Sex differences among subcutaneous implantable cardioverter-defibrillator recipients: a propensity-matched, multicentre, international analysis from the i-SUSI project.

AIMS: Women have been historically underrepresented in implantable cardioverter-defibrillator (ICD) trials. No data on sex differences regarding subcutaneous ICDs (S-ICD) carriers have been described. Aim of our study was to investigate sex-related differences among unselected S-ICD recipients. METHODS AND RESULTS: Consecutive patients enrolled in the multicentre, international i-SUSI registry were analysed. Comparisons between sexes were performed using a 1:1 propensity matching adjusted analysis for age, body mass index (BMI), left ventricular function, and substrate. The primary outcome was the rate of appropriate shocks during follow-up. Inappropriate shocks and other device-related complications were deemed secondary outcomes. A total of 1698 patients were extracted from the i-SUSI registry; 399 (23.5%) were females. After propensity matching, two cohorts of 374 patients presenting similar baseline characteristics were analysed. Despite similar periprocedural characteristics and a matched BMI, women resulted at lower risk of conversion failure as per PRAETORIAN score (73.4% vs. 81.3%, P = 0.049). Over a median follow-up time of 26.5 [12.7-42.5] months, appropriate shocks were more common in the male cohort (rate/year 3.4% vs. 1.7%; log-rank P = 0.049), while no significant differences in device-related complications (rate/year: 6.3% vs. 5.8%; log-rank P = 0.595) and inappropriate shocks (rate/year: 4.3% vs. 3.1%; log-rank P = 0.375) were observed. After controlling for confounders, sex remained significantly associated with the primary outcome (aHR 1.648; CI 0.999-2.655, P = 0.048), while not resulting predictor of inappropriate shocks and device-related complications. CONCLUSION: In a propensity-matched cohort of S-ICD recipients, women are less likely to experience appropriate ICD therapy, while not showing higher risk of device-related complications. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT0473876.

Left Atrial Appendage Occlusion in Patients With Anticoagulation Failure vs Anticoagulation Contraindication.

BACKGROUND: Left atrial appendage occlusion (LAAO) provides mechanical cardioembolic protection for atrial fibrillation (AF) patients who cannot use oral anticoagulation therapy (OAT). Patients with a thrombotic event despite OAT are at high risk for recurrence and may also benefit from LAAO. OBJECTIVES: This study sought to investigate the efficacy of LAAO in AF patients with a thrombotic event on OAT compared to: 1) LAAO in AF patients with a contraindication for OAT; and 2) historical data. METHODS: The international LAAO after stroke despite oral anticoagulation (STR-OAC LAAO) collaboration included patients who underwent LAAO because of thrombotic events on OAT. This cohort underwent propensity score matching and was compared to the EWOLUTION (Evaluating Real-Life Clinical Outcomes in Atrial Fibrillation Patients Receiving the WATCHMAN Left Atrial Appendage Closure Technology) registry, which represents patients who underwent LAAO because of OAT contraindications. The primary outcome was ischemic stroke. Event rates were compared between cohorts and with historical data without OAT, yielding relative risk reductions based on risk scores. RESULTS: Analysis of 438 matched pairs revealed no significant difference in the ischemic stroke rate between the STR-OAC LAAO and EWOLUTION cohorts (2.5% vs 1.9%; HR: 1.37; 95% CI: 0.72-2.61). STR-OAC LAAO patients exhibited a higher thromboembolic risk (HR: 1.71; 95% CI: 1.04-2.83) but lower bleeding risk (HR: 0.39; 95% CI: 0.18-0.88) compared to EWOLUTION patients. The mortality rate was slightly higher in EWOLUTION (4.3% vs 6.9%; log-rank P = 0.028). Relative risk reductions for ischemic stroke were 70% and 78% in STR-OAC LAAO and EWOLUTION, respectively, compared to historical data without OAT. CONCLUSIONS: LAAO in patients with a thrombotic event on OAT demonstrated comparable stroke rates to the OAT contraindicated population in EWOLUTION. The thromboembolic event rate was higher and the bleeding rate lower, reflecting the intrinsically different risk profile of both populations. Until randomized trials are available, LAAO may be considered in patients with an ischemic event on OAT.

Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology.

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

Early Clinical Outcomes and Advantages of a Novel-Size Adjustable Second-Generation Cryoballoon: A Proof-of-Concept Study.

(1) Background/Objective Balloon-guided catheter ablation (CA) has emerged as an alternative option for atrial fibrillation (AF) management. The recent introduction of a novel-size adjustable second-generation cryoballoon (CB) system offers innovations, but clinical outcomes remain unexplored. This study aims to assess the acute performance of the POLARx FIT™ CB system in AFCA. (2) Methods: Consecutive patients undergoing AF ablation with the POLARx FIT™ CB system in our center were included. The primary outcome was the rate of 31 mm balloon-size utilization, with secondary outcomes including acute pulmonary vein isolation (PVI) rate, periprocedural complications, and in-hospital AF recurrences. (3) Results: Twenty-four patients with a mean age of 59.5 years, predominantly male (87.5%), and exhibiting paroxysmal AF (91.7%) were enrolled. Procedural characteristics demonstrated a high acute success rate (100% PV isolation) with a favorable safety profile. Notably, the 31 mm CB configuration was utilized in 51% of applications, showcasing its adaptability in challenging anatomies. No major complications occurred, with two patients experiencing in-hospital self-limiting AF recurrences. (4) Conclusions: This study represents the first comprehensive assessment of the POLARx FIT™ CB system in AF ablation. While acknowledging the study's limitations, this novel CB emerges as a promising tool, warranting further exploration in larger studies with extended follow-up periods.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project.

AIMS: Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers. METHODS AND RESULTS: International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006]. CONCLUSION: In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up. CLINICALTRIALS.GOV IDENTIFIER: NCT0473876.

Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation.

INTRODUCTION: Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI). METHODS: The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared. RESULTS: Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies. CONCLUSION: LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

BACKGROUND AND AIMS: Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. METHODS: All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. RESULTS: 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). CONCLUSIONS: Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Novel SCN5A gene mutation in a patient affected by multifocal ectopic premature Purkinje-related contractions syndrome.

We report the case of a 36-year-old woman who presented to the emergency department complaining of palpitations and asthenia. Investigations showed frequent ventricular ectopy and severe left ventricular ejection fraction impairment. She was diagnosed with a peculiar condition defined multifocal ectopic premature Purkinje-related contractions syndrome, which in some cases can be associated with a dilated cardiomyopathy phenotype. Genetic testing showed a novel mutation in the SCN5A gene (c.673C > G). In the context of acute left ventricular dysfunction in a young patient, we discuss the clinical presentation of this rare condition and its clinical management, as well as its genetic substrate.

Implantable loop recorders in patients with Brugada syndrome: the BruLoop study.

BACKGROUND AND AIMS: Available data on continuous rhythm monitoring by implantable loop recorders (ILRs) in patients with Brugada syndrome (BrS) are scarce. The aim of this multi-centre study was to evaluate the diagnostic yield and clinical implication of a continuous rhythm monitoring strategy by ILRs in a large cohort of BrS patients and to assess the precise arrhythmic cause of syncopal episodes. METHODS: A total of 370 patients with BrS and ILRs (mean age 43.5 ± 15.9, 33.8% female, 74.1% symptomatic) from 18 international centers were included. Patients were followed with continuous rhythm monitoring for a median follow-up of 3 years. RESULTS: During follow-up, an arrhythmic event was recorded in 30.7% of symptomatic patients [18.6% atrial arrhythmias (AAs), 10.2% bradyarrhythmias (BAs), and 7.3% ventricular arrhythmias (VAs)]. In patients with recurrent syncope, the aetiology was arrhythmic in 22.4% (59.3% BAs, 25.0% VAs, and 15.6% AAs). The ILR led to drug therapy initiation in 11.4%, ablation procedure in 10.9%, implantation of a pacemaker in 2.5%, and a cardioverter-defibrillator in 8%. At multivariate analysis, the presence of symptoms [hazard ratio (HR) 2.5, P = .001] and age >50 years (HR 1.7, P = .016) were independent predictors of arrhythmic events, while inducibility of ventricular fibrillation at the electrophysiological study (HR 9.0, P < .001) was a predictor of VAs. CONCLUSIONS: ILR detects arrhythmic events in nearly 30% of symptomatic BrS patients, leading to appropriate therapy in 70% of them. The most commonly detected arrhythmias are AAs and BAs, while VAs are detected only in 7% of cases. Symptom status can be used to guide ILR implantation.

Practical guide on left atrial appendage closure for the non-implanting physician: an international consensus paper.

A significant proportion of patients who suffer from atrial fibrillation (AF) and are in need of thromboembolic protection are not treated with oral anticoagulation or discontinue this treatment shortly after its initiation. This undertreatment has not improved sufficiently despite the availability of direct oral anticoagulants which are associated with less major bleeding than vitamin K antagonists. Multiple reasons account for this, including bleeding events or ischaemic strokes whilst on anticoagulation, a serious risk of bleeding events, poor treatment compliance despite best educational attempts, or aversion to drug therapy. An alternative interventional therapy, which is not associated with long-term bleeding and is as effective as vitamin K anticoagulation, was introduced over 20 years ago. Because of significant improvements in procedural safety over the years, left atrial appendage closure, predominantly achieved using a catheter-based, device implantation approach, is increasingly favoured for the prevention of thromboembolic events in patients who cannot achieve effective anticoagulation. This management strategy is well known to the interventional cardiologist/electrophysiologist but is not more widely appreciated within cardiology or internal medicine. This article introduces the devices and briefly explains the implantation technique. The indications and device follow-up are more comprehensively described. Almost all physicians who care for adult patients will have many with AF. This practical guide, written within guideline/guidance boundaries, is aimed at those non-implanting physicians who may need to refer patients for consideration of this new therapy, which is becoming increasingly popular.

Catheter Ablation for Ventricular Tachycardia in Patients With Desmoplakin Cardiomyopathy.

BACKGROUND: Desmoplakin (DSP) pathogenic/likely pathogenic (P/LP) variants are associated with malignant phenotypes of arrhythmogenic cardiomyopathy (DSP-ACM). Reports of outcomes after ventricular tachycardia (VT) ablation in DSP-ACM are scarce. OBJECTIVES: In this study, the authors sought to report on long-term outcomes of VT ablation in DSP-ACM. METHODS: Patients with P/LP DSP variants at 9 institutions undergoing VT ablation were included. Demographic, clinical, and instrumental data as well as all ventricular arrhythmia (VA) events were collected. Sustained VAs after the index procedure were the primary outcome. A per-patient before and after ablation comparison of rates of VA episodes per year was performed as well. RESULTS: Twenty-four DSP-ACM patients (39.3 ± 12.1 years of age, 62.5% male, median 6,116 [Q1-Q3: 3,362-7,760] premature ventricular complexes [PVCs] per 24 hours, median 4 [Q1-Q3: 2-11] previous VA episodes per patient at ablation) were included. Index procedure was most commonly endocardial/epicardial (19/24) The endocardium of the right ventricle (RV), the left ventricle (LV), or both ventricles were mapped in 8 (33.3%), 9 (37.5%), and 7 (29.2%) cases, respectively. Low voltage potentials were found in 10 of 15 patients in the RV and 11 of 16 in the LV. Endocardial ablation was performed in 18 patients (75.0%). Epicardial mapping in 19 patients (79.2%) identified low voltage potentials in 17, and 16 received epicardial ablation. Over the following 2.9 years (Q1-Q3: 1.8-5.5 years), 13 patients (54.2%) experienced VA recurrences. A significant reduction in per-patient event/year before and after ablation was observed (1.4 [Q1-Q3: 0.5-2.4] to 0.1 [Q1-Q3: 0.0-0.4]; P = 0.009). Two patients needed heart transplantation, and 4 died (3 of heart failure and 1 noncardiac death). CONCLUSIONS: VT ablation in DSP-ACM is effective in reducing the VA burden of the disease, but recurrences are common. Most VT circuits are epicardial, with both LV and RV low voltage abnormalities. Heart failure complicates clinical course and is an important cause of mortality.

Differences in underlying cardiac substrate among S-ICD recipients and its impact on long-term device-related outcomes: Real-world insights from the iSUSI registry.

BACKGROUND: Outcome comparisons among subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with nonischemic cardiomyopathies are scarce. OBJECTIVE: The aim of this study was to evaluate differences in device-related outcomes among S-ICD recipients with different structural substrates. METHODS: Patients enrolled in the i-SUSI (International SUbcutaneouS Implantable cardioverter defibrillator registry) project were grouped according to the underlying substrate (ischemic vs nonischemic) and subgrouped into dilated cardiomyopathy, hypertrophic cardiomyopathy, Brugada syndrome (BrS), arrhythmogenic right ventricular cardiomyopathy (ARVC). The main outcome of our study was to compare the rates of appropriate and inappropriate shocks and device-related complications. RESULTS: Among 1698 patients, the most common underlying substrate was ischemic (31.7%), followed by dilated cardiomyopathy (20.5%), BrS (10.8%), hypertrophic cardiomyopathy (8.5%), and ARVC (4.4%). S-ICD for primary prevention was more common in the nonischemic cohort (70.9% vs 65.4%; P = .037). Over a median (interquartile range) follow-up of 26.5 (12.6-42.8) months, no differences were observed in appropriate shocks between ischemic and nonischemic patients (4.8%/y vs 3.9%/y; log-rank, P = .282). ARVC (9.0%/y; hazard ratio [HR] 2.492; P = .001) and BrS (1.8%/y; HR 0.396; P = .008) constituted the groups with the highest and lowest rates of appropriate shocks, respectively. Device-related complications did not differ between groups (ischemic: 6.4%/y vs nonischemic: 6.1%/y; log-rank, P = .666), nor among underlying substrates (log-rank, P = .089). Nonischemic patients experienced higher rates of inappropriate shocks than did ischemic S-ICD recipients (4.4%/y vs 3.0%/y; log-rank, P = .043), with patients with ARVC (9.9%/y; P = .001) having the highest risk, even after controlling for confounders (adjusted HR 2.243; confidence interval 1.338-4.267; P = .002). CONCLUSION: Most S-ICD recipients were primary prevention nonischemic cardiomyopathy patients. Among those, patients with ARVC tend to receive the most frequent appropriate and inappropriate shocks and patients with BrS the least frequent appropriate shocks.

Left ventricular assist device in the presence of subcutaneous implantable cardioverter defibrillator: Data from a multicenter experience.

BACKGROUND: Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure (HF). Subcutaneous implantable cardioverter defibrillator (S-ICD) might be a viable alternative to conventional ICDs with a lower risk of short- and long-term of device-related complications and infections.The aim of this multicenter study was to evaluate the outcomes and management of S-ICD recipients who underwent LVAD implantation. METHODS: The study population included patients with a preexisting S-ICD who underwent LVAD implantation for advanced HF despite optimal medical therapy. RESULTS: The study population included 30 patients (25 male; median age 45 [38-52] years).The HeartMate III was the most common LVAD type. Median follow-up in the setting of concomitant use of S-ICDs and LVADs was 7 months (1-20).There were no reports of inability to interrogate S-ICD systems in this population. Electromagnetic interference (EMI) occurred in 21 (70%) patients. The primary sensing vector was the one most significantly involved in determining EMI. Twenty-seven patients (90%) remained eligible for S-ICD implantation with at least one optimal sensing vector. The remaining 3 patients (10%) were ineligible for S-ICD after attempts of reprogramming of sensing vectors. Six patients (20%) experienced inappropriate shocks (IS) due to EMI. Six patients (20%) experienced appropriate shocks. No S-ICD extraction because of need for antitachycardia pacing, ineffective therapy or infection was reported. CONCLUSIONS: Concomitant use of LVAD and S-ICD is feasible in most patients. However, the potential risk of EMI oversensing, IS and undersensing in the post-operative period following LVAD implantation should be considered. Careful screening for EMI should be performed in all sensing vectors after LVAD implantation.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

BACKGROUND AND AIMS: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. METHODS: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. RESULTS: One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. CONCLUSIONS: North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.