Heart Rhythm Society 03/2014; · 4.56 Impact Factor
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    ABSTRACT: Background Early repolarization (ER) is associated with an increased risk of death from cardiac causes. Recent evidence supports ER’s role as a modifier and/or predictor of risk in many cardiac conditions. Objectives Determine the prevalence of ER amongst genotype positive patient with Long QT syndrome (LQTS) and evaluate its utility in predicting risk of symptoms. Methods ER was defined as QRS slurring and/or notching associated with ≥1 mV QRS-ST junction (J-point) elevation in at least 2 contiguous leads, excluding the anterior precordial leads. The ECG with the most prominent ER was used for analysis. Major ER was defined as ≥ 2 mm J point elevation. Symptoms of LQTS included cardiac syncope, documented polymorphic ventricular tachycardia (VT) and resuscitated cardiac arrest. Results One hundred and thirteen patients (mean age 41 ± 19, 63 female) were reviewed in whom 414 (mean 3.7 ± 1.5) ECGs were analyzed. Of these, there were 30 patients (27%) with a history of symptoms. Fifty patients (44%) had ER, and 19 patients (17%) had major ER. Patients with major ER were not different than patients without major ER with respect to age, sex, LQT type, longest QTc recorded, number of patients with QTc> 500 msec, or use of beta blockade. Univariate and independent predictors of symptom status included the presence of major ER, longest QTc recorded > 500 msec, and female sex. Conclusion ER ≥ 2 mm was the strongest independent predictor of symptom status related to LQTS, along with female sex and QTc > 500 msec.
    Heart Rhythm. 01/2014;
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    ABSTRACT: Background The Integrated Diagnostics (ID) algorithm is an implantable device-based tool that collates data pertaining to heart rhythm, heart rate, intrathoracic fluid status, and activity, producing a risk score that correlates with 30-day risk of heart failure (HF) hospitalization. Objective We sought to validate the ID algorithm using the RAFT trial. Methods Diagnostic measures of the algorithm include OptiVol fluid index, night-time heart rate, minutes of patient activity, heart rate variability, and combined measure of cardiac rhythm and biventricular pacing. Monthly evaluations of ID parameters were assessed for development of heart failure symptoms, and hospitalization for heart failure. Results 1,224 patients were included, 741 with CRT-D devices and 483 ICD only. Average age was 66±9 years and 83% were male. 37,861 months of follow-up data were available, with 258 HF hospitalizations (event rate 0.68% per month). There were 33 HF hospitalizations during low-risk months (0.21% per month), 123 during medium risk months (0.66% per month), and 102 during high-risk months (2.61% per month). Compared to low-risk months, the relative risk of HF hospitalizations during medium-risk months was 2.9 [2.0-4.4] and during high-risk months was 10.7 [6.9-16.6]. Multivariable analysis demonstrated that each ID variable had independent association with HF hospitalization. Conclusions Risk of HF as determined by the ID algorithm correlated with HF hospitalization and several HF symptoms and signs among patients in the RAFT trial. This may present a useful adjunct to detect early signs of heart failure and adjust therapy to reduce morbidity and costs involved with hospital admission.
    Heart Rhythm. 01/2014;
  • Lorne J. Gula, Peter Leong-Sit, Allan C. Skanes
    Heart Rhythm. 01/2014;
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    ABSTRACT: A 40-year-old woman without structural heart disease was referred for non-documented palpitations associated with ventricular pre-excitation. The baseline electrocardiogram showed preexcitation suggestive of a posteroseptal accessory pathway (AP). With incremental right atrial pacing, atrioventricular (AV) conduction time over the AP was cycle length dependent (decremental), and maximal preexcitation was observed at pacing cycle length 320 ms (Figure 1). This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 12/2013; · 3.48 Impact Factor
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    ABSTRACT: Sudden cardiac death (SCD) remains the leading cause of death in hemodialysis patients. We performed a retrospective electrocardiograph (ECG) and chart review to determine whether hemodialysis modality, frequency, or duration could predict change in ECG parameters associated with SCD. Frequent nocturnal hemodialysis was associated with an improvement in Tpeak to Tend within 365 days (83.8-71.8 ms, p = 0.005) and past 365 days of dialysis initiation (85.9-77.1 ms, p = 0.005) and improvement in QRS amplitude variation within 365 days (0.0583-0.0297, p = 0.025) and past 365 days of dialysis initiation (0.0546-0.0332, p = 0.029). Compared with intermittent conventional hemodialysis, more frequent nocturnal (15/25 vs. 3/14, p = 0.04) and intermittent nocturnal hemodialysis (INHD) (6/8 vs. 3/14, p = 0.03) patients decreased Tpeak to Tend. More short-hours daily than INHD patients increased T-wave amplitude variation (16/25 vs. 1/8, p = 0.02). These improvements occurred before changes in Cornell or Sokolow-Lyon electrocardiographic left ventricular mass. Thus, it appears that hemodialysis modalities of longer duration are associated with improvements in electrocardiographic parameters associated with SCD. Prospective trials are required to determine whether dialysis prescription reduces SCD, cardiovascular morbidity, and mortality in hemodialysis patients.
    ASAIO journal (American Society for Artificial Internal Organs: 1992) 12/2013; · 1.39 Impact Factor
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    ABSTRACT: Atrioesophageal fistula (AEF) is an infrequent complication of radiofrequency (RF) ablation for atrial fibrillation (AF). The aim of this study was to determine the prevalence and operator-dependent factors associated with AEF using a nationwide survey of electrophysiologists (EP). Thirty-eight EPs performing AF ablation between 2008 and 2012 were invited to complete a web-based questionnaire assessing the prevalence and factors associated with AEF. Responses were obtained from 25 EPs (68 %) accounting for 7,016 AF ablations. Five cases of proven AEF (0.07 %) were reported. Operators who reported AEF [AEF (+)] more often used general anesthesia (GA) [90 % AEF (+) vs. 44 % AEF (-), p = 0.046]. AEF (+) operators were also more likely to be users of the non-brushing technique in the posterior wall of the LA [5 (100 %) AEF (+) vs. 5 (25 %) AEF (-), p = 0.005]. The combined usage of GA and non-brushing technique during LA posterior wall ablation had a strong association with AEF (+) operators [4 (80 %) AEF (+) vs. 2 (10 %) AEF (-), p = 0.002]. There was a trend towards higher maximal RF energy setting in the posterior wall [47.4 + 7.6 AEF (+) vs. 40.2 + 8 AEF (-), p = 0.09]. Other procedure parameters were similar. The reported prevalence of AEF among Canadian AF ablators is 0.07 %. AEF was associated with high mortality. The use of GA and non-brushing movements during posterior wall ablation were two factors associated with AEF.
    Journal of Interventional Cardiac Electrophysiology 12/2013; · 1.39 Impact Factor
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    ABSTRACT: Understanding the relationship between genotype and phenotype has become an integral part of the diagnosis and management of patients with inherited arrhythmias and cardiomyopathies. Given the existence of background noise, the majority of genetic testing results should be incorporated into clinical decision making as probabilistic, rather than deterministic, in the diagnosis and management of inherited arrhythmias. This case report captures multiple snapshots of clinical care in the evolution of a diagnosis of a single patient, highlighting the need for repeated phenotypic and genotypic assessment for both the patient and their family.
    Clinical Genetics 11/2013; · 4.25 Impact Factor
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    ABSTRACT: Background: Nephrologists need effective screening tools to identify hemodialysis patients at elevated risk for sudden cardiac death, the leading cause of death in this population. QTc intervals longer than 450 ms in males and 470 ms in females, measured by the gold standard tangent method (trueQTc), are prolonged and increase sudden cardiac death in healthy populations and patients with long QT syndrome. Methods: We performed a retrospective ECG and chart review of hemodialysis patients. Our first objective was to determine if machine-measured QTc intervals (macQTc) could be used to identify dialysis patients with prolonged trueQTc. Our second objective was to determine at what macQTc could prolonged trueQTc be confidently diagnosed. Results: macQTc differed from the trueQTc by an average of 16.54 ms, and by at least 20 ms in 46.8, 36.1, 53.6, 50.0 and 57.1% of all, short-hours daily hemodialysis, intermittent conventional hemodialysis, frequent nocturnal hemodialysis and intermittent nocturnal hemodialysis patients, respectively. The positive predictive value, negative predictive value, sensitivity and specificity of prolonged macQTc predicting prolonged trueQTc was 57.6, 92.6, 79.1 and 81.8%, respectively. Thus, macQTc is inaccurate at predicting the gold standard trueQTc in hemodialysis patients. macQTc greater than 480 ms in hemodialysis patients predicts trueQTc prolongation with a positive predictive value of 95.2%, but with a low sensitivity of 32.3%. Conclusion: In hemodialysis patients, ECG macQTc intervals are insufficiently sensitive or specific to predict prolonged trueQTc intervals, unless >480 ms. © 2013 S. Karger AG, Basel.
    Nephron Clinical Practice 11/2013; 124(1-2):113-118. · 1.65 Impact Factor
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    ABSTRACT: istinguishing retrograde nodal conduction from extranodal conduction utilizing an accessory pathway (AP) can sometimes be challenging. We propose a simple method to distinguish nodal from extranodal ventriculo-atrial (VA) conduction regardless of AP location. This is based on the principle that moving the pacing site progressively from the basal region towards the entrance of the His-Purkinje system should shorten VA time for nodal but not for AP conduction. Sixty-seven patients with supraventricular tachycardia were prospectively recruited. Quadripolar catheters were placed at the right ventricular (RV) apex, right atrium, His and coronary sinus (CS). The RV septum was sequentially paced at 4 sites: (1) basal, (2) high midventricle , (3) low midventricle (4) and apex at a cycle length 100 ms shorter than the resting cycle length. Stimulus to atrial (SA) interval was measured using the proximal CS atrial electrogram. Group 1 (n=33) had nodal VA conduction; all patients had typical AVNRT. Group 2 (n=34) had extranodal VA conduction via an AP; 19 left-sided, 6 right-sided and 9 posteroseptal. In group 1, the SA interval decreased significantly as pacing site moved closer towards the apex [(site 1) 166±35ms; (site 2) 153±32ms; (site 3) 149±32ms; (site 4) 154±33ms, p<0.001 respectively at sites 2-4 compared with site 1]. In contrast, in group 2, SA interval increased significantly towards the apex [(site 1) 149±45ms; (site 2) 158±43ms; (site 3) 161±43ms; (site 4) 163±40ms, p<0.001 respectively at sites 2-4 compared with site 1] The SA interval site 2 - SA interval site 1 ≤ 0 ms for nodal and > 0 ms for extranodal conduction had optimal sensitivity and specificity (nodal: Se= 97.0%, Sp= 85.3%, extranodal: Se= 85.3%, Sp= 97.0%). Differential sequential pacing of the RV septum reliably distinguishes retrograde AV nodal conduction from accessory pathway conduction.
    Heart rhythm: the official journal of the Heart Rhythm Society 09/2013; · 4.56 Impact Factor
  • The Canadian journal of cardiology 08/2013; · 3.12 Impact Factor
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    ABSTRACT: The initial experience with left atrial esophageal fistula (LAEF) secondary to atrial fibrillation (AF) ablation procedures revealed a near universal mortality. A comprehensive description of the principles of LAEF repair in the modern era and its resulting impact on morbidity and mortality are lacking in the literature. To describe the presentation, surgical management and outcomes of patients with LAEF. A retrospective cohort analysis of 29 patients was performed, including previously unpublished cases of surgically repaired LAEF from 4 institutions (n=6), and all published cases of surgically repaired (n=16) or stented (n=7) LAEF. The average age was 55±13 years, 75% male, undergoing radiofrequency energy catheter ablation (n=26), cryoablation (n=1), high intensity focused ultrasound ablation (n=1) and surgical mini-MAZE (n=1), and presenting 30±12 days post ablation procedure. Overall 55% of patients receiving an intervention for LAEF died (41% surgical repair; 100% stent). Patients who did not receive primary esophageal repair were more likely to experience post-operative complications including mediastinitis, need for percutaneous endoscopic gastrostomy (PEG) feeds, esophageal stent or death (P=0.05). Additionally, interposing tissue between the repaired esophagus and LA resulted in fewer post-operative complications (P=0.02). While improved relative to initial reports, mortality associated with LAEF remains high after corrective intervention. Primary esophageal repair with the placement of tissue between the repaired esophagus and LA may result in lower morbidity and mortality.
    Heart rhythm: the official journal of the Heart Rhythm Society 08/2013; · 4.56 Impact Factor
  • Gary A Wright, Allan C Skanes
    Journal of Cardiovascular Electrophysiology 07/2013; · 3.48 Impact Factor

Publication Stats

4k Citations
1,075.72 Total Impact Points

Institutions

  • 1999–2014
    • The University of Western Ontario
      • Department of Medicine
      London, Ontario, Canada
  • 2013
    • Lawson Health Research Institute
      London, Ontario, Canada
  • 2011–2013
    • The University of Calgary
      • Department of Cardiac Sciences
      Calgary, Alberta, Canada
    • Southlake Regional Health Centre
      Bradford West Gwillimbury, Ontario, Canada
    • University of Bordeaux
      Burdeos, Aquitaine, France
    • St. Vincent's Hospital Sydney
      • Department of Cardiology
      Sydney, New South Wales, Australia
    • University of British Columbia - Vancouver
      • Division of Cardiology
      Vancouver, British Columbia, Canada
  • 2005–2012
    • Montreal Heart Institute
      • Department of Medicine
      Montréal, Quebec, Canada
    • Université de Montréal
      Montréal, Quebec, Canada
  • 2000–2012
    • London Health Sciences Centre
      • Division of Cardiology
      London, Ontario, Canada
    • Queen's University
      • Division of Cardiology
      Kingston, Ontario, Canada
  • 2004–2011
    • Robarts Research Institute
      • Imaging Research Laboratories
      London, Ontario, Canada
  • 2009
    • I.R.C.C.S. Policlinico San Donato
      Milano, Lombardy, Italy
  • 2000–2004
    • Lakehead University Orillia Campus
      Orillia, Ontario, Canada