Standard vs Augmented Ablation of Paroxysmal Atrial Fibrillation for Reduction of Atrial Fibrillation Recurrence: The AWARE Randomized Clinical Trial.

Importance: Recurrent atrial fibrillation (AF) commonly occurs after catheter ablation and is associated with patient morbidity and health care costs. Objective: To evaluate the superiority of an augmented double wide-area circumferential ablation (WACA) compared with a standard single WACA in preventing recurrent atrial arrhythmias (AA) (atrial tachycardia, atrial flutter, or atrial fibrillation [AF]) in patients with paroxysmal AF. Design, Setting, and Participants: This was a pragmatic, multicenter, prospective, randomized, open, blinded end point superiority clinical trial conducted at 10 university-affiliated centers in Canada. The trial enrolled patients 18 years and older with symptomatic paroxysmal AF from March 2015 to May 2017. Analysis took place between January and April 2022. Analyses were intention to treat. Interventions: Patients were randomized (1:1) to receive radiofrequency catheter ablation for pulmonary vein isolation with either a standard single WACA or an augmented double WACA. Main Outcomes and Measures: The primary outcome was AA recurrence between 91 and 365 days postablation. Patients underwent 42 days of ambulatory electrocardiography monitoring after ablation. Secondary outcomes included need for repeated catheter ablation and procedural and safety variables. Results: Of 398 patients, 195 were randomized to the single WACA (control) arm (mean [SD] age, 60.6 [9.3] years; 65 [33.3%] female) and 203 to the double WACA (experimental) arm (mean [SD] age, 61.5 [9.3] years; 66 [32.5%] female). Overall, 52 patients (26.7%) in the single WACA arm and 50 patients (24.6%) in the double WACA arm had recurrent AA at 1 year (relative risk, 0.92; 95% CI, 0.66-1.29; P = .64). Twenty patients (10.3%) in the single WACA arm and 15 patients (7.4%) in the double WACA arm underwent repeated catheter ablation (relative risk, 0.72; 95% CI, 0.38-1.36). Adjudicated serious adverse events occurred in 13 patients (6.7%) in the single WACA arm and 14 patients (6.9%) in the double WACA arm. Conclusions and Relevance: In this randomized clinical trial of patients with paroxysmal AF, additional ablation by performing a double ablation lesion set did not result in improved freedom from recurrent AA compared with a standard single ablation set. Trial Registration: ClinicalTrials.gov Identifier: NCT02150902.

Characterization of arrhythmia substrate to ablate persistent atrial fibrillation (COAST-AF): Randomized controlled trial design and rationale.

BACKGROUND: Atrial low voltage area (LVA) catheter ablation has emerged as a promising strategy for ablation of persistent atrial fibrillation (AF). It is unclear if catheter ablation of atrial LVA increases treatment success rates in patients with persistent AF. OBJECTIVE: The primary aim of this trial is to assess the potential benefit of adjunctive catheter ablation of atrial LVA in addition to pulmonary vein isolation (PVI) in patients with persistent AF, when compared to PVI alone. The secondary aims are to evaluate safety outcomes, the quality of life and the healthcare resource utilization. METHODS/DESIGN: A multicenter, prospective, parallel-group, 2-arm, single-blinded randomized controlled trial is under way (NCT03347227). Patients who are candidates for catheter ablation for persistent AF will be randomly assigned (1:1) to either PVI alone or PVI + atrial LVA ablation. The primary outcome is 18-month documented event rate of atrial arrhythmia (AF, atrial tachycardia or atrial flutter) post catheter ablation. Secondary outcomes include procedure-related complications, freedom from atrial arrhythmia at 12 months, AF burden, need for emergency department visits/hospitalization, need for repeat ablation for atrial arrhythmia, quality of life at 12 and 18 months, ablation time, and procedure duration. DISCUSSION: Characterization of Arrhythmia Mechanism to Ablate Atrial Fibrillation (COAST-AF) is a multicenter randomized trial evaluating ablation strategies for catheter ablation. We hypothesize that catheter ablation of atrial LVA in addition to PVI will result in higher procedural success rates when compared to PVI alone in patients with persistent AF.

Augmented wide area circumferential catheter ablation for reduction of atrial fibrillation recurrence (AWARE) trial: Design and rationale.

BACKGROUND: Recurrence of atrial fibrillation (AF) after a pulmonary vein isolation procedure is often due to electrical reconnection of the pulmonary veins. Repeat ablation procedures may improve freedom from AF but are associated with increased risks and health care costs. A novel ablation strategy in which patients receive "augmented" ablation lesions has the potential to reduce the risk of AF recurrence. OBJECTIVE: The Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence (AWARE) Trial was designed to evaluate whether an augmented wide-area circumferential antral (WACA) ablation strategy will result in fewer atrial arrhythmia recurrences in patients with symptomatic paroxysmal AF, compared with a conventional WACA strategy. METHODS/DESIGN: The AWARE trial was a multicenter, prospective, randomized, open, blinded endpoint trial that has completed recruitment (ClinicalTrials.gov NCT02150902). Patients were randomly assigned (1:1) to either the control arm (single WACAlesion set) or the interventional arm (augmented- double WACA lesion set performed after the initial WACA). The primary outcome was atrial tachyarrhythmia (AA; atrial tachycardia [AT], atrial flutter [AFl] or AF) recurrence between days 91 and 365 post catheter ablation. Patient follow-up included 14-day continuous ambulatory ECG monitoring at 3, 6, and 12 months after catheter ablation. Three questionnaires were administered during the trial- the EuroQuol-5D (EQ-5D) quality of life scale, the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale, and a patient satisfaction scale. DISCUSSION: The AWARE trial was designed to evaluate whether a novel approach to catheter ablation reduced the risk of AA recurrence in patients with symptomatic paroxysmal AF.

Landing on the spot: Approaches to outflow tract PVCs; from ECG to EGMs to intracardiac echocardiography.

Premature ventricular complexes (PVCs) are increasingly recognized, as the use of ECG wearables becomes more widespread. In particular, PVCs arising from both the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) comprise the majority of these arrhythmias and form a significant component of an electrophysiology practice. A keen understanding of the correlative anatomy of the outflow tracts, in addition to recognizing key ECG indices illustrating PVC sites of origin, are fundamental in preparing for a successful ablation. Patient selection, incorporating symptomatology, structural disease, and PVC burden can pose a challenge, though tools such as the ABC-VT risk score may help identify those patients with a higher risk of clinical deterioration. Utilizing intracardiac echocardiography to highlight salient anatomic features not visible with fluoroscopy allows for a more precise and safer ablation. Interpretation of intracardiac EGMs, and the careful examination for low amplitude highly fractionated pre-potentials, enhanced by the advent of new developed mapping/ablation catheters, remains crucial. Utilizing these tools will guide the electrophysiologist to an efficient and effective outflow tract PVC ablation.

Post-operative pain following cardiac implantable electronic device implantation: insights from the BRUISE CONTROL trials.

AIMS: Post-operative pain following cardiac implantable electronic device (CIED) insertion is associated with patient dissatisfaction, emotional distress, and emergency department visits. We sought to identify factors associated with post-operative pain and develop a prediction score for post-operative pain. METHODS AND RESULTS: All patients from the BRUISE CONTROL-1 and 2 trials were included in this analysis. A validated Visual Analogue Scale (VAS) was used to assess the severity of pain related to CIED implant procedures. Patients were asked to grade the most severe post-operative pain, average post-operative pain, and pain on the day of the first post-operative clinic. Multivariable regression analyses were performed to identify predictors of significant post-operative pain and to develop a pain-prediction score. A total of 1308 patients were included. Multivariable regression analysis found that the presence of post-operative clinically significant haematoma {CSH; P value < 0.001; odds ratio (OR) 3.82 [95% confidence interval (CI): 2.37-6.16]}, de novo CIED implantation [P value < 0.001; OR 1.90 (95% CI: 1.47-2.46)], female sex [P value < 0.001; OR 1.61 (95% CI: 1.22-2.12)], younger age [<65 years; P value < 0.001; OR 1.54 (95% CI: 1.14-2.10)], and lower body mass index [<20 kg/m2; P value < 0.05; OR 2.05 (95% CI: 0.98-4.28)] demonstrated strong and independent associations with increased post-operative pain. An 11-point post-operative pain prediction score was developed using the data. CONCLUSION: Our study has identified multiple predictors of post-operative pain after CIED insertion. We have developed a prediction score for post-operative pain that can be used to identify individuals at risk of experiencing significant post-operative pain.

Relationship between quality of life and burden of recurrent atrial fibrillation following ablation: CAPCOST multicentre cohort study.

AIMS: Atrial fibrillation (AF) significantly impairs patients' quality of life (QOL). We performed this study to investigate the effect of AF-ablation success and atrial fibrillation burden (AFB) on QOL measures. METHODS AND RESULTS: Overall, 230 patients with paroxysmal AF refractory to antiarrhythmic drugs were enrolled and underwent ablation in a multicentre, prospective cohort. Electrocardiogram, 48-h Holter, Canadian Cardiovascular Society Severity of Atrial Fibrillation (CCS-SAF), short form-12 (SF-12), and Atrial Fibrillation Effect on Quality of life (AFEQT) scales were used to assess patients. Atrial fibrillation burden was defined as total duration of AF during the month prior to each visit (h/month). The change in AFB was calculated as the difference between the month prior to the 12-month post-ablation and the baseline pre-ablation. The Minimal Clinically Important Difference (MCID) was considered as a 19-point change for AFEQT and 3-5-point change for SF-12 scores. There was significant rise in the AFEQT and SF12 and decrease in CCS-SAF score post-AF ablation; however, the magnitude of these changes was greater in patients without AF recurrence (P < 0.05). The QOL score that best differentiated patients with and without recurrence was AFEQT, while, CCS-SAF was the most specific score. Patients with AFB decrease >19 h/month had significantly greater change in QOL scores. Atrial fibrillation burden < 24 h/month at 12-months post-ablation was associated with significant changes in QOL and CCS-SAF when adjusting for baseline scores and other covariates. These changes were consistent with the MCID of these measures. CONCLUSION: Patients experience significant improvements in QOL post-ablation, which correlate with a decrease in AFB despite ongoing brief recurrences of AF. CLINICAL TRIAL REGISTRATION: NCT01562912. https://www.clinicaltrials.gov/ct2/show/NCT01562912? term=capcost&rank=1.

Effect of Direct Oral Anticoagulants, Warfarin, and Antiplatelet Agents on Risk of Device Pocket Hematoma: Combined Analysis of BRUISE CONTROL 1 and 2.

BACKGROUND: Oral anticoagulant use is common among patients undergoing pacemaker or defibrillator surgery. BRUISE CONTROL (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial; NCT00800137) demonstrated that perioperative warfarin continuation reduced clinically significant hematomas (CSH) by 80% compared with heparin bridging (3.5% versus 16%). BRUISE-CONTROL-2 (NCT01675076) observed a similarly low risk of CSH when comparing continued versus interrupted direct oral anticoagulant (2.1% in both groups). Using patient level data from both trials, the current study aims to: (1) evaluate the effect of concomitant antiplatelet therapy on CSH, and (2) understand the relative risk of CSH in patients treated with direct oral anticoagulant versus continued warfarin. METHODS: We analyzed 1343 patients included in BRUISE-CONTROL-1 and BRUISE-CONTROL-2. The primary outcome for both trials was CSH. There were 408 patients identified as having continued either a single or dual antiplatelet agent at the time of device surgery. RESULTS: Antiplatelet use (versus nonuse) was associated with CSH in 9.8% versus 4.3% of patients (P<0.001), and remained a strong independent predictor after multivariable adjustment (odds ratio, 1.965; 95% CI, 1.202-3.213; P=0.0071). In multivariable analysis, adjusting for antiplatelet use, there was no significant difference in CSH observed between direct oral anticoagulant use compared with continued warfarin (odds ratio, 0.858; 95% CI, 0.375-1.963; P=0.717). CONCLUSIONS: Concomitant antiplatelet therapy doubled the risk of CSH during device surgery. No difference in CSH was found between direct oral anticoagulant versus continued warfarin. In anticoagulated patients undergoing elective or semi-urgent device surgery, the patient specific benefit/risk of holding an antiplatelet should be carefully considered. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT00800137, NCT01675076.

Comparison of efficacy of phased multipolar versus traditional radiofrequency ablation: A prospective, multicenter study (CAPCOST).

BACKGROUND: Multipolar phased pulmonary vein ablation catheter (PVAC), specifically its second-generation (PVAC-Gold), has been associated with reduced procedural time for atrial fibrillation (AF) ablation compared to traditional catheters. We performed this study to compare the efficacy of PVAC with point-by-point radiofrequency (RF) ablation. METHODS: This is a multicenter-cohort study (2012-2017), involving patients with symptomatic, paroxysmal AF refractory to at least one antiarrhythmic medication. Overall, 230 patients were enrolled to (A) PVAC and (B) control groups. Subanalyses were done for ablations performed with PVAC-Gold, and for ablations performed without left atrial (LA) ablation in addition to pulmonary vein isolation. Electrocardiogram and 48-h Holter monitoring were used to assess patients at 3, 6, 9, and 12 months postablation. Recurrence was defined as any atrial arrhythmia >30 s excluding an initial 3-month blanking period. RESULTS: Freedom from any atrial arrhythmia at 12 months postablation was 35.70% and 52.80% in groups A and B, respectively (P = .01). Freedom from atrial arrhythmia was not significantly different when limiting the PVAC cohort to PVAC-Gold and excluding patients with additional LA ablation (A: 44.30%; B: 44.30%, P = .80). Procedural and ablation time was significantly lower in group A than B. Multivariate regression model showed female gender (odds ratio [OR] = 2.90) and recurrence during blanking period (OR = 6.60) as significant predictors of recurrence. CONCLUSION: This study suggests that PVAC may achieve less freedom from AF than point-by-point RF; however, efficacy is similar when comparing PVAC-Gold and point-by-point stand-alone PV isolation. PVAC is associated with significantly reduced procedural times for AF ablation.

Concomitant anti-platelet therapy in warfarin-treated patients undergoing cardiac rhythm device implantation: A secondary analysis of the BRUISE CONTROL trial.

BACKGROUND: Anti-platelet therapy is commonly used in patients receiving oral anticoagulation and may increase bleeding risk among patients undergoing cardiac implantable electronic device (CIED) surgery. We sought to determine the proportion of anticoagulated patients who are concomitantly receiving anti-platelet therapy, the associated risk of clinically significant hematoma (CSH), and the proportion of patients in whom anti-platelet usage is guideline-indicated. METHODS: A secondary analysis of the Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial (BRUISE CONTROL). Patients who were receiving warfarin, had an annual predicted risk of thromboembolism of ≥5% and were scheduled to undergo non-emergent CIED surgery were randomized to continued warfarin versus heparin bridging. In the current analysis, patients were divided into those receiving anti-platelet therapy and those not receiving anti-platelet therapy. The incidence of CSH was compared in both groups. The proportion of patients on potentially inappropriate and potentially interruptible antiplatelet therapy was estimated. RESULTS: All 681 patients enrolled in BRUISE CONTROL were included, of whom 280 received and 401 did not receive anti-platelet therapy. Anti-platelet therapy increased the risk of CSH (relative risk, 1.72; 95% confidence interval (CI), 1.09 to 2.72; P = 0.02). Of the 280 patients receiving anti-platelet therapy, 97 (34.6%) had no guideline indication for concomitant anti-platelet therapy and an additional 146 (52.1%) were on anti-platelet therapy that could potentially have been interrupted around CIED surgery. CONCLUSIONS: Concomitant anti-platelet therapy in patients receiving anticoagulation is associated with a significant risk of CSH. The majority of concomitant anti-platelet therapy is potentially inappropriate or interruptible. TRIAL REGISTRATION: clinicaltrials.gov Identifier: (NCT00800137).

Novel criterion for the differential diagnosis of wide QRS complexes and wide complex tachycardia using the initial activation of QRS on leads V1 and V2: Differential diagnosis of wide QRS based on V1-V2.

BACKGROUND: Many diagnostic criteria for the differential diagnosis of wide complex tachycardia (WCT) are complex and not completely accurate. Incorrect diagnosis is also related to error in applying criteria. OBJECTIVES: To propose a novel reliable criterion for wide QRS complexes' differential diagnosis. MATERIAL AND METHODS: One hundred Electrocardiograms (ECGs) with wide QRS complexes were analyzed using the ECG software. Five variables were measured during the first 20 ms of QRS in leads V1 and V2 and compared between premature ventricular contraction (PVC) and conducted supraventricular impulse with bundle branch block (BBB) groups. The best discriminant variable was identified. The validity of this variable was tested on a group of 20 patients who had WCT during an electrophysiology study. RESULTS: Almost all variables were statistically different between PVC and BBB groups. The sum of voltages in absolute value of vectors during the initial 20 ms of the QRS in leads V1 and V2 (ΣV1 + V2) was the most discriminant between the two groups (131 ±â€¯85 microvolt [µV] vs. 498 ±â€¯392 µV, p < 0.01). A ΣV1 + V2 < 258 µV (rounded to <0.25 millivolt [mV]) diagnosed PVCs with good sensitivity and specificity (90% and 85% respectively). The ΣV1 + V2 in WCT group had lower values in VT versus supra-ventricular tachycardia (SVT) group (0.53 ±â€¯0.35 mV vs. 1.79 ±â€¯1.04 mV, p = 0.004). CONCLUSIONS: The ΣV1 + V2 < 258 µV is a reliable criterion for PVC diagnosis. It could be measured accurately using ECG Software, which could be programmed to calculate it automatically, limiting the risk of human error. The ΣV1 + V2 also seems capable of discriminating between VT and SVT.

Canadian Registry of Implantable Electronic Device Outcomes: Longer-term follow-up of the Riata lead under advisory.

BACKGROUND: The Riata lead advisory was announced in 2011 and has posed unique management challenges because of cable externalization and insulation abrasion, in some cases leading to sudden loss of defibrillation. OBJECTIVE: The purpose of this study was to provide further data on the rate of electrical failure in a population of patients with a Riata lead under advisory. METHODS: Using the Canadian Registry of Electronic Device Outcomes, prospective follow-up data were collected on 1352 Riata leads under advisory in 17 implantable cardioverter-defibrillator (ICD) implantation centers in Canada. Data on electrical and structural failure were collected, as well as periprocedural complications related to lead revision (abandonment or extraction). RESULTS: Of the 1352 leads included in this 12-month follow-up cohort, 110 leads were revised. Mean follow-up time was 10.4 ± 1.5 years. The 12-year rate of electrical failure for the 8Fr lead was 9.45%, whereas the 10-year failure rate for the 7Fr lead was 7.25% and was not found to be accelerating. Of the leads revised because of advisory only (patient preference, advisory related, electrical or structural failure), the majority were abandoned (n = 54 [76.0%]), whereas 17 (24.0%) were extracted using power tools. The rate of major complications in each group was 5.6% and 5.9%, respectively. CONCLUSION: This report provides further data on the risk of electrical lead failure over a long lead dwell time. The risk of failure exceeds the risk of periprocedural major complications, indicating that the risk-to-benefit ratio is favorable to revise the lead in appropriate clinical scenarios.

Intracardiac ablation for atrioventricular nodal reentry tachycardia using a 6 mm distal electrode cryoablation catheter: Prospective, multicenter, North American study (ICY-AVNRT STUDY).

INTRODUCTION: Radiofrequency (RF) ablation is effective for slow pathway ablation, but carries a risk of inadvertent AV block requiring permanent pacing. By comparison, cryoablation with a 4-mm distal electrode catheter has not been reported to cause permanent AV block but has been shown to be less effective than RF ablation. We sought to define the safety and efficacy of a 6-mm distal electrode cryoablation catheter for slow pathway ablation in patients with atrioventricular nodal reentry tachycardia (AVNRT). METHODS AND RESULTS: Twenty-six U.S. and eight Canadian centers participated in the study. Patients with supraventricular tachycardia (SVT) thought likely to be AVNRT were enrolled. If AVNRT was inducible and confirmed to be the clinical SVT, then the slow pathway was targeted with a cryoablation catheter using a standardized protocol of best practices. Acute success was defined as inducibility of no more than one echo beat after cryoablation. Primary efficacy was defined as acute success and the absence of documented recurrent AVNRT over 6 months of follow-up. Primary safety was a composite of serious procedure-related adverse events and/or device-related complications. Note that 397 subjects met enrollment criteria after the EP study and received cryoablation. Mean ablation procedure duration (including a waiting period) was 89 ± 40 minutes, and mean fluoroscopy time was 4.8 ± 5.9 minutes. Isoproterenol was administered before cryoablation in 53% and after the last lesion in 85% of cases. Acute procedural success was realized in 95% (378 of 397) of subjects. No subject received a permanent pacemaker due to AV block. The slow pathway could not be ablated in 19 subjects, including: 12 due to inefficacy, 2 due to transient AV block, and 5 due to both inefficacy and transient AV block. RF ablation was used in the same procedure in 11 of 19 failed subjects, and was ineffective in 3 subjects. Among the group with acute success, 10 subjects (2.7%) had documented recurrent AVNRT over the 6-month follow-up period, and all occurred within 3 months of the index cryoablation. Serious procedure-related adverse events occurred in 4 subjects (1.0%), including one each: tamponade, pulmonary embolism, femoral vein hemorrhage, and diagnostic EP catheter knotting. None of these serious adverse events were related to use of the cryoablation catheter. Overall, 93% of subjects had successful slow pathway ablation at 6 months with the study cryoablation catheter. CONCLUSIONS: Cryoablation for AVNRT using a focal 6-mm catheter was safe and effective. It resulted in a low risk of recurrence over 6 months of follow-up with no incidence of AV block requiring permanent pacing.

The Dx-AF study: a prospective, multicenter, randomized controlled trial comparing VDD-ICD to VVI-ICD in detecting sub-clinical atrial fibrillation in defibrillator patients.

PURPOSE: Atrial fibrillation (AF) is the most common cardiac dysrhythmia. Appropriate detection of AF and early initiation of oral anticoagulation therapy are critical to reduce the risk of stroke. Patients with implantable cardioverter defibrillators (ICD) are at high risk of developing AF. The purpose of the Dx-AF study is to demonstrate that a novel single-lead VDD-ICD system (Linox smart S DX) will facilitate adequate recognition of sub-clinical AF and ultimately stroke prevention with a comparable safety profile in comparison to VVI-ICD. METHODS AND RESULTS: Dx-AF is a prospective, randomized controlled, open-label trial. Patients who are indicated to receive a single-chamber ICD will be randomized to a VDD-ICD (experimental group) or single-chamber ICD (control group). We have used a sample size of 355, which after generous allowance for loss-to-follow-up, yields a sample size of 378 patients at up to 13 Canadian sites. The trial will enroll patients with ischemic or non-ischemic cardiomyopathy, age > 50 years, LVEF < 50%, scheduled for primary or secondary prevention single-chamber ICD, with no ECG-documented history of AF or flutter. The primary (efficacy) outcome of this study will be the time to the first detected and confirmed episode of AF or atrial flutter lasting at least 6 min. The secondary (safety) outcome will be a composite outcome of serious device-related complications. The proposed follow-up period in this trial will be 36 months after randomization. CONCLUSIONS: The Dx-AF Study should provide significant scientific evidence and guidance to an adequate ICD system choice and early AF detection/management hence improve clinical outcomes in a large patient population.

Clinically Significant Pocket Hematoma Increases Long-Term Risk of Device Infection: BRUISE CONTROL INFECTION Study.

BACKGROUND: The BRUISE CONTROL trial (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial) demonstrated that a strategy of continued warfarin during cardiac implantable electronic device surgery was safe and reduced the incidence of clinically significant pocket hematoma (CSH). CSH was defined as a post-procedure hematoma requiring further surgery and/or resulting in prolongation of hospitalization of at least 24 h, and/or requiring interruption of anticoagulation. Previous studies have inconsistently associated hematoma with the subsequent development of device infection; reasons include the retrospective nature of many studies, lack of endpoint adjudication, and differing subjective definitions of hematoma. OBJECTIVES: The BRUISE CONTROL INFECTION (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial Extended Follow-Up for Infection) prospectively examined the association between CSH and subsequent device infection. METHODS: The study included 659 patients with a primary outcome of device-related infection requiring hospitalization, defined as 1 or more of the following: pocket infection; endocarditis; and bloodstream infection. Outcomes were verified by a blinded adjudication committee. Multivariable analysis was performed to identify predictors of infection. RESULTS: The overall 1-year device-related infection rate was 2.4% (16 of 659). Infection occurred in 11% of patients (7 of 66) with previous CSH and in 1.5% (9 of 593) without CSH. CSH was the only independent predictor and was associated with a >7-fold increased risk of infection (hazard ratio: 7.7; 95% confidence interval: 2.9 to 20.5; p < 0.0001). Empiric antibiotics upon development of hematoma did not reduce long-term infection risk. CONCLUSIONS: CSH is associated with a significantly increased risk of infection requiring hospitalization within 1 year following cardiac implantable electronic device surgery. Strategies aimed at reducing hematomas may decrease the long-term risk of infection. (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial [BRUISE CONTROL]; NCT00800137).

Relation between detection rate and inappropriate shocks in single versus dual chamber cardioverter-defibrillator--an analysis from the OPTION trial.

The programming of implantable cardioverter-defibrillators (ICDs) influences inappropriate shock rates. The aim of the study is to analyse rates of patients with appropriate and inappropriate shocks according to detection zones in the OPTION trial. All patients received dual chamber (DC) ICDs randomly assigned to be programmed either to single chamber (SC) or to DC settings including PARAD+ algorithm. In a post-hoc analysis, rates of patients with inappropriate and appropriate shocks were calculated for shocks triggered at heart rates ≥ 170 bpm (ventricular tachycardia zone) and at rates ≥ 200 bpm (ventricular fibrillation zone). In the SC group, higher rates of patients with total and inappropriate shocks were delivered at heart rates ≥ 170 bpm than at rates ≥ 200 bpm (total shocks: 21.1% vs. 16.6%; p = 0.002; inappropriate shocks: 7.6% vs. 4.5%, p = 0.016; appropriate shocks: 15.2% vs. 13.5%; p = n.s.). No such differences were observed in the DC group (total shocks: 14.3% vs. 12.6%; p = n.s.; inappropriate shocks: 3.9% vs. 3.6%; p = n.s.; appropriate shocks: 12.2% vs. 10.4%; p = n.s.). The higher frequency of patients with total shocks with SC settings than with DC settings that benefit from PARAD+ was driven by a higher percentage of patients with inappropriate shocks in the VT zone (170-200 bpm) in the SC population.

Reduced risk for inappropriate implantable cardioverter-defibrillator shocks with dual-chamber therapy compared with single-chamber therapy: results of the randomized OPTION study.

OBJECTIVES: The OPTION (Optimal Anti-Tachycardia Therapy in Implantable Cardioverter-Defibrillator Patients Without Pacing Indications) trial sought to compare long-term rates of inappropriate shocks, mortality, and morbidity between dual-chamber and single-chamber settings in implantable cardioverter-defibrillators (ICDs) patients. BACKGROUND: The use of dual-chamber ICDs potentially allows better discrimination of supraventricular arrhythmias and thereby reduces inappropriate shocks. However, it may lead to detrimental ventricular pacing. METHODS: This prospective multicenter, single-blinded trial enrolled 462 patients with de novo primary or secondary prevention indications for ICD placement and with left ventricular ejection fractions ≤40% despite optimal tolerated pharmacotherapy. All patients received atrial leads and dual-chamber defibrillators that were randomized to be programmed either with dual-chamber or single-chamber settings. In the dual-chamber setting arm, the PARAD+ algorithm, which differentiates supraventricular from ventricular arrhythmias, and SafeR mode, to minimize ventricular pacing, were activated. In the single-chamber setting arm, the acceleration, stability, and long cycle search discrimination criteria were activated, and pacing was set to VVI 40 beats/min. Ventricular tachycardia detection was required at rates between 170 and 200 beats/min, and ventricular fibrillation detection was activated above 200 beats/min. RESULTS: During a follow-up period of 27 months, the time to the first inappropriate shock was significantly longer in the dual-chamber setting arm (p = 0.012, log-rank test), and 4.3% of patients in the dual-chamber setting group compared with 10.3% in the single-chamber setting group experienced inappropriate shocks (p = 0.015). Rates of all-cause death or cardiovascular hospitalization were 20% for the dual-chamber setting group and 22.4% for the single-chamber setting group and satisfied the pre-defined margin for equivalence (p < 0.001). CONCLUSIONS: Therapy with dual-chamber settings for ICD discrimination combined with algorithms for minimizing ventricular pacing was associated with reduced risk for inappropriate shock compared with single-chamber settings, without increases in mortality and morbidity. (Optimal Anti-Tachycardia Therapy in Implantable Cardioverter-Defibrillator [ICD] Patients Without Pacing Indications [OPTION]; NCT00729703).

Charting a course for cardiac electrophysiology training in Canada: the vital role of fellows in advanced cardiovascular care.

Canadian electrophysiology (EP) fellowship programs have evolved in an ad hoc fashion over 30 years. This evolution has occurred in many fields in medicine and is natural when innovators and pioneers attract research fellows who help change the status quo from predominantly research to a predominantly clinical application and focus. Fellows not only push their supervisors and their centres into new areas of inquiry but also function at the most advanced level to encourage and teach junior trainees and to provide examples of excellence to residents, medical students, and other health professionals. Funding for fellows has never been provided in the traditional way through the Ministry of Health or the Ministry of Advanced Education. Each Canadian centre has over the years found novel ways to fund fellowship programs, and many centres have used value-adds from procurement programs. These sources of funding are eroding as provincial government agencies are beginning to assume procurement responsibilities and local flexibility to fund fellowships is lost. In particular, provincial government agencies feel that valuable financial resources should be restricted to Canadian trainees only, despite the international consensus that fellowship is an essential time for advanced trainees to travel abroad to acquire a broad a range of experience, learn new techniques and approaches, make lifelong research connections, and hopefully return home with these skills and expertise. This article summarizes the long history of EP fellowship training in Canada, as well as EP fellowship experiences at home and abroad by Canadian electrophysiologists, in an attempt to contextualize these new realities.

Anticoagulation management pre- and post atrial fibrillation ablation: a survey of canadian centres.

BACKGROUND: Anticoagulation in patients undergoing atrial fibrillation (AF) ablation is crucial to minimize the risk of thromboembolic complications. There are broad ranges of approaches to anticoagulation management pre and post AF ablation procedures. The purpose of this study was to determine the anticoagulation strategies currently in use in patients peri- and post AF ablation in Canada. METHODS: A Web-based national survey of electrophysiologists performing AF ablation in Canada collected data regarding anticoagulation practice prior to ablation, periprocedural bridging, and duration of postablation anticoagulation. RESULTS: The survey was completed by 36 (97%) of the 37 electrophysiologists performing AF ablation across Canada. Prior to AF ablation, 58% of electrophysiologists started anticoagulation for patients with paroxysmal AF CHADS(2) scores of 0 to 1, 92% for paroxysmal AF CHADS(2) scores ≥ 2, 83% for persistent AF CHADS(2) scores of 0 to 1, and 97% for persistent AF CHADS(2) scores ≥ 2. For patients with CHADS(2) 0 to 1, warfarin was continued for at least 3 months by most physicians (89% for paroxysmal and 94% for persistent AF). For patients with CHADS(2) ≥ 2 and with no recurrence of AF at 1 year post ablation, 89% of physicians continued warfarin. CONCLUSIONS: Although guidelines recommend long-term anticoagulation in patients with CHADS(2) ≥ 2, 11% of physicians would discontinue warfarin in patients with no evidence of recurrent AF 1 year post successful ablation. Significant heterogeneity exists regarding periprocedural anticoagulation management in clinical practice. Clinical trial evidence is required to guide optimal periprocedural anticoagulation and therapeutic decisions regarding long-term anticoagulation after an apparently successful catheter ablation for AF.

Psychological impact of surveillance in patients with a defibrillator lead under advisory: a prospective evaluation.

BACKGROUND: Implantable cardioverter defibrillator (ICD) leads are subject to technical failures and the impact of the resulting public advisories on patient welfare is unclear. The psychological status of patients who received an advisory for their Medtronic Fidelis ICD lead (Medtronic Inc., Minneapolis, MN, USA) and followed either by self-surveillance for alarm or home monitoring with CareLink was evaluated prospectively and compared to patients with ICDs not under advisory. METHODS: One hundred sixty consecutive consenting patients (90 alarms, 24 Carelinks, 46 controls) were recruited within 1.5 years of advisory notification. Advisory patients were seen immediately before being told that the automatic lead surveillance utilized since the advisory had been inadequate in warning of impending fracture, as well as 1 and 6 months after programming was optimized. Depression, anxiety, quality of life (QoL), and ICD-related concerns were assessed. RESULTS: Symptoms of depression and state anxiety were experienced by 31% and 48% of patients, respectively. QoL was impaired on all subscales. No significant group differences in distress and ICD-related concerns emerged at baseline or at follow-up. At baseline, alarm patients reported greater limitations because of body pain compared to controls (P < 0.05). All patients showed a significant reduction in body pain-related QoL at the final versus first two evaluations (P < 0.001). Advisory patients were significantly less satisfied with surveillance at follow-up than at baseline (P < 0.05). CONCLUSIONS: There was limited evidence for worse psychosocial functioning in those at risk for ICD lead fracture, irrespective of surveillance method. However, many control and advisory patients experienced chronic distress for which counseling may prove beneficial.

Assessment of the sensitivity of detecting drug-induced QTc changes using subject-specific rate correction.

AIMS: To quantify the sensitivity of QT heart-rate correction methods for detecting drug-induced QTc changes in thorough QT studies. METHODS: Twenty-four-hour Holter ECGs were analyzed in 66 normal subjects during placebo and moxifloxacin delivery (single oral dose). QT and RR time series were extracted. Three QTc computation methods were used: (1) Fridericia's formula, (2) Fridericia's formula with hysteresis reduction, and (3) a subject-specific approach with transfer function-based hysteresis reduction and three-parameter non-linear fitting of the QT-RR relation. QTc distributions after placebo and moxifloxacin delivery were compared in sliding time windows using receiver operating characteristic (ROC) curves. The area under the ROC curve (AUC) served as a measure to quantify the ability of each method to detect moxifloxacin-induced QTc prolongation. RESULTS: Moxifloxacin prolonged the QTc by 10.6 ± 6.6 ms at peak effect. The AUC was significantly larger after hysteresis reduction (0.87 ± 0.13 vs. 0.82 ± 0.12, p<0.01) at peak effect, indicating a better discriminating capability. Subject-specific correction further increased the AUC to 0.91 ± 0.11 (p<0.01 vs. Fridericia with hysteresis reduction). The performance of the subject-specific approach was the consequence of a substantially lower intra-subject QTc standard deviation (5.7 ± 1.1 ms vs. 8.8 ± 1.2 ms for Fridericia). CONCLUSION: The ROC curve provides a tool for quantitative comparison of QT heart rate correction methods in the context of detecting drug-induced QTc prolongation. Results support a broader use of subject-specific QT correction.