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Background: The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown., Methods: We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%)., Results: We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure., Conclusions: The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.)., (Copyright © 2024 Massachusetts Medical Society.)

The prevalence of congenital heart disease (CHD) has surged in recent decades, owing to a substantial reduction in mortality. As individuals with CHD age, they become increasingly susceptible to late complications including arrhythmias. These arrhythmias often arise decades after surgical intervention and significantly impact quality of life, hospitalizations, and mortality. Catheter ablation has gained widespread acceptance as a critical intervention for managing arrhythmias in patients with CHD. However, anatomical and physiological features unique to this population pose challenges to standard manual ablation procedures, potentially impacting safety and efficacy. Robotic magnetic-guided navigation (RMN) has emerged as a technological solution to address these challenges. By utilizing soft and flexible catheters equipped with magnets at their tips, RMN enables robotic steering and orientation of catheters in three-dimensional space. This technology overcomes obstacles such as distorted vascular pathways and complex post-surgical reconstructions to facilitate access to target chambers and improve maneuverability within the heart. In this review, we present an overview of the safety and efficacy evidence for RMN-guided catheter ablation in CHD patients and highlight potential advantages. Additionally, we provide a detailed case presentation illustrating the practical application of RMN technology in this population. Although the literature on RMN-guided ablation in patients with CHD remains limited, it has shown promise in achieving successful outcomes, particularly in cases where manual ablation failed or was deemed non-feasible. Further validation through large-scale prospective studies is necessary to fully ascertain the benefits of RMN technology in this patient population.

Background: There are no randomized data to inform the extent to which transvenous cardiac leads cause tricuspid regurgitation (TR)., Objectives: This study sought to determine the effect of a transvenous implantable cardioverter-defibrillator (TV-ICD) on TR severity, and secondarily, on right ventricular (RV) size and function., Methods: We evaluated TR severity before and 6 months after implantable cardioverter-defibrillator insertion in a post hoc analysis of adults randomized to receive a transvenous (n = 252) or subcutaneous implantable cardioverter-defibrillator (S-ICD) (n = 251) device. TR and RV size and systolic function were assessed by echocardiographic images analyzed in a core laboratory., Results: At baseline, at least mild TR was present in 30% of individuals. At 6 months, the proportion of participants with any TR in the TV-ICD group was 42% vs 19% in the S-ICD group (P < 0.001). The proportion with moderate or severe TR was 7% in the TV-ICD group vs 2% in the S-ICD group (P = 0.021). At 6 months, the OR of at least 1 grade worsening of TR in the TV-ICD group as compared with the S-ICD group was 7.2 (95% CI: 3.3-15.8; P < 0.001). There were no differences between groups with respect to RV size or systolic function., Conclusions: Six months following TV-ICD insertion, there was a 7-fold increase in the risk of at least 1 grade worsening of TR, with 7% of individuals having TR that was moderate or severe. There was no detectable difference in RV size or function; however, longer follow-up is needed., Competing Interests: Funding Support and Author Disclosures This study was funded by Boston Scientific through an unrestricted research grant. Boston Scientific did not have any input into the preparation of this manuscript. Dr Leong has received consultancy fees from Boston Scientific. Dr Mondésert has received consultancy and speaking fees from Bostin Scientific, Abbott, Medtronic, and Biotronik. Dr Joza has received research support from Medtronic Inc; consulting fees from Boston Scientific; and honoraria from Biosense Webster Canada. Dr Healey has received research support and speaking fees from BMS/Pfizer, Boston Scientific, and Medtronic; speaking fees from Servier; and consultancy fees from Bayer and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Fenestrating a Fontan baffle has been associated with improved perioperative outcomes in patients with univentricular hearts. However, longer-term potential adverse effects remain debated. We sought to assess the impact of a fenestrated Fontan baffle on adverse cardiovascular events including all-cause mortality, cardiac transplantation, atrial arrhythmias, and thromboemboli., Methods: A multicentre North American retrospective cohort study was conducted on patients with total cavopulmonary connection Fontan baffle, with and without fenestration. All components of the composite outcome were independently adjudicated. Potential static and time-varying confounders were taken into consideration, along with competing risks., Results: A total of 407 patients were followed for 10.4 (7.1-14.4) years; 70.0% had fenestration of their Fontan baffle. The fenestration spontaneously closed or was deliberately sealed in 79.9% of patients a median of 2.0 years after Fontan completion. In multivariable analysis in which a persistent fenestration was modelled as a time-dependent variable, an open fenestration did not confer a higher risk of the composite outcome (hazard ratio, 1.18; 95% confidence interval, 0.71-1.97; P = 0.521). In secondary analyses, an open fenestration was not significantly associated with components of the primary outcome: that is, mortality or transplantation, atrial arrhythmias, or thromboemboli. However, sensitivity analyses to assess the possible range of error resulting from imprecise dates for spontaneous fenestration closures could not rule out significant associations between an open fenestration and atrial arrhythmias or thromboemboli., Conclusions: In this multicentre study, no significant association was identified between an open fenestration in the Fontan baffle and major adverse cardiovascular events., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Cardiac implantable electronic device (CIED) infections are a highly morbid and potentially fatal complication of CIED implantation. Prompt diagnosis is paramount to the proper management of such infections. This review seeks to highlight the pathophysiology, risk factors, diagnostic approach, and prevention strategies for CIED infection, with an emphasis on pocket infection. Management will be discussed in detail, with complete device removal representing the standard of case, but with conservative management representing a potential alternative for patients at high risk for extraction. The high prevalence of CIED in the cardiac population renders understanding of this subject essential for the practicing clinician., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Despite improved childhood survival of congenital heart disease (CHD) as a result of advances in management, late-onset sudden cardiac death (SCD) from malignant ventricular arrhythmias remains a leading cause of mortality in adults with CHD. Preventing SCD in these patients requires an understanding of the underlying pathophysiological mechanisms. Many CHD patients experience significant hemodynamic stress on the subpulmonary right ventricle (RV), leading to pathologic remodeling. Unlike acquired heart disease in which left ventricular pathology is prevalent, RV pathologies are crucial in the SCD pathogenesis in CHD patients. This review examines the mechanisms and management of SCD related to subpulmonary RV pathologies in CHD patients., Competing Interests: Disclosures Dr Khairy is supported by the André Chagnon Research Chair in Electrophysiology and Congenital Heart Disease. Other authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: There is a paucity of data regarding sex-related differences on cardiac outcomes in the context of transposition of the great arteries (TGA) with a systemic right ventricle and biventricular physiology (sRV-biV). Moreover, the long-term impact of pregnancy on cardiac outcomes remains unknown., Objectives: The purpose of this study was to identify sex-related differences and the influence of pregnancy on cardiac outcomes in TGA sRV-biV population., Methods: A retrospective cohort study was conducted on 213 adults with TGA sRV-biV, 82 (38.4%) women, age 42.6 ± 12.8 years, with a median follow-up of 16 years. Cardiac events, interventions, last follow-up sRV-biV dysfunction, and heart failure (HF) medications were compared between men vs women, and women with vs without pregnancies resulting in live births., Results: Women had a lower incidence of nonsustained ventricular tachycardia (HR: 1.80; 95% CI: 1.04-3.09, P  = 0.035) and nonsignificantly fewer HF-related hospitalizations than men (HR: 2.10; 95% CI: 0.95-4.67, P  = 0.069) in univariable analysis. At the last follow-up, women had a lower prevalence of moderate to severe sRV-biV dysfunction than men ( P  < 0.001) and were less frequently prescribed HF therapy. Women had fewer implantable cardioverter-defibrillators for primary prevention than men ( P  = 0.016), with no difference for secondary prevention. Women who had pregnancies resulting in live births (N = 47), had a high prevalence of cardiac events in the 15 (IQR: 9-28) years following pregnancy with no significant differences with those without (N = 32) pregnancies., Conclusions: Women with a sRV-biV have fewer adverse cardiovascular events than men. Due to sRV-biV, pregnancy remains with high maternal risk but is not associated with worse long-term cardiac outcomes under rigorous multidisciplinary cardio-obstetrical care., Competing Interests: Dr Khairy is supported by the André Chagnon research chair in electrophysiology and congenital heart disease. Dr Chaix is supported by a clinician research scholarship from the Fonds de recherche du Québec-Santé (FRQS. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Patients with congenital heart disease (CHD) and their parents face challenges throughout their lives that can lead to anxiety lasting into adulthood. We aim to assess the association between perceived parenting practices and anxiety beyond paediatric medical-surgical histories in adults with CHD., Methods: A cross-sectional study of adults with CHD was conducted at the Montreal Heart Institute (MHI). Perception of parental practices during childhood was retrospectively assessed with the use of validated self-report questionnaires, and anxiety in adulthood was assessed with the use of the Hospital Anxiety and Depression Scale. Sociodemographic and medical information were collected from a questionnaire and medical records. Hierarchic multiple linear regression was conducted., Results: Of the 223 participants, the mean age was 46 ± 14 years and 59% were female. Perceived parenting practices explained more variance (11%) in the anxiety score than paediatric medical-surgical history (2%). In our final model, anxiety was significantly associated with age, parental history of anxiety, and positive parenting practices, but not with overprotection., Conclusions: Parenting practices are associated with anxiety in adults with CHD beyond paediatric medical-surgical history and sociodemographic. Positive parenting practices may be protective against anxiety in adulthood. Longitudinal studies are needed to determine causality., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Aim: Patient reported outcomes (PROs) provide important insights into patients' acceptance of their medical devices. ATLAS, a randomized, multi-center, open-label clinical trial, recently reported fewer perioperative complications in S-ICD compared to TV-ICD patients. This study reports PROs, including device-specific and generic quality of life (QOL) from the ATLAS trial., Methods and Results: Device-specific QOL was the primary PRO using the Florida Patient Acceptance Survey (FPAS) at 1-and 6-months post-implantation. Secondary outcomes included generic QOL using the Medical Outcomes Survey (SF-36) pre-implant and 6-months post-implantation. FPAS and SF-36 were analyzed using ANCOVA. Pain measured using a Numeric Rating Scale, at 1-and 6-months, anesthetic, BMI and within/between differences were analyzed using descriptive statistics and mixed-effects linear models (MLM). Of the 503 patients randomized in ATLAS, 404 had complete FPAS data to include in this analysis. Participant characteristics were balanced. There were no significant differences between S-ICD and TV-ICD for FPAS or SF-36, across timepoints. Mean total FPAS scores increased from 73.73 (16.09) to 77.05 (16.13) and 74.43 (15.35) to 78.25 (15.88) for S-ICD and TV-ICD, respectively, (p <0.001). PROs suggested that both devices were associated with good QOL., Conclusion: Device-specific and generic QOL were similar between S-ICD and TV-ICD groups up to 6-months post-implantation indicating that regardless of device type, both groups reported good device specific QOL in ATLAS patients. S-ICD patients reported higher pain scores at implant, but pain decreased by 6 months. The findings offer evidence that can be included during shared decision-making. The inclusion of patient partners in ATLAS provided opportunity to measure PROs that were deemed important to patients., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: The Fontan procedure is the palliative procedure of choice for patients with single ventricle physiology. Pulmonary vascular disease (PVD) is an important contributor to Fontan circulatory failure., Areas Covered: We review the pathophysiology of PVD in patients with Fontan palliation and share our initial experience with optical coherence tomography (OCT) in supplementing standard hemodynamics in characterizing Fontan-associated PVD. In the absence of a sub-pulmonary ventricle, low pulmonary vascular resistance (PVR; ≤2 WU/m 2 ) is required to sustain optimal pulmonary blood flow. PVD is associated with adverse pulmonary artery (PA) remodeling resulting from the non-pulsatile low-shear low-flow circulation. Predisposing factors to PVD include impaired PA growth, endothelial dysfunction, hypercoagulable state, and increased ventricular end-diastolic pressure. OCT parameters that show promise in characterizing Fontan-associated PVD include the PA intima-to-media ratio and wall area ratio (i.e. difference between the whole-vessel area and the luminal area divided by the whole-vessel area)., Expert Opinion: OCT carries potential in characterizing PVD in patients with Fontan palliation. PA remodeling is marked by intimal hyperplasia, with medial regression. Further studies are required to determine the role of OCT in informing management decisions and assessing therapeutic responses.

Background: Despite chronic therapies, atrial fibrillation (AF) leads to rapid ventricular rates (RVR) often requiring intravenous treatments. Etripamil is a fast-acting, calcium-channel blocker administered intranasally affecting the atrioventricular node within minutes., Methods: Reduction of Ventricular Rate in Patients with Atrial Fibrillation evaluated the efficacy and safety of etripamil for the reduction of ventricular rate (VR) in patients presenting urgently with AF-RVR (VR ≥110 beats per minute [bpm]), was randomized, double-blind, placebo-controlled, and conducted in Canada and the Netherlands. Patients presenting urgently with AF-RVR were randomized (1:1, etripamil nasal spray 70 mg: placebo nasal spray). The primary objective was to demonstrate the effectiveness of etripamil in reducing VR in AF-RVR within 60 minutes of treatment. Secondary objectives assessed achievement of VR <100 bpm, reduction by ≥10% and ≥20%, relief of symptoms and treatment effectiveness; adverse events; and additional measures to 360 minutes., Results: Sixty-nine patients were randomized, 56 dosed with etripamil (n=27) or placebo (n=29). The median age was 65 years; 39% were female patients; proportions of AF types were similar between groups. The difference of mean maximum reductions in VR over 60 minutes, etripamil versus placebo, adjusting for baseline VR, was -29.91 bpm (95% CI, -40.31 to -19.52; P <0.0001). VR reductions persisted up to 150 minutes. Significantly greater proportions of patients receiving etripamil achieved VR reductions <100 bpm (with longer median duration <100 bpm), or VR reduction by ≥10% or ≥20%, versus placebo. VR reduction ≥20% occurred in 66.7% of patients in the etripamil arm and no patients in placebo. Using the Treatment Satisfaction Questionnaire for Medication-9, there was significant improvement in satisfaction on symptom relief and treatment effectiveness with etripamil versus placebo. Serious adverse events were rare; 1 patient in the etripamil arm experienced transient severe bradycardia and syncope, assessed as due to hypervagotonia., Conclusions: Intranasal etripamil 70 mg reduced VR and improved symptom relief and treatment satisfaction. These data support further development of self-administered etripamil for the treatment of AF-RVR., Registration: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04467905., Competing Interests: Disclosures Dr Camm has received grants and personal fees from Boehringer Ingelheim, Bayer, Pfizer, Bristol-Myers Squibb, and Daiichi Sankyo; personal fees from Medtronic, Boston Scientific, Menarini, and Biotronik; and support from Anthos, Sanofi, Abbott, GlaxoSmithKline, and Johnson & Johnson. Dr Piccini has received grants for clinical research from Abbott, the American Heart Association, the Association for the Advancement of Medical Instrumentation, Bayer, Boston Scientific, iRhythm, and Philips and serves as a consultant to Abbott, AbbVie, ARCA biopharma, Bayer, Boston Scientific, Bristol-Myers Squibb (Myokardia), Element Science, Itamar Medical, LivaNova, Medtronic, ElectroPhysiology Frontiers, ReCor, Sanofi, Philips, and UpToDate. Dr Alings has no disclosures to report. Drs Dorian, Ip, and Stambler serve on the steering committee for Milestone Pharmaceuticals. Dr Gosselin has no disclosures to report. Drs Kowey and Mondésert are consultants for Milestone Pharmaceuticals. Drs Prins, Roux, van Eck, and Al Windy have no disclosures to report. Drs Thermil, Shardonofsky, and Bharucha are employees of Milestone Pharmaceuticals. Dr Roy has no disclosures to report.

This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Arrhythmias are a common complication associated with tetralogy of Fallot (ToF), one of the most prevalent forms of congenital heart disease. As illustrated by this case-based review, various forms of arrhythmias can be encountered across the lifespan of patients with ToF, from infancy to older adulthood. These include atrioventricular block, junctional ectopic tachycardia, and atrial and ventricular arrhythmias. Arrhythmias have important implications on the health and quality of life of patients with ToF and require treatment by caregivers with dedicated expertise. The choice of pharmacologic and/or interventional therapies to alleviate symptoms, avoid complications, and mitigate risks depends in part on the type, severity, and frequency of the arrhythmia, as well as on the particularities of individual clinical scenarios. Preventing, monitoring for, and managing arrhythmias are an integral component of the care of patients with ToF throughout their lifespan that is critical to optimizing health outcomes., (© 2023 The Authors.)

Patients with congenital heart disease associated with a higher risk for ventricular arrhythmias (VA) and sudden cardiac death (SCD) can be divided conceptually into those with discrete mechanisms for reentrant monomorphic ventricular tachycardia (VT) (Group A) and those with more diffuse substrates (Group B). Part I of this review addresses Group A lesions, which predominantly consist of tetralogy of Fallot and related variants. Well-defined anatomic isthmuses for reentrant monomorphic VT are interposed between surgical scars and the pulmonary or tricuspid annulus. The most commonly implicated critical isthmus for VT is the conal septum that divides subpulmonary from subaortic outlets. Programmed ventricular stimulation can be helpful in risk stratification. Although catheter ablation is not generally considered an alternative to the implantable cardioverter-defibrillator (ICD) for prevention of SCD, emerging data suggest that there is a subset of carefully selected patients who may not require ICDs after successful monomorphic VT ablation., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Up to one-half of adults with congenital heart disease (CHD) experience psychological distress, including anxiety., Objectives: This paper sought to: 1) assess the contribution of illness perception in explaining anxiety symptoms beyond sociodemographic and medical variables in adults with CHD; and 2) investigate the potential mediating effect of coping style., Methods: CHD adult patients were recruited at Montreal Heart Institute between June 2019 and April 2021 for this cross-sectional study. Participants responded to self-reported questionnaires (Hospital Anxiety and Depression Scale, Brief Illness Perception Questionnaire, and Brief COPE). Medical characteristics (CHD complexity, NYHA functional class, and cardiac devices) were collected from medical records. We conducted hierarchical multiple linear regression and mediation analyses., Results: Of the 223 participants (mean age 46 ± 14 years, 59% women), 15% had clinically significant anxiety symptoms. Medical and sociodemographic variables explained 15% of the variation in anxiety symptoms. Adding illness perception explained an additional 18% of the variation in anxiety. This R 2 change was significant ( F [1,188] = 49.06, P  < 0.0001). Illness perception explained more variance (18%) than medical and sociodemographic variables combined. A more threatening perception of illness was associated with greater anxiety symptoms (β = 0.45, P  < 0.0001). Furthermore, illness perception was associated with coping, which was linked to reduced anxiety symptoms. Coping response style accounted for 20% of the total effect of illness perception on anxiety., Conclusions: Illness perception and coping are associated with anxiety in adults with CHD. Future initiatives should assess whether targeting these potentially modifiable factors effectively prevents or mitigates anxious symptoms in adults with CHD., Competing Interests: This work was carried out with financial assistance from the 10.13039/501100012651Montreal Heart Institute Foundation, Montréal, Québec, Canada. Dr Brouillette has received funding from the Montreal Heart Institute Foundation and Clinical Research Scholars – Junior 1 from the Fonds de recherche du Québec-Santé (FRQS). Dr M-P. Dubé has received grants from Canadian Institutes of Health Research (CIHR), and the Montreal Heart Institute Foundation; has received consulting fees and stock from Dalcor, outside the submitted work; and has the following patents: Methods for Treating or Preventing Cardiovascular Disorders and Lowering Risk of Cardiovascular Events (US20190070178A1), Genetic Markers for Predicting Responsiveness to Therapy with HDL-Raising or HDL Mimicking Agent (US20170233812A1), and Methods for using low-dose colchicine after myocardial infarction (pending). Dr Ibrahim has received grants and consulting fees from Edward and Opsens; payments or honoraria from Abbott, Medtronic, Boston Scientific, Opsens, and Edwards; and support for attending meetings and/or travel from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Background: Etripamil is a fast-acting, intranasally administered calcium-channel blocker in development for on-demand therapy outside a health-care setting for paroxysmal supraventricular tachycardia. We aimed to evaluate the efficacy and safety of etripamil 70 mg nasal spray using a symptom-prompted, repeat-dose regimen for acute conversion of atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia to sinus rhythm within 30 min., Methods: RAPID was a multicentre, randomised, placebo-controlled, event-driven trial, conducted at 160 sites in North America and Europe as part 2 of the NODE-301 study. Eligible patients were aged at least 18 years and had a history of paroxysmal supraventricular tachycardia with sustained, symptomatic episodes (≥20 min) as documented by electrocardiogram. Patients were administered two test doses of intranasal etripamil (each 70 mg, 10 min apart) during sinus rhythm; those who tolerated the test doses were randomly assigned (1:1) using an interactive response technology system to receive either etripamil or placebo. Prompted by symptoms of paroxysmal supraventricular tachycardia, patients self-administered a first dose of intranasal 70 mg etripamil or placebo and, if symptoms persisted beyond 10 min, a repeat dose. Continuously recorded electrocardiographic data were adjudicated, by individuals masked to patient assignment, for the primary endpoint of time to conversion of paroxysmal supraventricular tachycardia to sinus rhythm for at least 30 s within 30 min after the first dose, which was measured in all patients who administered blinded study drug for a confirmed atrioventricular-nodal-dependent event. Safety outcomes were assessed in all patients who self-administered blinded study drug for an episode of perceived paroxysmal supraventricular tachycardia. This trial is registered at ClinicalTrials.gov, NCT03464019, and is complete., Findings: Between Oct 13, 2020, and July 20, 2022, among 692 patients randomly assigned, 184 (99 from the etripamil group and 85 from the placebo group) self-administered study drug for atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia, with diagnosis and timing confirmed. Kaplan-Meier estimates of conversion rates by 30 min were 64% (63/99) with etripamil and 31% (26/85) with placebo (hazard ratio 2·62; 95% CI 1·66-4·15; p<0·0001). Median time to conversion was 17·2 min (95% CI 13·4-26·5) with the etripamil regimen versus 53·5 min (38·7-87·3) with placebo. Prespecified sensitivity analyses of the primary assessment were conducted to test robustness, yielding supporting results. Treatment-emergent adverse events occurred in 68 (50%) of 99 patients treated with etripamil and 12 (11%) of 85 patients in the placebo group, most of which were located at the administration site and were mild or moderate, and all of which were transient and resolved without intervention. Adverse events occurring in at least 5% of patients treated with etripamil were nasal discomfort (23%), nasal congestion (13%), and rhinorrhea (9%). No serious etripamil-related adverse events or deaths were reported., Interpretation: Using a symptom-prompted, self-administered, initial and optional-repeat-dosing regimen, intranasal etripamil was well tolerated, safe, and superior to placebo for the rapid conversion of atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia to sinus rhythm. This approach could empower patients to treat paroxysmal supraventricular tachycardia themselves outside of a health-care setting, and has the potential to reduce the need for additional medical interventions, such as intravenous medications given in an acute-care setting., Funding: Milestone Pharmaceuticals., Competing Interests: Declaration of interests BSS, PTS, BM, MC, PRK, JPP, SDP, and AJC are consultants for Milestone Pharmaceuticals. AJC has received grants and personal fees from Boehringer Ingelheim, Bayer, Pfizer, Bristol-Myers Squibb, and Daiichi Sankyo; personal fees from Medtronic, Boston Scientific, Menarini, and Biotronik; and support from Anthos, Sanofi, Abbott, GlaxoSmithKline, and Johnson & Johnson. PRK has received personal fees from Acesion Pharma, Allergan, Astellas Pharma, AstraZeneca, AtriCure, Boehringer Ingelheim, Bristol-Myers Squibb, Chattem, Correvio, Daiichi Sankyo, GlaxoSmithKline, InCarda Therapeutics, Johnson & Johnson, Medtronic, Merck, Novartis, Pfizer, Roche, and Sanofi-Aventis; serves on a data safety monitoring board for Eli Lilly; and has equity in CardioNet. SDP has received personal fees from Medtronic, Boston Scientific, Pfizer, Bristol-Myers Squibb, Janssen Pharmaceuticals, Philips, Zoll, and Sanofi-Aventis and research grants from Boston Scientific, Gilead Sciences, Pfizer, Bristol-Myers Squibb, the US Food and Drug Administration, Janssen Pharmaceuticals, Philips, Medtronic, and Sanofi-Aventis. HH has received lecture and consultancy fees from Abbott, Biotronik, Daiichi Sankyo, Pfizer-BMS, Medscape, and Springer Healthcare and unconditional research grants through the University of Antwerp and/or the University of Hasselt from Abbott, Bayer, Biotronik, Biosense Webster, Boston Scientific, Boehringer Ingelheim, Daiichi Sankyo, Fibricheck/Qompium, Medtronic, and Pfizer-BMS, all outside of the scope of this work. JLM has received grants and personal fees from Medtronic, Microport, and Sanofi. JPP has received grants for clinical research from Abbott, the American Heart Association, the Association for the Advancement of Medical Instrumentation, Bayer, Boston Scientific, iRhythm, and Philips and serves as a consultant to Abbott, AbbVie, ARCA biopharma, Bayer, Boston Scientific, Bristol Myers Squibb (Myokardia), Element Science, Itamar Medical, LivaNova, Medtronic, ElectroPhysiology Frontiers, ReCor, Sanofi, Philips, and UpToDate. AV has received personal fees from MedLumics and Adagio Medical and research grants from Bayer, Biosense Webster, and Medtronic. JMW has received personal fees from Sanofi-Aventis, Bristol-Myers Squibb, and Janssen Pharmaceuticals and a research grant from Milestone Pharmaceuticals. PTS has equity in Milestone Pharmaceuticals. DBB, FP, and SS are employees of Milestone Pharmaceuticals. JEI, MA, BSS, PD, and AJC serve on the steering committee for Milestone Pharmaceuticals. JH declares no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: With the advent of conduction system pacing, use of the Medtronic SelectSecure Model 3830 lead has increased substantially. However, with this increased use, the potential need for lead extraction also will increase. Lumenless lead construction requires an understanding of both applicable tensile forces as well as lead preparation techniques that can influence consistent extraction., Objective: The purpose of this study was to use bench testing methodologies to characterize the physical properties of lumenless leads and to describe related lead preparation methods that support known extraction techniques., Methods: Multiple 3830 lead preparation techniques, commonly used in extraction practices, were compared on the bench to assess rail strength (RS) in simple traction and use conditions with simulated scar. Retention of the IS1 connector vs severing the lead body preparation techniques were compared. Distal snare and rotational extraction tools were evaluated., Results: The retained connector method provided higher RS compared to the modified cut lead method: mean 11.42 lbf (9.85-12.73 lbf) vs 8.51 lbf (1.66-14.32 lbf), respectively. Snare use distally did not significantly affect RS: mean 11.05 lbf (8.58-13.95 lbf). Lead damage occurred with the TightRail extraction tool at angles ≥90°, which could occur with right-sided implants., Conclusions: When extracting SelectSecure leads, the retained connector method to maintain cable engagement benefits preservation of the extraction RS. Limiting traction force to <10 lbf (4.5 kgf) and avoiding poor lead preparation methods are critical to consistent extraction. Femoral snaring does not change RS when needed and offers a method to regain lead rail in cases of distal cable fracture., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The presence of a systemic right ventricle (sRV) with biventricular physiology (biV) is associated with increased patient morbidity and mortality. To date, no pharmacologic therapy for heart failure has been proven effective for patients with systolic dysfunction of the sRV-biV. We designed a randomized, double-blind, placebo-controlled crossover trial to compare sacubitril/valsartan treatment to placebo in adults (aged ≥ 18 years) with moderate-to-severe sRV-biV dysfunction and New York Heart Association functional class II to III symptoms. Two primary efficacy endpoints are assessed in the trial: exercise capacity (submaximal exercise duration) and neurohormonal activation (N-terminal prohormone brain natriuretic peptide). Secondary objectives include assessing a change in the Kansas City Cardiomyopathy Questionnaire score and evaluating the safety and tolerance of sacubitril/valsartan. A 6-week open run-in phase identifies the maximum tolerated dose of sacubitril/valsartan, up to 97 mg/103 mg twice daily. After a 2-week washout period, patients are randomized 1:1 to sacubitril/valsartan treatment vs placebo for a 24-week phase, followed by another 2-week washout period and subsequent crossover to the alternative treatment arm for an additional 24-week phase. Data to assess primary and secondary endpoints are collected at baseline and at the end of each phase. A total of 48 patients is required to provide > 80% power to detect a 30% difference in distance walked and in N-terminal prohormone brain natriuretic peptide levels with sacubitril/valsartan treatment vs placebo, each with a 2-sided P -value of 0.025. In summary, the P rospective Comparison of A ngiotensin R eceptor-Neprilysin Inhibitor vs Pl a cebo in Patients With C ongenital S ys temic R ight V entricular Heart Failure Trial (PARACYS-RV) should determine the role of sacubitril/valsartan in treating heart failure in patients with sRV-biV and carries the potential to alter management of this patient population., (© 2023 The Authors.)

Background: Robotic magnetic navigation (RMN) has emerged as a potential solution to overcome challenges associated with catheter ablation of arrhythmias in patients with congenital heart disease (CHD)., Objectives: To assess safety and efficacy of RMNguided catheter ablation in patients with CHD., Design and Methods: A systematic review and pooled analysis was conducted on patients with CHD who underwent RMNguided catheter ablation. Random effects models were used to generate pooled estimates with the inverse variance method used for weighting studies., Results: Twentyfour nonoverlapping records included 167 patients with CHD, mean age 36.5 years, 44.6% female. Type of CHD was simple in 27 (16.2%), moderate in 32 (19.2%), and complex in 106 (63.5%). A total of 202 procedures targeted 260 arrhythmias, the most common being macroreentrant atrial circuits. The mean procedural duration was 207.5 minutes, with a mean fluoroscopy time of 12.1 minutes. The pooled acute success rate was 89.2% [95% CI (77.8%, 97.4%)]. Freedom from arrhythmia recurrence was 84.5% [95% CI (72.5%, 94.0%)] over a mean follow-up of 24.3 months. The procedural complication rate was 3.5% with no complication attributable to RMN technology., Conclusion: RMN-guided ablation appears to be safe and effective across a variety of arrhythmia substrates and types of CHD.

Background: Left atrial appendage occlusion (LAAO) has emerged over the last two decades as an efficient and safe alternative to oral anticoagulation for stroke prevention. However, LAAO remains challenging due to the variety of anatomies and the multiple steps required to complete the procedure., Aims: We report the first series of in-human experience of the new all-in-one VersaCross Connect system designed to access the left atrium in conjunction with the delivery sheath for deployment of the WATCHMAN FLX device., Methods: We prospectively included the first nine consecutive cases of LAAO using the new VersaCross Connect system for WATCHMAN FLX device implantation at the Montreal Heart Institute and Vancouver General Hospital and collected procedural duration (defined as time from femoral access to closure) and time from transseptal puncture to device delivery., Results: VersaCross Connect system use for WATCHMAN FLX implantation was successful in all patients. No procedural complication was reported. Mean procedural time was 31 ± 6.3 min with a fluoroscopy time of 6.7 ± 4.9 min. The mean delay between the transseptal puncture and device implantation was 12.2 ± 1.9 min., Conclusions: We showed that the VersaCross Connect system was safe and successfully used in all first nine cases. This new system helped improve the efficiency of the procedure., (© 2022 Wiley Periodicals LLC.)

Background: Pharmacologic termination of paroxysmal supraventricular tachycardia (PSVT) often requires medically supervised intervention. Intranasal etripamil, is an investigational fast-acting, nondihydropyridine, L-type calcium channel blocker, designed for unsupervised self-administration to terminate atrioventricular nodal-dependent PSVT. Phase 2 results showed potential safety and efficacy of etripamil in 104 patients with PSVT., Methods: NODE-301, a phase 3, multicenter, double-blind, placebo-controlled study evaluated the efficacy and safety of etripamil nasal spray administered, unsupervised in patients with symptomatic sustained PSVT. After a medically supervised etripamil test dose while in sinus rhythm, patients were randomized 2:1 to receive etripamil 70 mg or placebo. When PSVT symptoms developed, patients applied a cardiac monitor and attempted a vagal maneuver; if symptoms persisted, they self-administered blinded treatment. An independent Adjudication Committee reviewed continuous electrocardiogram recordings. The primary efficacy endpoint was termination of adjudicated PSVT within 5 hours after study drug administration., Results: NODE-301 accrued 156 positively adjudicated PSVT events treated with etripamil (n=107) or placebo (n=49). The hazard ratio for the primary endpoint, time-to-conversion to sinus rhythm during the 5-hour observation period, was 1.086 (95% CI, 0.726-1.623; P =0.12). In predefined sensitivity analyses, etripamil effects (compared with placebo) occurred at 3, 5, 10, 20, and 30 minutes ( P <0.05). For example, at 30 minutes, there was a 53.7% of SVT conversion in the treatment arm compared to 34.7% in the placebo arm (hazard ratio, 1.87 [95% CI, 1.09-3.22]; P =0.02). Etripamil was well tolerated; adverse events were mainly related to transient nasal discomfort and congestion (19.6% and 8.0%, respectively, of randomized treatment-emergent adverse events., Conclusions: Although the primary 5-hour efficacy endpoint was not met, analyses at earlier time points indicated an etripamil treatment effect in terminating PSVT. Etripamil self-administration during PSVT was safe and well tolerated. These results support continued clinical development of etripamil nasal spray for self-administration during PSVT in a medically unsupervised setting., Registration: URL: https://www., Clinicaltrials: gov; Unique identifier: NCT03464019.

Background: Vitamin K antagonists (VKAs) are frequently prescribed to patients with congenital heart disease (CHD) for atrial arrhythmias or Fontan palliation, but there is a paucity of data regarding time spent in the therapeutic range (TTR). We sought to determine the TTR in patients with CHD and atrial arrhythmias or Fontan palliation prescribed VKAs and explore associations with thromboembolic and bleeding events., Methods: A multicentre North American cohort study was conducted on patients with CHD who received VKAs for sustained atrial arrhythmia or Fontan palliation. TTR was calculated using the Rosendaal linear interpolation method. Generalized estimating equations were used to explore factors associated with time outside the therapeutic range., Results: A total of 567 patients, aged 33 ± 17 years, 56% female, received VKAs for 11.5 ± 8.4 years for atrial arrhythmias (63.0%) or Fontan palliation (58.0%). CHD was simple, moderate, and complex in 10.8%, 20.3%, and 69.0%, respectively. Site investigators perceived good control over international normalized ratio (INR) levels in most patients (75.3%), with no or minor compliance or adherence issues (85.6%). The mean TTR was 41.9% (95% confidence interval [CI], 39.0%-44.8%). Forty-seven (8.3%) and 34 (6.0%) patients had thromboembolic and bleeding events, respectively. Thromboembolic events were associated with a higher proportion of time below the therapeutic range (31.3% vs 19.1%, P = 0.003) and bleeding complications with a higher proportion of time above the therapeutic range (32.5% vs 19.5%, P = 0.006)., Conclusions: Patients with CHD who receive VKAs spend < 42% of their time with INR levels in the therapeutic range, with repercussions regarding thromboembolic and bleeding complications., (Copyright © 2022 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Fontan palliation results in a hemodynamically complex circulation with multisystem consequences, which in the long term adversely affect many body processes. Systemic venous hypertension, nonpulsatile low-shear pulmonary blood flow, and low cardiac output are the 3 main characteristics of a Fontan circulation, leading to unavoidable slowly progressive failure. An appreciation of how the hemodynamics of a Fontan circulation change with time and relate to the various modes of Fontan circulatory failure is important. Accurate hemodynamic assessment aid this understanding and may permit early identification of potentially treatable drivers of decline. While no evidence-based or guideline-directed pharmacologic management strategy has been established in Fontan patients, understanding the hemodynamics of Fontan circulation failure will assist in the rational selection of potentially helpful drug therapies for individual patients. In this review, we present hemodynamic concepts of the optimal Fontan physiology and Fontan circulatory failure, review practical aspects of invasive hemodynamic assessment, and discuss the role of drug therapies in increasing systemic venous blood flow return and decreasing ventricular filling pressures in Fontan circulation. Often complementary to catheter-based or surgical interventions, pharmacologic management aims at preserving patency of the circuit, adequate systolic and diastolic ventricular function, atrioventricular valve function, an unobstructed ventricular outflow tract, and pulmonary vascular integrity in order to maintain an acceptable cardiac output., (Copyright © 2022 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

As a result of remarkable progress in operative techniques and cardiology care during childhood, Fontan patients continue to age and require team-based multidisciplinary expertise to manage complications encountered in adulthood. They face particular challenges in terms of altered hemodynamic stressors, cardiac and hepatic failure, and arrhythmias. Arrhythmias in Fontan patients are highly prevalent and associated with underlying anatomy, surgical technique, and postoperative sequelae. Diagnostic tools, treatments, and device strategies for arrhythmias in Fontan patients should be adapted to the specific anatomy, type of surgical repair, and clinical status. Great strides in our understanding of arrhythmia mechanisms, options and techniques to obtain access to relevant cardiac structures, and application of both old and new technologies have contributed to improving cardiac implantable electronic device (CIED) therapies for this unique population. In this state-of-the-art review, we discuss the various arrhythmias encountered in Fontan patients, their diagnosis, and options for treatment and prevention, with a focus on CIEDs. Throughout, access challenges particular to the Fontan circulation are considered. Recently developed technologies, such as the subcutaneous implantable cardioverter defibrillator, carry the potential to be transformative but require awareness of Fontan-specific issues. Moreover, new leadless pacing technology represents a promising strategy that may soon become applicable to Fontan patients with sinus-node dysfunction. CIEDs are essential tools in managing Fontan patients, but the complex clinical scenarios that arise in this patient population are among the most challenging for the electrophysiologist treating patients with congenital heart disease., (Copyright © 2022 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The identification of low-voltage proarrhythmic areas for catheter ablation of scar-mediated ventricular tachycardia (VT) remains challenging. Integration of myocardial perfusion imaging (single-photon emission computed tomography/computed tomography; SPECT/CT) and electroanatomical mapping (EAM) may improve delineation of the arrhythmogenic substrate., Objective: To assess the feasibility of SPECT/CT image integration with voltage maps using the EnSite Precision system (Abbott) in patients undergoing scar-mediated VT ablation., Methods: Patients underwent SPECT/CT imaging prior to left ventricular (LV) EAM with the EnSite Precision mapping system. The SPECT/CT, EAM data, and ablation lesions were retrospectively co-registered in the EnSite Precision system and exported for analysis. Segmental tissue viability scores were calculated based on SPECT/CT perfusion and electrogram bipolar voltage amplitude. Concordance, specificity, and sensitivity between the 2 modalities as well as the impact of SPECT/CT spatial resolution were evaluated., Results: Twenty subjects (95% male, 67 ± 7 years old, left ventricular ejection fraction 36% ± 11%) underwent EAM and SPECT/CT integration. A concordance of 70% was found between EAM and SPECT/CT for identification of cardiac segments as scar vs viable, with EAM showing a 68.5% sensitivity and 76.4% specificity when using SPECT/CT as a gold standard. Projection on low-resolution 3D geometries led to an average decrease of 38% ± 22% of the voltage points used., Conclusion: The study demonstrated the feasibility of integrating SPECT/CT with EAM performed retrospectively for characterization of anatomical substrates during VT ablation procedures., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)