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PURPOSE SharpSense™ technology is an upgradable software enhancement introduced to the Abbott Confirm Rx™ insertable cardiac monitor (ICM). This study aims to characterize the real-world performance of SharpSense algorithms by comparing device detected pause and bradycardia episodes before and after the SharpSense upgrade. METHODS Confirm Rx devices with at least 90 days monitoring each before and after SharpSense upgrade were included in the study. Bradycardia and pause detections and subcutaneous electrocardiograms (SECGs) within 90 days before and after the upgrade were extracted from Merlin.net™ patient care network for evaluation and adjudicated by expert adjudicators. RESULTS A total of 197 devices were included in the analysis. Devices were implanted for syncope (35.0%), atrial fibrillation (32.5%), cryptogenic stroke (16.8%), and other indications including palpitations (15.7%). The SharpSense upgrade significantly reduced the number of bradycardia detections by 86.8% and pause detections by 93.1%. In adjudicated SECGs, the upgrade significantly reduced false positive (FP) bradycardia episodes by 91.5% and FP pause episodes by 82.8%. The percentage of devices with at least one FP episode was reduced from 39 to 20% for bradycardia and from 52 to 35% for pause. The number of devices with FP rate greater than 1 episode per week was reduced from 23 to 8% for bradycardia and from 39 to 20% for pause. CONCLUSIONS In this real-world performance evaluation, the algorithms incorporated in SharpSense software upgrade in Confirm Rx ICMs substantially reduced false positive bradycardia and pause detections and the number of transmitted SECGs for clinic review.

Highlights • This review summarizes the current state of cardiac radioablation (CRA) for ventricular tachycardia. • Clinical data and radiobiologic principles supporting CRA are reviewed. • An example workflow, including guidance for interpreting cardiac mapping, is provided., Cardiac radioablation with SBRT is a very promising non-invasive modality for the treatment of refractory VT and potentially other cardiac arrhythmias. Initial reports indicate that it is relatively safe and associated with excellent responses, particularly in reduction of ICD-related events, need for anti-arrhythmic medications, and resulting in significantly improved quality of life for patients. Establishment of objective criteria for candidates for cardiac radioablation will accelerate the adoption of this important radiation therapy modality in the treatment of refractory VT and other cardiac arrhythmias in the coming years. In addition, in order to develop more prospective safety and efficacy data, treatment of patients should ideally be performed in the context of clinical trials or prospective registries at, or in collaboration with, experienced centers. Taken together, the future of cardiac radioablation is rich and worthy of further investigation to become a standard treatment in the armamentarium against refractory VT.

Purpose Cardiac radioablation using stereotactic body radiation therapy is gaining popularity as a noninvasive treatment for otherwise refractory ventricular arrhythmias. As radiation oncologists might be unaccustomed to the lexicon used by cardiologists to describe the location of arrhythmogenic foci, a preliminary guide to cardiac-specific anatomy and orientation is needed to foster effective communication between the radiation oncologist and cardiology team. Methods and Materials Electrocardiogram-gated and respiratory-gated computed tomography imaging was acquired per institutional protocol. Additional relevant imaging modalities are described. The American Heart Association 17-segment model is described in detail because this framework is used frequently by cardiologists to describe the location left ventricular abnormalities. Results A step-by-step guide is provided for properly rotating the heart from standard orthogonal views obtained during radiation simulation to the cardiac-specific orientation needed to appreciate the 17-segment model. Once the proper configuration is achieved, the location of each segment is defined in detail. Conclusions This atlas serves as an introduction to the relevant anatomy and principles, and it provides a suggested approach to help delineate cardiac radioablation targets using the established American Heart Association 17-segment model.

Introduction Frequent right AQ4ventricular pacing (≥40%) with a transvenous pacemaker (TVP) is associated with the risk of pacing‐induced cardiomyopathy (PICM). Leadless pacemakers (LPs) have distinct physical and mechanical differences from TVP. The risk of PICM with LP is not known. To identify incidence, predictors, and long‐term outcomes of PICM in LP and TVP patients. Methods The study comprised all pacemaker‐dependent patients with LP or TVP who had left ventricular ejection fraction (LVEF) of ≥50 from 2014 to 2019. The incidence of PICM (≥10% LVEF drop) was assessed with an echocardiogram. Predictors for PICM were identified using multivariate analysis. Long‐term outcomes after cardiac resynchronization (CRT) were assessed in both groups. Results A total of 131 patients with TVP and 67 with LP comprised the study. All patients in the TVP group and the majority in the LP group underwent atrioventricular node ablation. The mean follow‐up duration in TVP and LP groups was 592 ± 549 and 817 ± 600 days, respectively. A total of 18 (13.7%) patients in TVP and 2 (3%) in LP developed PICM after a median duration of 254 (interquartile range: 470) days. The incidence of PICM was significantly higher with TVP compared with LP (p = .02). TVP as pacing modality was a positive (odds ratio [OR]: 1.07) while age was negative (OR: 0.94) predictor for PICM on multivariable analysis. Both patients in LP and all except two in the TVP group responded to CRT. Conclusion Incidence of PICM is significantly lower with LP compared with TVP in pacemaker‐dependent patients. Age and TVP as pacing modality were predictors for PICM.

Background The leadless Micra transcatheter-pacing system (Micra-TPS) is implanted via a femoral approach using a 27-French introducer sheath. The Micra Transcutaneous Pacing Study excluded patients with inferior vena cava (IVC) filters. Objective To examine the feasibility and safety of Micra-TPS implantation through an IVC filter. Methods This multicenter retrospective study included patients with an IVC filter who underwent a Micra-TPS implantation. Data for clinical and IVC filter characteristics, preprocedure imaging, and procedural interventions were collected. The primary outcome was a successful leadless pacemaker (LP) implantation via a femoral approach in the presence of an IVC filter. Periprocedural and delayed clinical complications were also evaluated. Results Of the 1528 Micra-TPS implants attempted, 23 patients (1.5%) had IVC filters. The majority (69.6%) of IVC filters were permanent. Six (26.1%) patients underwent preprocedural imaging to assess for filter patency. One patient's filter was retrieved before LP implantation. The primary outcome was achieved in 21 of 22 patients (95.5%) with an existing IVC filter. An occluded IVC precluded LP implantation in one patient. Difficulty advancing the stiff guidewire or the 27-Fr sheath was encountered in five patients. These cases required repositioning of the wire (n = 2), gradual sheath upsizing (n = 2), or balloon dilation of the filter (n = 1). Postprocedure fluoroscopy revealed intact filters in all cases. During a median 6-month follow-up, there were no clinical complications related to the filter or the Micra-TPS. Conclusion This multicenter experience demonstrates the feasibility and safety of Micra-TPS implantation via an IVC filter without acute procedural or delayed clinical complications.

Leadless pacemakers (LPs) have emerged as a meaningful alternative to transvenous pacemakers for single-ventricular pacing. LPs eliminate many of lead- and pocket-associated complications observed with transvenous pacemakers. Owing to the lack of atrioventricular synchronous pacing until recently, the use of LP was generally reserved for those patients who either required minimal ventricular pacing or had permanent atrial fibrillation. The only commercially available LP is the Micra transcatheter pacing system (Micra-TPS, Medtronic Inc. Fridley, Minnesota), which requires insertion of a 27-F (outer diameter) introducer sheath in the femoral vein. The LP is delivered to the right ventricle using a 23-F delivery catheter. Owing to the need for a large-bore sheath, the pivotal studies for the Micra transcatheter pacing system excluded patients with indwelling inferior vena cava filters and included only a few patients with bioprosthetic or repaired tricuspid valve. Subsequent real-world experience has demonstrated the overall safety and feasibility of LP placement, and use in various unconventional clinical settings has been validated, albeit with specific precautions. Additionally, incorporation of adjunctive techniques and strategies can improve the safety of the procedure in routine clinical settings as well. The objective of this state-of-the-art review is to highlight the key procedural elements to facilitate safe and efficient implantation of LP in routine as well as in unique clinical settings.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an important tool in the armamentarium of an electrophysiologist. Multiple randomized trials over the last decade have shown that S-ICDs are as efficacious as the transvenous ICDs and eliminate complications related to vascular access. In this review, we highlight issues unique to S-ICD implantation, focusing not only on the surgical implantation procedure, but also the pre- and postimplant management of the patient.

Background Experience with retrieval of a Watchman left atrial (LA) appendage (LAA) closure device (WD) is limited. An embolized or grossly malpositioned WD warrants retrieval to minimize the risk of thromboembolic complications and vascular occlusion. Objective The purpose of this study was to report approaches for percutaneous retrieval of a WD from multicenter experience. Methods Data on successful WD retrievals were obtained from high-volume operators. Data included clinical characteristics; structural characteristics of the LA and LAA; and procedural details of the deployment and retrieval procedure, type of retrieval (immediate: during the same procedure; delayed: during a separate procedure after the successful deployment), equipment used, complications, and postretrieval management. Results Ten successful percutaneous and 1 surgical retrievals comprised this study. Seven patients had immediate retrieval, while 4 had delayed retrieval. The median duration before delayed retrieval was 45 days (range 1–45 days). The median LAA diameter and size of a successfully deployed WD was 16 mm (range 14–24 mm) and 21 mm (range 21–30 mm), respectively. A WD was retrieved from the LA (n = 1), LAA (n = 2), left ventricle (n = 2), and aorta (n = 6). The reason for retrieval from the LAA was inadequate deployment, resulting in a significant peri-device leak. Retrieval from the LA or LAA was successfully performed using snares (n = 2) and a Raptor grasping device (n = 1). Retrieval from the left ventricle was achieved with a snare (n = 1) and surgery (n = 1). Retrieval from the aorta required snares (n = 5) and retrieval forceps (n = 1). Five patients were successfully reimplanted with a larger size WD. The only complication during percutaneous retrieval was a pseudoaneurysm. Conclusion Retrieval of an embolized or malpositioned WD is feasible, and familiarity with snares and grasping tools can facilitate a successful removal.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is the latest option among devices clinically available for the prevention of sudden cardiac death, with experience from previous trials and postmarketing studies supporting the feasibility and safety of this kind of system. The extracardiac positioning of the S-ICD obviates the need for transvenous leads, which translates into lower incidence rates of lead-related complications and systemic infections. This review will highlight the results of pertinent studies related to the perioperative management of S-ICDs and review potential approaches to minimizing the risk of complications such as hematoma at the pulse generator location, unsuccessful defibrillation due to suboptimal S-ICD lead and generator positioning, and postoperative pain. An extensive literature search using PubMed was conducted to identify relevant articles.

Purpose: Guidelines have differing recommendations for aspirin use in patients with an indication for anticoagulation. The purpose of this study was to evaluate the incidence of major bleeding and thromboembolic events (TEs) in patients with atrial fibrillation (AF) receiving warfarin alone (monotherapy group) versus warfarin plus aspirin (combination therapy group). Methods: This was a retrospective, cohort study including patients from a pharmacist-run anticoagulation clinic. Inclusion criteria were patients with AF receiving anticoagulation between January 2013 and January 2014 observed over 5 years. Results: One hundred forty-two patients were included in the combination group versus 89 in monotherapy group. In the combination group, 60 (42.3%) patients were on aspirin for no apparent indication, 19 (13.4%) had stable coronary artery disease and diabetes, and 26 (18.3%) had diabetes alone. Major bleeding occurred in 21 (14.9%) patients in the combination group versus 7 (7.9%) patients in the monotherapy group (odds ratio [OR] = 2.02, 95% confidence interval [CI]: 0.78-5.91; P = .17). TE occurred in 10 (7%) patients in the combination group versus 4 (4.5%) in the monotherapy group (OR = 1.61, 95% CI: 0.44-7.24; P = .57). There was no significant difference in bleeding ( P = .85) or TE ( P = .37) rates between aspirin indications in the combination group. Conclusion: Combination therapy versus monotherapy may increase bleeding risk with little benefit in decreasing AF-related stroke or cardiovascular events.

Implantable loop recorder (ILR) is preferred strategy for prolonged rhythm monitoring.The purpose of this study was to report the incidence and causes of false-positive (FP) diagnoses during remote monitoring with ILR.During a 4-week study period, all consecutive remote transmissions in patients with ILR (Reveal LINQ, Medtronic) implanted for atrial fibrillation (AF) surveillance, cryptogenic stroke (CS), and syncope were reviewed. A nurse specializing in device management and an electrophysiologist adjudicated all transmissions. Primary endpoint of the study was incidence of FP in patients with AF, CS, and syncope.A total of 695 remote transmissions (scheduled downloads: 414; Alerts: 281) sent from 559 patients were adjudicated. The majority of patients had ILR for AF surveillance (n = 321), followed by CS (n =168) and syncope (n = 70) with nominal programming for rhythm diagnosis. Incidence of FP transmissions during the study period was 46%, 86%, and 71% in patients with AF, CS, and syncope, respectively. Incidence of FP transmissions was higher in patients with CS and syncope than in patients with AF (P.001). For scheduled transmissions, primary causes of FP were signal dropout and undersensing; for alert transmissions, primary reasons for FP were premature atrial and ventricular ectopy.Incidence of FP during remote monitoring with nominal settings on this ILR was substantial, ranging from 46% to 86% depending on the indication for implantation. Adjudication of these transmissions required a considerable time commitment from electrophysiologists and device clinic personnel but would be required to avoid misdiagnosis and potential errors in clinical management.

Introduction COVID-19 infection is associated with many different systemic complications. Among these, cardiovascular system complications are particularly important as these are associated with significant mortality. There are many different subgroups of cardiovascular complications, with Arrhythmias being one of them. Arrhythmias are especially important as there are a substantial percentage of patients who have arrhythmia after a COVID-19 infection, and these patients are seen with an increased mortality rate. The main interest of this review is understanding some of the specific post-COVID-19 arrhythmic complications and their predisposing factors. Areas covered This paper will highlight the findings of studies on cardiovascular system disease after COVID-19 infection, different specific arrhythmic complications of COVID-19, and changes in electrophysiologic interventions post-COVID-19 outbreak in different centers around the world. An extensive literature search was made to find pertinent articles. Expert Opinion Studies show us that a significant percentage of COVID-19 patients have arrhythmia. Many distinct types of arrhythmias are associated with COVID-19 infection, and specific risk factors of these arrhythmias are important as this information can be used to detect and prioritize certain at-risk patients for early treatment, which can mean life or death in some cases.

Background Sudden cardiac death (SCD) in the adult population is poorly studied, although determining its etiology is crucial for management and prognosis [1]. Cardiovascular magnetic resonance imaging (CMR) is being increasingly utilized in SCD survivors [1,2]. The role of late gadolinium enhancement (LGE) imaging in patients with recent SCD and no significant coronary artery disease (CAD) is well established, but there is no data on the additive role of T1 and T2 mapping [1–3]. Purpose This is a retrospective study to assess the role of CMR including T1 and T2 mapping in SCD survivors. Methods Between 01/2016 and 12/2019, we retrospectively analyzed patients who underwent CMR on a Siemens Magnetom Avanto 1.5 T scanner within 4 weeks of SCD. CMR protocol included cine imaging, T1 and T2 mapping, and LGE imaging. Native and post-contrast myocardial T1 values were measured within the septum on the mid short axis (SAX) and extracellular volume fraction was calculated using the standard formula. T2 values were measured in six mid segments on the mid SAX map. Additional measurements were performed if long axis T2 maps were available. Clinical data, electrocardiography (ECG), transthoracic echocardiography (TTE), coronary computed tomography angiography (CCTA), and left heart catheterization (LHC) were reviewed from the electronic health record. An ischemic evaluation was performed in 33 (94%) of patients. Results A total of 35 patients who underwent CMR for SCD were included for analysis (mean age 46.9±14.1 years; 20 (57%) male). SCD etiology was established based on clinical data, ECG, TTE, CCTA, and LHC in 9 (26%) patients. CMR provided the most probable SCD etiology in an additional 20 (57%) patients with T1 and T2 mapping abnormalities seen in 18 (51%) patients. Diagnoses determined by CMR included myocarditis (35%), hypertrophic cardiomyopathy (CMP) (20%), left ventricular non-compaction CMP (15%), dilated CMP (10%), takotsubo CMP (5%), and myocardial infarction with non-obstructive CAD (15%) (Table, Figure). Elevated native T1 was seen in 15 (43%) (mean T1 1069±60 ms; site specific normal Conclusions CMR has significant diagnostic and prognostic value in assessing SCD etiology compared to non-CMR based evaluation. Myocarditis is a common underdiagnosed cause of SCD in adult patients well seen in a CMR protocol with T1 and T2 mapping. Myocardial inflammation monitoring in SCD survivors with serial CMRs using T1 and T2 mapping could influence clinical decision making by justifying pharmacotherapy modification and timing of ICD implantation. To conclude, CMR with T1 and T2 mapping provides high diagnostic yield in the investigation of SCD etiology. Funding Acknowledgement Type of funding sources: None.

INTRODUCTION Defibrillation testing (DT) is recommended during the subcutaneous defibrillator (S-ICD) placement. We sought to compare 10 J shock impedance in sinus rhythm (SR) with 65 J defibrillation impedance and evaluate device position on a postimplant chest X-ray (CXR) using an intermuscular (IM) technique. METHODS Consecutive S-ICD implantations between 12/2019 and 12/2020 at The Ohio State University were reviewed. All implantations were performed using a two-incision IM technique. Standard DT with 65 J shock and 10 J shock in SR were performed unless contraindicated. The PRAETORIAN score was calculated based on CXR. RESULTS A total of 37 patients (age: 47.2 ± 15.8 years old, male: n = 26 [70.3%], body mass index: 30.1 ± 6.7 kg/m2 ) underwent IM S-ICD implantation, and of those, 27 (73%) underwent both 65 J shock and 10 J shock in SR. The coefficient of determination (R2 ) between 10 J shock impedance and 65 J shock impedance was 0.84. The mean of an impedance difference was 1.6 ± 4.8 Ω (minimum - 11 and maximum 8). Postimplant CXR was available for 33 out of 37 patients (89.2%). The PRAETORIAN score was less than 90 in all patients and the mean score was 32.7 ± 8.8. CONCLUSION We demonstrated that 10 J shock impedance in SR correlated well with 65 J defibrillation impedance during IM S-ICD implantation. An IM implantation technique provides excellent generator location on postimplant CXR. The IM technique combined with 10 J shock in SR may be sufficient to predict and ensure the defibrillation efficacy of the S-ICD.

Introduction Subcutaneous cardiac rhythm monitors (SCRMs) provide continuous ambulatory electrocardiographic monitoring for surveillance of known and identification of infrequent arrhythmias. SCRMs have proven to be helpful for the evaluation of unexplained symptoms and correlation with intermittent cardiac arrhythmias. Successful functioning of SCRM is dependent on accurate detection and successful transmission of the data to the device clinic. As the use of SCRM is steadily increasing, the amount of data that requires timely adjudication requires substantial resources. Newer algorithms for accurate detection and modified workflow systems have been proposed by physicians and the manufacturers to circumvent the issue of data deluge. Areas covered This paper provides an overview of the various aspects of ambulatory rhythm monitoring with SCRMs including indications, implantation techniques, programming strategies, troubleshooting for issue of false positive and intermittent connectivity and strategies to circumvent data deluge. Expert commentary : SCRM is an invaluable technology for prolonged rhythm monitoring. The clinical benefits from SCRM hinge on accurate arrhythmia detection, reliable transmission of the data and timely adjudication for possible intervention. Further improvement in SCRM technology is needed to minimize false positive detection, improve connectivity to the central web-based server and devise strategies to minimize data deluge.

Background The perioperative anesthesia care during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving. Objective To assess the feasibility and safety of S-ICD implantation with monitored anesthesia care (MAC) versus general anesthesia (GA) in a tertiary care center. Methods This is a single-center retrospective study of patients undergoing S-ICD implantation between October 2012 and May 2019. Patients were categorized into MAC and GA group based on the mode of anesthesia. Procedural success without escalation to GA was the primary endpoint of the study, whereas intraprocedural hemodynamics, need of pharmacological support for hypotension and bradycardia, length of the procedure, stay in the post-anesthesia care unit, and postoperative pain were assessed as secondary endpoints. Results The study comprises 287 patients with MAC in 111 and GA in 176 patients. Compared to MAC, patients in GA group were younger and had a higher body mass index. All patients had successful S-ICD implantation. Only one patient (0.9%) in the MAC group was converted to GA. Despite a similar baseline heart rate (HR) and mean arterial blood pressure (MAP) in both groups, patients with GA had significantly lower HR and MAP during the procedure and more frequently required pharmacological hemodynamic support. Length of the procedure, stay in the postanesthesia care unit, and postoperative pain was similar in both groups. Conclusion This retrospective experience suggests that implantation of S-ICD is feasible and safe with MAC. Use of GA is associated with more frequent administration of hemodynamic drugs during S-ICD implantation.

Introduction: Leadless pacemakers (LPs) are the latest advancement in the field of pacing. Experience from pivotal trials and post-marketing studies has proven the feasibility and safety of these devices. The LPs obviate the need of pulse generator pocket and leads, which translates into lower incidence of lead related complications and pocket related infections. This review will summarize the existing literature on the LPs, specifically indications; implant procedure, unique situations and long- term follow up.Areas covered: This review will summarize the results of published pivotal trials. Several multicenter studies where LP was used in the unique situations such as during concomitant AV node ablation and across bioprosthetic valve will also be discussed. An extensive search using PUBMED was performed to identify the relevant articles.Expert commentary: The use of LPs is expanding and the published results a preferential use of such devices for patients who need single ventricle pacing. Additionally, the use of these devices in several unique situations such as patients with inferior vena cava filters, bioprosthetic tricuspid valves and concomitant atrio-ventricular nodal (AV) ablation has also been shown to be safe.

Background Central sleep apnea (CSA) is a breathing disorder caused by the intermittent absence of central respiratory drive. Transvenous phrenic nerve stimulation is a new therapeutic option, recently approved by the FDA , for the treatment of CSA. Objective To describe the technique used to implant the transvenous phrenic nerve stimulation system (the remedē System, Respicardia, Inc). Methods The remedē System is placed in the pectoral region, typically on the right side. A single stimulation lead is placed in either the left pericardiophrenic vein (PPV) or the right brachiocephalic vein (RBC). A sensing lead is placed into the azygous vein to detect respiration. Results In the remedē System Pivotal trial, 147 of 151 (97%) patients were successfully implanted with the system. Sixty-two percent of stimulation leads were placed in the PPV and 35% in the RBC. Mean procedure time was 2.7 ± 0.8 hours and 94% of patients were free from implant-related serious adverse events through 6 months. Conclusion In patients with CSA, transvenous phrenic nerve stimulation is an effective and safe therapy with an implant procedure similar to that of cardiac implantable electronic devices.

Funding Acknowledgements Type of funding sources: None. Background The insertable cardiac monitor (ICM) is an essential tool for the ambulatory diagnosis of arrhythmias. However, definitive diagnoses still rely on time-consuming, manual adjudication of electrograms (EGMs) transmitted to the patient care network. This EGM review burden may be minimized by automatically selecting a subset of EGMs for fast review without delaying the diagnosis. Purpose Develop EGM selection strategies to reduce the EGM review burden without delaying diagnoses. Methods A retrospective analysis of 1,000 randomly selected Abbott Confirm Rx devices with 90+ days of remote transmission history was performed, regardless of transmission frequency, and all EGMs were adjudicated as either true or false positive (TP, FP). Up to 3 EGMs per day per arrhythmia type were prioritized for review based on ventricular rate and episode duration, with rules specific to each arrhythmia type: atrial fibrillation (AF), tachycardia, bradycardia, and pause. The resulting reduction in EGM review burden and TP days (patient-days with at least 1 TP EGM), as well as any diagnostic delay from the first transmitted TP, were calculated relative to reviewing all transmitted EGMs. Results In this population and transmission period, at least one AF, tachycardia, bradycardia, and pause EGM was transmitted by 424, 343, 190, and 325 unique devices, respectively, with a total of 35,723, 12,239, 19,752, and 28,002 EGMs, and a total of 6,163, 1,572, 1,438, and 646 TP days. For these patients with ≥1 EGM, the median [IQR] EGM transmission rate was 2.6 [0.7, 11.6], 1.1 [0.4, 4.7], 2.1 [0.6, 10.7], and 3.4 [0.6, 29.9] EGMs/patient/month, respectively. The optimal EGM selection strategy reduced this EGM review burden by 43%, 67%, 76%, and 50%, while only missing 3.4%, 2.2%, 0.3%, and 0.2% of TP days, respectively. Ultimately, 97%, 99%, 99%, and 99% of devices with a TP AF, tachycardia, bradycardia, or pause EGM exhibited no diagnostic delay vs. reviewing all transmitted EGMs. Conclusion EGM prioritization rules for selecting up to 3 episodes/day significantly reduced EGM burden across all patients, not just "frequent fliers," with no delay-to-diagnosis in >97% of patients who exhibited a true arrhythmia. Implementing these rules on the patient care network may improve clinical workflow and ICM patient management. Abstract Figure.

INTRODUCTION The LARIAT epicardial suture snaring device has been fraught with technical challenges and procedural complications. Over time, technique modification and improved operator experience have helped overcome many of these challenges. METHODS AND RESULTS: Studies reporting left atrial appendage epicardial closure over a 12-year period from 2009 to 2020 were evaluated. The primary efficacy outcome evaluated was left atrial appendage closure with residual flow ≤1 mm. Safety outcomes evaluated were periprocedural and long term complications after device placement. Nine studies consisting of 1430 patients were included in this analysis, of which 1386 (97%) underwent successful device placement. The mean age was 69.3 years, with a mean CHADS2 -VASC score of 3.78. Primary efficacy end point was achieved in 95.8% patients immediately after device placement, and in 92.8% patients on long term follow-up. Early procedural complications consisted of pericardial effusion 5.6%, cardiac perforation 2.7%, pericarditis 2.6%, and need for open heart surgery 1.5%. Long term complications consisted of all-cause mortality 2.3%, stroke 1.5%, and left atrial appendage thrombus 2.3%. Reduced complications were noted using micropuncture needles (2.20% vs. 10.14%; p

Objective The aim of this study was to assess temporal changes and clinical implications of peridevice leak (PDL) after left atrial appendage closure. Background Endocardial left atrial appendage closure devices are alternatives to long-term oral anticoagulation (OAC) for patients with atrial fibrillation. PDL > 5 mm may prohibit discontinuation of OAC. Methods Patients included in the study had: 1) successful Watchman device implantation without immediate PDL; 2) new PDL identified at 45 to 90 days using transesophageal echocardiography; 3) eligibility for OAC; and 4) 1 follow-up transesophageal echocardiographic study for PDL surveillance. Relevant clinical and imaging data were collected by chart review. The combined primary outcome included failure to stop OAC after 45 to 90 days, transient ischemic attack or stroke, device-related thrombi, and need for PDL closure. Results Relevant data were reviewed for 1,039 successful Watchman device implantations. One hundred eight patients (10.5%) met the inclusion criteria. The average PDL at 45 to 90 days was 3.2 ± 1.6 mm. On the basis of a median PDL of 3 mm, patients were separated into ≤3 mm (n = 73) and >3 mm (n = 35) groups. In the ≤3 mm group, PDL regressed significantly (2.2 ± 0.8 mm vs 1.6 ± 1.4 mm; P = 0.002) after 275 ± 125 days. In the >3 mm group, there was no significant change in PDL (4.9 ± 1.4 mm vs 4.0 ± 3.0 mm; P = 0.12) after 208 ± 137 days. The primary outcome occurred more frequently (69% vs 34%; P = 0.002) in the >3 mm group. The incidence of transient ischemic attack or stroke in patients with PDL was significantly higher compared with patients without PDL, irrespective of PDL size. Conclusions New PDL detected by transesophageal echocardiography at 45 to 90 days occurred in a significant percentage of patients and was associated with worse clinical outcomes. PDL ≤ 3 mm tended to regress over time.

Introduction: The effects of bone marrow cell (BMC) therapy in patients with chronic ischemic heart disease (CIHD) remain controversial. Hypothesis: We hypothesized that injection of BMCs in patients with CIHD would improve left ventricular (LV) structure and function. We also hypothesized that BMC therapy would improve clinical outcomes in CIHD patients. Methods: We performed a systemic review and meta-analysis of pooled data from published randomized controlled trials (RCTs) that evaluated the efficacy of BMC administration in patients with CIHD. The effects of BMC injection on LV ejection fraction (LVEF), LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV), infarct size, and patient outcomes were analyzed using random-effects meta-analysis. Results: The literature search yielded 30 RCTs enrolling 1,548 patients. Transplantation of BMCs resulted in an improvement in LVEF in cell-treated patients compared with controls (2.89%; 95% confidence interval (CI): 1.80 to 3.97; P P = 0.14) and LVEDV (-5.95 ml; 95% CI: -12.09 to 0.18 ml; P =0.06). The improvement in LVEDV was more pronounced (-7.42 ml; 95% CI: -13.68 to -1.17ml; P =0.02) in patients with baseline LVEF Conclusions: BMC injection improves cardiac function and remodeling in patients with CIHD. These benefits are more pronounced in patients with LVEF

Background: Implantable cardioverter-defibrillator (ICD) therapy prevents sudden cardiac death in selected patients with heart failure. When a primary prevention ICD arrives at elective replacement interval (ERI), conventional management is to replace the device. However, the effectiveness of ICDs in patients with nonischemic and ischemic cardiomyopathy (NICM and ICM, respectively) whose left ventricular ejection fraction (LVEF) improved to ≥50% before replacement is unclear. Hypothesis: The therapeutic benefit of primary prevention ICD for NICM is attenuated by the recovery of LVEF at the time of ERI. Methods: Consecutive patients presenting for first time primary prevention ICD battery change-out at a single quaternary care center between 1/1/2008 and 6/27/2019 were included. The primary endpoint was the rate of ICD therapy (ICD discharge and anti-tachycardia pacing) according to LVEF recovery at ERI. Results: During the study period 6851 ICDs were placed, of which 310 underwent battery change-out, of whom 100 did not receive therapy from the first ICD, of whom 44 had NICM. The demographics of the NICM cohort are in the table. Following ERI, 0 (0%) with NICM and recovered LVEF had received ICD therapy, whereas 13 (30%) with persistently low LVEF had received therapy (p = 0.07). Furthermore, among patients without recovered LVEF, the NICM group had a lower rate of therapy (4, 12%) than the ICM group (12, 32%) (p=0.04). Conclusion: Rates of ICD therapy provided by primary prevention ICD after first battery change out trended towards a significantly lower rate in NICM patients with LVEF that recovered to ≥50% than those without LVEF recovery. No other patient demographic significantly predicted therapy-free survival but the analysis was limited by sample size. A prospective study with a larger cohort would be necessary to better estimate therapy-free survival.

Introduction: Patients with end stage renal disease (ESRD) often progress to hemodialysis (HD), where permanent access such as arteriovenous fistula (AVF) is needed. Due to associated cardiovascular comorbidities, several of these patients also require cardiac implantable electronic devices (CIEDs) for pacing or defibrillation needs. HD vascular access is their lifeline, yet prolonged use is fraught with complications which often necessitate the eventual use of both upper extremities. Conventional CIEDs require placement of leads through subclavian veins which limits the ability to use that extremity for AVF. Novel devices such as subcutaneous defibrillator and leadless pacemakers do not require placement of leads in the upper extremity and may offer an advantage in HD patients to preserve both upper extremities for AVF. Objective: To compare the incidence of successful use of contralateral upper extremity for AVF following HD access failure in patients with novel and conventional devices. Methods: This study included all patients who underwent placement of novel leadless and conventional devices during the last 10 years at the Ohio State University. Incidence of successful use of contralateral upper extremity for AVF following HD access failure was assessed as the primary outcome. Incidence of initial HD access failure was assessed as a secondary outcome. Results: A total of 58 patients with novel devices (subcutaneous defibrillator: 30 and leadless pacemaker: 28) comprised the interventional group, while a total of 25 patients with conventional devices comprised the control group. The primary outcome occurred in 18% of the interventional group and 0% of the control group (p < 0.01). Incidence of initial access failure was 46% in the interventional group and 40% in the control group (p= 0.2). Conclusion: Patients on HD have a high incidence of access failure and often require use of the contralateral upper extremity for AVF. Presence of novel devices provides the option for contralateral access compared to conventional transvenous devices. Where possible and clinically indicated, novel devices should be preferred over conventional transvenous devices in ESRD and HD patients.

Background: Recent enhancements have been introduced to the Abbott Confirm Rx™ insertable cardiac monitor (ICM) arrhythmia detection algorithms (SharpSense™). This study aims to characterize the real-world performance of SharpSense™ algorithms, in the upgraded ICM devices by comparing device detected pause and bradycardia (brady) episodes before and after the SharpSense™ upgrade. Methods: Confirm Rx™ devices with at least 90 days monitoring each before and after SharpSense™ upgrade were included in the study. Brady and pause episodes were extracted from Merlin.net™ patient care network for evaluation and adjudicated by expert adjudicators. Results: A total of 197 devices were included in the analysis. Devices were implanted for syncope (35%), AF management (33%), and other indications, including cryptogenic stroke and palpitations (32%). The SharpSense™ upgrade significantly reduced the total number of detected episodes by 92% (pause: 93%, brady: 87%) and the rate of transmitted episodes by 73.6% from 50.3 to 13.3 (pause: 34.9 to 6.0, brady: 7.8 to 1.5) episodes per patient-week (p < 0.001). SharpSense™ reduced false positive episodes by 82.8% and 91.5% for pause and brady, respectively. The percentage of devices with at least one false positive episode was reduced from 52% to 35% for pause and from 39% for 20% for brady. The number of devices with false positive rate greater than 1 episode per week was reduced from 39% to 20% for pause and from 23% to 8% for brady. Conclusion: SharpSense™ upgrade resulted in substantial reduction of pause and bradycardia episode detections, false positive detections, and frequency of transmitted episodes for clinic review.

As leadless pacing (LP) use is expected to increase, it becomes increasingly essential that operators become familiar with the tools and techniques needed to retrieve an LP successfully. The purpose of this review is to describe a stepwise approach for the successful retrieval of tine-based LP devices, including ways to minimize complications.

Background Atrial fibrillation (AF) driver mechanisms are obscured to clinical multielectrode mapping approaches that provide partial, surface‐only visualization of unstable 3‐dimensional atrial conduction. We hypothesized that transient modulation of refractoriness by pharmacologic challenge during multielectrode mapping improves visualization of hidden paths of reentrant AF drivers for targeted ablation. Methods and Results Pharmacologic challenge with adenosine was tested in ex vivo human hearts with a history of AF and cardiac diseases by multielectrode and high‐resolution subsurface near‐infrared optical mapping, integrated with 3‐dimensional structural imaging and heart‐specific computational simulations. Adenosine challenge was also studied on acutely terminated AF drivers in 10 patients with persistent AF. Ex vivo, adenosine stabilized reentrant driver paths within arrhythmogenic fibrotic hubs and improved visualization of reentrant paths, previously seen as focal or unstable breakthrough activation pattern, for targeted AF ablation. Computational simulations suggested that shortening of atrial refractoriness by adenosine may (1) improve driver stability by annihilating spatially unstable functional blocks and tightening reentrant circuits around fibrotic substrates, thus unmasking the common reentrant path; and (2) destabilize already stable reentrant drivers along fibrotic substrates by accelerating competing fibrillatory wavelets or secondary drivers. In patients with persistent AF, adenosine challenge unmasked hidden common reentry paths (9/15 AF drivers, 41±26% to 68±25% visualization), but worsened visualization of previously visible reentry paths (6/15, 74±14% to 34±12%). AF driver ablation led to acute termination of AF. Conclusions Our ex vivo to in vivo human translational study suggests that transiently altering atrial refractoriness can stabilize reentrant paths and unmask arrhythmogenic hubs to guide targeted AF driver ablation treatment.

Objectives This study reports resource use and economic implications of rhythm monitoring with subcutaneous cardiac rhythm monitors (SCRMs). Background SCRMs generate a substantial amount of data that requires timely adjudication for appropriate clinical care. Resource use for SCRM monitoring is not known. Methods The study included consecutive transmissions during 4 weeks from 1,811 SCRMs. Resource use was quantified by assessment of time commitment of device clinic personnel and electrophysiologists for data adjudication. Incidence and characteristics of false positive (FP) episodes were assessed. Impact of custom programming for arrhythmia detection on incidence of FP episodes and resource use was analyzed. Results A total of 1,457 transmissions (alerts = 462; full downloads = 995) were received during study period. Average device clinic personnel time for adjudication of 1 transmission was 15 ± 6 min. This totaled to 364 h spent (2.3 full-time staff) over the 4-week period, which translated into a salary cost of $12,000 U.S. dollars (USD). Average time spent by an electrophysiologist for 1 transmission was 1.5 ± 1 min and totaled to 37 h for 4 weeks, which translated into an estimated cost of $9,600 USD. Of 1,457 total transmissions, 512 (35%) represented multiple transmissions from the same patients, which resulted in no additional reimbursement. Incidence of FP episodes in the entire cohort was 50% and was variable in alert (60%) and full download (49%) (p = 0.04) transmissions. When SCRMs with manufacturer suggested nominal programming and institutional custom programming were compared, there was a reduction in FP episodes (55% vs. 16%; p = 0.01), which translated to a 34% reduction in resource use for data adjudication. Conclusions SCRM data adjudication requires significant resources. Custom programming for SCRMs may overcome the data deluge.

Cardiac electrophysiology (EP) procedures are frequently performed in patients with cardiac arrhythmias, chronic heart failure, and sudden cardiac death. Most EP procedures involve fluoroscopy, which results in radiation exposure to physicians, patients, and EP lab staff. Accumulated radiation exposure is a known health detriment to patients and physicians.This review will summarize radiation exposure, dose metrics, complications of radiation exposure, factors affecting radiation exposure, minimizing radiation exposure, zero or near-zero fluoroscopy strategies, and up-to-date research in the area of reducing radiation exposure and best practices.Comprehensive strategies should be implemented in EP laboratories to minimize radiation exposure with standard fluoroscopy. There are routine techniques that can mitigate significant amounts of radiation exposure using standard equipment within the EP lab. The operators need to emphasize that EP practices routinely incorporate non-ionizing radiation sources for cardiac imaging (e.g. magnetic resonance imaging, advanced electroanatomical mapping systems, intracardiac ultrasonography) in addition to other novel technologies to mitigate radiation exposure to patients and physicians.

Leadless pacemakers (LPs) have emerged as a meaningful alternative to transvenous pacemakers for single-ventricular pacing. LPs eliminate many of lead- and pocket-associated complications observed with transvenous pacemakers. Owing to the lack of atrioventricular synchronous pacing until recently, the use of LP was generally reserved for those patients who either required minimal ventricular pacing or had permanent atrial fibrillation. The only commercially available LP is the Micra transcatheter pacing system (Micra-TPS, Medtronic Inc. Fridley, Minnesota), which requires insertion of a 27-F (outer diameter) introducer sheath in the femoral vein. The LP is delivered to the right ventricle using a 23-F delivery catheter. Owing to the need for a large-bore sheath, the pivotal studies for the Micra transcatheter pacing system excluded patients with indwelling inferior vena cava filters and included only a few patients with bioprosthetic or repaired tricuspid valve. Subsequent real-world experience has demonstrated the overall safety and feasibility of LP placement, and use in various unconventional clinical settings has been validated, albeit with specific precautions. Additionally, incorporation of adjunctive techniques and strategies can improve the safety of the procedure in routine clinical settings as well. The objective of this state-of-the-art review is to highlight the key procedural elements to facilitate safe and efficient implantation of LP in routine as well as in unique clinical settings.

This report outlines the first commercial application of RemoteControl? (Medtronic, Minneapolis, MN, USA) technology that affords real-time remote testing and programming of a cardiac implantable electronic device (CIED) without the need for clinical device specialists (manufacturer's representatives and device clinic nurses) in the electrophysiology (EP) lab This article is protected by copyright All rights reserved

To evaluate diagnostic accuracy of different protocols of contrast enhanced computed tomography venogram (CTV) for LAA thrombus detection in patients undergoing AF ablation and study the correlation of the novel LAA enhancement index (LAA-EI) to LAA flow velocity obtained using transesophageal echocardiography (TEE).Study comprised of patients undergoing CTV and TEE on the same day from October 2016 to December 2017. Three CTV scanning protocols (described in results), were evaluated wherein ECG gating was used only for those with sinus rhythm on day of CTV. LAA-EI was calculated as Hounsfield Unit (HU) in the LAA divided by the HU unit in the center of the LA. The diagnostic accuracy for CTV was calculated in comparison to TEE. The LAA-EI was compared to LAA emptying velocities as obtained from TEE.590 patients with 45.6% non-ECG-gated without delayed imaging, 26.9% non-ECG-gated with delayed imaging and 27.5% ECG-gated with delayed imaging, were included in the study. All three protocols had 100% negative predictive value with improvement in specificity from 61.8% to 98.1% upon adding delayed imaging. The LAA-EI correlated significantly with reduced LAA flow velocities (r = 0.45, p .0001). The mean LAA emptying velocity in patients with LAA-EI of ≤ 0.6 was significantly lower than in those with LAA-EI of0.6 (36.2 cm/s [95% CI: 32.6-39.7] vs, (58 cm/s [95% CI 55.3-60.8]), respectively (p .0001).CTV with delayed imaging (with or without ECG gating) is highly specific in ruling out LAA thrombus. The novel LAA-EI can detect low LAA flow velocities.

BACKGROUND: Catheter ablation (CA) is an established treatment for patients with symptomatic atrial fibrillation (AF). The purpose of this study was to evaluate the safety and efficacy of single CA in AF patients with extreme obesity (body mass index [BMI] ≥ 40 kg/m2) and its long-term impact on body weight. METHODS: Patients with BMI ≥40 kg/m2 who underwent CA at the Ohio State University between 2012 and 2016 were included. The primary efficacy endpoint was no atrial arrhythmia lasting > 30 seconds without anti-arrhythmic drugs during 1-year follow-up after a single procedure. RESULTS: Out of 230 AF patients with BMI ≥ 40 kg/m2 undergoing CA, pulmonary vein isolation was achieved in 226 (98%) patients.Seventeen patients (7.4%) experienced acute major complications, including pericardial effusion, vascular complications and respiratory failure. Patient characteristics for 135 patients with complete 1-year follow-up were as follows: mean age 58.6 ± 9.6 years, mean BMI 44.5±4.7 kg/m2, female 63 (47%), non-paroxysmal AF 100 (74%), median CHA2DS2-VASc score 2 (IQR:1-3). In this cohort, the primary efficacy endpoint was achieved in 44 (33%) patients. Paroxysmal AF was associated with higher CA success compared to non-paroxysmal (51 vs. 26% [p < 0.01]).There was no significant weight change even in patients with successful AF CA. CONCLUSIONS: Extreme obesity is associated with low AF CA success, particularly in those with non-paroxysmal AF. Successful AF CA was not associated with long-term weight reduction. A better treatment strategy is needed in this population of AF and extreme obesity

Implantable loop recorders (ILRs) are commonly used for long-term arrhythmia monitoring. Optimal R-wave amplitude is required for adequate rhythm detection. The manufacturer of the Reveal LINQ ILR (Medtronic, Findley, Minnesota) recommends subcutaneous insertion of the device at 45° in the frontal

BACKGROUND Cardiac implantable electronic device (CIED) infections associated with large, mobile vegetation adds to the complexity of lead extraction and is associated with significant patient morbidity and mortality. OBJECTIVE To show the feasibility of concomitant cardiovascular implantable electronic device extraction and vacuum-assisted removal of lead-related vegetations. METHODS This is a single-center retrospective case series of consecutive patients with persistent bacteremia, sepsis, or endocarditis despite medical therapy who have vegetations >2 cm and subsequently underwent immediate CIED lead extraction after debulking with vacuum-assisted suction. RESULTS Eight patients underwent successful removal of 17 leads immediately after debulking of vegetations with vacuum-assisted device suction. Debulking procedure was not successful in 1 patient due to inability to direct the vacuum suction device into proper position. There were no intraprocedure complications related to the vacuum-assisted debulking. One patient required open sternotomy for tear of the coronary sinus ostium related to extraction of a left ventricular pacing electrode. There was no mortality within 30 days of the procedure. CONCLUSIONS Based upon these clinical results, it is feasible for patients with infected CIED systems that have large right-sided vegetations to undergo vacuum-assisted debulking then immediately followed by percutaneous CIED removal in whom surgical removal is considered high risk.

Successful pulmonary vein isolation (PVI) is the most reliable predictor of success after ablation in patients with atrial fibrillation (AF). Adenosine triphosphate (ATP) unmasks the dormant conduction and can be used to improve the effectiveness of PVI. The impact of ATP guided PVI on clinical outcomes is discordant in various randomized controlled trials (RCTs).To delineate the incremental benefit of ATP during PVI in patients with AF through a meta-analysis.Database searches through January 2017 identified 5 RCTs (enrolling 2839 patients) comparing ATP guided PVI versus standard PVI (non-ATP). Four trials exclusively studied paroxysmal AF while one trial included both paroxysmal and non-paroxysmal AF patients. Baseline characteristics, dose of adenosine and ablation strategies were clearly identified among all the trials. The risk ratio (RR) for AF episodes lasting30 s after 3-month blanking period was calculated with random effects meta-analysis and showed no difference at a median follow up of 12 months [RR: 1.02, 95 % Confidence interval (CI): 0.85 to 1.25; p = 0.82]. Similarly, the number of repeat ablation was similar in both groups [RR: 1.02, 95 % CI: 0.63, 1.56; p = 0.98].ATP guided PVI does not decrease the recurrence of AF or the need for repeat ablation at 12 months.

Background: Expert opinion recommends performing exercise testing with initiation of Class Ic antiarrhythmic medication. Objective: To evaluate the rate and reason for discontinuation of Ic agent within the first year of follow up, with particular attention to rate of proarrhythmia and the value of routine treadmill testing. Methods: This is a single center retrospective cohort study including consecutive patients with atrial arrhythmias who were initiated on a Class Ic agent from 2011 to 2016. Data was collated from chart review and pharmacy database. Results: The study population included 300 patients (55% male, mean age 61; mean ejection fraction, 56%) started on flecainide (n = 153; 51%) and propafenone (n = 147; 49%). Drug initiation was completed while hospitalized on telemetry and the staff electrophysiologists directed dosing. There was one proarrhythmic event during initiation (0.3%). The primary reason for not being discharged on Ic agent was due to detection of proarrhythmia (n = 15) or ischemia (n = 1) with treadmill testing (5.3%). Exercise testing was the single significant variable to affect the decision to discontinue Ic drug, p

Background The impact of left atrial appendage (LAA) exclusion, comparing an epicardial LAA or an endocardial LAA device, on systemic homeostasis remains unknown. Objectives This study compared the effects of epicardial or endocardial LAA devices on the neurohormonal profiles of patients, emphasizing the roles of the renin-angiotensin-aldosterone system and the autonomic nervous system. Methods This is a prospective, single-center, observational study including 77 patients who underwent LAA closure by an epicardial (n = 38) or endocardial (n = 39) device. Key hormones involved in the adrenergic system (adrenaline, noradrenaline), renin-angiotensin-aldosterone system (aldosterone, renin), metabolic system (adiponectin, free fatty acids, insulin, β-hydroxybutyrate, and free glycerols), and natriuresis (atrial and B-type natriuretic peptides) were assessed immediately before the procedure, immediately after device deployment, at 24 h, and at 3 months follow-up. Results In the epicardial LAA device group, when compared with baseline blood adrenaline, noradrenaline and aldosterone were significantly lower at 24 h and 3 months (p Conclusions There are substantial differences in hemodynamics and neurohormonal effects of LAA exclusion with epicardial and endocardial devices. Further studies are required to elucidate the underlying mechanism of these physiological changes.

During early experience with subcutaneous implantable cardioverter-defibrillators (S-ICD), several patients had inappropriate shocks from T-wave oversensing (TWOS) during exercise. This prompted some operators to perform routine treadmill exercise tests after implantation of S-ICD to screen for TWOS. Meanwhile, improvements have been made in the detection algorithms by the manufacturer.To assess whether routine treadmill exercise post S-ICD implantation is warranted.Patients undergoing S-ICD implantation from October 2012 to December 2016 who were able to complete a treadmill exercise were included in the study. The amplitude of R and T waves as assessed by the device programmer at rest and peak exercise was calculated and incidence of TWOS recorded.Eighty-seven patients with complete treadmill exercise test data were included in the final analysis. The majority of the patients received S-ICD for primary prevention. Nine percent of the included patients had hypertrophic obstructive cardiomyopathy. During treadmill exercise, there was significant increase in the heart rate from rest (77 ± 14 beats per minute) to peak exercise (133 ± 14 beats per minute; P.0001). There was no significant difference between R-wave amplitude at rest (2 ± 0.77 mV) and peak exercise (1.88 ± 0.94 mV; P = .36). Similarly, there was no significant difference between T-wave amplitude at rest (0.27 ± 0.19 mV) and peak exercise (0.33 ± 0.23 mV; P = .06). The incidence of TWOS during exercise was zero.With current screening and detection algorithms for S-ICD, routine treadmill exercise does not result in additional discrimination of patients susceptible to TWOS.

Objectives The clinical characteristics, electrophysiological mechanisms, and ablation outcomes of post-surgical atrial fibrillation ablation (SAFA) atrial tachycardias (ATs) have not been studied in a large, multicenter cohort. Background ATs are often seen following SAFA. Methods Analysis was performed on 137 patients (age, 62 ± 10 years; 74% male) who underwent catheter ablation for symptomatic post-SAFA AT from 2004 to 2013 at 3 high-volume institutions in the United States. Results A total of 137 patients had 149 ATs that were mapped; 103 (69%) had a left atrial (LA) origin and 46 (31%) had a right atrial origin. Of the 149, a total of 44 (30%) had a focal mechanism, with 29 (66%) having an LA origin, with 53% localized to LA posterior wall. Of the 105 re-entrant ATs, 74 (71%) were of LA origin. The predominant circuits were cavotricuspid isthmus (n = 25), perimitral (n = 19), LA roof (n = 17), left pulmonary veins (n = 13), right pulmonary vein/LA septum (n = 12), and LA appendage (n = 7). A total of 93% of patients had ≥1 pulmonary vein reconnection requiring reisolation. Catheter ablation resulted in termination and noninducibility of 97% of right atrial and 93% of LA ATs. Over a 12-month follow-up, 80% of patients were free of any AT or AF. Conclusions In this large multicenter cohort of post-SAFA ATs, most were of LA origin, with macro–re-entry being the most common arrhythmia mechanism. Wide variability in location of AT circuits was seen in both right atrial and LA and likely reflects underlying arrhythmogenic substrate and differences in modified SAFA techniques. Catheter ablation was highly successful in eliminating the culprit AT with favorable long-term outcomes.

Dofetilide is a class III antiarrhythmic drug that has been reported to be safe and efficacious in the treatment of atrial dysrhythmias with a known initial risk of QT prolongation and torsades de pointes (TdP). As a result, the Federal Drug Administration (FDA) mandated in-hospital dofetilide initiation and adherence to a common dosing protocol. However, there is a lack of clarity on how to manage dofetilide re-initiation.An observational survey was performed including 347 cardiologists in the United States and worldwide to evaluate the deviations from approved manufacturer's protocol during dofetilide initiation and re-initiation among practicing cardiologists.Most practicing cardiologists were cautious about outpatient dofetilide use and adhered to the manufacturer's in-patient dofetilide protocol during de-novo initiation and reported low incidence of TdP in clinical practice. There were substantial differences among practicing cardiologists with deviation from the manufacturer's protocol during re-initiation of dofetilide. About 21% cardiologists always admitted patients to the hospital while 37% admitted patients10% of the time for dofetilide re-initiation. Only 4% reported major adverse events with outpatient dofetilide re-initiation. There was also wide variation regarding monitoring of electrolytes and QT interval as an outpatient with dofetilide.There is significant practice pattern variation in the use of dofetilide for the management of AF. This degree of variation noted is concerning and is a reflection of the current lack of substantial clinical evidence in the re-initiation dofetilide protocol to help direct the provider.

Background There have been an increasing number of atrial fibrillation (AF) patients with Watchman® left atrial appendage occlusion (LAAO) device, requiring catheter ablation (CA) for maintenance of normal sinus rhythm. In this study, we describe our experience with the feasibility and safety of CA in patients with a preexisting Watchman LAAO device. Methods This was a retrospective multicenter AF registry of 60 patients with Watchman® LAAO device who underwent CA for AF. Baseline clinical and procedural characteristics of the included subjects were retrieved from review of medical records and were analyzed. Results The mean age was 72.7±4.9 years and the mean CHADS2 score was 2.3±0.6. All patients had successful pulmonary vein isolation (PVI). The left atrial appendage (LAA) was electrically active in 34 (56%) while reentrant tachycardia and AF triggers were seen in 17 (28%) patients. Electrical isolation was attempted in these 17 patients with only 10 achieving complete LAA isolation. Repeat imaging showed new peri-device leaks in 30% (12/40) patients, while new significant peri-device leaks (≥5 mm) were noted in 10% (10/40) of patients after RFA, respectively, requiring continuation of oral anticoagulation. There were a higher proportion of patients with severe peri-device leaks (≥5 mm) after LAA isolation. However, >50% of those leaks sealed off on follow-up TEE. Conclusion AF ablation is a feasible and safe in patients with preexisting Watchman LAAO device. Electrical isolation of the LAA could be difficult and when attempted can result in increased risk of short-term peri device leak and recurrence of AT/AF in almost all patients. This article is protected by copyright. All rights reserved

Leadless pacemaker (LP) extraction is a relatively new field with limited operator experience. We sought to report a comparison of retrieval process for Nanostim vs Micra transcatheter LPs. The list of retrievals for the Micra transcatheter pacemaker system (TPS) was obtained from Medtronic whereas Nanostim data was obtained from centers that participated in the Leadless II study. Details of retrieval such as indication, days post implantation, complications, and post procedure device management were obtained from the manufacturer database for each site, and any missing details were obtained from individual operators. Extractions performed on the same day were labeled as “Early” and thereafter were labeled as “Late.” A total of 113 retrievals were attempted (73 in Nanostim and 40 in Micra TPS). The most common reasons for retrieval were battery advisory and inadequate pacing threshold (n = 16) for Nanostim and Micra, respectively. Success rate in Nanostim group was around 90% (66/73) compared with 100% in Micra group (p = 0.049). Late retrieval occurred in 50% of Micra TPS cases (20/40) compared with 100% of Nanostim LP cases. Median time to extraction was 46 days for Micra TPS and 256 days for Nanostim LP (p