Background: There is a paucity of Canadian studies using patient-level data to analyze the costs of catheter ablation (CA) for atrial fi brillation (AF). We sought to identify the health care resource use, costs, and cost predictors of CA. Methods: A cost analysis was performed in a population of AF patients treated with CA in Central Zone Nova Scotia from 2010 to 2018. Costs were compared 2 years before ablation (pre-CA) with costs 2 years

BACKGROUND Electrical lead abnormalities (ELAs) can result in device malfunction, leading to significant morbidity in patients with cardiac implantable electronic devices (CIEDs). OBJECTIVE We sought to determine the prevalence and management of ELAs in patients with CIEDs. METHODS This was a retrospective cohort study of patients implanted with a CIED between 2012 and 2019 at a tertiary care center. The primary outcome was ELA defined as increased capture threshold (>2! implantation value), decreased sensing (<0.5 implantation value), change in impedance (.50% over 3 months), or nonphysiologic potentials. A secondary outcome of device clinic utilization was also collected. RESULTS There were 2996 unique patients (35% female) included with 4600 leads (57% Abbott, 43% Medtronic). ELAs were observed in 135 (3%) leads, including 124 (92%) Abbott and 10 (7%) Medtronic leads (hazard ratio 9.25, P < .001). Mean follow-up was 4.5 6 2.2 years. ELAs were associated smaller lead French size, atrial location, and Abbott leads. Lead revision was required in 28% of cases. Patients with lead abnormalities had 38% more in-clinic visits per patient year of follow-up compared with those without (P < .001). CONCLUSION ELAs were more frequent in certain models, which increased rates of revision and follow-up. Identification of factors that mitigate these abnormalities to improve lead performance are required to improve care for these devices and provide efficient healthcare.

Surface ECG is a useful tool to guide mapping of focal atrial tachycardia (AT).

We have previously developed an intraprocedural system to identify VT exit sites in real-time on the patient-specific CT/MRI geometry using 3-lead ECGs (leads III, V2, V6) during catheter ablation for ventricular tachycardia (RAPID-VT).

BACKGROUND:Implantable cardioverter-defibrillators (ICDs) reduce mortality in patients with reduced left ventricular ejection fraction (LVEF). We investigated sex disparities in a contemporary Canadian population for utilization of primary prevention ICDs. METHODS:This was a retrospective cohort study on patients with reduced LVEF admitted to hospitals from 2010 to 2020 in Nova Scotia (population = 971,935). RESULTS:There were 4406 patients eligible for ICDs: 3108 (71%) men and 1298 (29%) women. The mean follow-up time was 3.9 ± 3.0 years. Rates of coronary disease were similar between men and women (45.8% vs 44.0%; P = 0.28), but men had lower LVEF (26.6 ± 5.9% vs 27.2 ± 5.8%; P = 0.0017). The referral rate for ICD was 11% (n = 487), with 13% of men (n = 403) and 6.5% of women (n = 84) referred (P < 0.001). The ICD implantation rate in the population was 8% (n = 358), with 9.5% of men (n = 296) and 4.8% of women (n = 62) (P < 0.001) receiving the device. Men were more likely than women to receive an ICD (odds ratio 2.08, 95% confidence interval 1.61-2.70; P < 0.0001)). There was no significant difference in mortality between men and women (P = 0.2764). There was no significant difference in device therapies between men and women (43.8% vs 31.1%; P = 0.0685). CONCLUSIONS:A significant disparity exists in the utilization of primary prevention ICDs between men and women in a contemporary Canadian population.

Patients who suffer from Atrial Fibrillation (AF) are high users of healthcare resources and consequently lead to greater costs of management. Treatment with Catheter Ablation (CA) was shown to be a high value treatment however, there is a paucity of recent Canadian studies using patient level data to estimate the costs associated with AF before and after CA. We sought to identify the healthcare resource use, costs, and cost-effectiveness of CA and explore the impact of Contact Force Sensing (CFS) on these parameters.

AIMS:Catheter ablation is superior to escalated antiarrhythmic drugs among patients with ventricular tachycardia (VT) and prior myocardial infarction (MI). However, it is uncertain whether clinical VT characteristics, should influence choice of therapy. The purpose of this study was to evaluate whether presentation with electrical storm and the clinical VT cycle length predicted response to ablation vs. escalated antiarrhythmic therapy.METHODS AND RESULTS:All patients enrolled in the Ventricular Tachycardia Ablation vs. Escalated Antiarrhythmic Drug Therapy in Ischaemic Heart Disease (VANISH) trial were included. The association between VT cycle length and presentation with electrical storm and the primary outcome of death, subsequent VT storm or appropriate ICD shock was evaluated. Among the study population of 259 patients, escalated antiarrhythmic drug therapy had worse outcomes for those presenting with a VT cycle length >400 ms [<150 b.p.m., 89/259, hazard ratio (HR) 1.7 (1.02-3.13)]. This effect was more pronounced among those taking amiodarone at baseline [HR of 2.22 (1.19-4.16)]. Presentation with VT storm (32/259) did not affect the primary outcome between groups. However, those presenting with VT storm on amiodarone had a trend towards worse outcomes with escalated antiarrhythmic therapy [HR 4.31 (0.55-33.93)].CONCLUSION:The VT cycle length can influence response to either ablation or escalated drug therapy in patients with VT and prior MI. Those with slow VT had improved outcomes with ablation. Patients presenting with electrical storm demonstrated similar outcomes to the overall trial population, with a trend to benefit of catheter ablation, particularly in those on amiodarone.

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): 1. Canadian Institutes of Health Research (CIHR) 2. Additional financial support from St. Jude Medical and Biosense Webster Background Recurrent shocks for ventricular tachycardia (VT) are associated with an increased risk of heart failure and mortality and have a negative influence on quality of life. Catheter ablation has been shown to improve VT event-free survival in patients with antiarrhythmic drug (AAD)-refractory VT and prior myocardial infarction (MI); however, the effects of ablation on shock burden has yet to be investigated. Purpose Our primary objectives were to compare the shock-treated VT event burden and appropriate shock burden following randomization to treatment with either catheter ablation or escalated AAD therapy among VT patients with prior MI in the Ventricular tachycardia AblatioN versus escalated antiarrhythmic drug therapy in Ischemic Heart disease (VANISH) randomized trial. Methods Recurrent event analyses were performed using the intention-to-treat population of the VANISH trial. Shock-treated VT event burden was defined as the total number of VT events treated with ≥1 appropriate internal or external shocks. Appropriate shock burden was defined as the total number of appropriate internal and external shocks delivered, regardless of the number of VT events. All VT events and implantable cardioverter defibrillator (ICD) therapies were adjudicated by reviewers blinded to the treatment allocation. Three recurrent event models were used to compare the shock burden between treatment arms (Anderson-Gill (AG), Frailty, and Prentice, Williams, and Peterson Total Time (PWP-TT). Each model clustered by patient and accounted for competing risk of death with the Fine and Gray sub-distributions hazards model. Results Of the 259 patients enrolled in the VANISH trial [median age 69.8 (IQR 63.0-74.2) years, 7.0% women], 132 patients were randomized to ablation and 129 patients to escalated AAD therapy. Over a median follow-up of 23.4 (IQR 14.7-40.4) months, there were 138 shock-treated VT events [39.07 (95% CI 33.14-46.07) shock-treated VT events per 100 person-years] in the ablation arm and 218 shock-treated VT events [64.60 (95% CI 56.49–73.84) shock-treated VT events per 100 person-years] in the escalated AAD therapy arm (Figure 1). Ablation patients had a 40% lower shock-treated VT event burden (ie. number of shock-treated VT events) compared to patients randomized to escalated AAD therapy [Figure 1; AG HR 0.60 (95% 0.38-0.95)]. Further, there was also a statistically significant reduction in the appropriate shock burden (i.e. number of appropriate shocks) among ablation patients (169 appropriate shocks) compared to escalated AAD therapy patients (266 appropriate shocks) [Figure 1; AG HR 0.61 (95% CI 0.37-0.96)]. All results were consistent between the 3 recurrent event models. Conclusion Among patients with AAD-refractory VT and a prior MI, catheter ablation reduced shock-treated VT event burden and appropriate shock burden compared to escalated AAD therapy.

BackgroundPoint-of-care ultrasound (POCUS) has become a useful diagnostic tool across multiple specialties. However, no standardized curriculum is currently in place for Canadian Internal Medicine (IM) residency programs. This report aims to describe the development of a longitudinal POCUS curriculum at Dalhousie University and reports on resident knowledge, confidence, and perceived clinical utility of POCUS also.MethodsResidents in the core IM program were invited to complete a POCUS survey and knowledge test in December 2019. The survey evaluated self-reported confidence in acquired POCUS skills and clinical use in practice, whereas the knowledge test evaluated image interpretation skills.ResultsA total of 34/45 (75.6%) residents participated, who agreed that POCUS training should be a formal component of residency (4.56 ± 0.56). Scores on the knowledge test improved based on time spent in the curriculum, with postgraduate year (PGY) 1s scoring an average of 70.0% (21/30) and PGY3s 82.8% (24.9/30; P = 0.02). Residents reported the strongest confidence in lung imaging for detecting A and B lines (4.10 ± 0.79), pleural effusions (3.92 ± 0.90), and lung sliding (3.89 ± 0.92).ConclusionDalhousie University is among the first IM programs in Canada to implement a formal longitudinal POCUS curriculum, which has enabled the incremental acquisition of POCUS knowledge, confidence, and clinical utility amongst residents. RésuméContexteL’échographie au point d’intervention (POCUS) est devenue un outil de diagnostic utile dans de multiples spécialités. Toutefois, aucun programme normalisé n’est en place actuellement dans les programmes de résidence en médecine interne au Canada. Ce rapport vise à décrire l’élaboration d’un programme longitudinal sur la POCUS à l’Université Dalhousie et rend compte des connaissances et de l’assurance des résidents relatives à la POCUS et de leur perception quant à son utilité clinique.MéthodologieDes résidents du programme de médecine interne tronc commun ont été invités à répondre à un sondage sur la POCUS et à effectuer un test de connaissances en décembre 2019. Le sondage a évalué le degré d’assurance quant aux compétences acquises sur la POCUS et à son utilisation clinique dans la pratique, tandis que le test de connaissances a évalué les compétences en matière d’interprétation des images. RésultatsAu total, 34 des 45 résidents ayant participé au sondage (75,6 %) sont d’avis que la formation sur la POCUS devrait être une composante officielle de la résidence (4,56 ± 0,56). Les scores du test de connaissances s’améliorent en fonction du temps passé dans le programme, le score des résidents de première année d’études postdoctorales (PGY-1) étant de 70,0 % (21/30) en moyenne et celui des résidents de troisième année (PGY-3) de 82,8 % (24,9/30; P = 0,02). Les résidents mentionnent faire preuve de la meilleure assurance en matière d’imagerie pulmonaire dans la détection des lignes A et B (4,10 ± 0,79), des épanchements pleuraux (3,92 ± 0,90) et des glissements pulmonaires (3,89 ± 0,92). ConclusionL’Université Dalhousie figure parmi les premiers programmes de médecine interne au Canada à mettre en œuvre un programme longitudinal officiel sur la POCUS, ce qui a permis l’acquisition progressive parmi les résidents des connaissances et de l’assurance relatives à la POCUS et de l’utilité clinique de cet outil de diagnostic.

Electrical lead abnormalities can lead to device malfunction with significant morbidity and mortality in patients with pacemakers or implantable cardioverter defibrillators (ICDs). We sought to determine the rates of electrical lead anomalies in a cohort of patients with pacemakers and ICDs. All patients implanted with a pacemaker or ICD lead in 2012-2019 at a single center were included. The primary outcome was any electrical lead anomaly. The criteria for lead anomalies included: increased capture threshold (≥2x implant value); decreased sensing (≤0.5 implant value); sudden change in impedance (change >50% over 3 months); inappropriate shocks/NSVT/loss of pacing secondary to sensing of electrical noise artifacts from non-physiologic potentials. There were 3028 patients (35% women) included with 4869 leads (37% atrial, 58% right ventricular, 5% left ventricular; 52% Abbott, 47% Medtronic). Lead anomalies were observed in 131 (3%); 121 Abbott leads, 10 Medtronic leads. Abbott leads had a significantly reduced lead survival rate (see Figure). Electrical noise was detected in 98%, impedance change 4%, increased threshold 7%, decreased sensing 7%. Response to the issue was observation 58%, reprogramming 14% and revision 27%. No patient deaths due to lead anomalies were observed. Lead anomalies were associated with Abbott leads (OR 9.2), atrial location (OR 1.8) and certain operators (OR 1.1). Electrical lead anomalies are more frequent in certain lead models. Further identification of factors that may mitigate these anomalies to improve lead performance are required to prevent morbidity for patients with these devices.

BACKGROUND There are little data on the use of virtual care for patients with arrhythmia. We evaluated a virtual clinic platform, in conjunction with specialist care, for patients with symptomatic atrial fibrillation (AF). METHODS This was a prospective, observational cohort study evaluating an online educational and treatment platform, with a randomized sub-study examining the use of an ambulatory singlelead electrocardiogram heart monitor (AHM). Follow-up was 6 months. The main outcome was patients' platform use; success was defined as 90% of patients using the platform at least once, and 75% using it at least twice. The primary outcome in the AHM sub-study was Atrial Fibrillation Symptom Severity (AFSS) score. Other outcomes included patient satisfaction questionnaires, quality of life, emergency department visits, and hospitalizations for AF. RESULTS We enrolled 94 patients between July 2018 and May 2019; 83% of patients logged in at least once and 54.3% more than once. Patients who were older, were male, or had new-onset AF were more likely to log in to the platform. Satisfaction scores were high; 70%-94% of patients responded favorably. Quality-of-life scores improved at 3 and 6 months. In the AHM sub-study (n = 71), those who received an AHM had lower AFSS scores (least square mean difference -2.52, 95% CI -4.48 to -0.25, P =.03). There was no difference in emergency department visits or hospitalizations. CONCLUSION The online platform did not reach our feasibility target but was well received. Allocation of an AHM was associated with improved quality of life. Virtual AF care shows promise and should be evaluated in further research.

We have previously developed an intraprocedural RAPID-VT localization system to identify VT exit sites in real-time on the patient-specific CT/MRI mesh surface using 3-lead ECGs (leads III, V2, V6). To assess prospectively the localization performance and ablation outcomes of the RAPID-VT system. Eleven consecutive consenting patients with ischemic cardiomyopathy undergoing VT ablation had preprocedural CT/MRI scans. A reconstructed LV endocardial mesh surface was registered to the electroanatomic shell during the procedure and imported into the RAPID-VT program. During the procedure, predicted VT exit sites were used to guide mapping and ablation. The localization accuracy was quantified by comparing estimated sites against sites clinically identified using activation, entrainment and pace mapping. Thirteen accurately identified VT exit sites, pooled from 9 patients (mean procedure time 286.7±31.8 mins, were identified by using a combination of activation, entrainment and pace-mapping, and were used as the “ground truth” for comparisons. The RAPID-VT system had a mean localization error of 8.6±3.2 mm for the 13 VTs. Two patients were excluded due to technical problems with data acquisition. After targeting all inducible VTs, no VT was inducible at the end of the procedure in 7/9 patients. The RAPID-VT system based on the patient-specific CT/MRI mesh surface can be feasibly used in real-time to guide VT mapping and ablation.

Abstract Background There is clear evidence that patients with prior myocardial infarction and a reduced ejection fraction benefit from implantation of a cardioverter-defibrillator (ICD). It is unclear whether this benefit is altered by whether or not revascularization is performed prior to ICD implantation. Methods This was a retrospective cohort study following patients who underwent ICD implantation from 2002 to 2014. Patients with ischemic cardiomyopathy and either primary or secondary prevention ICDs were selected for inclusion. Using the electronic medical record, cardiac catheterization data, revascularization status (percutaneous coronary intervention or coronary bypass surgery) were recorded. The outcomes were mortality and ventricular arrhythmia. Results There were 606 patients included in the analysis. The mean age was 66.3 ± 10.1 years, 11.9% were women, and the mean LVEF was 30.5 ± 12.0, 58.9% had a primary indication for ICD, 82.0% of the cohort had undergone coronary catheterization prior to ICD implantation. In the overall cohort, there were fewer mortality and ventricular arrhythmia events in patients who had undergone prior revascularization. In patients who had an ICD for secondary prevention, revascularization was associated with a decrease in mortality (HR 0.46, 95% CI (0.24, 0.85) p = 0.015), and a trend towards fewer ventricular arrhythmia (HR 0.62, 95% CI (0.38, 1.00) p = 0.051). There was no association between death or ventricular arrhythmia with revascularization in patients with primary prevention ICDs. Conclusion Revascularization may be beneficial in preventing recurrent ventricular arrhythmia, and should be considered as adjunctive therapy to ICD implantation to improve cardiovascular outcomes.

Background: To facilitate ablation of ventricular tachycardia (VT), an automated localization system to identify the site of origin of left ventricular activation in real time using the 12-lead ECG was developed. The objective of this study was to prospectively assess its accuracy. Methods: The automated site of origin localization system consists of 3 steps: (1) localization of ventricular segment based on population templates, (2) population-based localization within a segment, and (3) patient-specific site localization. Localization error was assessed by the distance between the known reference site and the estimated site. Results: In 19 patients undergoing 21 catheter ablation procedures of scar-related VT, site of origin localization accuracy was estimated using 552 left ventricular endocardial pacing sites pooled together and 25 VT-exit sites identified by contact mapping. For the 25 VT-exit sites, localization error of the population-based localization steps was within 10 mm. Patient-specific site localization achieved accuracy of within 3.5 mm after including up to 11 pacing (training) sites. Using 3 remotes (67.8±17.0 mm from the reference VT-exit site), and then 5 close pacing sites, resulted in localization error of 7.2±4.1 mm for the 25 identified VT-exit sites. In 2 emulated clinical procedure with 2 induced VTs, the site of origin localization system achieved accuracy within 4 mm. Conclusions: In this prospective validation study, the automated localization system achieved estimated accuracy within 10 mm and could thus provide clinical utility.

BACKGROUND To facilitate catheter ablation of ventricular tachycardia (VT), we previously developed an automated method to identify sources of left ventricular (LV) activation in real time using 12-lead electrocardiography (ECG), the accuracy of which depends on acquisition of a complete electroanatomic (EA) map. OBJECTIVE The purpose of this study was to assess the feasibility of using a registered cardiac computed tomogram (CT) rather than an EA map to permit real-time localization and avoid errors introduced by incomplete maps. METHODS Before LV VT ablation, 10 patients underwent CT imaging and 3-dimensional reconstruction of the cardiac surface to create a triangle mesh surface, which was registered to the EA map during the procedure and imported into custom localization software. The software uses QRS integrals from leads III, V-2, and V-6; derives personalized regression coefficients from pacing at >= 5 sites with known locations; and estimates the location of unknown activation sites on the 3-dimensional patient-specific LV endocardial surface. Localization accuracy was quantified for VT exit sites in millimeters by comparing the calculated against the known locations. RESULTS The VT exit site was identified for 20 VTs using activation and entrainment mapping, supplemented by pace-mapping at the scar margin. The automated localization software achieved incremental accuracy with additional pacing sites and had a mean localization error of 6.9 +/- 5.7 mm for the 20 VTs. CONCLUSION Patient-specific CT geometry is feasible for use in real-time automated localization of ventricular activation and may avoid reliance on a complete EA map.

To facilitate catheter ablation of VT, we have previously developed an automated method to identify sources of LV activation in real time using 12-lead ECG, the accuracy of which depends on a complete 3D cardiac geometry. Objective: To assess feasibility of using a registered cardiac CT rather than electroanatomic (EA) map to permit real-time localization and avoid errors introduced by incomplete maps. Prior to LV VT ablation, 10 patients had CT imaging and 3D reconstruction of the cardiac surface to create a triangle mesh surface, which was registered to the EA map during the procedure and imported into the custom localization software. The software uses QRS integrals from leads III, V2, V6, derives personalized regression coefficients from pacing at ≥5 sites with known locations, and estimates location of unknown activation sites on the 3D patient-specific LV endocardial surface. Localization accuracy was quantified for VT-exit sites in millimeters by comparing the calculated against the known locations. The VT-exit site was identified for 21 VTs using activation and entrainment mapping, supplemented by pace-mapping at the scar margin. The automated localization software gained accuracy with additional pacing sites, and had a mean localization error of 7.2 ± 5.8 mm for the 21 VTs. Patient-specific CT geometry is feasible for use in real-time automated localization of ventricular activation and may avoid reliance on a complete electroanatomic map.

Introduction: Infusion-needle catheter ablation of VT within deep intramural substrate requires accurate identification of appropriate targets. We have developed an automated method for localizing ...