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Background: Ablation of septal accessory pathways (SAPs) is associated with an increased risk of heart block. Data on outcomes of SAP ablation in adults are limited., Objectives: To describe outcomes of SAP ablation in our center., Methods: Patients with Wolff-Parkinson-White syndrome (WPW) undergoing an EP study at our center between January 2008 and August 2019 were identified from our institutional database. Location of the pathway was noted as anteroseptal (AS), midseptal (MS), or posteroseptal (PS). Outcomes of the ablation including success, complication rates, and recurrences were also recorded., Results: Thirty-three patients with SAP underwent 35 EP studies: AS (n = 13), MS (n = 5), and PS (n = 15). Thirty pathways were targeted for ablation, two of which required a 2nd procedure resulting in 32 attempts at ablation in 30 patients. In the remaining 3 patients, SAP did not have malignant features and were not targeted for ablation. Single-procedure success rate was 28/30 (93.33%): 9/10 AS, 5/5 MS, and 14/15 PS ablations. One AS pathway was successfully ablated during a 2nd procedure. Two complications were observed: 1 pericardial effusion in a patient who underwent epicardial mapping and ablation of both PS and right free wall APs. Additionally, transient 2:1 AV block occurred during an MS pathway ablation that recovered during follow-up and did not require permanent pacing procedure., Conclusion: In this single-center experience, ablation of manifest SAP was associated with high success rates and low complication rates. No instances of permanent heart block requiring pacing occurred., (© 2020. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Whether insurance status influences practice patterns in implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) defibrillators, when indicated, is not known., Methods and Results: We analyzed the NCDR ICD Registry to evaluate associations of insurance status with guidelines-based receipt of CRT, as well as device-type, complication rates, and use of optimal medical therapy defined by guidelines. Among 798,028 patients with de novo ICD implants, we included only patients < 65 years (those older have Medicare) and excluded those admitted before 2006 (n=1,835) or with insurance coverage other than Medicare, Medicaid or private insurance (n=25,695) leaving 286,556 for analysis. Inverse probability of treatment weighting was used to control for imbalances between groups. Mean age was 53 years, 29% were female. Patients with private insurance and Medicare were more likely to receive CRT-D when indicated (79.6%, OR 1.19 95% CI 1.09-1.28, P <.001 and 78.5%, OR 1.11 95% CI 1.01-1.21 P = .03, respectively) compared to the uninsured (76.7%). The uninsured were also more likely than other groups to receive a single-chamber device. Complication rates did not differ. Uninsured patients were, however, more likely to receive optimal medical therapy, particularly in the subgroup receiving the implant for primary prevention., Conclusions: In propensity-weighted analysis, uninsured patients are less likely to receive CRT when indicated but more likely to be receiving optimal medical therapy at discharge. Reasons for differences in device implantation practices based on insurance status require further study., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Wider availability of continuous rhythm monitoring has made feasible the incorporation of metrics of atrial fibrillation (AF) burden and duration into the decision to initiate anticoagulation. However, the relationship between thresholds of burden and duration and underlying risk factors at which anticoagulation should be considered remains unclear., Objective: The purpose of this study was to evaluate the relationships of these metrics with each other and the outcome of stroke/transient ischemic attack (TIA)., Methods: We identified patients with cardiovascular implantable electronic devices (CIEDs) with atrial leads who had at least 1 interrogation in 2016 demonstrating nonpermanent AF and were not receiving oral anticoagulation (OAC). We evaluated the relationship between burden (ie, percentage of time spent in AF), the longest single episode of AF, and risk factors (ie, CHA 2 DS 2 -VASc score) in predicting risk of stroke/TIA., Results: The study included 384 patients with mean follow-up of 3.2 ± 0.8 years and incidence of stroke/TIA of 14.8% during follow-up (∼4.6% per year). The burden of AF and the duration of longest episode demonstrated a significant positive correlation to each other but not CHA 2 DS 2 -VASc score. Importantly, although the CHA 2 DS 2 -VASc score was predictive of stroke/TIA, neither burden nor duration was associated with stroke/TIA., Conclusion: Among patients with CIED-detected AF not receiving OAC, the amount of AF (measured by either burden or duration) does not seem to significantly impact stroke risk, whereas CHA 2 DS 2 -VASc score does. These data suggest that among patients with CIED-detected AF, once AF occurs, stroke risk seems to be predominantly driven by underlying risk factors., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Micra leadless pacemaker has progressed from a single chamber pacemaker that can deliver VVIR pacing to a pacing device that can provide atrio-ventricular (AV) synchrony via a unique pacing algorithm that relies on identifying mechanical atrial contraction. This novel algorithm has its own limitations and intricacies. In this paper, we review this algorithm, suggest steps for troubleshooting and programming these devices and provide clinical examples of Micra AV cases that required changes in programming for adequate tracking of atrial activity., (© 2020 The Authors. Journal of Cardiovascular Electrophysiology Published by Wiley Periodicals LLC.)

Background: Data on the management of Micra transcatheter pacing system (TPS) at the time of an upgrade or during battery depletion is limited., Objective: We sought to evaluate the management patterns of patients implanted with a Micra TPS during long-term follow-up., Methods: We retrospectively identified patients who underwent Micra implantation from April 2014 to November 2019. We identified patients who underwent extraction (n = 11) or had an abandoned Micra (n = 12)., Results: We identified 302 patients who received a Micra during the period of the study. Mean age was 72.7 ± 15.4 years, 54.6% were men, and left ventricular ejection fraction was 51.9 ± 5.2%. Mean follow-up was 1105.5 ± 529.3 days. Procedural complications included pericardial tamponade (n = 1) treated with pericardiocentesis, significant rise in thresholds (n = 6) treated with reimplantation (n = 4), and major groin complications (n = 2). Indications for extraction included an upgrade to cardiac resynchronization therapy (CRT) device (n = 3), bridging after extraction of an infected transvenous system (n = 3), elevated thresholds (n = 3), and non-Micra-related bacteremia (n = 2). The median time from implantation to extraction was 78 days (interquartile range: 14-113 days), with the longest extraction occurring at 1442 days. All extractions were successful, with no procedural or long-term complications. Indications for abandonment included the need for CRT (n = 6), battery depletion (n = 2), increasing thresholds/failure to capture (n = 3), and pacemaker syndrome (n = 1). All procedures were successful, with no procedural or long-term complications., Conclusion: In this large single-center study, 6% of patients implanted with a Micra required a system modification during long-term follow-up, most commonly due to the requirement for CRT pacing. These patients were managed successfully with extraction or abandonment., (© 2020 Wiley Periodicals LLC.)

Shared decision-making has become a new focus of health policy. Though its core elements are largely agreed upon, there is little consensus regarding which outcomes to prioritize for policy-mandated shared decision-making.

Purpose of Review: The COVID-19 pandemic has significantly impacted the delivery of education for all specialties, including cardiac electrophysiology. This review will provide an overview of the COVID-19 spurred digital transformation of electrophysiology education for practicing clinicians and trainees in electrophysiology and cover the use of social media in these educational efforts., Recent Findings: Major international, national, and local meetings and electrophysiology fellowship-specific educational sessions have transitioned rapidly to virtual and distanced learning, enhanced by social media. This has allowed for participation in educational activities by electrophysiologists on a wider, more global scale. Social media has also allowed rapid dissemination of new advances, techniques, and research findings in real time and to a global audience, but caution must be exercised as pitfalls also exist., Summary: The digital and social media transformation of cardiac electrophysiology education has arrived and revolutionized the way education is delivered and consumed. Continued hybrid in-person and virtual modalities will provide electrophysiologists the flexibility to choose the best option to suit their individual needs and preferences for continuing education., Competing Interests: Conflict of interestChristopher V. DeSimone, Susan P. Etheridge, Piotr Futyma, Rakesh Gopinathannair, Rajesh Kabra, Sandeep A. Saha, Faisal M. Merchant declares that they have no conflict of interest. Tina Baykaner reports grants from the National Institutes of Health, lecturing fees from Biotronik, and consulting fees PaceMate. Janet K. Han reports lecturing fees from Abbott, Boston Scientific and Medtronic. Rajesh Kabra reports grants from Abbott, Biosense Webster and Medtronic. Martin K. Stiles reports lecturing and consulting fees from Boehringer Ingelheim, consulting fees from Ceryx Medical and lecturing fees from Medtronic., (© This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021.)

Background: Women undergoing atrial fibrillation catheter ablation (AFCA) have higher rates of vascular complications and major bleeding. However, most studies have been underpowered to detect differences in rarer complications such as stroke/transient ischemic attack (TIA) and procedural mortality., Methods: We performed a systematic review of databases (PubMed, World of Science, and Embase) to identify studies published since 2010 reporting AFCA complications by sex. Six complications of interest were (1) vascular/groin complications; (2) pericardial effusion/tamponade; (3) stroke/TIA; (4) permanent phrenic nerve injury; (5) major bleeding; and (6) procedural mortality. For meta-analysis, random effects models were used when heterogeneity between studies was ≥50% (vascular complications and major bleeding) and fixed effects models for other endpoints., Results: Of 5716 citations, 19 studies met inclusion criteria, comprising 244,353 patients undergoing AFCA, of whom 33% were women. Women were older (65.3 ± 11.2 vs. 60.4 ± 13.2 years), more likely hypertensive (60.6% vs. 55.5%) and diabetic (18.3% vs. 16.5%), and had higher CHA 2 DS 2 -VASc scores (3.0 ± 1.8 vs. 1.4 ± 1.4) (p < .0001 for all comparisons). The rates of all six complications were significantly higher in women. However, despite statistically significant differences, the overall incidences of major complications were very low in both sexes: stroke/TIA (women 0.51% vs. men 0.39%) and procedural mortality (women 0.25% vs. men 0.19%)., Conclusion: Women experience significantly higher rates of AFCA complications. However, the incidence of major procedural complications is very low in both sexes. The higher rate of complications in women may be partially attributable to older age and a higher prevalence of comorbidities at the time of ablation. More detailed studies are needed to better define the mechanisms of increased risk in women and to identify strategies for closing the sex gap., (© 2020 Wiley Periodicals LLC.)

Background: Cardiovascular and arrhythmic events have been reported in hospitalized COVID-19 patients. However, arrhythmia manifestations and treatment strategies used in these patients have not been well-described. We sought to better understand the cardiac arrhythmic manifestations and treatment strategies in hospitalized COVID-19 patients through a worldwide cross-sectional survey., Methods: The Heart Rhythm Society (HRS) sent an online survey (via SurveyMonkey) to electrophysiology (EP) professionals (physicians, scientists, and allied professionals) across the globe. The survey was active from March 27 to April 13, 2020., Results: A total of 1197 respondents completed the survey with 50% of respondents from outside the USA, representing 76 countries and 6 continents. Of respondents, 905 (76%) reported having COVID-19-positive patients in their hospital. Atrial fibrillation was the most commonly reported tachyarrhythmia whereas severe sinus bradycardia and complete heart block were the most common bradyarrhythmias. Ventricular tachycardia/ventricular fibrillation arrest and pulseless electrical activity were reported by 4.8% and 5.6% of respondents, respectively. There were 140 of 631 (22.2%) respondents who reported using anticoagulation therapy in all COVID-19-positive patients who did not otherwise have an indication. One hundred fifty-five of 498 (31%) reported regular use of hydroxychloroquine/chloroquine (HCQ) + azithromycin (AZM); concomitant use of AZM was more common in the USA. Sixty of 489 respondents (12.3%) reported having to discontinue therapy with HCQ + AZM due to significant QTc prolongation and 20 (4.1%) reported cases of Torsade de Pointes in patients on HCQ/chloroquine and AZM. Amiodarone was the most common antiarrhythmic drug used for ventricular arrhythmia management., Conclusions: In this global survey of > 1100 EP professionals regarding hospitalized COVID-19 patients, a variety of arrhythmic manifestations were observed, ranging from benign to potentially life-threatening. Observed adverse events related to use of HCQ + AZM included prolonged QTc requiring drug discontinuation as well as Torsade de Pointes. Large prospective studies to better define arrhythmic manifestations as well as the safety of treatment strategies in COVID-19 patients are warranted.

Purpose: Sizing of the left atrial appendage (LAA) ostium prior to occlusion (LAAO) is routinely performed with transesophageal echocardiography (TEE). We sought to compare the utility of sizing via fluoroscopy to TEE for percutaneous LAAO., Methods: We retrospectively evaluated all patients undergoing percutaneous LAAO at our institution from April 2015 through January 2018 (n = 195). We evaluated baseline characteristics, maximum measured ostium size (for both TEE and fluoroscopy), and differences in measured size to device size for both techniques., Results: Of the total cohort, 185 (95%) had both intraoperative TEE and fluoroscopic images available for analysis and were included in the final analysis. The mean age was 74 years and 64% were male. Hypertension was present in 89%, diabetes in 30%, and stroke in 32% of patients. The mean ejection fraction was 51%. The most common LAA morphology was "wind sock" (52%). Measured ostial diameter on fluoroscopy was larger compared with TEE (2.04 ± 3.43 mm larger on fluoroscopy, p < 0.001). Ostium diameter on TEE was more closely correlated to the size of the device implanted compared with fluoroscopy (0.76 vs. 0.61, p = 0.001)., Conclusions: Fluoroscopy results in larger estimated LAA ostium diameter compared with TEE. Despite this, TEE was more strongly correlated to operator choice in device sizing, which may reflect practice patterns. Because compression of the ostium on the device is necessary for long-term procedural success, under-sizing may lead to a higher rate of leaks. Prospective evaluation of the utility of routine fluoroscopic sizing compared with TEE is warranted.

Background: Outcomes of catheter ablation for persistent atrial fibrillation (PeAF) are suboptimal. The convergent procedure (CP) may offer improved efficacy by combining endocardial and epicardial ablation., Methods: We reviewed 113 consecutive patients undergoing the CP at our institution. The cohort was divided into two groups based on the presence (n = 92) or absence (n = 21) of continuous rhythm monitoring (CM) following the CP. Outcomes were reported in two ways. First, using a conventional definition of any atrial fibrillation/atrial tachycardia (AF/AT) recurrence lasting >30 seconds, after a 90 day blanking period. Second, by determining AF/AT burden at relevant time points in the group with CM., Results: Across the entire cohort, 88% had either persistent or long-standing persistent AF, mean duration of AF diagnosis before the CP was 5.1 ± 4.6 years, 45% had undergone at least one prior AF ablation, 31% had impaired left ventricle ejection fraction and 62% met criteria for moderate or severe left atrial enlargement. Mean duration of follow-up after the CP was 501 ± 355 days. In the entire cohort, survival free from any AF/AT episode >30 seconds at 12 months after the blanking period was 53%. However, among those in the CM group who experienced recurrences, mean burden of AF/AT was generally very low (<5%) and remained stable over the duration of follow-up. Ten patients (9%) required elective cardioversion outside the 90 day blanking period, 11 patients (9.7%) underwent repeat ablation at a mean of 229 ± 178 days post-CP and 64% were off AADs at the last follow-up. Procedural complications decreased significantly following the transition from transdiaphragmatic to sub-xiphoid surgical access: 23% versus 3.8% (P = .005) CONCLUSIONS: In a large, consecutive series of patients with predominantly PeAF, the CP was capable of reducing AF burden to very low levels (generally <5%), which appeared durable over time. Complication rates associated with the CP decreased significantly with the transition from transdiaphragmatic to sub-xiphoid surgical access. Future trials will be necessary to determine which patients are most likely to benefit from the convergent approach., (© 2020 Wiley Periodicals, Inc.)

Background: Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death., Methods: We have developed a real-time, closed-loop system to record and analyze RA from multiple intracardiac leads, and deliver dynamically R-wave triggered pacing stimuli during the absolute refractory period. We have evaluated the ability of this system to control RA and reduce arrhythmia susceptibility, in vivo., Results: R-wave triggered pacing can induce RA, the magnitude of which can be modulated by varying the amplitude, pulse width, and size of the pacing vector. Using a swine model (n=9), we demonstrate that to induce a 1 µV change in the alternans voltage on the body surface, coronary sinus and left ventricle leads, requires a delivered charge of 0.04±0.02, 0.05±0.025, and 0.06±0.033 µC, respectively, while to induce a one unit change of the K score , requires a delivered charge of 0.93±0.73, 0.32±0.29, and 0.33±0.37 µC, respectively. For all body surface and intracardiac leads, both Δ(alternans voltage) and ΔK score between baseline and R-wave triggered paced beats increases consistently with an increase in the pacing pulse amplitude, pulse width, and vector spacing. Additionally, we show that the proposed method can be used to suppress spontaneously occurring alternans (n=7), in the presence of myocardial ischemia. Suppression of RA by pacing during the absolute refractory period results in a significant reduction in arrhythmia susceptibility, evidenced by a lower S rank score during programmed ventricular stimulation compared with baseline before ischemia., Conclusions: We have developed and evaluated a novel closed-loop method to dynamically modulate RA in a swine model. Our data suggest that suppression of RA directly reduces arrhythmia susceptibility and reinforces the concept that RA plays a critical role in the pathophysiology of arrhythmogenesis.

Randomized trials inform the use of implantable cardioverter-defibrillators (ICDs) for prevention of sudden cardiac death, yet management of patients considering ICD generator replacement procedures remains largely dependent on clinical judgment. Thus, we performed a systematic review of all studies evaluating outcomes associated with ICD generator replacement. We queried PubMed, Embase, Web of Science, and the Cochrane Database of Systematic Reviews for relevant studies with a prespecified search and adjudication strategy (PROSPERO registration number CRD42018100818) to evaluate outcomes including (1) survival; (2) clinical complications (eg, infection, hematoma); or (3) incidence of ICD therapy. From 1607 unique titles, 37 studies met inclusion criteria, describing outcomes for 238,949 patients. Procedural mortality was rare, but complications including reoperation (median 4.57%; range 0.38%-10.31%), infections (median 2.01%; range 0.03%-9.27%), and hematoma (median 1.22%, range 0.17%-2.53%) were observed in a small fraction of patients. Appropriate ICD therapy after generator replacement was common (median rate 23.03%; range 10.9%-31.4%), with an overall annualized event rate of 8.52% at median duration of follow-up of 32.4 months. Appropriate ICD therapy continued to occur at a significant annual rate even in patients who no longer met implantation criteria (5.27%) and in patients who never previously received ICD therapy (4.87%). This analysis of published observational data regarding ICD generator replacement procedures identifies relatively low risks of procedural complications and clinically meaningful rates of appropriate ICD therapies. These estimates may guide clinical decisions and inform the design of definitive trials., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: There are limited data on cardiac implantable electronic device implantation (CIED) in patients with persistent left superior vena cava (PLSVC)., Objective: To describe the outcomes of implanting CIEDs with a focus on cardiac resynchronization therapy (CRT) in patients with PLSVC., Methods: We identified all patients with a PLSVC that underwent CIED implantation from December 2008 until February 2019 at our institution by querying the electronic medical record (n = 34). We then identified controls in a 3:1 fashion (n = 102) by matching on device type (CRT vs non-CRT). Procedure success, complications, fluoroscopy and procedural time were recorded. Outcomes were compared using a two-way analysis of variance test and conditional regression modeling for continuous and categorical variables, respectively., Results: A total of 34 patients with PLSVC underwent 38 procedures. Four patients underwent dual chamber system implantation followed by a subsequent upgrade to CRT. Thirteen patients underwent CRT implantation: one was implanted via the right subclavian while the rest were implanted via the PLSVC. Left ventricular (P = .06). Procedure and fluoroscopy times were significantly higher in the PLSVC as compared with the control group (97.7 vs 66.1 minute, P < .001 and 18.1 minute vs 8.7 minutes, P = .005, respectively)., Conclusion: CIED implant in patients with PLSVC is feasible but technically more challenging and appears to be associated with higher risk of right ventricular lead dislodgment., (© 2020 Wiley Periodicals, Inc.)

Pacing induced cardiomyopathy (PICM) is most commonly defined as a drop in left ventricle ejection fraction (LVEF) in the setting of chronic, high burden right ventricle (RV) pacing. Recent data suggest, however, that some individuals may experience the onset of heart failure symptoms more acutely after pacemaker implantation. Definitions of PICM which emphasize drop in LVEF may underestimate the incidence of deleterious effects from RV pacing. Treatment of PICM has primarily focused on upgrade to cardiac resynchronization therapy (CRT) when LVEF has dropped. However, emerging data suggest that conduction system pacing (CSP) may offer an opportunity to prevent PICM in the first place., (© 2019 Wiley Periodicals, Inc.)

Objectives: The aim of this study was to define risk factors and develop a predictive risk score for new pacemaker implantation (PMI) after transcatheter aortic valve replacement (TAVR)., Background: TAVR has become an accepted treatment alternative for patients with severe aortic stenosis at elevated surgical risk. New PMI is a common occurrence after TAVR and is associated with poorer outcomes., Methods: All patients without prior valve procedures undergoing elective TAVR with the Edwards SAPIEN 3 at a single institution (n = 1,266) were evaluated. Multivariate analysis was performed to evaluate for predictors of PMI in this population in a derivation cohort of patients with complete data (n = 778), and this model was used to develop the Emory risk score (ERS), which was tested in a validation cohort (n = 367)., Results: Fifty-seven patients (7.3%) in the derivation cohort required PMI. In a regression model, history of syncope (odds ratio [OR]: 2.5; p = 0.026), baseline right bundle branch block (OR: 4.3; p < 0.001), QRS duration ≥138 ms (OR: 2.5; p = 0.017), and valve oversizing >15.6% (OR: 1.9; p = 0.041) remained independent predictors of PMI and were included in the ERS. The ERS was strongly associated with PMI (per point increase OR: 2.2; p < 0.001) with an area under the receiver-operating characteristic curve of 0.778 (p < 0.001), which was similar to its performance in the derivation cohort., Conclusions: A history of syncope, right bundle branch block, longer QRS duration, and higher degree of oversizing are predictive of the need for PMI after TAVR. Additionally, the ERS for PMI was developed and validated, representing a simple bedside tool to aid in risk stratification for patients for undergoing TAVR., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. We developed a 12-lead, blue-tooth/Smart-Phone (Android) based electrocardiogram (ECG) acquisition and monitoring system (cvrPhone), and an application to estimate RA, in real-time. In in-vivo swine studies (N = 17), 12-lead ECG signals were recorded at baseline and following coronary artery occlusion. RA was estimated using the Fast Fourier Transform (FFT) method using a custom developed algorithm in JAVA. Underlying ischemia was detected using a custom developed ischemic index. RA from each lead showed a significant (p < 0.05) increase within 1 min of occlusion compared to baseline (n = 29). Following myocardial infarction, spontaneous ventricular tachycardia episodes (n = 4) were preceded by significant (p < 0.05) increase of RA prior to the onset of the tachy-arrhythmias. Similarly, the ischemic index exhibited a significant increase following myocardial infarction (p < 0.05) and preceding a tachy-arrhythmic event. In conclusion, RA can be effectively estimated using surface lead electrocardiograms by analyzing beat-to-beat variability in ECG morphology using a smartphone based platform. cvrPhone can be used to detect myocardial ischemia and arrhythmia susceptibility using a user-friendly, clinically acceptable, mobile platform.

Extraction of transvenous leads via the femoral route might be needed when extraction via the implant vein fails or when retained lead fragments exist. The skill set required for this procedure is unique as it relies on the ability to snare and the use of a variety of shelf tools. In this era of leadless pacing, this skill set might be called upon more frequently. In this article, we review the data, tools, and procedural steps of femoral lead extraction and retrieval/extraction of leadless pacemakers., (© 2019 Wiley Periodicals, Inc.)

Background: Implantation of the MICRA Leadless pacemaker requires the use of a 27 French introducer, blunt delivery system and device fixation to the myocardium via nitinol tines. While prior studies have proven its safety, it is unclear whether performing this procedure with uninterrupted anticoagulation exposes patients to increased risks. We sought to investigate the feasibility and safety of continuing therapeutic anticoagulation during the periprocedural period., Methods: We evaluated all patients undergoing MICRA placement at our institution between April 2014 and August 2018 with complete follow-up data (n = 170). Patients were stratified into two groups: those on active anticoagulation (OAC, n = 26), defined as having an International normalized ratio >2.0 or having continued a direct oral anticoagulant, and those not anticoagulated (Off-OAC, n = 144). We evaluated for a composite outcome of all major complications, including access site complications and pericardial effusion., Results: OAC and Off-OAC groups had similar mean age (74 ± 13 vs 75 ± 13 years; P = .914). The OAC group had a nonsignificantly lower prevalence of end-stage renal disease (8% vs 17%; P = .375) and aspirin use (27% vs 47%; P = .131). Those in the OAC group were more likely to be on warfarin than those in the Off-OAC group (81% vs 30%; P < .001). The rate of the composite endpoint was similar between the OAC and Off-OAC groups (3.8 % vs 1.4%, respectively; P = .761). Length of stay was similar between groups (1.3 ± 2.6 vs 2.3 ± 3.4 days; P = 0.108)., Conclusion: Continuation of therapeutic anticoagulation during MICRA implantation appears to be feasible, safe and associated with shorter hospitalization among appropriately selected individuals., (© 2019 Wiley Periodicals, Inc.)

Background: Consensus statements on lead extraction give consideration to open surgical removal in the setting of large vegetations, to mitigate the risk of massive embolism that may occur with percutaneous lead removal. Vacuum-assisted debulking (VD) of large vegetations as an adjunct to percutaneous lead extraction may provide an opportunity to mitigate these risks., Methods: We retrospectively identified all patients undergoing lead extraction at our institution for endovascular infection from 2012 to 2018 and stratified them into two groups based on presence of adjunctive VD (n = 6) or without VD (no-VD, n = 39). VD was performed with the AngioVac system (Angio-Dynamics, Latham, NY, USA)., Results: Across the cohort, mean age was 62 ± 15 years, ejection fraction was 41 ± 16%, and 39% had end-stage renal disease on dialysis. Defibrillator systems were present in 71%, and 22% had cardiac resynchronization devices. Mean duration of the oldest extracted lead was 6.3 ± 4.9 years. There were no significant differences in baseline covariates between groups. Those in the VD group were significantly less likely to have Staphylococcus aureus as a causative organism (P = .04). In the VD group, vegetations targeted for debulking ranged in size from 1.8 to 6 cm (longest dimension). There were no operative deaths or clinically evident embolic events in either group. The overall nonfatal complication rate in the VD group was higher (33.3% vs 2.3%, P = .043)., Conclusion: VD can be performed as an adjunct to percutaneous lead extraction with a reasonable safety profile. The relative safety and efficacy of this approach removal requires further study., (© 2019 Wiley Periodicals, Inc.)

Background: Data suggests that same day discharge after implantation of trans-venous pacemakers is safe and feasible. We sought to determine whether same day discharge was feasible and safe following implantation of Medtronic MICRA leadless pacemakers., Methods: We retrospectively identified all patients undergoing MICRA placement at our institution between April 2014 to August 2018 (n=167). Patients were stratified into two groups: those discharged on the same day as their procedure (SD, n=25), and those observed for at least one night in the hospital (HD, n=142). The primary endpoint included a composite of major complications including: access site complications, new pericardial effusion, device dislodgement, and need for device revision up to approximately 45 days of follow up., Results: SD and HD had similar age (75±13 vs. 75±13 years, p=0.923), prevalence of male sex (49 vs. 44%, p=0.669), and frequency of high-grade heart block as an indication for pacing (38 vs. 32%, p=0.596). There were more Caucasians in the SD group (72 vs. 66%, p=0.038). The rate of the composite endpoint was statistically non-significantly higher in the HD group (3.5% vs. 0.0%, p=1.00). The rates of each individual components comprising the composite endpoint were similar between groups., Conclusions: Our data suggest that in appropriately selected patients, same day discharge can occur safely following Micra leadless pacemaker implantation.

Background: Sleep disordered breathing manifested as sleep apnea (SA) is prevalent in the general population, and while it is associated with increased morbidity and mortality risk in some patient populations, it remains under-diagnosed. The objective of this study was to assess the accuracy of respiration-rate (RR) and tidal-volume (TV) estimation algorithms, from body-surface ECG signals, using a smartphone based ambulatory respiration monitoring system (cvrPhone)., Methods: Twelve lead ECG signals were collected using the cvrPhone from anesthetized and mechanically ventilated swine (n = 9). During ECG data acquisition, the mechanical ventilator tidal-volume (TV) was varied from 250 to 0 to 750 to 0 to 500 to 0 to 750 ml at respiratory rates (RR) of 6 and 14 breaths/min, respectively, and the RR and TV values were estimated from the ECG signals using custom algorithms., Results: TV estimations from any two different TV settings showed statistically significant difference (p < 0.01) regardless of the RR. RRs were estimated to be 6.1±1.1 and 14.0±0.2 breaths/min at 6 and 14 breaths/min, respectively (when 250, 500 and 750 ml TV settings were combined). During apnea, the estimated TV and RR values were 11.7±54.9 ml and 0.0±3.5 breaths/min, which were significantly different (p<0.05) than TV and RR values during non-apnea breathing. In addition, the time delay from the apnea onset to the first apnea detection was 8.6±6.7 and 7.0±3.2 seconds for TV and RR respectively., Conclusions: We have demonstrated that apnea can reliably be detected using ECG-derived RR and TV algorithms. These results support the concept that our algorithms can be utilized to detect SA in conjunction with ECG monitoring., Competing Interests: The authors have declared that no competing interests exist.

Background: The performance of Abbott/St. Jude Medical (Sylmar CA) Tendril pacing leads has not been well characterized., Objective: We sought to assess the performance of Tendril leads as compared with that of different pacing leads., Methods: We retrospectively identified patients implanted with the following leads: Tendril leads 1888 TC, 2088 TC, and 1688 TC, Medtronic (Fridely, MN) 4076 CapSureFix Novus, and Boston Scientific (Natick, MA) FINELINE II Sterox Pacing EZ leads (models 4469, 4470, and 4471). The primary end point was the incidence of lead malfunction assessed by Kaplan-Meier analysis., Results: During the study period, 9782 leads were implanted, including 8512 Tendril leads, 731 Medtronic 4076 CapSureFix Novus leads, and 539 FINELINE II leads. A total of 540 leads (5.5%) malfunctioned during a mean follow-up of 3.6 ± 2.9 years. Lead malfunction manifested predominantly as noise and/or low impedance (95%). Lead malfunction rates were significantly higher at 5 years for Tendril vs non-Tendril leads (7.0% vs 2.1%; P < .001). The highest rate of failure at 5 years was seen in the Tendril 1888 TC leads (9.9%), followed by Tendril 1688 (5.7%) and Tendril 2088 (5.2%) leads. In contrast, malfunction rates were significantly lower for the Medtronic 4076 (2.6%) and FINELINE II (1.7%) leads. During follow-up to 10 years, the incidence of lead malfunction for Optim-insulated Tendril leads (models 1888 TC and 2088 TC) was significantly higher than that for the non-Optim-insulated Tendril 1688 TC lead (24.5% vs 7.1%) (P = .008)., Conclusion: Tendril leads appear to have a higher rate of malfunction than do comparator leads. Optim insulation may partly explain the higher failure rate., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background The incidence of cancer treatment-induced arrhythmia ( CTIA ) associated with novel, targeted chemotherapeutic agents ( TCA s) has not been well described. Methods and Results We identified all patients treated at our institution from January 2010 to December 2015 with selected TCA s. We defined CTIA as any new arrhythmia diagnosis code within 6 months after treatment initiation. As a comparison, we also identified patients treated with anthracycline chemotherapy during the same period. We identified 5026 patients, of whom 2951 (58.7%) received TCA s and 2075 (41.3%) received anthracycline chemotherapy. In the overall cohort, 601 patients (12.0%) developed CTIA . Patients with CTIA were significantly older and more likely to have hypertension, diabetes mellitus, congestive heart failure, coronary disease, and sleep apnea. The incidence of CTIA at 6 months was significantly lower in the TCA group (9.3% versus 15.8%; P<0.001). In multivariate analysis, a history of hypertension (hazard ratio, 1.63; 95% confidence interval, 1.34-1.98), congestive heart failure (hazard ratio, 2.12; 95% confidence interval, 1.78-2.68), and male sex (hazard ratio, 1.25; 95% confidence interval, 1.06-1.47) were associated with a significantly increased risk of CTIA , whereas treatment with TCA s, compared with anthracycline chemotherapy, was associated with a significantly lower risk (hazard ratio, 0.60; 95% confidence interval, 0.51-0.71). Conclusions Compared with anthracyclines, treatment with TCAs was associated with an ≈40% reduced risk of new-onset arrhythmia diagnoses during the first 6 months of treatment.

Pacing-induced cardiomyopathy (PICM) is a well described phenomenon that occurs in a minority of patients exposed to high-burden right ventricular (RV) pacing. Although several risk factors may identify patients at increased risk of PICM, many individuals tolerate high-burden RV pacing for many years without obviously deleterious effects, and the ability to identify those at highest risk remains insufficient. Treatment of PICM has primarily involved upgrade to cardiac resynchronization therapy once signs of cardiomyopathy manifest. The emergence of His bundle pacing may offer an opportunity to prevent PICM before it occurs., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Guidelines suggest that patients who receive implantable cardioverter-defibrillators (ICDs) for primary prevention should be expected to live more than one year after placement. However, tools for validating this prognosis are not sufficiently predictive. We sought to identify definitive predictors of one-year survival after ICD placement. By reviewing medical records and the Social Security Death Index, we analyzed baseline characteristics and survival outcomes of 3,164 patients who underwent ICD placement at our institution from January 2006 through March 2014. Survival outcome could be confirmed for 2,346 patients (74%). Of these, 184 (7.8%) died within one year of ICD placement. We noted significant differences in numerous variables between those who lived and died. However, multivariable analysis revealed only 5 independent predictors of earlier death: worse New York Heart Association functional class (hazard ratio [HR]=1.87 per class [95% CI, 1.22-2.87]; P <0.01); lower serum sodium level (HR=0.93 per 1 mEq/L increase [95% CI, 0.88-0.99]; P =0.04); atrial fibrillation (HR=1.81 [95% CI, 1.03-3.21]; P =0.04); chronic lung disease (HR=2.05 [95% CI, 1.20-3.51]; P <0.01), and amiodarone use (HR=10.1 [95% CI, 4.51-22.5]; P <0.01). Using receiver operating characteristic curves, we developed a model with an area under the curve of 0.718 that predicted death at one year after ICD implantation. Despite significant univariate differences between the ICD recipients who did and did not live beyond one year, we found only moderate predictors of survival. Better tools are needed to predict outcomes when considering ICD placement for primary prevention.

Background: Recommendations regarding performance of magnetic resonance imaging (MRI) in non-MRI conditional pacemaker and defibrillator recipients are evolving. Previous studies have suggested low adverse event rates with MRI in nonconditional cardiac implantable electronic device (CIED) recipients, but low power limits optimal characterization of risk., Objective: The purpose of this study was to perform a systematic review and meta-analysis to characterize the clinical risk associated with MRI in CIED recipients in order to improve power., Methods: PubMed and CINAHL indexed articles from 1990 to 2017 were queried. A random effects model was used for meta-analysis of continuous variables. Safety outcomes were evaluated with descriptive statistics., Results: Seventy studies of non-MRI conditional devices undergoing MRI were identified, allowing for analysis of 5099 patients who underwent a total of 5908 MRI studies. Heterogeneity in lead parameter changes was observed within studies, although smaller variances were noted between studies. All lead characteristics and battery voltages showed very small, clinically insignificant changes when assessed as a pooled cohort, although cases of clinically relevant outcomes were also noted (lead failure 3, implantable cardioverter-defibrillator shock 1, electrical reset 94). Electrical resets were found only in older devices. Defibrillator function was unchanged, and inappropriate shocks were avoided with pre-MRI programming changes., Conclusion: This review demonstrated low lead failure and clinical event rates in non-MRI conditional pacemaker and defibrillator recipients undergoing MRI. Observed changes were small and interstudy variance was low, suggesting that the composite event rates offer a reasonable estimate of true effect. The observed adverse events reinforce the need for ongoing vigilance and caution, particularly with older devices., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Defibrillation threshold (DFT) testing is recommended with the subcutaneous implantable cardioverter defibrillator (SICD)., Objective: To describe first shock efficacy for appropriate SICD therapies stratified by the presence of implant DFT testing., Methods: We reviewed all patients receiving SICDs at our institution and stratified them based on whether implant DFT testing was performed. Appropriate shocks were reviewed to see if ventricular tachycardia/ventricular fibrillation (VT/VF) terminated with a single shock. First shock efficacy was stratified by implant DFT status., Results: 178 patients implanted with SICDs and followed in our center were included in this study. Of these, 135 (76%) underwent DFT testing (DFT (+) group). In the DFT (+), 80 appropriate shocks were needed to treat 69 episodes of VT/VF. The first shock was effective in 61 out of 69 episodes (88.4%), whereas multiple shocks were required to terminate VT/VF in the remaining eight episodes. Among 43 patients without implant DFT testing (DFT (-) group), 20 appropriate shocks to treat 17 episodes of VT/VF occurred in seven patients. VT/VF was successfully terminated with the first shock in 16 out of 17 episodes (first shock efficacy 94.1 %). There was no significant difference in first shock effectiveness between those with and without implant DFT testing (P  =  0.97)., Conclusion: A strategy that omits DFT testing at implant did not appear to compromise the effectiveness of the SICD. These data suggest that routine DFT testing at SICD implant might not be necessary. Randomized trials are needed to confirm this finding., (© 2018 Wiley Periodicals, Inc.)

Background: The decision to abandon or extract superfluous sterile leads is controversial., Objective: The purpose of this study was to compare procedural outcomes and long-term survival of patients with and those without abandoned leads undergoing lead extraction (LE)., Methods: Retrospective review of all patients who had undergone transvenous LE at our institution from January 2007 to May 2016 was performed. Patients were stratified into 2 groups based on the presence (group 1) or absence (group 2) of abandoned leads., Results: Among 774 patients who had undergone LE procedures, 38 (4.9%) had abandoned leads (group 1). Dwell time of the oldest extracted lead was longer in group 1 vs group 2 (7.6 ± 4.9 years vs 5.6 ± 4.4 years; P = .017), as was infection as an indication for LE (76% vs 33%; P <.001). A bailout femoral approach was more commonly required in group 1 than in group 2 (18.4% vs 6%; P = .007). Complete procedural success rates were similar (92.1% in group 1 vs 95.0% in group 2; P = .439), but there was a trend toward lower clinical success in group 1 (92.1% vs 97.4%; P = .088), primarily due to failure to remove all hardware in the setting of infection. Major procedural complication rates were similar (2.6% in group 1 vs 1.2% in group 2; P = .397), as was long-term survival (mean follow-up 2.3 ± 2.2 years)., Conclusion: Abandoned leads at the time of LE were associated with increased procedural complexity, including a higher rate of bailout femoral extraction, and may be associated with lower clinical success. Among appropriately selected patients, consideration should be given to LE instead of abandonment., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The benefits of aerobic fitness in relation to all-cause and cardiovascular mortality is well established; however, the associations of long-term change in cardiorespiratory fitness (CRF) with incident heart failure (HF) and atrial fibrillation (AF) have not been studied before. The Kuopio Ischaemic Heart Disease Risk Factor Study is a prospective cohort comprising men aged 42 to 60 years from the city of Kuopio and its surroundings, with a baseline examination between 1984 and 1989 (V1), a re-examination at 11 years (V2), and up to 15 years of follow-up from V2. CRF, as assessed by VO 2 max, was measured at both visits using respiratory gas exchange during maximal exercise tolerance test. The difference (ΔVO 2 max) was estimated as VO 2 max (V2) - VO 2 max (V1). Participants with no missing data on both baseline and 11-year exercise test were included (n = 481). The mean ΔVO 2 max was -5.4 ml/min⋅kg (standard deviation 5.4). During a median follow-up of 14.3 years (interquartile range 13.3 to 15.1), 46 incident HF (9.6%) and 73 incident AF (15.2%) events were recorded. In a multivariate analysis adjusted for baseline age, baseline VO 2 max, systolic blood pressure, smoking, type 2 diabetes, and cardiovascular disease, per 1 ml/min⋅kg higher ΔVO 2 max was log linearly associated with incident HF with a 10% relative risk reduction of HF (hazard ratio 0.90, 95% confidence interval 0.83 to 0.97). No significant relation of ΔVO 2 max with incident AF was observed. In conclusion, overall long-term improvement in CRF is associated with reduced risk of HF, indicating the importance of maintaining good CRF over time., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: The purpose of the current study is to characterize and quantify the impact of complete atrioventricular block (cAVB) on heart failure hospitalization (HFH) and healthcare utilization in pacemaker (PM) patients., Methods: Patients ≥ 18 years implanted with a dual-chamber PM from April 2008 to March 2014 were selected from the MarketScan® Commercial and Medicare Supplemental claims databases. Patients with ≤ 1-year continuous MarketScan enrollment prior to and post-implant, and those with prior HF diagnosis were excluded. Patients were dichotomized into those with cAVB, defined as a 3rd degree AVB diagnosis or AV node ablation in the year prior to PM implant, versus those without any AVB (noAVB). Post-implant HFH and associated costs were compared based on inpatient claims., Results: The study cohort included 21,202 patients, of which 14,208 had no AVB and 6994 had cAVB, followed for 2.39 and 2.27 years, respectively. Patients with cAVB were associated with a significantly increased risk of cumulative HFH (HR 1.59 [95% CI 1.35-1.86] p < 0.001) and significantly higher costs ($636 [609-697] vs $369 [353-405] per pt-year, p < 0.001) compared to those with no AVB., Conclusions: Among dual-chamber PM patients without prior HF, cAVB is associated with a significantly increased risk of HFH and greater HF-related healthcare utilization. Identifying patients at high risk for HF in the setting of RV pacing, and potentially earlier use of biventricular or selective conduction system pacing, may reduce HF-related healthcare utilization.

Background: The utility of standard distal bipolar electrograms (sEGMs) for assessing catheter-tissue contact may be obscured by the presence of far-field signals. Microelectrode electrograms (mEGMs) may overcome this limitation., Methods: We compared 5 mEGM characteristics (amplitude, frequency content, temporal signal variability, presence of injury current, and amplitude differential between bipoles) with the sEGM for determining tissue contact in 20 patients undergoing ablation of typical atrial flutter. Visualization of catheter-tissue contact by intracardiac echocardiography (ICE) served as the gold standard for assessing contact. Correlation between electrograms and ICE-verified contact level was reported as percent concordance., Results: Three of 5 mEGM characteristics demonstrated significantly better concordance with ICE-verified contact level than the sEGM (52% concordance with ICE): mEGM frequency content (59% concordance with ICE, P < .001 for comparison with sEGM); mEGM amplitude (concordance 59%, P < .001); and mEGM presence of injury current (56% concordance, P = .001). Concordance of amplitude differential between mEGM bipoles with ICE (49%) was not significantly different than the sEGM ( P = .638) whereas mEGM temporal variability (39%) was significantly worse than the sEGM. Using a median of all 5 mEGM characteristics provided additive information (concordance with ICE 64%) and was significantly better than all of the individual mEGM characteristics except frequency content ( P = .976)., Conclusion: Microelectrode EGMs (in particular frequency content, amplitude, and presence of injury current) can improve real-time assessment of catheter contact compared to the use of standard bipolar EGMs. Broader use of mEGMs may enhance ablation efficacy.

Aims: End-stage renal disease (ESRD) increases the risk of implantable cardioverter-defibrillator (ICD) infection. We sought to define outcomes of lead extraction in patients with ESRD., Methods and Results: Implantable cardioverter-defibrillator lead extractions at our institution from January 2006 to March 2014 were stratified by absence (Control-Ex, n = 465) or presence (ESRD-Ex, n = 43) of ESRD. Procedural outcomes and survival were determined by medical records review. Survival in the ESRD-Ex group was compared with a contemporaneous cohort with ESRD undergoing ICD lead implantation (ESRD-I, n = 127). Among extraction patients, those with ESRD were more likely to be extracted for infection (74.4% vs. 28.6%, P < 0.001). Extraction procedure success (Control-Ex: 97% vs. ESRD-Ex: 93%, P = 0.17) and procedural deaths (Control-Ex: 1.1% vs. ESRD-Ex: 2.3%, P = 0.413) were similar. Survival 1 year following extraction was worse in the ESRD-Ex group compared with the Control-Ex, with a survival rate of 65.6% vs. 92.6% (P < 0.001); these curves continued to diverge through year 3. One-year survival in the ESRD-Ex group was worse than among ESRD patients undergoing ICD implant (ESRD-I), but these curves converged and survival was similar by year 3., Conclusions: Implantable cardioverter-defibrillator lead extraction can be performed safely and effectively in patients with ESRD. However, despite high rates of procedural success, long-term mortality following extraction in ESRD patients is substantial. Much of the long-term mortality risk appears to be accounted for by the presence of ESRD and an indication for an ICD., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)

Background: Patients with atrial fibrillation (AF) often undergo AV junction ablation (AVJA) and pacemaker implantation. Right ventricular (RV) pacing contributes to increased risk of heart failure (HF), which may be mitigated by biventricular pacing. We sought to determine the impact of AVJA concurrent with RV versus biventricular pacemaker implantation on AF and HF hospitalizations., Methods and Results: The MarketScan Commercial and Medicare Supplemental claims database was used to select 18- to 100-year-old patients with AF with pacemaker implantation. Patients were divided into those with an RV and a biventricular pacemaker and further into those who did (AVJA + ) or did not undergo concurrent ablation. Separately, the AVJA + group was divided into those receiving RV versus biventricular pacemakers. AF and HF hospitalization rates were compared between groups after matching on demographics, comorbidities, and baseline hospitalization rates. The study included 24 361 patients, with RV (n=23 377) or biventricular (n=984) pacemakers; 1611 patients underwent AVJA. AVJA + was associated with reduced AF hospitalization risk (RV hazard ratio [HR], 0.31; P <0.001; biventricular HR, 0.20; P =0.003) compared with no AVJA. However, HF hospitalization risk was increased for RV (HR, 1.63; P =0.001), but not biventricular (HR, 0.98; P =0.942), pacemakers. In AVJA + patients, biventricular pacing was associated with reduced risk of HF hospitalization versus RV pacing (HR, 0.62; P =0.017)., Conclusions: In a large cohort of patients with AF, AVJA + significantly reduced AF hospitalizations, irrespective of whether an RV or a biventricular pacemaker was implanted. However, AVJA was associated with a marked HF hospitalization increase in patients with an RV pacemaker, which was ameliorated with biventricular pacing., (© 2017 The Authors and Abbott. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background: The efficacy of implantable cardioverter-defibrillators (ICD) for primary prevention of sudden cardiac death (SCD) has not been studied in patients with end-stage renal disease (ESRD) and left ventricular dysfunction. We sought to identify predictors of long-term survival among ICD recipients with and without ESRD., Methods: Patients implanted with an ICD at our institution from January 2006 to March 2014 were retrospectively identified. Clinical and demographic characteristics were collected. Patients were stratified by the presence of ESRD at the time of ICD implant. Mortality data were collected from the Social Security Death Index (SSDI)., Results: A total of 3453 patients received an ICD at our institution in the pre-specified time period, 184 (5.3%) of whom had ESRD. In general, ESRD patients were sicker and had more comorbidities. Kaplan Meier survival curve showed that ESRD patients had worse survival as compared with non-dialysis patients ( p <0.001). Following adjustment for differences in baseline characteristics, patients with ESRD remained at increased long-term mortality in the Cox model. The one-year mortality in the ESRD patients was 18.1%, as compared with 7.7% in the non-dialysis cohort ( p <0.001). The three-year mortality in ESRD patients was 43%, as compared with 21% in the non-dialysis cohort ( p <0.001)., Conclusion: ESRD patients are at significantly increased risk of mortality as compared with a non-dialysis cohort. While the majority of these patients survive more than one year post-diagnosis, the three-year mortality is high (43%). Randomized studies addressing the benefits of ICDs in ESRD patients are needed to better define their value for primary prevention of SCD.

Aim: To identify predictors of need for repeat procedures after initial atrial fibrillation (AF) ablation., Methods: We identified a cohort undergoing first time AF ablation at our institution from January 2004 to February 2014 who had cardiac magnetic resonance (CMR) imaging performed prior to ablation. Clinical variables and anatomic characteristics (determined from CMR) were assessed as predictors of need for repeat ablation. The decision regarding need for and timing of repeat ablation was at the discretion of the treating physician., Results: From a cohort of 331 patients, 142 patients (43%) underwent repeat ablation at a mean of 13.6 ± 18.4 mo after the index procedure. Both male gender (81% vs 71%, P = 0.05) and lower ejection fraction (57.4% ± 10.3% vs 59.8% ± 9.4%, P = 0.04) were associated with need for repeat ablation. On pre-ablation CMR, mean pulmonary vein (PV) diameters were significantly larger in all four PVs among patients requiring repeat procedures. In multivariate analysis, increased right superior PV diameter significantly predicted need for repeat ablation (odds ratio 1.08 per millimeter increase in diameter, 95%CI: 1.00-1.16, P = 0.05). There were also trends toward significance for increased left and right inferior PV sizes among those requiring repeat procedures., Conclusion: Increased PV size predicts the need for repeat AF ablation, with each millimeter increase in PV diameter associated with an approximately 5%-10% increased risk of requiring repeat procedures., Competing Interests: Conflict-of-interest statement: None reported.

Implantable cardioverter defibrillators (ICDs) reduce the risk of sudden cardiac death in patients with impaired left ventricular ejection fraction (LVEF). However, there are limited data on the long-term benefit of ICD therapy in patients whose LVEF subsequently improves. We conducted a meta-analysis to evaluate the effect of LVEF improvement on ICD therapy during follow-up. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated using random-effects modeling. Sixteen studies with 3,959 patients were included in our analysis. Study arms were defined by LVEF improvement at follow-up (improved LVEF [>35%]: 1,622; low LVEF [≤35%] 2,337). Mean age (64.8 vs 64.9 years, p = 0.97) was similar, whereas men were overrepresented in the persistent low LVEF group (79% vs 72%, p <0.001). Appropriate ICD therapy rate was 9.7% (improved LVEF) versus 21.8% (low LVEF) over a median follow-up period of 2.9 years. In the meta-analysis, improved LVEF group had significantly lower (3.3% vs 7.2% per year IRR 0.52; CI 0.38 to 0.70; p <0.001) appropriate ICD therapies which was uniformly seen across all subgroups (ICD-only studies: IRR 0.59; p = 0.004) (cardiac resynchronization therapy-defibrillator-only studies: IRR 0.31; p = 0.002) (super-responder studies [mean LVEF > 45%]: IRR 0.53; p = 0.002). Inappropriate ICD therapy rates were, however, similar in both groups (3.01% vs 2.56% per year IRR 0.76; CI 0.43 to 1.36; p = 0.35). All-cause mortality rates in our meta-analysis favored (3.63% vs 8.23% per year IRR 0.49; CI 0.35 to 0.69; p <0.001) the improved LVEF group. In conclusion, our meta-analysis demonstrates that an improvement in LVEF is associated with a significantly reduced risk of ventricular arrhythmia and mortality. However, inappropriate ICD therapy rates remain similar., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Octogenarians account for a significant percentage of patients with indwelling pacemakers or defibrillators., Objectives: To determine procedural outcomes and long-term survival after lead extraction (LE) in octogenarians., Methods: We retrospectively identified all patients who underwent defibrillator or pacemaker LE at our institution between January 1, 2007 and May 31, 2016. Patients were stratified based on age into two groups: <80 years old (Group 1, n = 674) or ≥80 (Group 2, n = 100). Outcomes were determined by medical records review and query of the Social Security Death Index., Results: Patients in Group 2 were more likely to be hypertensive (77% vs 61%, P = 0.02), more like to have coronary artery disease (50% vs 39%, P = 0.049), and more likely to be extracted for infectious indications (47% vs 33%, P = .009). The number of leads extracted per procedure was 2.0 ± 0.8 and the mean dwell time of the oldest extracted lead was 5.6 ± 4.3 years, without significant differences between groups. Extraction procedure success (Group 1: 94.7%, Group 2: 96%, P = 0.808) and procedural deaths (Group 1: 0.9% vs Group 2: 0%, P = 1.0) were similar. There was no significant difference in survival up to 3 years following LE between groups., Conclusion: At experienced centers, LE can be performed safely in octogenarians with procedural success rates and long-term survival comparable to younger individuals., (© 2017 Wiley Periodicals, Inc.)

Background: Little is known about advance directive (AD) utilization in implantable cardioverter-defibrillator (ICD) recipients., Objective: The purpose of this study was to define the prevalence and predictors of ADs in patients with ICDs., Methods: We identified ICD recipients with ADs at our institution. The primary end point was the prevalence of an AD documented up to 1 year after device implant and the secondary end point was the cumulative prevalence of an AD., Results: Of 2549 patients with ICDs, 701 (27.5%) were followed for at least 1 year after device implant, and of those 701 patients, 164 (23.4%) had ADs documented before or within 1 year of ICD implant. The prevalence of ICD recipients with ADs increased overtime, reaching approximately 10% in the most recent years of analysis. However, only 1 AD specifically addressed the ICD as part of end-of-life decision making. In multivariable analysis, more recent year of device implant and prior cardiovascular hospitalization were positively associated with having an AD within 1 year of implant. The cumulative prevalence of an AD at any time after implant reached about 30%, with more recent implant year, prior cardiovascular hospitalization, and palliative care consultation positively associated with the presence of an AD and black race associated with a lower cumulative prevalence., Conclusion: In a tertiary academic medical center, most patients with ICDs still do not have ADs, and even when they do, the ICDs are rarely addressed as part of the directive. Several predictors of ADs emerged, which may provide opportunities to improve utilization of ADs in ICD recipients., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Although right ventricular pacing can contribute to cardiomyopathy, the impact of complete atrioventricular block (cAVB) on heart failure (HF) development in pacemaker patients has not been well characterized. We evaluated the incidence and time course for developing HF after pacemaker implantation for cAVB., Methods and Results: A MarketScan database identified patients undergoing dual-chamber pacemaker implantation from 2008 to 2014. Patients with cAVB were identified by an atrioventricular node ablation or diagnosis of third-degree AVB. Patients with ≥1 year of continuous MarketScan enrollment before and after implant and without a previous diagnosis of HF were dichotomized into those with cAVB and without AVB. The primary end point was new HF assessed over acute (0-6 months) and chronic (6 months to 4 years) phases post-pacemaker implantation. The cohort included 6994 cAVB patients and 14 208 patients without AVB, followed for 2.35 years (interquartile range, 1.62-3.39 years). After adjustment for baseline covariates, patients with cAVB experienced an increased risk of new-onset HF in the acute phase (hazard ratio, 1.62; 95% confidence interval, 1.48-1.79; P <0.001). Although the risk of HF remained elevated among those with cAVB in the chronic phase, the effect was attenuated (hazard ratio, 1.16; 95% confidence interval, 1.08-1.25; P <0.001). After pacemaker implantation, younger patients (≤55 years of age) and those with an antecedent history of atrial fibrillation experienced the highest risk of HF associated with cAVB., Conclusions: Patients with a diagnosis of cAVB, and thus presumed to have a higher burden of right ventricular pacing, experienced an increased risk of new-onset HF after pacemaker implantation compared with those without AVB. Better tools are needed to identify patients at high risk of developing HF in the setting of right ventricular pacing and to determine whether these patients benefit from upfront biventricular pacing., (© 2017 American Heart Association, Inc.)

Objectives: This study compared risks associated with magnetic resonance imaging (MRI) in patients with non-MRI conditional and MRI conditional pacing and defibrillator systems with particular attention to clinically actionable outcomes., Background: While recipients of new MRI conditional pacemaker and defibrillator systems may undergo MRI scanning with very low risk, safety and regulatory concerns persist regarding such scanning in recipients of non-MRI conditional systems., Methods: Patients with any cardiac device who were referred for MRI were prospectively enrolled at a single center and underwent scanning at 1.5 Tesla. Pre- and postscan lead characteristic changes, system integrity, and symptoms were analyzed. A comparison was made between non-MRI conditional and MRI conditional devices., Results: 105 patients were evaluated allowing for comparison of 97 scans with non-MRI conditional devices and 16 scans with MRI conditional devices. The cohort included those with pacemaker dependency, defibrillator, and cardiac resynchronization devices. Small, nonsignificant changes were observed in lead characteristics following scanning, and there was no significant difference when comparing non-MRI and MRI conditional devices. Lead parameter changes did not require lead revision or programming changes. No device reset, failures, or premature scan termination was observed., Conclusions: 1.5 T MRI scanning in patients with MRI conditional and non-MRI conditional cardiac devices was performed with similar, low clinical risk., (© 2017 Wiley Periodicals, Inc.)

Background: Extraction of pacemaker and defibrillator leads in young adults may be technically challenging because of more extensive fibrosis and calcification in this patient population., Objective: The purpose of this study was to examine outcomes of lead extraction (LE) in young adults at our institution., Methods: We retrospectively identified all patients who underwent LE at our institution between January 1, 2007, and May 31, 2016. Patients were divided by age into 2 groups: <40 years (group 1, n = 84) or ≥40 years (group 2, n = 690). Outcomes were determined by medical records review., Results: Patients in group 2 had a higher overall average number of leads extracted per procedure compared to group 1 (1.64 ± 0.80 vs 1.45 ± 0.64; P <.001). Lead dwell time was similar in the 2 groups (5.7 ± 5 years vs 5.6 ± 4.3 years; P = .95). The younger cohort tended to require femoral extraction techniques more frequently (9.5% vs 4.4%; P = .055). Extraction procedural success (group 1: 94.1%, group 2: 94.9%; P = .792), major complications (group 1: 0%, group 2: 1.3%; P = 1), and periprocedural mortality (group 1: 0%, group 2: 0.86%; P = 1) were similar in the 2 groups., Conclusion: LE can be performed safely and effectively in young adults. Despite the lower number of leads extracted per procedure and the similar lead dwell time, younger adults more frequently required the use of femoral extraction tools, thus highlighting the importance of performing these procedures in centers with advanced expertise in extraction techniques., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Lead extraction (LE) infrequently requires the use of the "bailout" femoral approach. Predictors and outcomes of femoral extraction are not well characterized., Objective: The aim of this study was to determine the predictors of need for femoral LE and its outcomes., Methods: Consecutive patients who underwent LE at our centers were identified. Baseline demographic characteristics, procedural outcomes, and clinical outcomes were ascertained by medical record review. Patients were stratified into 2 groups on the basis of the need for femoral extraction., Results: A total of 1080 patients underwent LE, of whom 50 (4.63%) required femoral extraction. Patients requiring femoral extraction were more likely to have leads with longer dwell time (9.5 ± 6.0 years vs 5.7 ± 4.3 years; P < .001), to have more leads extracted per procedure (2.0 ± 1.0 vs 1.7 ± 0.9; P = .003), and to have infection as an indication for extraction (72% vs 37.2%; P < .001). Procedural and clinical success was lower in the femoral extraction group than in the nonfemoral group (58% and 76% vs 94.7% and 97.9 %, respectively; P < .001). Major periprocedural complications (0% vs 1.3%; P = 1.0) and periprocedural mortality (0% vs 0.8%; P = 1.0) were similar between the 2 groups., Conclusion: In this study, femoral extraction was needed in ~5% of LEs. Longer lead dwell time, higher number of leads extracted per procedure, and the presence of infection predicted the need for femoral extraction. Procedural success of femoral extraction was low, highlighting the fact that this approach is mostly used as a bailout strategy and thus selects for more challenging cases., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)