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Background: Atrial fibrillation (AF) and heart failure (HF) frequently coexist and can be challenging to treat. Pharmacologically based rhythm control of AF has not proven to be superior to rate control. Ablation-based rhythm control was compared with rate control to evaluate if clinical outcomes in patients with HF and AF could be improved. Methods: This was a multicenter, open-label trial with blinded outcome evaluation using a central adjudication committee. Patients with high-burden paroxysmal (>4 episodes in 6 months) or persistent (duration Results: From December 1, 2011, to January 20, 2018, 411 patients were randomly assigned to ablation-based rhythm control (n=214) or rate control (n=197). The primary outcome occurred in 50 (23.4%) patients in the ablation-based rhythm-control group and 64 (32.5%) patients in the rate-control group (hazard ratio, 0.71 [95% CI, 0.49–1.03]; P =0.066). Left ventricular ejection fraction increased in the ablation-based group (10.1±1.2% versus 3.8±1.2%, P =0.017), 6-minute walk distance improved (44.9±9.1 m versus 27.5±9.7 m, P =0.025), and NT-proBNP demonstrated a decrease (mean change –77.1% versus –39.2%, P P =0.0036), as did the AF Effect on Quality of Life score (least-squares mean difference of 6.2 [95% CI, 1.7–10.7]; P =0.0005). Serious adverse events were observed in 50% of patients in both treatment groups. Conclusions: In patients with high-burden AF and HF, there was no statistical difference in all-cause mortality or HF events with ablation-based rhythm control versus rate control; however, there was a nonsignificant trend for improved outcomes with ablation-based rhythm control over rate control. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01420393.

Item does not contain fulltext BACKGROUND: Cardiac implantable electronic device infection is a major complication that usually requires device removal. PADIT (Prevention of Arrhythmia Device Infection Trial) was a large cluster crossover trial of conventional versus incremental antibiotics. OBJECTIVES: This study sought to investigate independent predictors of device infection in PADIT and develop a novel infection risk score. METHODS: In brief, over 4 6-month periods, 28 centers used either conventional or incremental prophylactic antibiotic treatment in all patients. The primary outcome was hospitalization for device infection within 1 year (blinded endpoint adjudication). Multivariable logistic prediction modeling was used to identify the independent predictors and develop a risk score for device infection. The prediction models were internally validated with bootstrap methods. RESULTS: Device procedures were performed in 19,603 patients, and hospitalization for infection occurred in 177 (0.90%) within 1 year of follow-up. The final prediction model identified 5 independent predictors of device infection (prior procedures [P], age [A], depressed renal function [D], immunocompromised [I], and procedure type [T]) with an optimism-corrected C-statistic of 0.704 (95% confidence interval: 0.660 to 0.744). A PADIT risk score ranging from 0 to 15 points classified patients into low (0 to 4), intermediate (5 to 6) and high (>/=7) risk groups with rates of hospitalization for infection of 0.51%, 1.42%, and 3.41%, respectively. CONCLUSIONS: This study identified 5 independent predictors of device infection and developed a novel infection risk score in the largest cardiac implantable electronic device trial to date, warranting validation in an independent cohort. The 5 independent predictors in the PADIT score are readily adopted into clinical practice. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot]; NCT01002911).

Background The Prevention of Arrhythmia Device Infection Trial (PADIT) investigated whether intensification of perioperative prophylaxis could prevent cardiac implantable electronic device (CIED) infections. Compared with a single dose of cefazolin, the perioperative administration of cefazolin, vancomycin, bacitracin, and cephalexin did not significantly decrease the risk of infection. Our objective was to compare the microbiology of infections between study arms in PADIT. Methods This was a post hoc analysis. Differences between study arms in the microbiology of infections were assessed at the level of individual patients and at the level of microorganisms using the Fisher exact test. Results Overall, 209 microorganisms were reported from 177 patients. The most common microorganisms were coagulase-negative staphylococci (CoNS; 82/209 [39.2%]) and S. aureus (75/209 [35.9%]). There was a significantly lower proportion of CoNS in the incremental arm compared with the standard arm (30.1% vs 46.6%; P = .04). However, there was no significant difference between study arms in the frequency of recovery of other microorganisms. In terms of antimicrobial susceptibility, 26.5% of microorganisms were resistant to cefazolin. CoNS were more likely to be cefazolin-resistant in the incremental arm (52.2% vs 26.8%, respectively; P = .05). However, there was no difference between study arms in terms of infections in which the main pathogen was sensitive to cefazolin (77.8% vs 64.3%; P = .10) or vancomycin (90.8% vs 90.2%; P = .90). Conclusions Intensification of the prophylaxis led to significant changes in the microbiology of infections, despite the absence of a decrease in the overall risk of infections. These findings provide important insight on the physiopathology of CIED infections. Trial registration NCT01002911.

Background Infection of implanted medical devices has catastrophic consequences. For cardiac rhythm devices, pre-procedural cefazolin is standard prophylaxis but does not protect against methicillin-resistant gram-positive organisms, which are common pathogens in device infections. Objective This study tested the clinical effectiveness of incremental perioperative antibiotics to reduce device infection. Methods The authors performed a cluster randomized crossover trial with 4 randomly assigned 6-month periods, during which centers used either conventional or incremental periprocedural antibiotics for all cardiac implantable electronic device procedures as standard procedure. Conventional treatment was pre-procedural cefazolin infusion. Incremental treatment was pre-procedural cefazolin plus vancomycin, intraprocedural bacitracin pocket wash, and 2-day post-procedural oral cephalexin. The primary outcome was 1-year hospitalization for device infection in the high-risk group, analyzed by hierarchical logistic regression modeling, adjusting for random cluster and cluster-period effects. Results Device procedures were performed in 28 centers in 19,603 patients, of whom 12,842 were high risk. Infection occurred in 99 patients (1.03%) receiving conventional treatment, and in 78 (0.78%) receiving incremental treatment (odds ratio: 0.77; 95% confidence interval: 0.56 to 1.05; p = 0.10). In high-risk patients, hospitalization for infection occurred in 77 patients (1.23%) receiving conventional antibiotics and in 66 (1.01%) receiving incremental antibiotics (odds ratio: 0.82; 95% confidence interval: 0.59 to 1.15; p = 0.26). Subgroup analysis did not identify relevant patient or site characteristics with significant benefit from incremental therapy. Conclusions The cluster crossover design efficiently tested clinical effectiveness of incremental antibiotics to reduce device infection. Device infection rates were low. The observed difference in infection rates was not statistically significant. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot] [PADIT]; NCT01002911)

Background Subcutaneous implantable cardioverter-defibrillators provide an alternative to transvenous defibrillation but require higher shock outputs and offer no antitachycardia pacing. The Substernal Pacing Acute Clinical Evaluation (SPACE) study evaluated the feasibility of pacing from an extravascular substernal location. Objectives The primary purpose of the SPACE study was to characterize pacing from the substernal space. Secondary objectives included evaluating extracardiac stimulation and recording electrograms. Methods The SPACE study prospectively evaluated the feasibility of pacing with a commercially available electrophysiology catheter acutely implanted in the substernal space via minimally invasive subxiphoid access. Pacing data were collected in ≥7 vectors using constant current stimulation up to 20 mA and pulse width up to 10 ms. Results Catheter placement was successful in all 26 patients who underwent the procedure, with a mean placement time of 11.7 ± 10.1 minutes. Eighteen patients (69%) had successful ventricular capture in ≥1 tested vector. The mean pacing threshold at a pulse width of 10 ms was 7.3 ± 4.2 mA across all vectors (5.8 ± 4.4 V). Failed capture was generally associated with suboptimal catheter placement or presumed air ingression. A low level of extracardiac stimulation was observed in 1 patient. The mean R-wave amplitude ranged from 2.98 to 4.11 mV in the unipolar configuration and from 0.83 to 3.95 mV in the bipolar configuration. Conclusion The data from the SPACE study demonstrate that pacing is feasible from the extravascular substernal location. A substernal electrode configuration has the potential to provide pacing in a future extravascular device without need for intracardiac hardware placement.

Background/objective We compared health-related quality of life (HRQoL) in patients randomized to escalated therapy and those randomized to ablation for ventricular tachycardia in the VANISH trial. Methods HRQoL was assessed among VANISH patients at baseline and 3-, 6-, and 12-month follow-up visits. Four validated instruments were used: the SF-36, the implanted cardioverter defibrillator (ICD) Concerns questionnaire (ICDC), the Hospital Anxiety and Depression Scale (HADS), and the EuroQol five dimensions questionnaire (EQ-5D). Linear mixed-effects modeling was used for repeated measures with SF-36, HADS, ICDC, and EQ-5D as dependent variables. In a second model, treatment was subdivided by amiodarone use prior to enrollment. Results HRQoL did not differ significantly between those randomized to ablation or escalated therapy. On subgroup analysis, improvement in SF-36 measures was seen at 6 months in the ablation group for social functioning (63.5-69.3, P = 0.03) and energy/fatigue (43.0-47.9, P = 0.01). ICDC measures showed a reduction in ICD concern in the ablation group at 6 months (10.4-8.7, P = 0.01) and a reduction in ICD concern in the escalated therapy group at 6 months (10.9-9.4, P = 0.04). EQ-5D measures showed a significant improvement in overall health in ablation patients at 6 months (63.4-67.3, P = 0.04). Conclusion Patients in the VANISH study randomized to ablation did not have a significant change in quality of life outcomes compared to those randomized to escalated therapy. Some subgroup findings were significant, as those randomized to ablation showed persistent improvement in SF-36 energy/fatigue and ICD concern, and transient improvement in SF-36 social functioning and EQ-5D overall health.

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.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.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.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.).

Background The VANISH trial (Ventricular Tachycardia Ablation Versus Escalated Antiarrhythmic Drug Therapy in Ischemic Heart Disease) compared the effectiveness of escalated antiarrhythmic drug therapy to catheter ablation in patients with prior myocardial infarction, an implanted defibrillator, and ventricular tachycardia (VT). The effectiveness of these interventions in patients on sotalol versus amiodarone was compared. Methods and Results Analysis was conducted based on whether patients had recurrent VT, despite amiodarone (amio-refractory) or nonamiodarone drugs (sotalol-refractory). Outcomes included death, VT storm, appropriate implantable cardioverter defibrillator shock, and any ventricular arrhythmia. At baseline, 169 (65.2%) were amio-refractory, and 90 (34.7%) were sotalol-refractory (1 patient on procainamide rather than sotalol). Amio-refractory patients had more renal insufficiency (23.7% versus 10%; P =0.0008), worse New York Heart Association class (82.3% II/III versus 65.5%; P =0.0003), and lower ejection fraction (29±9.7% versus 35.2±11%; P P =0.020). Sotalol-refractory patients had trends toward higher mortality and VT storm with ablation, with no effect on implantable cardioverter defibrillator shocks. Within the escalated drug therapy arm, amio-refractory patients had a higher rate of the composite outcome (hazard ratio, 1.94; 95% confidence interval, 1.14–3.29; P =0.0144) and a trend to higher mortality (hazard ratio, 2.40; 95% confidence interval, 0.93–6.22; P =0.07), whereas mortality was not different between amio- and sotalol-refractory patients within the ablation treatment group. Conclusions Patients with amio-refractory VT have a higher rate of ventricular arrhythmia and mortality than those with sotalol-refractory VT and derive greater benefit of catheter ablation than for patients with sotalol-refractory VT who are switched to amiodarone. CLINICAL TRIAL REGISTRATION URL: https://clinicaltrials.gov . Unique identifier: NCT00905853.

BACKGROUND Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations. METHODS AND RESULTS Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P < 0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P < 0.001). CONCLUSIONS Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

LIA and LinoxIntroduction Medtronic's Lead Integrity Alert (LIA) software algorithm is useful for detecting abnormal parameters across various ICD-lead families. However, its utility in the assessment of the Biotronik Linox™ family of high-voltage (HV) leads is unknown. Methods We conducted a retrospective cohort study to assess the performance of the LIA algorithm to detect abnormalities and lead failure in Linox ICD-leads. All LIA-enabled Medtronic devices connected to an active Linox lead were included. The alerts were adjudicated by 2 blinded electrophysiologists and correlated with clinical data. Results Between 2008 and 2012, data from 208 patients with 564 patient-years of follow-up were available for analysis. The median follow-up duration was 32 (IQR 21–41 months). Twenty-one LIA triggers were noted in 20 different patients. The median delay until a positive LIA was 32 months (IQR 21–41 months) postimplant with a 5-year lead survival free from LIA of 76%. Ninety-five percent (19/20) LIA alerts were true lead failures. The most common LIA triggers were short V–V intervals (85%) and nonsustained ventricular tachycardia (85%). Abrupt changes of the ICD-lead impedance occurred in 5/20 triggers. Inappropriate ICD-shocks were strongly associated with a positive LIA (30% vs. 7.4%; P = 0.006). Of the explanted Linox leads 53% had visible abnormalities. The sensitivity, specificity, and positive predictive value for lead failure in the presence of a LIA trigger were 87%, 99.5%, and 95.2%, respectively. Conclusions A positive LIA trigger in Biotronik Linox ICD-leads is highly predictive of lead failure. LIA is useful in ongoing surveillance of lead performance.

Introduction: The VANISH trial enrolled patients with prior myocardial infarction, an implanted defibrillator and ventricular tachycardia (VT) despite antiarrhythmic (AAD) drugs and compared the effectiveness of escalated AAD therapy to catheter ablation. We sought to compare the effectiveness of these interventions in patients with sotalol-refractory VT versus amiodarone-refractory VT. Methods: All patients enrolled in the VANISH study were included (n=259). VT recurrence was compared in patients despite amiodarone (amio-refractory) as compared to non-amiodarone drugs (sotalol-refractory). Outcomes were a composite of death, VT storm, appropriate ICD shock, each of these components and any ventricular arrhythmia. Results: At baseline, 169 (65.2%) were amio-refractory and 90 (34.7%) were sotalol-refractory (1 patient was enrolled with VT despite procainamide). Amio-refractory patients had more renal insufficiency (23.7% vs 10%, p=0.0008), worse NYHA class (82.3% II/III vs 65.5%, p=0.0003), and lower ejection fraction (29 ± 9.7% vs 35.2 ± 11%, p Conclusions: The benefit of catheter ablation is greater for patients with amio-refractory VT than for patients with sotalol-refractory VT who are then switched to amiodarone.

ObjectivesAn evidence-based emergency department (ED) atrial fibrillation and flutter (AFF) pathway was developed to improve care. The primary objective was to measure rates of new anticoagulation (AC) on ED discharge for AFF patients who were not AC correctly upon presentation.MethodsThis is a pre-post evaluation from April to December 2013 measuring the impact of our pathway on rates of new AC and other performance measures in patients with uncomplicated AFF solely managed by emergency physicians. A standardized chart review identified demographics, comorbidities, and ED treatments. The primary outcome was the rate of new AC. Secondary outcomes were ED length of stay (LOS), referrals to AFF clinic, ED revisit rates, and 30-day rates of return visits for congestive heart failure (CHF), stroke, major bleeding, and death.ResultsED AFF patients totalling 301 (129 pre-pathway [PRE]; 172 post-pathway [POST]) were included; baseline demographics were similar between groups. The rates of AC at ED presentation were 18.6% (PRE) and 19.7% (POST). The rates of new AC on ED discharge were 48.6 % PRE (95% confidence interval [CI] 42.1%-55.1%) and 70.2% POST (62.1%-78.3%) (20.6% [pppConclusionsThe evidence-based pathway led to an improvement in the rate of patients with new AC upon discharge, a reduction in ED LOS, and decreased revisit rates for CHF.

Early Failure of the Biotronik LinoxIntroduction The Linox and Durata implantable cardioverter defibrillator (ICD) leads were introduced to British Columbia (BC) in 2008. We determined their performance and the potential risk factors for lead failure in a large population-based patient registry. Methods and Results We used the BC Cardiac Registry, a mandatory Governmental database of ICD implants, to identify all recipients of Linox and Durata leads in BC between October 2008 and April 2012, and those subsequently undergoing reoperation. Lead failure was defined as recurrent nonphysiological high-rate sensing unrelated to external electromagnetic interference or T-wave oversensing; a sudden rise in impedance unrelated to perforation or lead dislodgement; or abnormal lead parameters with definite evidence of lead fracture or insulation failure. We determined the estimated cumulative lead survival by the Kaplan–Meier method, and the risk factors for lead failure in a proportional hazards model. Over a median of 39 (27–50) months, the Linox failed more frequently than the Durata (16/477 [3.4%] vs. 4/838 [0.4%]; P < 0.001), and had a significantly lower estimated cumulative survival (91.6 [80.6–96.5]% vs. 99.4 [98.4–99.8]% at 5 years; P < 0.0001). Linox failure was characterized by high-rate nonphysiological sensing (11 cases), and/or a sudden impedance rise (7 cases). Insulation failure was clearly confirmed in 6 cases of Linox failure. Female sex was a significant risk factor for Linox failure (adjusted HR = 2.1[1.3–3.4]; P = 0.004). Conclusions This multicenter registry indicates a high rate of Linox lead failure, particularly in female patients. Ongoing surveillance of the Linox ICD lead performance is recommended.

Background Conflicting data exist regarding the association between left ventricular (LV) lead position and benefit from cardiac resynchronization therapy. We evaluated the relationships between LV lead positions and the risk of death or hospitalization for heart failure (HF) in the cardiac resynchronization therapy arm of the R esynchronization-Defibrillation for A mbulatory Heart F ailure T rial (RAFT). Methods LV lead position was categorized by site investigator (MD) and in a chest radiograph core laboratory (CXR) as "anterior," "lateral," or "posterior" in the short axis, and "basal," "mid," or "apical" in the long axis. Agreement between MD and CXR LV lead position classification was evaluated and the independent relationship between LV lead position and clinical outcome was assessed using Cox multivariable models. Results Agreement between MD and CXR LV lead position was poor (κ ≤ 0.26). Over 39 ± 20 months, 140 of 447 (31.3%) patients met the RAFT primary end point (death or HF hospitalization). In adjusted analyses, neither MD-determined nor CXR-determined anterior or apical LV lead position was significantly associated with the primary outcome. However, CXR-defined apical LV lead position was associated with a higher risk of HF hospitalization (hazard ratio, 1.99; P = 0.004). Conclusions Poor agreement between implanting physician and core lab CXR-based categorizations of LV lead position was observed. Neither categorization method resulted in significant associations between apical or anterior LV lead position and the risk of the composite primary outcome of death or heart failure hospitalization. However, CXR-defined apical lead position was associated with increased risk of HF hospitalization.

Background The St. Jude Medical Riata family of implantable cardioverter-defibrillator (ICD) leads has demonstrated a high rate of externalized conductors and electrical failure. Objective Given similar design elements of Durata to Riata, the purpose of this study was to assess the rates of failure of the Riata ST Optim and Durata lead families in Canada. Methods All Canadian ICD-implanting centers were invited to submit follow-up information on all Optim-coated ICD leads implanted. Electrical failure was defined as a rapid change in impedance or pacing capture threshold leading to lead revision, or oversensing due to noise. Externalized conductors were defined as appearance of conductor wires outside the lead body. Systematic fluoroscopic screening for externalized conductors was not performed. Results As of December 1, 2012, 15 of 25 centers provided data on 3981 leads (44% of those sold in Canada during the same timeframe): 3477 Durata and 504 Riata ST Optim leads. The most common model numbers were 7122 (1516 leads [38%]), 7121 (707 leads [18%]), and 7120 (622 leads [16%]). Mean follow-up duration from implant to December 1, 2012, was 4.47 ± 0.48 years for Riata ST Optim leads and 2.00 ± 1.10 years for Durata leads. The annual rate of lead failure was 0.27% per year for Riata ST Optim leads and 0.24% per year for Durata leads. No instances of externalized conductors were identified in the failed leads. No deaths were attributed to lead failure; however, 2 patients experienced inappropriate shocks due to lead failure. Conclusion The overall electrical failure rates of the Riata ST Optim and Durata leads appear to be low, and no instances of externalized conductors were observed.

Background A unique form of lead failure has been described in the Riata (8-F) and Riata ST (7-F) silicone defibrillation lead degradation of the outer insulation, resulting in the externalization of conductor cables. Objective To assess rates of lead revision due to lead failure in Riata leads affected by the Riata advisory. Methods Nineteen implantable cardioverter-defibrillator implant and follow-up centers were surveyed. Results As of March 1, 2012, there were 5043 known affected leads implanted in Canada. Data on 4358 (86.4%) leads were obtained; 65.3% of these were Riata (8-F) and 32.4% were Riata ST (7-F) leads. The median time from implant to last follow-up was 5 years. Electrical abnormalities were reported in 4.6% of the affected leads; 8.0% of these were found to have concomitant radiographic evidence of externalization. The rate of electrical failure was higher in the 8-F (5.2%) vs 7-F (3.3%) leads ( P = .007). Oversensing with or without inappropriate shocks was reported in 39.8% of the leads with confirmed failure. Abnormally high or low impedance values (29.9%) and elevated pacing capture thresholds (43.8%) were frequently reported. One death (0.5%) attributed to lead failure was reported. Among the leads that were replaced, 21% were extracted. Two major complications (1.0%) were attributed to extraction of these leads. Conclusions The overall rate of lead failure in the Riata (8-F) and Riata ST (7-F) leads is higher than previously reported by using passive surveillance data. The impact of recent advisories related to these leads is not yet apparent.

International audience; AIMS: The ALternate Site Cardiac ResYNChronization (ALSYNC) study evaluated the feasibility and safety of left ventricular endocardial pacing (LVEP) using a market-released pacing lead implanted via a single pectoral access by a novel atrial transseptal lead delivery system. METHODS AND RESULTS: ALSYNC was a prospective clinical investigation with a minimum of 12-month follow-up in 18 centres of cardiac resynchronization therapy (CRT)-indicated patients, who had failed or were unsuitable for conventional CRT. The ALSYNC system comprises the investigational lead delivery system and LVEP lead. Patients required warfarin therapy post-implant. The primary study objective was safety at 6-month follow-up, which was defined as freedom from complications related to the lead delivery system, implant procedure, or the lead ≥70%. The ALSYNC study enrolled 138 patients. The LVEP lead implant success rate was 89.4%. Freedom from complications meeting the definition of primary endpoint was 82.2% at 6 months (95% CI 75.6-88.8%). In the study, 14 transient ischaemic attacks (9 patients, 6.8%), 5 non-disabling strokes (5 patients, 3.8%), and 23 deaths (17.4%) were observed. No death was from a primary endpoint complication. At 6 months, the New York Heart Association class improved in 59% of patients, and 55% had LV end-systolic volume reduction of 15% or greater. Those patients enrolled after CRT non-response showed similar improvement with LVEP. CONCLUSIONS: The ALSYNC study demonstrates clinical feasibility, and provides an early indication of possible benefit and risk of LVEP. CLINICAL TRIAL: NCT01277783

Background Following recent cases of nonphysiologic noise noted early after defibrillator implantation, the Canadian Heart Rhythm Society Device Committee decided to evaluate the implications of this problem. Objective To determine the incidence and consequences of nonphysiologic noise early after defibrillator implantation. Methods The Canadian Heart Rhythm Society Device Committee surveyed all Canadian defibrillator implanting centers regarding their implant volumes and number of cases where nonphysiologic noise had been noted early ( Results Responses were obtained from 20 of 23 surveyed implanting centers, with a total implant volume of 4960 defibrillators per year. The occurrence of nonphysiologic noise early after implantation was noted in 25 cases over the preceding 2 years (0.25%). Noise was detected in devices of all 3 of the leading volume device manufacturers. There were 2 cases of inappropriate shocks and 2 cases of symptomatic pacing inhibition. In 4 cases, removal of the lead from the header and retesting with the analyzer confirmed normal lead function. In all cases, the noise resolved within 24 hours. Conclusion Nonphysiologic noise early after defibrillator implantation was noted in 0.25% of procedures and was not limited to one specific manufacturer. This noise may result in an inappropriate shock or inhibition of pacing in a pacemaker-dependent patient. This transient phenomenon, possibly related to fluid and/or air in the header, appears to always resolve without surgical intervention.

Cardiac pacemakers and implantable cardioverter/defibrillators are becoming more common due to expanded indications and increasing patient survival. In addition, these device systems are being implanted in younger patients, which increases their necessity for long-term durability. Device adverse events can be seen early, during or following implantation (perforation, lead dislodgement, infection), or late (lead fraction, insulation failure or device system infection). These adverse events can, at least in part, be attributed to intrinsic device system structure. Since the initial pacemakers and implantable cardioverter/defibrillators, many modifications in both device system hardware and software have been made to enhance both their durability and function. The current era of devices appear to have made adjustments for previous inadequacies and promise to be reliable and to function well. Despite this, however, it is necessary for clinicians to be aware of possible malfunctions, their warning signs, and the appropriate course of action should these malfunctions be encountered. In this review we describe the common device system malfunctions and device system insertion complications.

Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations.Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P0.001).Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

Background— Social health is a dimension of quality of life, and refers to people’s involvement in, and satisfaction with social roles, responsibilities, and activities. The implantable cardioverter-defibrillator is associated with changes in overall quality of life, but little is known about sex differences in individual trajectories of change in social health. Methods and Results— We prospectively measured changes in 3 subscales of the SF-36v2 generic health questionnaire (role physical, role emotional, and social functioning), 2 Patient-Reported Outcomes Measurement Information System short forms (satisfaction with participation in social roles and satisfaction with participation in discretionary social activities), and the Florida Patient Acceptance Survey before and at 1, 2, and 6 months after implantation. Individual growth models of temporal change were estimated. The scores of the 6 indicators improved with time. The unconditional model demonstrated significant (fixed effects: P P Conclusions— Men and women differed in their trajectories of change in social health, both in terms of their starting points (ie, baseline scores) and their rates of change.

Background Malignant ventricular tachyarrhythmia early after cardiac surgery is an uncommon arrhythmic complication but has a negative impact on mortality. The purpose of this study was to evaluate the incidence of new-onset sustained postoperative ventricular tachycardia-ventricular fibrillation and to identify risk factors for the dysrhythmia. Methods Demographic, clinical, operative, and postoperative data, including a variable of postoperative ventricular tachycardia, were prospectively obtained from 4,748 patients undergoing nonemergency coronary artery bypass graft and(or) valve replacement with no history of sustained ventricular tachycardia or sudden death. A detailed analysis was performed to define the risk factors for the ventricular tachycardia and the prognostic impact of the arrhythmia on 30-day mortality was evaluated. Results Forty-five patients (0.95%) had sustained ventricular tachycardia or ventricular fibrillation and the initial episode occurred 3.9 ± 5.2 days (mean ± standard deviation) after surgery. By multivariate analysis, female sex (odds ratio, 1.982), left ventricular ejection fraction ( 50%, 4.771), the presence of pulmonary hypertension (3.066), the presence of systemic hypertension (2.391), and pump time (per 10 minutes, 1.085) were independently associated with the dysrhythmias. Early mortality of patients with the arrhythmia was 28.9%, strikingly higher than that of patients without ventricular tachycardia/ventricular fibrillation (1.9%). Conclusions Left ventricular ejection fraction is the strongest risk factor for new-onset postoperative sustained ventricular tachycardia-ventricular fibrillation; female sex, pump time, pulmonary and systemic hypertension are independent predictors of the dysrhythmias; the arrhythmia is associated with increased 30-day mortality after cardiac surgery.

Background Cable externalization and insulation abrasion are known to occur with the St Jude Medical Riata leads under advisory. The distribution of these abnormalities and how they relate to clinical presentation have not been well described. Objective In this study, we sought to determine the relationship between structural lead failure and clinical presentation by using the analysis of returned Riata products in Canada. Methods The analyses of returned Riata products in Canada were obtained from St Jude Medical, Sylmar, CA. These data were correlated with the clinical presentation of patients just before lead removal from service. Results As of May 1, 2013, there were 263 returned Riata leads in Canada. Of these, 43 (16.8%) were found to have insulation abrasion that was due to either lead-can or lead-other device interaction (70%) or inside-out abrasion (27.9%). The predilection of lead-to-can abrasion was seen in the Riata 7-F leads (84.2% vs 58.4%; P = .07), while inside-out abrasion was more common in the Riata 8-F leads (37.5% vs 15.8%; P = .12). Electrical abnormalities were frequent (20 of 31 [65.4%]) and most often due to electrical noise (45.2%), although inappropriate shocks were present (25.8%). Death occurred in 1 of 43 (2.3%) of those patients with an insulation defect in the lead-can abrasion group. Conclusion Lead-can abrasion is the most common form of insulation defect in the Riata group of leads under advisory. Management of this group of leads under advisory should not neglect the issue of lead-can abrasion, in addition to detection of cable externalization.

The Linox and Durata implantable cardioverter defibrillator (ICD) leads were introduced to British Columbia (BC) in 2008. We determined their performance and the potential risk factors for lead failure in a large population-based patient registry.We used the BC Cardiac Registry, a mandatory Governmental database of ICD implants, to identify all recipients of Linox and Durata leads in BC between October 2008 and April 2012, and those subsequently undergoing reoperation. Lead failure was defined as recurrent nonphysiological high-rate sensing unrelated to external electromagnetic interference or T-wave oversensing; a sudden rise in impedance unrelated to perforation or lead dislodgement; or abnormal lead parameters with definite evidence of lead fracture or insulation failure. We determined the estimated cumulative lead survival by the Kaplan-Meier method, and the risk factors for lead failure in a proportional hazards model. Over a median of 39 (27-50) months, the Linox failed more frequently than the Durata (16/477 [3.4%] vs. 4/838 [0.4%]; P0.001), and had a significantly lower estimated cumulative survival (91.6 [80.6-96.5]% vs. 99.4 [98.4-99.8]% at 5 years; P0.0001). Linox failure was characterized by high-rate nonphysiological sensing (11 cases), and/or a sudden impedance rise (7 cases). Insulation failure was clearly confirmed in 6 cases of Linox failure. Female sex was a significant risk factor for Linox failure (adjusted HR = 2.1[1.3-3.4]; P = 0.004).This multicenter registry indicates a high rate of Linox lead failure, particularly in female patients. Ongoing surveillance of the Linox ICD lead performance is recommended.

The Canadian Heart Rhythm Society (CHRS) Device Advisory Committee was commissioned to respond to advisories regarding cardiac rhythm device and lead performance on behalf of the CHRS. In the event of an advisory, the Chair uses an e-mail network to disseminate advisory information to Committee members broadly representative of the Canadian device community. A consensus recommendation is prepared by the Committee and made available to all Canadian centres on the CHRS Web site after approval by the CHRS executive. This collaborative approach using an e-mail network has proven very efficient in providing a rapid national response to device advisories. The network is an ideal tool to collect specific data on implanted device system performance and allows for prompt reporting of clinically relevant data to front-line clinicians and patients.

Background Acute end points of catheter ablation for ventricular tachycardia ( VT ) remain incompletely defined. The aim of this study is to identify causes for failure in patients with structural heart disease and to assess the relation of this acute outcome to longer‐term management and outcomes. Methods and Results From 2002 to 2010, 518 consecutive patients (84% male, 62±14 years) with structural heart disease underwent a first ablation procedure for sustained VT at our institution. Acute ablation failure was defined as persistent inducibility of a clinical VT . Acute ablation failure was seen in 52 (10%) patients. Causes for failure were: intramural free wall VT in 13 (25%), deep septal VT in 9 (17%), decision not to ablate due to proximity to the bundle of His, left phrenic nerve, or a coronary artery in 3 (6%), and endocardial ablation failure with inability or decision not to attempt to access the epicardium in 27 (52%) patients. In multivariable analysis, ablation failure was an independent predictor of mortality (hazard ratio 2.010, 95% CI 1.147 to 3.239, P =0.004) and VT recurrence (hazard ratio 2.385, 95% CI 1.642 to 3.466, P Conclusions With endocardial or epicardial ablation, or both, acute ablation failure was seen in 10% of patients, largely due to anatomic factors. Persistence of a clinical VT is associated with recurrence and comparatively higher mortality.

There is a relative paucity of data linking inappropriate implantable cardioverter-defibrillator (ICD) shocks to adverse clinical outcomes.To examine the association between inappropriate ICD shocks and mortality or heart transplantation in a large population cohort.A cohort study which included all subjects who underwent ICD implantation between 1998 and 2008 and were followed up at our institution.Multivariable Cox regression analyses were conducted to investigate the effect of inappropriate shocks on the risk of death and heart transplantation. Appropriate and inappropriate ICD therapies were modelled as time-dependent covariates.A total of 1698 patients were included. During a median follow-up of 30 months, there were 246 (14.5%) deaths and 42 (2.5%) heart transplants. The incidence of inappropriate shocks was 10% at 1 year and 14% at 2 years. In the adjusted model, inappropriate shocks were not associated with death or transplantation (HR=0.97, 95% CI 0.70 to 1.36, p value=0.873). In contrast, appropriate shocks were associated with adverse outcomes (HR=3.11, 95% CI 2.41 to 4.02, p value0.001). The lack of association between inappropriate shocks and outcomes persisted for those with severely impaired left ventricular function (ejection fraction30%) and for those receiving multiple inappropriate treatments.In this study, we observed no association between inappropriate ICD shocks and increased mortality or heart transplantation, even among those with severely impaired cardiac function. These findings question whether inappropriate ICD shocks lead to adverse outcomes.

Introduction: Atrial fibrillation and flutter (AFF) are the most common arrhythmias presenting to the emergency department. Without anticoagulation, AFF increases stroke risk; individuals with paroxysmal AFF have a similar prognosis. A coordinated ED AFF electronic order-set and management pathway was developed at our institution. The primary objective of this study was to measure rates of appropriate anticoagulation (AAC) on discharge from the ED for patients presenting with AFF not previously on antithrombotic or anticoagulant medications. Secondary objectives included comparison of the following outcomes pre and post-pathway (PRE & POST): AFF Clinic referral rates, ED return rates, and mortality. Methods: This was a retrospective case series of patients presenting to our quarternary care ED with AFF pre and post AFF pathway implementation. Cases were identified using an administrative database covering 120 000 annual ED visits. Trained research assistants and the primary investigator extracted data from the electronic medical record. 20% of all charts were double collected to ensure accuracy (k=0.85). Descriptive variables were described using counts, means, medians and confidence intervals. Chi-square statistics of dependent samples were calculated for the primary outcome. Results: We examined 307 cases of AFF presenting to our ED (n=130 PRE; n=177 POST). Demographic variables were similar PRE and POST: mean age (66.0 [95%CI 63.8-68.3] PRE; 65.0 [63.0-67.0] POST), % male (59.2% PRE; 59.3% POST), presenting rhythm (66.2% A.fib [58.0-74.3] A. flutter 29.2% [21.4-37.0] PRE; 61.0% A.fib [53.8-68.1] A. flutter 17.5% [11.9-23.1] POST), and CHADS2VASC score (2.1 [1.8-2.4] PRE; 1.9 [1.7-2.1] POST). The rate of AAC rose from 39.1% PRE to 77.8% POST (P < 0.01). AFF clinic referral rates increased from 16.9% PRE to 25.4% POST (not significant). ED return rates within 30 days for AFF, CHF, major bleeding and CVA were unchanged. 30 day mortality rates were not statistically different (1.5% PRE vs. 2.8% POST). Conclusion: The implementation of a coordinated ED AFF pathway was associated with significant improvements in the proportion of patients discharged with appropriate anticoagulation who had not previously been on antithrombotic or anticoagulant medications. ED return rates and mortality did not change significantly.

Introduction: Atrial fibrillation and flutter (AFF) are the most common arrhythmias presenting to the emergency department. A coordinated ED AFF electronic order-set and management pathway was developed in collaboration with cardiologists at our institution. The primary objective of this study was to compare the ED length of stay pre and post pathway implementation. Secondary objectives included comparison of the following outcomes pre and post-pathway (PRE & POST): AFF Clinic referral rates, ED return rates, and mortality. Methods: This was a retrospective case series of patients presenting to our quarternary care ED with AFF pre and post AFF pathway implementation. Cases were identified using an administrative database covering 120 000 annual ED visits. Trained research assistants and the primary investigator extracted data from the electronic medical record. 20% of all charts were double collected to ensure accuracy (k=0.85). Descriptive variables were described using counts, means, medians and confidence intervals. Chi-square statistics of dependent samples were calculated for the primary outcome. Results: We examined 307 cases of AFF presenting to our ED (n=130 PRE; n=177 POST). Demographic variables were similar PRE and POST: mean age (66.0 [95%CI 63.8-68.3] PRE; 65.0 [63.0-67.0] POST), % male (59.2% PRE; 59.3% POST), presenting rhythm (66.2% A.fib [58.0-74.3] A. flutter 29.2% [21.4-37.0] PRE; 61.0% A.fib [53.8-68.1] A. flutter 17.5% [11.9-23.1] POST), and CHADS2VASC score (2.1 [1.8-2.4] PRE; 1.9 [1.7-2.1] POST). The mean ED LOS decreased by 72.5 minutes (95% CI -22.9 to -122.1; P < 0.001). AFF clinic referral rates increased from 16.9% PRE to 25.4% POST (not significant). ED return rates within 30 days for AFF, CHF, major bleeding and CVA were unchanged. 30 day mortality rates were not statistically different (1.5% PRE vs. 2.8% POST). Conclusion: A coordinated ED AFF pathway was associated with a significant reduction in ED LOS without significant changes in ED return rates or mortality.

There are more than 200,000 Canadians living with permanent pacemakers or implantable defibrillators, many of whom will require surgery or invasive procedures each year. They face potential hazards when undergoing surgery; however, with appropriate planning and education of operating room personnel, adverse device-related outcomes should be rare. This joint position statement from the Canadian Cardiovascular Society (CCS) and the Canadian Anesthesiologists’ Society (CAS) has been developed as an accessible reference for physicians and surgeons, providing an overview of the key issues for the preoperative, intraoperative, and postoperative care of these patients. The document summarizes the limited published literature in this field, but for most issues, relies heavily on the experience of the cardiologists and anesthesiologists who contributed to this work. This position statement outlines how to obtain information about an individual’s type of pacemaker or implantable defibrillator and its programming. It also stresses the importance of determining if a patient is highly pacemaker-dependent and proposes a simple approach for nonelective evaluation of dependency. Although the document provides a comprehensive list of the intraoperative issues facing these patients, there is a focus on electromagnetic interference resulting from electrocautery and practical guidance is given regarding the characteristics of surgery, electrocautery, pacemakers, and defibrillators which are most likely to lead to interference. The document stresses the importance of preoperative consultation and planning to minimize complications. It reviews the relative merits of intraoperative magnet use vs reprogramming of devices and gives examples of situations where one or the other approach is preferable.

Following recent cases of nonphysiologic noise noted early after defibrillator implantation, the Canadian Heart Rhythm Society Device Committee decided to evaluate the implications of this problem.To determine the incidence and consequences of nonphysiologic noise early after defibrillator implantation.The Canadian Heart Rhythm Society Device Committee surveyed all Canadian defibrillator implanting centers regarding their implant volumes and number of cases where nonphysiologic noise had been noted early (24 hours) after implant over the preceding 2 years. For such cases, information regarding the manufacturer and occurrence of inappropriate shock or inhibition of pacing was reported.Responses were obtained from 20 of 23 surveyed implanting centers, with a total implant volume of 4960 defibrillators per year. The occurrence of nonphysiologic noise early after implantation was noted in 25 cases over the preceding 2 years (0.25%). Noise was detected in devices of all 3 of the leading volume device manufacturers. There were 2 cases of inappropriate shocks and 2 cases of symptomatic pacing inhibition. In 4 cases, removal of the lead from the header and retesting with the analyzer confirmed normal lead function. In all cases, the noise resolved within 24 hours.Nonphysiologic noise early after defibrillator implantation was noted in 0.25% of procedures and was not limited to one specific manufacturer. This noise may result in an inappropriate shock or inhibition of pacing in a pacemaker-dependent patient. This transient phenomenon, possibly related to fluid and/or air in the header, appears to always resolve without surgical intervention.

There are more than 200,000 Canadians living with permanent pacemakers or implantable defibrillators, many of whom will require surgery or invasive procedures each year. They face potential hazards when undergoing surgery; however, with appropriate planning and education of operating room personnel, adverse device-related outcomes should be rare. This joint position statement from the Canadian Cardiovascular Society (CCS) and the Canadian Anesthesiologists' Society (CAS) has been developed as an accessible reference for physicians and surgeons, providing an overview of the key issues for the preoperative, intraoperative, and postoperative care of these patients. The document summarizes the limited published literature in this field, but for most issues, relies heavily on the experience of the cardiologists and anesthesiologists who contributed to this work. This position statement outlines how to obtain information about an individual's type of pacemaker or implantable defibrillator and its programming. It also stresses the importance of determining if a patient is highly pacemaker-dependent and proposes a simple approach for nonelective evaluation of dependency. Although the document provides a comprehensive list of the intraoperative issues facing these patients, there is a focus on electromagnetic interference resulting from electrocautery and practical guidance is given regarding the characteristics of surgery, electrocautery, pacemakers, and defibrillators which are most likely to lead to interference. The document stresses the importance of preoperative consultation and planning to minimize complications. It reviews the relative merits of intraoperative magnet use vs reprogramming of devices and gives examples of situations where one or the other approach is preferable.

BACKGROUND: Patients with PMs or ICDs may be exposed to significant electromagnetic fields (EMF) from high voltage transmission lines (HVTL), which may interact with their device. To our knowledge, the rate of electromagnetic interference (EMI) has not been quantified nor have the circumstances of these EMIs. These were the objectives of the current registry. METHOD: Between February 2012 and March 2014, 18 296 device interrogations from patient visits to the PM/ICD clinic were reviewed (11 640 from PMs and 6 656 from ICDs). Fifty patients were recruited after noise episodes were seen during a routine follow-up interrogation. Only 10% of patients with noise episodes refused recruitment in the registry. Recruited patients were asked to keep a detailed log of their activities and travels. Their devices were then re-interrogated after 1, 4 and 12 weeks. Noise events registered on the devices interrogated in the PM/ICD clinic were correlated with a geographical map of the EMFs created by HVTLs, provided by Hydro-Quebec, the province of Quebec’s hydroelectric producer. RESULTS: Two patients were lost to follow-up. Of the remaining 48, 25 had further interference episodes for a total number of 1,080 episodes. Of these, 985 (91.2%) took place at home, 76 (7.1%), during an unknown activity (no activity recorded in the patient log at the time of the interference) and 19 (1.8%), during travels where a HVTL was identified in the vicinity. All of these travels, but one, were in motor vehicles which acted as a Faraday cage and shielded the patients and device from the electric field generated by the HVTLs. No episode was associated with a movement directly under a HVTL, on foot. There was no difference in the morphology of the noise signals based on the type of activity. A single inappropriate mode switch was noted as a result of the noise episodes. There was no relation between patient reported symptoms and the noise episodes. CONCLUSION: The overall rate of EMI is very low (0.3%) and the majority of episodes occur in the home environment. Despite the large number of patients sampled, there were no episodes of EMI linked to passage under a HVTL, which is reassuring from a public safety standpoint.

The Canadian Heart Rhythm Society (CHRS) Device Advisory Committee was commissioned in 2006 to develop a mechanism for responding to advisories regarding cardiac rhythm device and lead performance.In the event of an advisory, the Chair classifies the advisory as urgent, semi-urgent, or routine based on the nature of the threat to the patient and the number of patients affected. The Chair uses an e-mail network with the committee members to disseminate advisory information and to assemble a consensus recommendation. Committee membership is broadly representative of the Canadian device community, including both academic and nonacademic centers, adult and pediatric specialists, and includes balanced regional representation. Recommendations are approved by the CHRS executive and made available to all implant and follow-up centers on the CHRS website.With the Medtronic Fidelis lead advisory of October 15, 2007, the Chair classified the advisory as semi-urgent and initiated an e-mail discussion and preliminary survey of all Canadian implantable cardioverter-defibrillator (ICD) centers within 3 hours of advisory announcement. A CHRS membership statement was issued within 48 hours. Within 5 working days, sample letters to physicians and patients were posted for local adaptation and distribution. Complete data collection was obtained from all Canadian defibrillator centers. Analyses at 20, 25, 30, and 32 months suggest an accelerating course of failures (3.91% at 32 months, P.0001), with a reduced likelihood of presentation with inappropriate shocks (from 56% to 21%, P = .0003).A collaborative approach using an e-mail network provides a mechanism for a rapid national response to device advisories. The network allows collection of focused data on implanted device system performance and facilitates timely reporting of clinically relevant data to patients and clinicians.

Introduction: Permanent HIS Bundle pacing (HBP) is one of the most physiological ventricular pacing strategies available. Its wide spread adoption is limited due to challenges in HIS mapping, and requires femoral EP mapping to guide lead placement. We investigate whether unipolar pace mapping (PM) using the lead alone is a viable technique to locate the HB for lead deployment. Methods: Patients indicated for ventricular pacing were approached for HBP. An active fixation lead (SelectSecure®3830, Medtronic) inserted through its deflectable sheath was advanced to the right atrium via left pectoral approach.The cathode tip was positioned just outside the tip of the sheath. Unipolar PM was applied at 5V/0.5ms along the tricuspid septal annulus in anterior posterior direction. At the location with 12/12 ECG match to intrinsic QRS, and with pace to QRS delay >30ms, the lead was fixed. Unipolar sensing for HB electrogram was performed with the Medtronic 2090 analyzer (unfiltered, variable gain, sweep speed 50mm/sec). HBP implant thresholds, HB lead implant and fluoroscopy times, intrinsic and paced HV intervals, pre and post QRS and PR intervals were collected. Paired Student t -test was used for analysis. Results: 22 patients (16 male, mean age 69 yrs) underwent HBP. 19 patients had successful HBP, with 3 patients having para-Hisian septal pacing. The mean HBP implants threshold, HB lead implant and fluoroscopy times were 1.67±44V/0.6ms, 43±26min, and 13±12min respectively. The mean intrinsic and paced HV intervals were 60 and 44 ms respectively. After HBP, the QRS duration decreased from 160±44 to 132±43ms (p Conclusions: Unipolar PM of the His bundle using the Medtronic SelectSecure® lead system alone can accurately locate the HB for HBP with acceptable implant time and pacing thresholds. HBP also has the potential value of AVN and ventricular electrical resynchronization benefit. More data with longer-term follow up are needed before considering wide spread adoption.

Introduction: It is known that Cardiac Resynchronization Therapy (CRT) combining right ventricular (RV) apex pacing and left ventricular pacing (LVP) is ineffective in up to 35% of heart failure (HF) patients. Our hypothesis is that RV apical pacing bypasses the rapidly conducting right bundle and may further impede ventricular activation with LBBB hence a more physiological CRT is via HIS Bundle pacing (HBP) and LVP. We report of our early experience with Cardiac Electrical Resynchronization Therapy (CERT) incorporating HBP with LVP in patients with severe HF. Methods: Patients indicated for CRT were approached for CERT. In addition to an atrial and LV lead, patients also received a HBP lead. An active fixation lead (SelectSecure/Site® Medtronic) was used directly for HIS Bundle mapping and pacing. HBP implant thresholds, procedure and fluoroscopy times, pre and post implant QRS, PR interval, and NYHA class were collected. Student t -test was used for analysis. Results: 15 patients (13 male, mean age 70yrs) referred for CRT underwent successful CERT with mean follow up of 3.5±4.3 months. The mean implant HBP threshold, procedure and fluoroscopy time were 1.6V/0.6ms, 150min, and 26min respectively. All patients had QRS shortening with a mean of 64±21ms (pre CERT 182ms, post CERT 118ms, p ) and mean PR shortening of 81±101ms (pre CERT 254ms, post CERT 173ms, p Conclusions: HBP with LVP is effective in achieving electrical resynchronization, and has resulted in early improvement of HF symptoms. Evidence of reverse remodeling is pending. CERT needs to be further validated before considering for wide adoption.

Background Implantable cardioverter defibrillator (ICD) generator advisories present management dilemmas for physicians regarding competing risks of ICD failure and replacement-related complications. There is currently a paucity of long-term data concerning the complications associated with advisory ICD replacement. Objective In a large multicenter advisory ICD generator replacement cohort followed for 12 months, we aimed to assess replacement-related complications by performing a case-control determination of complication risk factors to identify characteristics that could assist with advisory ICD replacement decision making. Methods Twelve large ICD implanting centers reviewed the 1-year follow-up outcome of advisory ICDs replaced between October 2004 and October 2005. The complication cohort was characterized and compared in a nested case-control analysis with age- and gender-matched controls without complications from the same replacement population. Results At the 12 participating institutions, 451 of 2635 advisory ICD devices were replaced (17.1%). Over 355 ± 204 days of follow-up, there were 41 (9.1%) complications; 27 (5.9%) required reoperation and included two deaths. There were 14 minor complications (3.1%). Multivariate analysis demonstrated that the number of previous pocket procedures was associated with an increase in complications and that combined consultant and fellow operators was associated with a decrease in complications compared with a single operator alone. Conclusions Complications from advisory ICD generator replacement are frequent and include infection and, rarely, death. The risk of replacement is increased in patients with multiple previous pocket procedures.

Background Defibrillation threshold (DFT) testing has traditionally been a routine part of implantable cardioverter-defibrillator (ICD) implantation, despite a lack of compelling evidence that it predicts or improves outcomes. In the past, when devices were much less reliable, DFT testing seemed prudent; however, modern ICD systems have such a high rate of successful defibrillation that many electrophysiologists now question whether DFT testing is still worthwhile, particularly since DFT testing may now be the highest acute risk component of ICD implantation. Objective The purpose of this study was to systematically document complications directly attributable to intraoperative DFT testing. Methods We obtained data on DFT-related complications from all 21 adult ICD implant centers in Canada, covering the period from January 1, 2000, to September 30, 2006. Results There were a total of 19,067 ICD implants in Canada during the study period. There were three DFT testing–related deaths, five DFT testing–related strokes, and 27 episodes that required prolonged resuscitation. Two patients had significant clinical sequelae after prolonged resuscitation. Conclusions The risk of severe complications from intraoperative DFT testing appears small, even allowing for the underestimation of its true rate with the current study methodology. These slight but measurable risks must be considered when assessing the risk-benefit ratio of the procedure. Additional data from ongoing prospective ICD registries and/or clinical trials are required.