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Background: The extravascular implantable cardioverter-defibrillator (ICD) has a single lead implanted substernally to enable pause-prevention pacing, antitachycardia pacing, and defibrillation energy similar to that of transvenous ICDs. The safety and efficacy of extravascular ICDs are not yet known.Methods: We conducted a prospective, single-group, nonrandomized, premarket global clinical study involving patients with a class I or IIa indication for an ICD, all of whom received an extravascular ICD system. The primary efficacy end point was successful defibrillation at implantation. The efficacy objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients with successful defibrillation was greater than 88%. The primary safety end point was freedom from major system- or procedure-related complications at 6 months. The safety objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients free from such complications was greater than 79%.Results: A total of 356 patients were enrolled, 316 of whom had an implantation attempt. Among the 302 patients in whom ventricular arrhythmia could be induced and who completed the defibrillation testing protocol, the percentage of patients with successful defibrillation was 98.7% (lower boundary of the one-sided 97.5% confidence interval [CI], 96.6%; P<0.001 for the comparison with the performance goal of 88%); 299 of 316 patients (94.6%) were discharged with a working ICD system. The Kaplan-Meier estimate of the percentage of patients free from major system- or procedure-related complications at 6 months was 92.6% (lower boundary of the one-sided 97.5% CI, 89.0%; P<0.001 for the comparison with the performance goal of 79%). No major intraprocedural complications were reported. At 6 months, 25 major complications were observed, in 23 of 316 patients (7.3%). The success rate of antitachycardia pacing, as assessed with generalized estimating equations, was 50.8% (95% CI, 23.3 to 77.8). A total of 29 patients received 118 inappropriate shocks for 81 arrhythmic episodes. Eight systems were explanted without extravascular ICD replacement over the 10.6-month mean follow-up period.Conclusions: In this prospective global study, we found that extravascular ICDs were implanted safely and were able to detect and terminate induced ventricular arrhythmias at the time of implantation. (Funded by Medtronic; ClinicalTrials.gov number, NCT04060680.). [ABSTRACT FROM AUTHOR]

Purpose of Review: Survival statistics for out-of-hospital cardiac arrests remain unsatisfactory. Prompt defibrillation of shockable rhythms, such as ventricular fibrillation and pulseless ventricular tachycardia, is crucial for improving survival. Automated external defibrillators (AEDs) and wearable cardiac defibrillators (WCDs) seek to improve the survival rates following out-of-hospital cardiac arrests. We aim to review the indications, utility, advancements, and limitations of AEDs and WCDs, as well as their role in contemporary and future clinical practice., Recent Findings: Recent advancements in these technologies, such as smartphone applications and drone delivery of AEDs and less inappropriate shocks and decreased size of WCDs, have increased their ubiquity and efficacy. However, implementation of this technology remains limited due to lack of resources and suboptimal patient adherence., Summary: Out of hospital cardiac arrests continue to pose a significant public health challenge. Advancements in AEDs and WCDs aim to facilitate prompt defibrillation of shockable rhythms with the goal of improving survival rates. However, they remain underutilized due to limited resources and suboptimal patient adherence. As these technologies continue to evolve to become smaller, lighter and more affordable, their utilization and accessibility are expected to improve., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Barriers to maximizing patient benefit with implantable defibrillation devices include limited ability to tailor antitachycardia pacing (ATP) therapy in real-time and identify patients at risk of heart failure (HF) events early on. The Personalized Therapy study aims to evaluate the performance of two algorithms, intrinsic ATP TM (iATP) and TriageHF TM , to address these barriers in routine clinical practice., Methods and Results: The Personalized Therapy Study was designed as a prospective, multicenter, post-market registry study expected to enroll approximately 2,200 patients meeting the following criteria: (1) implanted with a study-eligible device regardless of procedure type; (2) Medtronic CareLink® Network enrolled; (3) TriageHF enabled within CareLink and High Risk Alert notifications turned ON; and (4) iATP enabled. The primary study objectives are to demonstrate iATP effectiveness in the fast ventricular tachycardia zone and estimate the positive predictive value of TriageHF high-risk status for worsening HF. Additionally, objectives include characterizing iATP effectiveness in all ventricular detection zones and characterizing TriageHF based clinical actions and related HF-hospitalizations., Conclusion: This study is expected to generate real-world evidence on the performance of the iATP and TriageHF algorithms, which aim to improve clinical practice by tailoring arrhythmia and HF therapies to individual patient disease state., (Copyright © 2024. Published by Elsevier Inc.)

With increasing volume of cardiac implantable electronic devices in the last decade, the indications for device extraction have increased. Multidisciplinary collaboration between cardiothoracic surgeons, cardiac anesthesiologists, and cardiac electrophysiologists has been recognized as an essential pre-requisite in pre-procedural planning to limit complications from this inherently risky procedure. Fortunately, the tools and techniques have continued to evolve to make extraction safer and more effective. This article discusses traditional and non-traditional techniques for transvenous lead extraction in addition to retrieval of leadless pacemakers., Competing Interests: Disclosure Dr.G. Ho is supported by grants from the American Heart Association, United States (AHA 19CDA34760021), National Institutes of Health, United States (NIH 1KL2TR001444), Muggleton Family via the Artificial Intelligence Arrhythmia Research Fund at UC San Diego Health, and reports founder shares in Vektor Inc and consulting for Medtronic and Kestra Inc. Dr U. Birgersdotter-Green reports honorarium from Medtronic, Biotronik, Boston Scientific, Abbott, and Philips. Dr T. Pollema report no disclosures., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Complications associated with cardiovascular implantable electronic devices may necessitate device and lead removal. An open approach to removal may be electively chosen in cases with high risk of complications or those requiring additional concomitant cardiac surgery. This study aimed to investigate outcomes of patients who underwent elective open lead extractions (OLE) at two large tertiary care centers., Methods: The records of 29 patients undergoing elective OLE were analyzed through retrospective chart review., Results: 69 total leads were extracted from 29 patients (77% completely, 23% partially). The average age of the oldest leads was 13.3 ± 11.3 years. Infective endocarditis with severe valvular insufficiency requiring valvular intervention (41%)-an infectious etiology, and tricuspid valve intervention to correct RV lead-related severe TR (38%)-a noninfectious etiology, were the most common reasons for OLE. 38% of the patients had additional co-primary or secondary indications for open extraction, such as CABG and pericardiectomies. The rate of major complications and procedural failure was 3% each (1/29). 30-day survival was 100%, and 1-year survival was 92%. The average length of hospital stay was 15 days and higher among those undergoing OLE for infectious indications., Conclusion: Open lead extractions offered a similar clinical success rate (97%) to transvenous extractions in this cohort and may be a viable alternative for those necessitating valvular intervention or when the risk of complications from TLE is considered very high., (© 2024 Wiley Periodicals LLC.)

Background: Substernal lead placement of the extravascular implantable cardioverter-defibrillator (EV ICD) permits both defibrillation at thresholds similar to those seen with transvenous ICDs and effective antitachycardia pacing (ATP), while avoiding the vasculature and associated complications. The global Pivotal study has shown the EV ICD system to be safe and effective through 6 months, but long-term experience has yet to be published. We aim to report the performance and safety of the EV ICD system throughout the study., Methods: The EV ICD Pivotal study was a prospective, global, single-arm, pre-market clinical study. Individuals with a class I or IIa indication for a single-chamber ICD per guidelines were enrolled. Freedom from major system- or procedure-related complications, as well as appropriate and inappropriate therapy rates, were assessed through 3 years using the Kaplan-Meier method. Anti-tachycardia pacing success was calculated using simple proportions., Results: An implant was attempted in 316 patients [25.3% female, 53.8±13.1 years old, 81.6% primary prevention, LVEF 38.9%±15.4%]. Of 299 patients with a successful implant, 24 experienced 82 spontaneous arrhythmic episodes that were appropriately treated with either ATP only (38, 46.3%), shock only (34, 41.5%), or both (10, 12.2%) for a Kaplan-Meier-estimated rate of first any appropriate therapy of 9.2% at 3 years. Antitachycardia pacing was successful in 77.1% (37/48) of episodes, and ATP usage significantly increased from discharge to last follow-up visit (P<0.0001). Shock therapy was successful in 100% (27/27) of discrete, spontaneous ventricular arrhythmias. The inappropriate shock rates at 1 and 3 years were 9.8% and 17.5%, respectively, with P-wave oversensing the predominant cause. No major intraprocedural complications were reported and the estimated freedom from system- or procedure-related major complications was 91.9% at 1 year and 89.0% at 3 years. The most common major complications were lead dislodgement (10 events; n=9 patients, 2.8%), postoperative wound or device pocket infection (n=8, 2.5%), and device inappropriate shock delivery (n=4, 1.3%). Twenty-four system revisions were performed as a result of major complications related to the EV ICD system or procedure., Conclusions: From implant to study completion, the EV ICD Pivotal study demonstrated that a single integrated system with an extravascular lead placed in the substernal space maintains high ATP success, effective defibrillation, and a consistent safety profile.

Background: The ability of computed tomography (CT) characteristics to predict the difficulty of transvenous lead extraction (TLE) is an evolving subject., Objective: To identify CT characteristics associated with increased TLE difficulty., Methods: All consecutive patients undergoing TLE at the University of California San Diego from January 2018 to February 2022 were analyzed, utilizing the UC San Diego Lead Extraction Registry. Patients underwent cardiac-gated chest CT scans with intravenous contrast; all scans were reviewed by a single radiologist. Lead extraction was performed per standard institutional protocol with the initial use of a laser sheath and crossover to a mechanical sheath as needed. Multivariable linear and logistic regression analyses were performed to identify predictors of individual lead-removal fluoroscopy time and mechanical sheath use, as markers of extraction difficulty., Results: A total of 343 patients were analyzed. The mean age of the study population was 63.8 ± 15.4 years; 71% were male. The mean lead dwell-in duration was 8.6 ± 5.7 years. In multivariable linear regression analysis, venous occlusion detected on CT was independently associated with higher individual lead-removal fluoroscopy time (p = 0.004), when adjusting for clinical characteristics such as lead dwell time. In multivariable logistic regression analysis, calcification and venous occlusion were independently associated with a higher need for mechanical sheath use during TLE (odds ratio:5.08, p < 0.001, 95% CI: 2.54-10.46) and (odds ratio:3.72, p < 0.001, 95% CI: 1.89-7.35), respectively., Conclusion: In patients undergoing TLE, venous occlusion identified by chest CT is associated with increased fluoroscopy time. Patients with lead-associated calcification or venous occlusion detected by chest CT are each five and three times more likely to require crossover from laser to a mechanical sheath., (© 2024 Wiley Periodicals LLC.)

We present a complex case of cardiac implantable electronic device infection and extraction in the setting of bacteremia, large lead vegetation, and patent foramen ovale. Following a comprehensive preprocedural workup including transesophageal echocardiogram and computed tomography lead extraction protocol, in addition to the involvement of multiple subspecialties, an open chest approach to extraction was deemed a safer option for eradication of the patient's infection. Despite percutaneous techniques having evolved as the preferred extraction method during the last few decades, this case demonstrates the importance of a thorough evaluation at an experienced center to determine the need for open chest extraction., Competing Interests: Disclosure There are no financial conflicts of interest to disclose., (Copyright © 2023 Elsevier Inc. All rights reserved.)

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I 2 ) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multisocietal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with fluorine-18 fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multifocal or diffuse heterogenous intense 18 F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more., (Copyright © 2024 by the American Society of Nuclear Cardiology, the American College of Cardiology, Heart Rhythm Society, and the Infectious Diseases Society of America. Published by Elsevier on behalf of the American Society of Nuclear Cardiology, the American College of Cardiology, Heart Rhythm Society, and by Oxford University Press on behalf of the Infectious Diseases Society of America. Published by Elsevier Inc. All rights reserved.)

Background: Cardiovascular implantable electronic device (CIED) infections are a common indication for device extraction. Early diagnosis and complete system removal are crucial to reduce morbidity and mortality. The lack of clear infectious symptoms makes the diagnosis of pocket infections challenging and may delay referral for extraction., Objective: We aimed to determine if inflammatory biomarkers can help diagnose CIED isolated pocket infection., Methods: We performed a retrospective analysis of all patients undergoing transvenous lead extraction for CIED infection at the University of California San Diego from 2012 to 2022 (N = 156). Patients were classified as systemic infection (n = 88) or isolated pocket infection (n = 68). Prospectively collected preoperative procalcitonin (PCT), C-reactive protein, and white blood cell count were compared between groups., Results: Pairwise comparisons revealed that the systemic infection group had a higher PCT than the control group ( P < .001) and the pocket infection group ( P = .009). However, there was no significant difference in PCT value between control subjects and isolated pocket infection subjects. Higher white blood cell count was only associated with systemic infection when compared with our control group ( P = .018)., Conclusion: In patients diagnosed with CIED infections requiring extraction, inflammatory biomarkers were not elevated in isolated pocket infection. Inflammatory markers are not predictive of the diagnosis of pocket infections, which ultimately requires a high level of clinical suspicion., (© 2024 Heart Rhythm Society. Published by Elsevier Inc.)

Background: Pulsed field ablation (PFA) induces cell death through electroporation using ultrarapid electrical pulses. We sought to compare the procedural efficiency characteristics, safety, and efficacy of ablation of atrial fibrillation (AF) using PFA compared with thermal energy ablation., Methods: We performed an extensive literature search and systematic review of studies that compared ablation of AF with PFA versus thermal energy sources. Risk ratio (RR) 95% confidence intervals (CI) were measured for dichotomous variables and mean difference (MD) 95% CI were measured for continuous variables, where RR < 1 and MD < 0 favor the PFA group., Results: We included 6 comparative studies for a total of 1012 patients who underwent ablation of AF: 43.6% with PFA (n = 441) and 56.4% (n = 571) with thermal energy sources. There were significantly shorter procedures times with PFA despite a protocolized 20-min dwell time (MD - 21.95, 95% CI - 33.77, - 10.14, p = 0.0003), but with significantly longer fluroscopy time (MD 5.71, 95% CI 1.13, 10.30, p = 0.01). There were no statistically significant differences in periprocedural complications (RR 1.20, 95% CI 0.59-2.44) or recurrence of atrial tachyarrhythmias (RR 0.64, 95% CI 0.31, 1.34) between the PFA and thermal ablation cohorts., Conclusions: Based on the results of this meta-analysis, PFA was associated with shorter procedural times and longer fluoroscopy times, but no difference in periprocedural complications or rates of recurrent AF when compared to ablation with thermal energy sources. However, larger randomized control trials are needed., (© 2023. The Author(s).)

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more., (© 2024 The American Society of Nuclear Cardiology, The American College of Cardiology, Heart Rhythm Society, and the Infectious Disease Society of America. Published by Elsevier on behalf of the American Society of Nuclear Cardiology, the American College of Cardiology, Heart Rhythm Society, and by Oxford University Press on behalf of the Infectious Disease Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Respiratory motion management strategies are used to minimize the effects of breathing on the precision of stereotactic ablative radiotherapy for ventricular tachycardia, but the extent of cardiac contractile motion of the human heart has not been systematically explored., Objective: We aim to assess the magnitude of cardiac contractile motion between different directions and locations in the heart., Methods: Patients with intracardiac leads or valves who underwent 4-dimensional cardiac computed tomography (CT) prior to a catheter ablation procedure for atrial or ventricular arrhythmias at 2 medical centers were studied retrospectively. The displacement of transvenous right atrial appendage, right ventricular (RV) implantable cardioverter-defibrillator, coronary sinus lead tips, and prosthetic cardiac devices across the cardiac cycle were measured in orthogonal 3-dimensional views on a maximal-intensity projection CT reconstruction., Results: A total of 31 preablation cardiac 4-dimensional cardiac CT scans were analyzed. The LV lead tip had significantly greater motion compared with the RV lead in the anterior-posterior direction (6.0 ± 2.2 mm vs 3.8 ± 1.7 mm; P = .01) and superior-inferior direction (4.4 ± 2.9 mm vs 3.5 ± 2.0 mm; P = .049). The prosthetic aortic valves had the least movement of all fiducials, specifically compared with the RV lead tip in the left-right direction (3.2 ± 1.2 mm vs 6.1 ± 3.8 mm, P = .04) and the LV lead tip in the anterior-posterior direction (3.8 ± 1.7 mm vs 6.0 ± 2.2 mm, P = .03)., Conclusion: The degree of cardiac contractile motion varies significantly (1 mm to 15.2 mm) across different locations in the heart. The effect of contractile motion on the precision of radiotherapy should be assessed on a patient-specific basis.

Background: Cardiac implantable electronic devices (CIEDs) infection remains a serious complication, causing increased morbidity and mortality. Early recognition and escalation to definitive therapy including extraction of the infected device often pose challenges., Objectives: The purpose of this study was to assess U.S.-based physicians current practices in diagnosing and managing CIED infections and explore potential extraction barriers., Methods: An observational survey was performed by the American College of Cardiology including U.S. physicians managing CIEDs from February to March 2022. Sampling techniques and screener questions determined eligibility. The survey featured questions on knowledge and experience with CIED infection patients and case scenarios., Results: Of 387 physicians completing the survey (20% response rate), 49% indicated familiarity with current guidelines regarding CIED infection. Electrophysiologists (EPs) (91%) were more familiar with these guidelines, compared to non-EP cardiologists (29%) and primary care physicians (23%). Only 30% of physicians specified that their institution had guideline-based protocols in place for managing patients with CIED infection. When presented with pocket infection cases, approximately 89% of EPs and 50% of non-EP cardiologists would follow guideline recommendation to do complete CIED system removal, while 70% of primary care physicians did not recommend guideline-directed treatment., Conclusions: There are gaps in familiarity of guidelines as well as the knowledge in practical management of CIED infection with non-extracting physicians. Most institutions lack a definite pathway. Addressing discrepancies, including guideline education and streamlining care or referral pathways, will be a key factor to bridging the gap and improving CIED infection patient outcomes., Competing Interests: This work was supported by Philips Image-Guided Therapy Corporation. The content has not been influenced in any way by its sponsor. Dr Lakkireddy is a consultant for Philips and Abbott and has received honoraria from Abbott, Medtronic, Boston Scientific, and Biosense Webster. Dr Rao has received honoraria from Medtronic, Boston Scientific, and Phillips. Dr Theriot is an employee of American College of Cardiology. Dr Ram is an employee of Philips Image-Guided Therapy Corporation. Dr Gao is an employee of Philips Image-Guided Therapy Corporation. Dr Cheung has received honoraria/consulting fees from Abbott, Biotronik, and Boston Scientific; and has received research support from Boston Scientific and fellowship grant support from Abbott, Biotronik, Boston Scientific, and Medtronic. Dr Birgersdotter-Green has received honoraria from Medtronic, Boston Scientific, Abbott, and Biotronik. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Pulsed field ablation (PFA) has emerged as a novel energy source for the ablation of atrial fibrillation (AF) using ultrarapid electrical pulses to induce cell death via electroporation., Objective: The purpose of this study was to compare the safety and acute efficacy of ablation for AF with PFA vs thermal energy sources., Methods: We performed an extensive literature search and systematic review of studies that evaluated the safety and efficacy of ablation for AF with PFA and compared them to landmark clinical trials for ablation of AF with thermal energy sources. Freeman-Tukey double arcsine transformation was used to establish variance of raw proportions followed by the inverse with the random-effects model to combine the transformed proportions and generate the pooled prevalence and 95% confidence interval (CI)., Results: We included 24 studies for a total of 5203 patients who underwent AF ablation. Among these patients, 54.6% (n = 2842) underwent PFA and 45.4% (n = 2361) underwent thermal ablation. There were significantly fewer periprocedural complications in the PFA group (2.05%; 95% CI 0.94-3.46) compared to the thermal ablation group (7.75%; 95% CI 5.40-10.47) ( P = .001). When comparing AF recurrence up to 1 year, there was a statistically insignificant trend toward a lower prevalence of recurrence in the PFA group (14.24%; 95% CI 6.97-23.35) compared to the thermal ablation group (25.98%; 95% CI 15.75-37.68) ( P = .132)., Conclusion: Based on the results of this meta-analysis, PFA was associated with lower rates of periprocedural complications and similar rates of acute procedural success and recurrent AF with up to 1 year of follow-up compared to ablation with thermal energy sources., (© 2023 Heart Rhythm Society. Published by Elsevier Inc.)

Background: Magnetic resonance imaging (MRI) safety in patients with an epicardial cardiac implantable electronic device (CIED) is uncertain., Objective: The purpose of this study was to assess the safety and adverse effects of MRI in patients who had surgically implanted epicardial CIED., Methods: Patients with surgically implanted CIEDs who underwent MRI with an appropriate cardiology-radiology collaborative protocol between January 2008 and January 2021 were prospectively studied in 2 clinical centers. All patients underwent close cardiac monitoring through MRI procedures. Outcomes were compared between the epicardial CIED group and the matched non-MRI-conditional transvenous CIED group., Results: Twenty-nine consecutive patients with epicardial CIED (41.4% male; mean age 43 years) underwent 52 MRIs in 57 anatomic regions. Sixteen patients had a pacemaker, 9 had a cardiac defibrillator or cardiac resynchronization therapy-defibrillator, and 4 had no device generator. No significant adverse events occurred in the epicardial or transvenous CIED groups. Battery life, pacing, sensing thresholds, lead impedance, and cardiac biomarkers were not significantly changed, except 1 patient had a transient decrease in atrial lead sensing function., Conclusion: MRI of CIEDs with epicardially implanted leads does not represent a greater risk than transvenous CIEDs when performed with a multidisciplinary collaborative protocol centered on patient safety., (Copyright © 2023. Published by Elsevier Inc.)

Background: Whether conduction system pacing (CSP) is an alternative option for cardiac resynchronization therapy (CRT) in patients with heart failure remains an area of active investigation., Objective: The purpose of this study was to assess the echocardiographic and clinical outcomes of CSP compared to biventricular pacing (BiVP)., Methods: This multicenter retrospective study included patients who fulfilled CRT indications and received CSP. Patients with CSP were matched using propensity score matching and compared in a 1:1 ratio to patients who received BiVP. Echocardiographic and clinical outcomes were assessed. Response to CRT was defined as an absolute increase of ≥5% in left ventricular ejection fraction (LVEF) at 6 months post-CRT., Results: A total of 238 patients were included. Mean age was 69.8 ± 12.5 years, and 66 (27.7%) were female. Sixty-nine patients (29%) had His-bundle pacing, 50 (21%) had left bundle branch area pacing, and 119 (50%) had BiVP. Mean follow-up duration in the CSP and BiVP groups was 269 ± 202 days and 304 ± 262 days, respectively (P = .293). The proportion of CRT responders was greater in the CSP group than in the BiVP group (74% vs 60%, respectively; P = .042). On Kaplan-Meier analysis, there was no statistically significant difference in the time to first heart failure hospitalization (log-rank P = .78) and overall survival (log-rank P = .68) between the CSP and BiVP groups., Conclusion: In patients with heart failure and reduced ejection fraction, CSP resulted in greater improvement in LVEF compared to BiVP. Large-scale randomized trials are needed to validate these outcomes and further investigate the different options available for CSP., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Despite the global COVID-19 pandemic, during the past 2 years, there have been numerous advances in our understanding of arrhythmia mechanisms and diagnosis and in new therapies. We increased our understanding of risk factors and mechanisms of atrial arrhythmias, the prediction of atrial arrhythmias, response to treatment, and outcomes using machine learning and artificial intelligence. There have been new technologies and techniques for atrial fibrillation ablation, including pulsed field ablation. There have been new randomized trials in atrial fibrillation ablation, giving insight about rhythm control, and long-term outcomes. There have been advances in our understanding of treatment of inherited disorders such as catecholaminergic polymorphic ventricular tachycardia. We have gained new insights into the recurrence of ventricular arrhythmias in the setting of various conditions such as myocarditis and inherited cardiomyopathic disorders. Novel computational approaches may help predict occurrence of ventricular arrhythmias and localize arrhythmias to guide ablation. There are further advances in our understanding of noninvasive radiotherapy. We have increased our understanding of the role of His bundle pacing and left bundle branch area pacing to maintain synchronous ventricular activation. There have also been significant advances in the defibrillators, cardiac resynchronization therapy, remote monitoring, and infection prevention. There have been advances in our understanding of the pathways and mechanisms involved in atrial and ventricular arrhythmogenesis.

Background: The mechanisms for atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) catheter ablation are unclear. Non-PV organized atrial arrhythmias (PAC, AT, macro-reentrant AFL) are possible contributors; however the prevalence and effect of their ablation on recurrent AF are unknown. We hypothesize that the identification and ablation of non-PV organized atrial arrhythmias were associated with less AF recurrence., Methods: Patients who underwent repeat ablation for recurrent AF after prior PVI were retrospectively enrolled. The prevalence and characteristics of PV reconnections and non-PV organized atrial arrhythmias were identified. The outcomes of time to clinical AF recurrence, heart failure (HF) hospitalization, and mortality were analyzed in patients using multivariable adjusted Cox regression., Results: In 74 patients with recurrent AF (age 66 ± 9 years, left atrial volume index 38 ± 10 ml/m 2 , 59% persistent AF), PV reconnections were found in 46 patients (61%), macro-reentrant atrial flutter in 27 patients (36%), and focal tachycardia in 12 patients (16%). Mapping and ablation of non-PV organized atrial arrhythmias were associated with a reduced recurrence of late clinical AF (adjusted HR 0.26, CI 0.08-0.85, p = 0.03) and the composite outcome of recurrence of late AF, HF hospitalization, and mortality (adjusted HR 0.38, CI 0.17-0.85, p = 0.02), with median follow-up of 1.6 (IQR 0.7-6.3) years. The presence of PV reconnections or empiric linear ablation was not associated with reduction in clinical AF or composite endpoints., Conclusion: The ablation of non-PV organized atrial arrhythmias resulted in a reduction of late clinical AF recurrence and composite outcome. In this challenging population, alternate mechanisms beyond PV reconnections need to be considered. Prospective studies are needed., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Background: Data on lead management in patients with congenital complete heart block (CCHB) with cardiac implantable electronic devices are lacking., Objective: The purpose of this study was to describe the natural history and outcomes in patients with CCHB with cardiac implantable electronic devices undergoing transvenous lead extraction (TLE)., Methods: Data on all attempted TLE procedures in patients with CCHB at 2 institutions between 2011 and 2021 were collected from a retrospective registry., Results: Overall, 16 patients (mean age at transvenous device implant 13.8 ± 4.7 years) were included. Before TLE, patients underwent an average of 2.25 ± 1.3 generator changes, 3 (19%) underwent cardiac resynchronization therapy upgrade, and 7 (44%) underwent a lead revision with subsequently abandoned leads. Mean patient age at TLE was 34.4 ± 9.4 years with a mean duration of lead implant of 19.2 ± 6.9 years. Lead malfunction (n = 11 [69%]) and infection (n = 5 [31%]) were the most common indications for TLE. A total of 38 leads were removed, with complete procedural success achieved in 14 of 16 (87.5%). Two (12.5%) major complications occurred, including right ventricular laceration and superior vena cava tear requiring sternotomies. All patients survived at 1-year follow-up., Conclusion: Patients with CCHB represent a unique cohort highlighted by several generator changes, lead revisions, and abandoned leads at a young age, along with a long duration of lead dwelling time and a high prevalence of lead malfunction requiring TLE. There may be a high risk of major complications during TLE, suggesting TLE should be performed only in experienced centers. Larger studies are needed to confirm these findings., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Limited data exists for outcomes in patients undergoing cardiovascular implantable electronic device (CIED) transvenous lead extraction (TLE) without clear indications for device reimplantation. The implantable loop recorder (ILR) may be an effective strategy for continuous monitoring in select individuals., Objective: This retrospective analysis aims to investigate patients who have undergone ILR implant following TLE without CIED reimplantation., Methods: Clinical data from consecutive patients who have undergone TLE with ILR implant and without CIED reimplantation from October 2016 to May 2020 at a single center were collected., Results: Among 380 patients undergoing TLE, 28 (7.7%) underwent ILR placement without CIED reimplantation. TLE indications were systemic infection (n = 13, 46.4%), pain at the site (n = 8, 28.6%), device/lead malfunction (n = 4, 14.2%), and other. Devices extracted included: dual-chamber and single-chamber pacemaker (n = 14, 50%; n = 4, 14.2%), dual-chamber implantable cardiac defibrillator (n = 10; 35.7%), and cardiac-resynchronization therapy with defibrillator (n = 1, 3.5%). Reasons for no reimplantation included no longer meeting CIED criteria (n = 14, 50%), patient preference (n = 9, 32.1%), and no clear or inappropriate indication for initial CIED implantation (n = 5, 18%). During an average of 12.3 ± 13.1 months of follow-up, there were no lethal arrhythmias, and four (13.3%) patients underwent permanent pacemaker reimplantation due to symptomatic sinus bradycardia and atrioventricular block with syncope as discovered on ILR. Three patients died due to unknown causes (n = 1), noncardiac (n = 1), and acute coronary syndrome (n = 1)., Conclusions: In patients undergoing TLE without reimplantation, an ILR may be an effective monitoring strategy in patients at low risk for cardiac arrhythmia., (© 2022 Wiley Periodicals LLC.)