Half-Normal Saline vs Normal Saline for Cavotricuspid Isthmus-Dependent Atrial Flutter Ablation.

Background: Cavotricuspid isthmus (CTI) ablation requires permanent bidirectional block to prevent recurrence of typical atrial flutter (AFL). Catheter irrigation with half-normal saline (HNS) produces larger and deeper lesions in experimental models compared with normal saline (NS). This study was performed to compare the clinical efficacy and safety of HNS vs NS irrigation for typical AFL ablation. Methods: Sixty patients undergoing catheter ablation of typical AFL were randomized 1:1 to NS or HNS irrigation. Endpoints included time to CTI block, acute reconnection, incidence of steam pops, and recurrence of AFL during follow-up. Results: Baseline characteristics were comparable between both arms. The mean age of the patients was 68.5 ± 8.2 years, 20% were female, and 32% had atrial fibrillation before being enrolled. Bidirectional CTI block was obtained in all patients with no difference in time to CTI block between groups (6.4 ± 4.4 minutes vs 7.6 ± 4.5 minutes, respectively; P = 0.15). There was a trend to less acute reconnection in the HNS group compared with NS (13.3% vs 26.6%; P = 0.46). Steam pops occurred in 4 patients using HNS vs none in the NS group, but no major complications were observed. During the follow-up, rate of AFL recurrence was similar between groups (6.7% with HNS vs 10% with NS; P = 0.5). There was no difference in time to recurrence (7.6 ± 6.9 vs 4.9 ± 4.5 months; P = 0.6). Conclusions: In this small pilot randomized controlled trial, there was no significant difference between HNS and NS for CTI ablation; however, HNS may increase the incidence of steam pops.

Contexte: Pour prévenir la récurrence d'un flutter auriculaire (flutter) typique, l'ablation de l'isthme cavotricuspidien exige un bloc de conduction bidirectionnel permanent. Dans des modèles expérimentaux, l'irrigation par cathéter au moyen d'un soluté demi-salin produit des lésions plus larges et plus profondes, comparativement à un soluté physiologique salin. La présente étude a été réalisée dans le but de comparer l'efficacité clinique et l'innocuité de l'irrigation au moyen d'un soluté demi-salin à celles de l'irrigation par un soluté physiologique salin dans les cas d'ablation d'un flutter. Méthodologie: Soixante patients soumis à une ablation d'un flutter typique par cathéter ont été répartis au hasard dans un rapport de 1:1 en deux groupes d'irrigation, soit par soluté demi-salin, soit par soluté physiologique salin. Les critères d'évaluation de l'étude étaient les suivants : temps écoulé jusqu'au bloc de l'isthme cavotricuspidien, reconnexion aiguë, jet de vapeur sonore (steam pop) et récidive de flutter durant le suivi. Résultats: Les caractéristiques initiales étaient comparables dans les deux groupes. Les patients avaient une moyenne d'âge de 68,5 ± 8,2 ans, 20 % étaient des femmes et 32 % présentaient une fibrillation auriculaire avant leur admission à l'étude. Un bloc bidirectionnel dans l'isthme cavotricuspidien a été obtenu chez tous les patients, sans différence entre les groupes en ce qui a trait au temps écoulé jusqu'à l'obtention du bloc isthmique (6,4 ± 4,4 minutes vs 7,6 ± 4,5 minutes, respectivement; p = 0,15). Une tendance vers un nombre plus faible de cas de reconnexion aiguë a été notée dans le groupe d'irrigation par soluté demi-salin, comparativement au soluté physiologique salin (13,3 % vs 26,6 %; p = 0,46). Un jet de vapeur sonore est survenu chez 4 patients recevant un soluté demi-salin contre aucun dans le groupe sous soluté physiologique salin, mais aucune complication importante n'a été relevée. Durant le suivi, le taux de récidive de flutter a été similaire dans les deux groupes (6,7 % sous soluté demi-salin vs 10 % sous soluté physiologique salin; p = 0,5). Aucune différence n'a été notée pour ce qui est du temps écoulé jusqu'à la survenue d'une récidive (7,6 ± 6,9 vs 4,9 ± 4,5 mois; p = 0,6). Conclusions: Dans cette petite étude pilote contrôlée et avec répartition aléatoire, aucune différence significative n'a été observée entre le soluté demi-salin et le soluté physiologique salin pour l'ablation de l'isthme; toutefois, le soluté demi-salin augmenterait la fréquence des cas de jet de vapeur sonore.

Performance and acute procedural outcomes of the EnSite Precision™ cardiac mapping system for electrophysiology mapping and ablation procedures: results from the EnSite Precision™ observational study.

BACKGROUND: The EnSite Precision™ cardiac mapping system (Abbott) is a catheter navigation and mapping system capable of displaying the three-dimensional (3D) position of conventional and sensor-enabled electrophysiology catheters, as well as displaying cardiac electrical activity as waveform traces and dynamic 3D maps of cardiac chambers. The EnSite Precision™ Observational Study (NCT-03260244) was designed to quantify and characterize the use of the EnSite Precision™ cardiac mapping system for mapping and ablation of cardiac arrhythmias in a real-world environment and evaluate procedural outcomes. METHODS: A total of 1065 patients were enrolled at 38 centers in the USA and Canada between 2017 and 2018 and were followed for 12 months post procedure for arrhythmia recurrence, medication use, and quality-of-life changes. Eligible subjects were adults undergoing a cardiac electrophysiology mapping and radiofrequency ablation procedure using the EnSite Precision™ System. RESULTS: A final cohort of 925 patients (64.3 years of age, 30.2% female) were analyzed. The primary procedural indication was atrial flutter in 48.1% (445/925), atrial fibrillation in 46.5% (430/925), and other arrhythmias in 5% (50/925). Electroanatomic mapping was performed in 81.5% (754/925) of patients. Mapping was stable throughout 79.8% (738/925) of procedures with initial mapping time of 8.6 min (IQR 4.7-15.0). Average mapping efficiency created with AutoMap or TurboMap was 164.9 ± 365.7 used points per minute. Median number of mapping points collected and used was 1752.5 and 811.0, respectively. Only 335/925 (36.2%) required editing and 66.0% (221/335) of these patients required editing of less than 10 points. Fluoroscopy was utilized in most cases (n = 811/925, 87.4%) with fluoroscopy time of 11.0 min (IQR 6.0-18.0). Overall median procedure time was 101.0 min (IQR 59.0-152.0). Acute procedural success was high for both atrial fibrillation (n = 422/430, 98.1%) and atrial flutter (n = 434/445, 97.5%). CONCLUSION: In a real-world study analysis, use of the EnSite Precision™ mapping system was associated with high procedural stability, short mapping times, high point density requiring infrequent editing, low fluoroscopy time, and high prevalence of acute procedural success.

Age-Related Changes in the Anatomy of the Triangle of Koch: Implications for Catheter Ablation of Atrioventricular Nodal Re-entry Tachycardia.

BACKGROUND: Atrioventricular nodal re-entrant tachycardia is the most common type of paroxysmal supraventricular tachycardia. We sought to assess whether important anatomic factors, such as the location of the slow pathway, proximity to the bundle of His, and coronary sinus ostium dimensions, varied with patient age, and whether these factors had an impact on procedural duration, acute success, and complications. METHODS: Baseline demographic and procedural data were collected, and the maps were analyzed. Linear regression models were performed to evaluate the associations between age and these anatomic variations. Associations were also assessed, with age categorized as being ≥ 60 years or < 60 years. RESULTS: The slow pathway was more commonly located in a superior location relative to the coronary sinus ostium in older patients. The location of the slow pathway moved in a superior direction by 1 mm for every increase in 2 years from the mean estimate of age. Additionally the slow pathway tended to be closer to the coronary sinus ostium in older patients, and the diameter of the ostium was larger in older patients. This resulted in longer procedure time, longer ablation times, and a greater need for long sheaths for stability. CONCLUSIONS: The location of the slow pathway becomes more superior and closer to the coronary sinus ostium with increasing age. Additionally, the coronary sinus diameter increases with age. These factors result in longer ablation and procedural times in older patients.

CONTEXTE: La tachycardie par réentrée nodale auriculoventriculaire est le type le plus fréquent de tachycardie supraventriculaire paroxystique. Nous avons voulu évaluer si des facteurs anatomiques importants, tels que l'emplacement de la voie lente, la proximité du faisceau de His et les dimensions de l'orifice du sinus coronaire (ostium), variaient avec l'âge, et si ces facteurs avaient un effet sur la durée de l'intervention, le succès à court terme et les complications. MÉTHODOLOGIE: Des données sur les caractéristiques démographiques initiales et l'intervention ont été recueillies, et les cartes obtenues ont été analysées. Des modèles de régression linéaire ont servi à déterminer les corrélations entre l'âge et ces variations anatomiques. Les corrélations ont aussi été évaluées selon des catégories d'âge, soit ≥ 60 ans et < 60 ans. RÉSULTATS: La voie lente a été repérée plus souvent dans un emplacement supérieur par rapport à l'orifice du sinus coronaire chez les patients plus âgés. L'emplacement de la voie lente s'était déplacé de 1 mm vers le haut pour chaque augmentation de 2 ans de l'estimation moyenne de l'âge. Par ailleurs, chez les patients plus âgés, la voie lente était généralement plus proche de l'orifice du sinus coronaire et le diamètre de l'orifice était élargi. Ces variations se sont traduites par une augmentation du temps d'intervention et d'ablation et par un besoin accru de longues gaines pour la stabilité. CONCLUSIONS: L'emplacement de la voie lente devient plus éloigné vers le haut et plus proche de l'orifice du sinus coronaire avec le vieillissement. De plus, le diamètre du sinus coronaire augmente avec l'âge. Ces facteurs entraînent des temps d'ablation et d'intervention plus longs chez les patients plus âgés.

The use of minimal fluoroscopy for cardiac electrophysiology procedures: A meta-analysis and review of the literature.

BACKGROUND: Conventional catheter ablation involves prolonged exposure to ionizing radiation, potentially leading to detrimental health effects. Minimal fluoroscopy (MF) represents a safer alternative, which should be explored. Data on the safety and efficacy of this technique are limited. HYPOTHESIS: Our hypothesis is that MF is of equal efficacy and safety to conventional catheter ablation with the use of fluoroscopy by performing a meta-analysis of both randomized controlled trials (RCTs) and real-world registry studies. METHODS: Pubmed and Embase were searched from their inception to July 2020 for RCTs, cohort and observational studies that assessed the outcomes of catheter ablation using a MF technique versus the conventional approach. RESULTS: Fifteen studies involving 3795 patients were included in this meta-analysis. There was a significant reduction in fluoroscopy and procedural time with no difference in acute success (odds ratio [OR]:0.74, 95% CI: 0.50-1.10, p = .14), long-term success (OR:0.92, 95% CI: 0.65-1.31, p = .38), arrhythmia recurrence (OR:1.24, 95% CI: 0.75-2.06, p = .97) or rate of complications. (OR:0.83, 95% CI: 0.46-1.48, p = .65). Additionally sub-group analysis for those undergoing catheter ablation for atrial fibrillation (AF) did not demonstrate a difference in success or complication rates (OR:0.86, 95% CI: 0.30-2.42, p = .77). Multivariate meta-regression did not identify the presence of moderator variables. CONCLUSION: This updated meta-analysis demonstrated an overall reduction in procedural and fluoroscopy time for those undergoing a minimal fluoroscopic approach. There was no significant difference in either acute or chronic success rates or complications between a MF approach and conventional approach for the management of all arrhythmias including those undergoing catheter ablation for AF.

Canadian national electrophysiology ablation registry report 2011-2016.

BACKGROUND/PURPOSE: Interventional cardiac electrophysiology (EP) is a rapidly evolving field in Canada; a nationwide registry was established in 2011 to conduct a periodic review of resource allocation. METHODS: The registry collects annual data on EP lab infrastructure, imaging, tools, human resources, procedural volumes, success rates, and wait times. Leading physicians from each EP lab were contacted electronically; participation was voluntary. RESULTS: All Canadian EP centres were identified (n = 30); 50 and 45 % of active centres participated in the last 2 instalments of the registry. A mean of 508 ± 270 standard and complex catheter ablation procedures were reported annually for 2015-2016 by all responding centres. The most frequently performed ablation targets atrial fibrillation (PVI) arrhythmia accounting for 36 % of all procedures (mean = 164 ± 85). The number of full time physicians ranges between 1 and 7 per centre, (mean = 4). The mean wait time to see an electrophysiologist for an initial non-urgent consult is 23 weeks. The wait time between an EP consult and ablation date is 17.8 weeks for simple ablation, and 30.1 weeks for AF ablation. On average centres have 2 (range: 1-4) rooms equipped for ablations; each centre uses the EP lab an average of 7 shifts per week. While diagnostic studies and radiofrequency ablations are performed in all centres, point-by-point cryoablation is available in 85 % centres; 38 % of the respondents use circular ablation techniques. CONCLUSIONS: This initiative provides contemporary data on invasive electrophysiology lab practices. The EP registry provides activity benchmarks on national trends and practices.

Catheter ablation for the management of atrial fibrillation: current technical perspectives.

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, with a prevalence that increases alongside the ageing population worldwide. The management of AF involves restoration of sinus rhythm through antiarrhythmic drug therapy. Yet, these medications have only modest efficacy in achieving long-term success, have not shown to result in a mortality benefit, are frequently not tolerated and have associated adverse side effects. Therefore, catheter ablation has become a valuable treatment approach for AF and even a viable first-line strategy in select cases. Traditionally, the combination of radiofrequency energy and a three-dimensional electroanatomical mapping system has been used to guide catheter ablation for AF. However, single-procedural efficacy and long-term outcomes still remain suboptimal for many patients, particularly those with persistent or long-standing AF. Recent advances in ablation technology and strategy, therefore, provide new procedural approaches for catheter-based treatment with the aim of overcoming current challenges in procedural duration and overall success. The aim of this paper was to provide an updated review of the current practices and techniques relating to ablation for AF and to compare the use of these strategies for paroxysmal and persistent AF.

Clinical assessment of AF pattern is poorly correlated with AF burden and post ablation outcomes: A CIRCA-DOSE sub-study.

BACKGROUND: Contemporary guidelines recommend that atrial fibrillation (AF) be classified into paroxysmal and persistent AF based on clinical assessment, with these categorizations forming the basis of therapeutic recommendations. While pragmatic, clinical assessment may introduce misclassification errors, which may impact treatment decisions. We sought to determine the relationship between AF classification, baseline AF burden, and post-ablation arrhythmia outcomes. DESIGN: The current study is a sub-analysis of a prospective, parallel-group, multicenter, single-blinded randomized clinical trial. All 346 patients enrolled in CIRCA-DOSE received an implantable cardiac monitor a median of 72 days prior to ablation. AF was classified as low burden paroxysmal, high burden paroxysmal, or persistent based on clinical assessment prior to device implantation. Prior to ablation patients were re-classified using the same definitions based on device monitoring data. Correlation between classifications, AF burden, and post-ablation arrhythmia outcomes were assessed. RESULTS: There was poor agreement between clinical and device-based AF classification (Cohen's kappa: 0.192). AF classification derived from pre-ablation continuous monitoring reflected baseline and post-ablation AF burden with greater accuracy and with less overlap between the AF classes (P < 0.01 for all categorical comparisons). Patients objectively classified as "Low Burden" paroxysmal by continuous monitoring data had significantly greater freedom from recurrent AF/AT/AFL compared to those classified as "High Burden" paroxysmal (hazard ratio [HR] 0.57 for AF/AT/AFL recurrence) or persistent AF (HR 0.19 for AF/AT/AFL recurrence). CONCLUSIONS: Classification of AF pattern based on pre-ablation continuous cardiac rhythm monitoring better predicted AF burden and freedom from recurrent AF post ablation. Despite the use of standardized definitions, classification of AF based on clinical assessment did not predict baseline AF burden, post ablation AF burden, or freedom from recurrent AF post ablation. TRIAL REGISTRATION: ClinicalTrials.govNCT01913522.

Canada-wide mixed methods analysis evaluating the reasons for inappropriate emergency department presentation in patients with a history of atrial fibrillation: the multicentre AF-ED trial.

OBJECTIVES: The primary objective of this study was to ascertain the reasons for emergency department (ED) attendance among patients with a history of atrial fibrillation (AF). DESIGN: Appropriate ED attendance was defined by the requirement for an electrical or chemical cardioversion and/or an attendance resulting in hospitalisation or administration of intravenous medications for ventricular rate control. Quantitative and qualitative responses were recorded and analysed using descriptive statistics and content analysis, respectively. Random effects logistic regression was performed to estimate the OR of inappropriate ED attendance based on clinically relevant patient characteristics. PARTICIPANTS: Participants ≥18 years with a documented history of AF were approached in one of eight centres partaking in the study across Canada (Ontario, Nova Scotia, Alberta and British Columbia). RESULTS: Of the 356 patients enrolled (67±13, 45% female), the majority (271/356, 76%) had inappropriate reasons for presentation and did not require urgent ED treatment. Approximately 50% of patients(172/356, 48%) were driven to the ED due to symptoms, while the remainder presented on the basis of general fear or anxiety (67/356, 19%) or prior medical advice (117/356, 33%). Random effects logistic regression analysis showed that patients with a history of congestive heart failure were significantly more likely to seek urgent care for appropriate reasons (p=0.03). Likewise, symptom-related concerns for ED presentation were significantly less likely to result in inappropriate visitation (p=0.02). When patients were surveyed on alternatives to ED care, the highest proportion of responses among both groups was in favour of specialised rapid assessment outpatient clinics (186/356, 52%). Qualitative content analysis confirmed these results. CONCLUSIONS: Improved education focused on symptom management and alleviating disease-related anxiety as well as the institution of rapid access arrhythmias clinics may reduce the need for unnecessary healthcare utilisation in the ED and subsequent hospitalisation. TRIAL REGISTRATION NUMBER: NCT03127085.

Pseudonormalization of the Typical Electrocardiography Repolarization Pattern of a Black Athlete.

Cardiac repolarization of black athletes has a distinctive pattern. During an episode of pericarditis, this pattern may evolve into a "pseudonormalized" electrocardiography (ECG). On resolution of the pericardial inflammation, the ECG may return to the normal variant for a black athlete, sounding the alarms of extended disease to the myocardium. Recognizing the normal variant for a black athlete will reduce the need for unnecessary further testing or treatments. The case is discussed in detail.

Dual-Antithrombotic Therapy With DOACs After Acute Coronary Syndrome or Percutaneous Coronary Intervention in Atrial Fibrillation: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND: The choice of antithrombotic therapy for atrial fibrillation (AF) patients who have an acute coronary syndrome (ACS) or have undergone percutaneous coronary intervention (PCI) is challenging. We aimed to assess outcomes between dual-antithrombotic therapy with the use of direct-acting oral anticoagulants (DOACs) plus an antiplatelet agent (dual therapy) compared with warfarin plus 2 antiplatelet agents (triple therapy) for AF patients after PCI or with ACS. METHODS: Systematic searches of multiple major databases were performed from their inception through September 2019. We included only randomized controlled trials. Odds ratios (ORs) were pooled with the use of a random-effects model. RESULTS: We identified 4 randomized controlled trials, which included 7168 patients. Compared with triple-antithrombotic therapy with warfarin, dual-antithrombotic therapy with DOACs was associated with a significant reduction in major bleeding (OR 0.56, 95% confidence interval [CI] 0.38-0.82; P = 0.003) as well as major bleeding or clinically relevant nonmajor bleeding (OR 0.53, 95% CI 0.38-0.75; P < 0.001). The rate of composite of death and ischemic events (stroke and myocardial infarction) was not statistically different between groups (OR 1.21, 95% CI 0.99-1.49; P = 0.06). There was no significant difference between groups in the rate of death (OR 1.20, 95% CI 0.95-1.53; P = 0.13). CONCLUSIONS: In patients with AF and recent ACS or PCI, the use of dual-antithrombotic therapy with DOACs was associated with less major bleeding and less major bleeding or clinically relevant nonmajor bleeding compared with triple therapy. The use of dual therapy also showed nonsignificantly higher composite of death and ischemic events but no difference in mortality.

Facilitated Coupling of Magnetic Introducers During Thoracoscopic Ablation of Atrial Fibrillation.

A 51-year-old man with long-standing persistent atrial fibrillation underwent a hybrid ablation procedure with right thoracoscopic epicardial ablation. Fluoroscopy was utilized in a novel way to visualize the magnetic tip catheters of the linear ablation surgical device and allow easier coupling of the tips, making this procedure more efficient and reducing the risk of improper positioning of the ablation device.

Hybrid ablation for atrial fibrillation: the importance of achieving transmurality and lesion validation.

Therapeutic ablation for atrial fibrillation (AF) has evolved significantly with progressive advancements in technology and surgical instruments. With the goal of minimizing surgical morbidity while maintaining the benefits of the traditional Cox-Maze procedure, surgical ablation for AF has undergone significant modifications. Most recently, an increased understanding of substrate complexity, predominantly in patients with persistent or long-standing persistent AF, has led to the development of a synergistic hybrid approach. The hybrid approach attempts to combine the benefits of epicardial ablation and catheter-based endocardial ablation in order to overcome the shortcomings associated with each technique alone. Importantly, the aid of electrophysiological intervention has provided new opportunities for evaluating lesion transmurality both acutely and in a staged approach. Therefore, the hybrid procedure may provide the optimal approach for the surgical treatment of AF, with the potential to tailor procedural treatment according to the patient's specific needs. In this review, we aim to provide an overview of current surgical techniques, including the implications of this novel hybrid approach in the management of AF and improving procedural outcomes. Recent findings from published studies are highlighted with a primary focus on the importance of lesion transmurality and validation in a hybrid setting.

Novel frequency analysis of signal-averaged electrocardiograms is predictive of adverse outcomes in implantable cardioverter defibrillator patients.

BACKGROUND: Current noninvasive risk stratification methods offer limited prediction of arrhythmic events when selecting patients for ICD implantation. Our laboratory has recently developed a signal processing metric called Layered Symbolic Decomposition frequency (LSDf) that quantifies the percentage of hidden QRS wave frequency components in signal-averaged ECG (SAECG) recordings. The purpose of this pilot study was to determine whether LSDf can be predictive of ventricular arrhythmia or death in an ICD patient cohort. METHODS AND RESULTS: Fifty-two ICD patients were recruited from 2008 to 2009. These were followed for a mean of 8.5 ± 0.4 years for the primary outcome of first appropriately treated ventricular arrhythmia (VT/VF) or death. Thirty-four subjects met the primary outcome. LSDf was significantly lower, and 12-lead QRS duration was significantly greater in patients meeting the primary outcome (12.14 ± 3.97% vs. 16.45 ± 3.73%; p = 0.001) and (111.59 ± 14.96 ms vs. 97.69 ± 13.51 ms; p = 0.012) respectively. A 13.25% LSDf threshold (0.74 sensitivity and 0.85 specificity) was selected based on an ROC curve. Kaplan-Meier survival analysis was conducted; patients above the 13.25% threshold demonstrated significantly better survival outcomes (log-rank p < 0.001). In Cox multivariate regression analysis, the LSDf threshold (13.25%) was compared to LVEF (28.5%), 12-lead QRSd (100 ms), age, % male sex, NYHA classification, and antiarrhythmic usage. LSDf was a predictor of the primary outcome (p = 0.005) and an independent predictor for solely ventricular arrhythmia (p = 0.002). CONCLUSION: Layered Symbolic Decomposition frequency analysis in SAECG recordings may be a viable predictor of negative ICD survival outcomes.