Very late recurrences after ablation of AVNRT have been reported. Age related alterations of nodal tissues caused by fibrous and fatty tissue infiltration and changes of the sympathovagal influence on the AV node, in turn altering AV nodal conduction and refractoriness, could set the stage for a previously not present substrate for AVNRT. Consequently, the occurrence of AVNRT many years after an ablation procedure may perhaps not always implicate a recurrence but instead an arrhythmia caused by a new substrate.

Background: Outcomes of catheter ablation (CA) among patients with non-paroxysmal atrial fibrillation (AF) are largely disappointing. Objective: We sought to evaluate the feasibility, effectiveness, and safety of a single-stage stepwise endo-/epicardial approach in patients with persistent/longstanding-persistent AF. Methods: We enrolled 25 consecutive patients with symptomatic persistent (n=4) or longstanding-persistent (n=21) AF and at least one prior endocardial procedure, who underwent CA using an endo-/epicardial approach. Our anatomical stepwise protocol included multiple endocardial as well as epicardial (Bachmann’s bundle [BB] and ligament of Marshall ablations) components, and entailed ablation of atrial tachycardias emerging during the procedure. The primary outcome was freedom from any AF/atrial tachycardia episode after a 3-month blanking period. The secondary outcome was patients’ symptom status during follow-up. Results: The stepwise endo-/epicardial approach allowed sinus rhythm restoration in 72% of patients, either directly (n=6, 24%) or after AF organization into atrial tachycardia (n=12, 48%). BB’s ablation was commonly implicated in arrhythmia termination. After a median follow-up of 266 days (interquartile range, 96 days), survival free from AF/atrial tachycardia was 88%. Antiarrhythmic drugs could be discontinued in 22 patients (88%). As compared to baseline, more patients were asymptomatic at 9-month follow-up (0% vs- 56%, p=0.02). Five patients (20%) developed mild medical complications, whereas one subject (4%) had severe kidney injury requiring dialysis. Conclusion: a single-stage endo-/epicardial CA resulted in favorable rhythm and symptom outcomes in a cohort of patients with symptomatic persistent/longstanding-persistent AF and one or more prior endocardial procedures. Epicardial ablation of BB was commonly implicated in procedural success.

Sympathectomy - A “one hit wonder” for life?Fabrizio R. Assis, M.D. Harikrishna Tandri, M.D.From Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Background: Contrast computed tomography (CT) is a useful tool for the detection of intracardiac thrombi. We aimed to assess the accuracy of the late-phase prone-position contrast CT (late-pCT) for thrombus detection in patients with persistent or long-standing persistent atrial fibrillation (AF). Methods: Early and late-phase pCT were performed in 300 patients with persistent or long-standing AF. If late-pCT did not show an intracardiac contrast defect (CD), catheter ablation (CA) was performed. Immediately prior to CA, intracardiac echocardiography (ICE) from the left atrium was performed to confirm thrombus absence and the estimation of the blood velocity of the left atrial appendage (LAA). For patients with CDs on late-pCT, CA performance was delayed, and late-pCT was performed again after several months following oral anticoagulant alterations or dosage increases. Results: Of the 40 patients who exhibited CDs in the early phase of pCT, six showed persistent CDs on late-pCT. In the remaining 294 patients without CDs on late-pCT, the absence of a thrombus was confirmed by ICE during CA. In all six patients with CD-positivity on late-pCT, the CDs vanished under the same CT conditions after subsequent anticoagulation therapy, and CA was successfully performed. Furthermore, the presence of residual contrast medium in the LAA on late-pCT suggested a decreased blood velocity in the LAA (≤ 15 cm/s) (sensitivity = 0.900 and specificity = 0.621). Conclusions: Late-pCT is a valuable tool for the assessment of intracardiac thrombi and LAA dysfunction in patients with persistent or long-standing persistent AF before CA.

Introduction: The subcutaneous-ICD (S-ICD) and its electrode were developed to avoid long-term complications of transvenous leads in the vasculature. Methods: We report a case of unexpected, inappropriate S-ICD shocks due to oversensing of high amplitude, non-physiologic, electrical noise artifacts that were not preceded by high impedance alerts or sensing electrogram noise detections. Results: Following explant, high-magnification, X-ray imaging of the S-ICD electrode demonstrated partial fracture of the distal sensing conductor located near a short radius bend in the electrode at the electrode-header interface. Conclusions: Clinicians should be aware of a potential for fatigue failure fracture of the S-ICD electrode. Recommendations for systematic S-ICD follow-up and troubleshooting are discussed.

Introduction Detail 3D mapping have been useful for effective radiofrequency catheter ablation. Rhythmia system can create the atrio-ventricular dual chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of Rhythmia system for catheter ablation of accessory pathways (AP). Methods From July 2015 to August 2020, 111 patients underwent ablation of APs. The dual chamber mappings were created in 50 patients [median age 15 (10-54), 32 male(64.0%)], while 61 patients underwent the radiofrequency (RF) ablations with conventional single chamber 3D mappings. The background characteristics and procedure details were compared between the dual chamber mapping group and conventional single chamber mapping group. Results The number of RF application [1 (1-3) vs 3 (1-6), p=0.0023], RF time [9.2 (2.0-95.7) vs 95.6 (4.1-248.7), p=0.0023], RF energy [248.4 (58.7-3328.2) vs 2867.6 (134.2-7728.4), p=0.0115] were significantly lower in dual chamber group. Fluoroscopy time [19.9 (14.2-26.1) vs 26.5 (17.7-43.4), p=0.0025], and fluoroscopy dose [52.5 (31.3-146.0) vs 119.0 (43.7-213.5), p=0.0249] were also significantly lower than in single chamber mapping group. Conclusion The dual chamber mappings were useful for effective ablation with reducing the radiation exposure.

Introduction: We aimed to investigate whether a modified implantation method facilitating a fully open umbrella can reduce the pericardial effusion/pericardial tamponade (PE/PT) rate after left atrial appendage closure (LAAC) with the LAmbre device compared with the conventional method (CM) in patients with non-valvular atrial fibrillation (NVAF). Methods and results: Patients with NVAF who received either isolated LAAC or combined catheter ablation and LAAC using the LAmbre device at the First Affiliated Hospital of Wenzhou Medical University from January 2018 to December 2019 were enrolled. CM was used for device implantation in the initial 59 patients, while a modified method (MM) was used in the remaining 165 patients. Successful implantation was achieved in 98.3% of patients in the CM group and in 98.8% in the MM group. A higher rate of a fully open umbrella (98.8% vs 69%, P<0.001), less requirement for recapture (46% vs 62.1%, P=0.036), and a lower incidence of delayed PE/PT (1.2% vs 8.6%, P=0.005) were found in the MM group compared with in the CM group. All of the five delayed PT events occurred in patients with combined treatment. An umbrella that was not fully open was the only factor associated with delayed PE/PT events in a multivariable Cox model. Conclusions: LAAC with the LAmbre device using an MM significantly increases the rate of a fully open umbrella and decreases the requirement for recapture and the incidence of delayed PE/PT. This method is more effective in patients with combined treatment.

JCE-21-0127

A document by Riccardo Cappato. Click on the document to view its contents.

Reflections from the Book of the Dead: Weighing the Impact of Epicardial Fat on Atrial Fibrillation Vulnerability T. Jared Bunch MDDepartment of Medicine, School of Medicine, University of Utah, Salt Lake City, UtahAddress for correspondence: T. Jared Bunch, M.D.University of Utah School of Medicine Department of Internal Medicine Division of Cardiovascular Medicine 30 North 1900 East, Room 4A100 Salt Lake City, UT 84132 Phone: 801-213-2387 E-mail: [email protected]

BACKGROUND Although low voltage zones (LVZs) in the left atrium (LA) are seen as arrhythmogenic substrate in some patients with atrial fibrillation (AF), pathophysiologic factors responsible for LVZ formation remain unclear. OBJECTIVE To elucidate the anatomical relation between the LA and ascending aorta responsible for remodeling of the anterior LA wall. METHODS We assessed the relation between existence of LVZs on the anterior LA wall and measurements taken on 3-dimensional computed tomography images obtained from 102 patients who underwent AF ablation. RESULTS Twenty-nine patients (28%) had LVZs >1.0 cm2 on the LA wall at the LA-ascending aorta contact area (LVZ Group); no LVZs were seen in the other 73 patients (No LVZ Group). In the LVZ Group (vs. No LVZ Group), the aorta-LA angle was smaller (21.0±7.7° vs. 24.9±7.1°, P = 0.015), the aorta-left ventricle (LV) angle was greater (131.3±8.8° vs. 126.0±7.9°; P = 0.005), non-coronary cusp (NCC) diameter was greater (20.4±2.2 mm vs. 19.3±2.5 mm; P = 0.036), and the NCC was closer to the anterior LA wall (2.29±0.68 mm vs. 2.76±0.79 mm; P = 0.006). The aorta-LA angle correlated positively with patients’ body mass index (BMI) and negatively with body weight and BMI. CONCLUSION Deviation of the ascending aorta course and distention of the NCC appear to be related to the development of LA anterior wall LVZs at the LA-ascending aorta contact area. Mechanical pressure exerted by extracardiac structures on the LA along with limited thoracic space may contribute to the development of LVZs associated with AF.

Title: Making the Cut for Generator ReplacementsAuthors: Venkatesh Ravi, MD1; Jeremiah Wasserlauf, MD, MS1;1: Section of electrophysiology, Division of Cardiology, Department of Medicine, Rush University Medical Center, Chicago, USACorresponding author:Jeremiah Wasserlauf, MD, MSAssistant Professor of Medicine,Cardiac Electrophysiology, Department of Internal Medicine/Division of Cardiology,Rush University Medical Center.1717 W. Congress Parkway, Suite 345, Chicago, IL 60612Email: [email protected]: NoneDisclosure: Dr. Jeremiah Wasserlauf has received consulting fees from Stryker. No other conflicts of interest to disclose.EditorialCardiac implantable electronic devices (CIED) have become a common treatment modality for cardiac arrhythmia with over 300,000 new implants every year in the United States. A growing number of patients will require device replacement procedures throughout their lifetime.1 In a registry of 1744 patients undergoing CIED replacement procedures, lead damage or dislodgement requiring revision was found to occur in 1% of patients without previously planned addition of leads.2 The resulting lead addition and extraction procedures give rise to added procedural time, risk of complications, prolonged hospitalization, and increased health care costs.2 Polyurethane and copolymer insulation materials are more susceptible to thermal damage when compared to silicone.3,4 Avoidance of lead damage during CIED replacement procedures has been a topic of increasing investigation, with studies evaluating differences between electrosurgical modes, power settings, blade orientation, and equipment manufacturers. Operators have the option to choose between standard electrocautery with non-insulated blades, and cautery with insulated blades (PEAK PlasmaBlade, Medtronic Inc., Minneapolis, MN, or Photonblade, Stryker, Kalamazoo, MI).Electrocautery operates by generating a high current density which results in resistive heating and thereby cuts or coagulates tissue. PlasmaBlade uses a proprietary power output waveform to deliver energy along the exposed edge of a thin, insulated electrode powered by a proprietary electrosurgical generator. Photonblade is an alternative insulated electrocautery blade that is compatible with a standard electrosurgical generator. In a retrospective study by Kypta et al, PlasmaBlade was associated with a lesser risk of lead damage and shorter procedure duration and hospital stay when compared with electrocautery and scissors.3 In an ex vivo animal tissue model using Photonblade, coagulation mode during cautery was associated with more damage than cut, and this effect was greatest when contact occurred using the active edge as opposed to the insulated flat side of the cautery blade, and when the lead insulation consisted of polyurethane or copolymer. Visible lead damage was found to be more common with PlasmaBlade when compared to Photonblade. 4In this edition of the Journal of Cardiovascular Electrophysiology , Ananwattanasuk et al performed a retrospective analysis of traditional electrocautery vs PlasmaBlade on lead parameters and complications following CIED generator replacement procedures.5 The study included 410 consecutive patients (840 leads) who underwent CIED replacement using conventional electrocautery (EC group) and 410 patients (824 leads) who underwent CIED replacement using PlasmaBlade (PK group). The power settings for the PK group were 6 in CUT mode and 8 in COAG mode. In the EC group, power output was set to 40 Watts for both CUT and COAG mode. CUT mode was used for tissue dissection and COAG was only used for hemostasis. The two groups had similar device systems and baseline characteristics. In comparison to the PK group, the EC group had a slightly lower proportion of silicone leads (78% vs 83%, p < 0.01) and a slightly higher proportion of polyurethane leads (19% vs 13%, p < 0.01). The study found no statistically significant difference in lead damage requiring lead revision between the EC group and PK group (0.6% vs 0.4%, p=0.5). There was no difference in procedural complications between the two groups (2.2% vs 1.2%, p = 0.28). There was no difference in lead sensing. There was a higher number of patients with a decrease in lead impedance in the PK group compared to the EC group (61.5% vs 52.1%, p < 0.01), and perhaps unexpectedly, more patients with an increase in lead impedance in the EC group compared to the PK group (46.8% vs 34.2%, p<0.01).On average, the change in pacing impedance changed less than 10% in both groups. A majority of leads in both groups were comprised of silicone which may have been a primary contributor to the low rate of lead damage observed. These findings contrast with the older retrospective study that found a lower risk of lead damage with PlasmaBlade compared to a historical control group where titanium scissors were used with conventional electrocautery for hemostasis. The difference observed in the prior study between groups, and the overall higher rates of lead damage in that study may have been related to the use of scissors or perhaps a greater proportion of leads with non-silicone insulation (lead insulation material was not reported). The present study by Ananwattanasuk et al contributes to the literature with a larger cohort of patients and contemporary operative technique.It is never too late to scrutinize the benefit of tools that have added costs as our procedural techniques evolve. The authors should be commended for rigorously collecting not only clinical outcomes but also electrical device parameters to assess for subclinical lead damage. Although generator replacements are short and less complex when compared to other EP procedures, the total cost of generator replacement procedures is estimated at several billion dollars yearly in the US alone.6 Leadless pacemakers and the evolution of modular systems are attractive and may solve some problems related to lead damage during generator replacements, or perhaps one day eliminate generator replacements altogether. However, with the current number of CIEDs in operation and the aging population, a growing number of patients will continue to require generator replacement procedures over the next several decades. The overall safety of generator replacement procedures has improved though advances such as avoidance of routine capsulectomy, antibiotic-impregnated pouches for appropriate candidates, and prolonged replacement intervals due to improved battery longevity. Through an unremitting focus on safety and cost-effectiveness, we will stay on the cutting edge of straightforward and complex procedures in the EP lab.References1. Greenspon AJ, Patel JD, Lau E, et al. 16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008. J Am Coll Cardiol. 2011;58:1001-1006.2. Poole JE, Gleva MJ, Mela T, et al. Complication rates associated with pacemaker or implantable cardioverter-defibrillator generator replacements and upgrade procedures: results from the REPLACE registry.Circulation. 2010;122:1553-1561.3. Kypta A, Blessberger H, Saleh K, et al. An electrical plasma surgery tool for device replacement–retrospective evaluation of complications and economic evaluation of costs and resource use. Pacing Clin Electrophysiol. 2015;38:28-34.4. Wasserlauf J, Esheim T, Jarett NM, et al. Avoiding damage to transvenous leads-A comparison of electrocautery techniques and two insulated electrocautery blades. Pacing Clin Electrophysiol.2018;41:1593-1599.5. Ananwattanasuk T, Jame S, Bogun F, et al. Journal of Cardiovascular Electrophysiology. 2021.6. Hauser RG. The growing mismatch between patient longevity and the service life of implantable cardioverter-defibrillators. J Am Coll Cardiol. 2005;45:2022-2025.

Abstract: Conventional stylet-driven leads with extendable helix can be implanted successfully for Left Bundle Branch Area Pacing (LBBAP) with a low acute complication rate. However, removal and repositioning techniques of these leads haven’t been yet described. We report 2 cases in which lead repositioning after a first unsuccessful attempt to LBBAP was associated with fracture of the helix rotating mechanism and failure to fully extract the pacing lead.

One Electrogram-Tracing Tells All: what is the mechanism of this supraventricular tachycardia?Moyuru Hirata, MD*, Yuji Wakamatsu, MD*, Koichi Nagashima, MD, PhD*, Sayaka Kurokawa, MD, PhD*, Naoto Otsuka, MD*, Seina Yagyu, MD*, Shu Hirata, MD*, Toshiko Nakai, MD, PhD*, Yasuo Okumura, MD, PhD*.*Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, JapanCorrespondenceKoichi Nagashima, MD, PhD; Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Ohyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, JapanTel: +81-3-3972-8111Fax: +81-3-3972-1098E-mail: [email protected] word count: 1036 words, 2 FiguresFunding: (None)Disclosures: (None)The work described was supported by departmental resources only.Keywords: narrow QRS tachycardia, atrioventricular nodal reentrant tachycardia, accessary pathway.

Abstract Background: Subcutaneous implantable cardioverter defibrillators (S-ICDs) avoid complications secondary to transvenous leads, but inappropriate shocks (ISs) are frequent. Furthermore, IS data from patients with Brugada syndrome (BrS) with an S-ICD are scarce. Objective: We aimed to establish the incidence, mechanisms, and predictors of S-ICD in this population. Methods: We analyzed the clinical and electrocardiographic characteristics, automated screening test data, device programming, and IS occurrence in adult patients with BrS with an S-ICD. Results: Thirty-nine patients were enrolled (69% male, mean age at diagnosis 46±13 years, mean age at implantation 48±13 years). During a mean follow-up of 26±21 months, 18% patients experienced IS. Patients with IS were younger at the time of diagnosis (36±8 versus 48±13 years, p=0.018) and S-ICD implantation (38±9 versus 50±23 years, p=0.019) and presented with spontaneous type 1 Brugada ECG pattern more frequently at diagnosis or during follow-up (71% versus 25%, p=0.018). During automated screening tests, patients with IS showed lower QRS voltage in the primary vector in the supine position (0.58±0.26 versus 1.10±0.35 mV, p=0.011) and lower defibrillator automated screening score (DASS) in the primary vector in the supine (123±165 versus 554±390 mV, p=0.005) and standing (162±179 versus 486±388 mV, p=0.038) positions. Age at diagnosis was the only independent predictor of IS (hazard ratio=0.873, 95% confidence interval: 0.767-0.992, p=0.037). Conclusion: IS was a frequent complication in patients with BrS with an S-ICD. Younger age was independently associated with IS. A more thorough screening process might help prevent IS in this population.

A document by Gregory Feld. Click on the document to view its contents.

Atrial fibrillation (AF) is the most common atrial arrhythmia but it is not a benign disease. AF is an important risk factor for thromboembolic events, causing significant morbidity and mortality. The left atrial appendage (LAA) plays an important role in thrombus formation but the ideal way to manage the LAA is still debated. The increasing popularity of surgical epicardial ablation and hybrid endo-epicardial ablation approaches, especially in patients with a more advanced diseased substrate, has raised the interest in epicardial LAA management. Minimally invasive treatment options for the LAA offer a unique opportunity to close the LAA with a clip device. This review highlights morphologic, electrophysiologic and surgical aspects of the left atrial appendage with regard to atrial fibrillation surgery, and aims to illustrate the different surgical management strategies.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF) However AF recurrence after a single ablation procedure is common and often attributed to ineffective lesion delivery during PVI. In this issue of the Journal of Cardiovascular Electrophysiology, Chen et al reported their experience with 122 patients who underwent an ablation index-high power (AI-HP) strategy RF ablation for AF using 50W power, targeting AI values of 550 on the anterior left atrium (LA), 400 on the posterior wall and inter-lesion distance (ILD) 6mm. They achieved 1st pass PVI in 96.7% of cases, mean RF time was 11.5min and total procedure time was only 55.8min. All patients had 72h-Holter monitor and trans-telephonic follow up. They reported 89.4% arrhythmia free survival among patients with paroxysmal AF and 80.4% among patients with persistent AF at 15-month follow up. Sixty (49%) patients had luminal esophageal temperature (LET) >390C out of which 3 (2.5%) had asymptomatic endoscopic esophageal erosions/erythema. Four (3%) patients had clinically apparent steam pops during ablation with no adverse clinical sequela. While AI-HP guided RF ablation may be an attractive strategy for PVI that likely reduces procedure times and probably has comparable efficacy to conventional ablation settings, its safety requires further evaluation. Feedback from the ablated tissue may need to be incorporated into optimized ablation energy parameters to further improve outcomes.