Laser- based PVI has been around for many years and this modality of ablation is to provide a continuous circular overlapping lesions around the PVs' ostia. In order to ensure the continuity of the lesion, a camera is embedded in the system as to guide the placement of sequential applications with the target to make an adequate overlapping of two contiguous lesions as to reduce the likelihood of gaps. The first version of the system required the operator to manually rotate the catheter as to create a continuous arc of lesion around the PV's ostium. This approach is time-consuming, with a substantial overall time for each PV. The evolvement of the technique has been recently offered, with a novel semi-automated VGLA as to improve ablation efficiency by using a motorized system which moves the laser arc continuously in order to reduce the application time and, hopefully, minimize the creation of gaps.
Can We Trust the Force?Frank Pelosi, Jr., MD, FHRS, FACCAssociate Professor of MedicineDepartment of Internal MedicineCardiac Electrophysiology SectionUniversity of Michigan Medical SchoolAnn Arbor, MichiganCorresponding Author:Frank Pelosi, Jr, MD, FACC, FHRS1500 East Medical Center DriveAnn Arbor MI. [email protected] words: contact force, radiofrequency ablationWord count: 1165 excluding referencesInvited manuscript for JCE-22-0822.R2
Is Esophageal Temperature Management Needed During Cryoballoon Ablation for Atrial Fibrillation?Bachir Lakkis MD, Marwan M. Refaat, MDDivision of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, LebanonRunning Title: Is Esophageal Temperature Management Needed During CBA for AF?Words: (excluding the title page and references): 462Keywords: Catheter Ablation, Atrial Fibrillation, Heart Diseases, Cardiovascular Diseases, Cardiac ArrhythmiasFunding: NoneDisclosures: NoneCorresponding Author:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FAAMATenured Professor of MedicineDirector, Cardiovascular Fellowship ProgramDepartment of Internal Medicine, Cardiovascular Medicine/Cardiac ElectrophysiologyDepartment of Biochemistry and Molecular GeneticsAmerican University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonUS Address: 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USAOffice: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)Atrial fibrillation (AF) is one of the most frequently occurring arrhythmias globally. Risk factors such as aging, hypertension, cardiac and pulmonary diseases, alcohol consumption, smoking, obesity and obstructive sleep apnea play an important role in the development of AF.(1-2) AF is a leading cause of ischemic stroke worldwide and is associated with increased mortality. (3) AF management depends on four pillars: risk factor management, anticoagulation depending on the CHA₂DS₂-VASc score, rate control and rhythm control. (4) The application of thermal energy in ablation, such as in cryoablation, can cause rare complications such as an esophageal injury, esophageal perforation and atrial-esophageal fistula. (5,6). Numerous technologies have been developed to avoid this problem and include esophageal temperature surveillance, using reduced temperatures, real time visualization of the esophagus in addition to making use of an esophageal cooling device. (7-9)In the current issue of the Journal of Cardiovascular Electrophysiology, Sink et al. have conducted a single-center pilot study to assess the utilization of an esophageal warming device to avoid the development of esophageal thermal injury (ETI) while utilizing cryoballoon ablation (CBA). Alternative studies have shown that using a cooling device has been beneficial in reducing the risk of ETI formation for patients undergoing RFA. (10,11) Thus, the authors have enrolled 42 patients undergoing CBA with AF refractory to medical therapy and have randomized them into 2 groups. In the first group, 23 patients undergoing CBA used an esophageal warming device such as esophageal heat-exchange tube (WRM) while the other 19 patients undergoing CBA used traditional luminal esophageal temperature (LET) to monitor the esophageal temperatures. The authors have conducted upper endoscopy monitoring of the esophagus the next day and subsequently, classified ETI into 4 grades. They have observed in the WRM group a paradoxical increase in ETI in comparison to the other group which used LET. Moreover, the authors have perceived a direct link between ETI formation, total freeze time and colder temperature usage. However, this study has several limitations, including the small population size. Furthermore, the study results are based on a single device employment which is EnsoETM® device (Attune Medical, Chicago, IL). Therefore, the effects of using other warming devices are not known.Overall, the authors should be praised on their efforts for conducting the first pilot study to evaluate the effects of using an esophageal warming device for patients undergoing CBA and for providing cardinal insight into the safety of utilizing such a device. In addition, the results of this study have tremendous clinical implications. Certainly, patients undergoing CBA might benefit from using higher temperature (above -51 °) and lower freezing time (<300 seconds) to avert developing ETI. Further studies incorporating more patients should be conducted to elucidate whether using an esophageal warming device is associated with a beneficial or a detrimental effect.References1. Kornej J, Börschel CS, Benjamin EJ, Schnabel RB. Epidemiology of Atrial Fibrillation in the 21st Century. Circulation Research. 2020;127(1):4-20. doi: doi:10.1161/CIRCRESAHA.120.316340.2. Maan A, Mansour M, Anter E, Patel VV, Cheng A, Refaat MM, Ruskin JN, Heist EK. Obstructive Sleep Apnea and Atrial Fibrillation: Pathophysiology and Implications for Treatment. Crit Pathw Cardiol Jun 2015; 14 (2): 81-5.3. Migdady I, Russman A, Buletko AB. Atrial Fibrillation and Ischemic Stroke: A Clinical Review. Semin Neurol. 2021;41(04):348-64.4. Chung MK, Refaat M, Shen WK, Kutyifa V, Cha YM, Di Biase L, Baranchuk A, Lampert R, Natale A, Fisher J, Lakkireddy DR. Atrial Fibrillation: JACC Council Perspectives. J Am Coll Cardiol. Apr 2020; 75 (14): 1689-1713.5. Kapur S, Barbhaiya C, Deneke T, Michaud GF. Esophageal Injury and Atrioesophageal Fistula Caused by Ablation for Atrial Fibrillation. Circulation. 2017;136(13):1247-55. doi: doi:10.1161/CIRCULATIONAHA.117.025827.6. D’Avila A, Ptaszek LM, Yu PB, Walker JD, Wright C, Noseworthy PA, Myers A, Refaat M, Ruskin JN: Left Atrial-Esophageal Fistula After Pulmonary Vein Isolation. Circulation May 2007; 115(17): e432-3.7. Dagres N, Anastasiou-Nana M. Prevention of atrial-esophageal fistula after catheter ablation of atrial fibrillation. Curr Opin Cardiol. 2011 Jan;26(1):1-5. doi: 10.1097/HCO.0b013e328341387d. PMID: 21099683.8. Leung LW, Gallagher MM, Santangeli P, Tschabrunn C, Guerra JM, Campos B, Hayat J, Atem F, Mickelsen S, Kulstad E. Esophageal cooling for protection during left atrial ablation: a systematic review and meta-analysis. J Interv Card Electrophysiol. 2020 Nov;59(2):347-355. doi: 10.1007/s10840-019-00661-5. Epub 2019 Nov 22. PMID: 31758504; PMCID: PMC7591442.9. Arruda, M.S., Armaganijian, L., Base, L.D., Rashidi, R. and Natale, A. (2009), Feasibility and Safety of Using an Esophageal Protective System to Eliminate Esophageal Thermal Injury: Implications on Atrial-Esophageal Fistula Following AF Ablation. Journal of Cardiovascular Electrophysiology, 20: 1272-1278. https://doi.org/10.1111/j.1540-8167.2009.01536.x10. Leung LW, Gallagher MM, Santangeli P, Tschabrunn C, Guerra JM, Campos B, Hayat J, Atem F, Mickelsen S, Kulstad E. Esophageal cooling for protection during left atrial ablation: a systematic review and meta-analysis. J Interv Card Electrophysiol. 2020 Nov;59(2):347-355. doi: 10.1007/s10840-019-00661-5. Epub 2019 Nov 22. PMID: 31758504; PMCID: PMC7591442.11. Tschabrunn CM, Attalla S, Salas J, Frankel DS, Hyman MC, Simon E, Sharkoski T, Callans DJ, Supple GE, Nazarian S, Lin D, Schaller RD, Dixit S, Marchlinski FE, Santangeli P. Active esophageal cooling for the prevention of thermal injury during atrial fibrillation ablation: a randomized controlled pilot study. J Interv Card Electrophysiol. 2022 Jan;63(1):197-205. doi: 10.1007/s10840-021-00960-w. Epub 2021 Feb 23. PMID: 33620619.
Catheter ablation has become the standard of care for the management of antiarrhythmic drug-refractory atrial fibrillation (AF) in many patients. The cornerstone of AF ablation includes pulmonary vein isolation (PVI) and energy delivery can sometimes extend beyond the atrial myocardium and result in collateral damage to adjacent structures, include the esophagus. While atrial esophageal fistula (AEF) is a generally a rare complication, there have been continued efforts aimed to reduce esophageal thermal injury during AF ablation. While emerging energy sources such as irreversible electroporation show exciting promise for selective, non-thermal targeting of myocardial tissue, safety and efficacy clinical trial evaluation is on-going. Therefore, strategies that can prevent esophageal thermal injury without adversely impacting lesion formation using conventional ablation technologies are still needed.
Introduction Post ablation of the accessory pathway (AP), the patient is observed in the catheterization laboratory for a variable period for resumption of pathway conduction. Aim of the study was to determine whether the administration of intravenous adenosine at 10 minutes after ablation of accessory pathway (AP) would have the same diagnostic accuracy as waiting for 30 minutes in predicting the resumption of AP conduction. Methods: This was a prospective interventional study conducted in two centers. Post ablation of the AP, intravenous adenosine was administered at 10 minutes to look for dormant pathway conduction. The response was recorded as positive (presence of pathway conduction), negative (absence), or indeterminate (not able to demonstrate AV and VA block and inability to ascertain AP conduction). Results: The study included 110 procedures performed in 109 patients. Adenosine administration at 10 minutes showed positive result in 3 cases (2.7%), negative result in 99 cases (90%) and indeterminate result in 8 cases (7.3%). Reconnection of accessory pathway at 30 minutes post ablation was seen in 8 cases (7.3%). Of these 8 cases, 10minutes adenosine administration showed positive test in 3 patients and negative test in 5 patients. Adenosine test at 10 minutes has a sensitivity, specificity, positive predictive value, and negative predictive value of 37.5%, 100%, 100% and 94.9% in identifying the recurrence of accessory pathway conduction at 30 minutes, respectively. Conclusion: Absence of pathway conduction on administration of adenosine 10 minutes post ablation does not help predict the absence of resumption of conduction thereafter.
A 72-year-old female with frequent palpitation was referred for radiofrequency ablation. The baseline 12-lead electrocardiogram and echocardiography results were normal. At baseline, the atrio-His (AH) and His-ventricular (HV) intervals were 90 and 41 ms, respectively. Dual atrioventricular (AV) nodal physiology or ventriculoatrial (VA) conduction was not observed during programmed atrial and ventricular stimulation. After isoproterenol infusion, VA conduction became decremental and concentric, with the earliest atrial activation seen at the His bundle (HB) region during ventricular pacing. A supraventricular tachycardia with a long RP interval (SVT) was induced by atrial extra-stimulation, without any jump-up in the AH interval. During the SVT, the AH and HV intervals were 180 and 180 ms, respectively, and the earliest atrial activation was recorded in the HB region (Figure 1A). During the SVT, transient 2:1AV conduction was observed (Figure 1B). Ventricular overdrive pacing at a pacing cycle length (CL) of 360 ms was performed during the SVT with a CL of 390ms (Figures 2A and B). Based on these observations, what is the mechanism of this tachycardia?
Introduction: Contact force-sensing catheters are widely used for ablation of cardiac arrhythmias. They allow quantification of catheter-to-tissue contact, which is an important determinant for lesion formation and may reduce the risk of complications. The accuracy of these sensors may vary across the measurement range, catheter-to-tissue angle, and amongst manufacturers and we aim to compare the accuracy and reproducibility of four different force sensing ablation catheters. Methods: A measurement setup containing a heated saline water bath with an integrated force measurement unit was constructed and validated. Subsequently, we investigated four different catheter models, each equipped with a unique measurement technology: Tacticath Quartz (Abbott), AcQBlate Force (Biotronik/Acutus), Stablepoint (Boston Scientific), and Smarttouch SF (Biosense Webster). For each model, the accuracy of three different catheters was measured within the range of 0-60 grams and at contact angles of 0°, 30°, 45°, 60°, and 90°. Results: In total, 6685 measurements were performed using 4x3 catheters (median of 568, IQR 511-606 measurements per catheter). Over the entire measurement-range, the force measured by the catheters deviated from the real force by the following absolute mean values: Tacticath 1.29g ±0.99g, AcQBlate Force 2.87g ±2.37g, Stablepoint 1.38g ±1.29g, and Smarttouch 2.26g ±2.70g. For some models, significant under- and overestimation of >10g were observed at higher forces. Mean absolute errors of all models across the range of 10-40g were <3g. Conclusion: Contact measured by force-sensing catheters is accurate with 1-3g deviation within the range of 10g to 40g. Significant errors can occur at higher forces with potential clinical consequences.
Mitigating Esophageal Injury after Atrial Fibrillation Ablation Guided by Ablation Index; CLOSEr to goalJason S. Chinitz, MD1 and Eli Q. Harris, MD21.South Shore University HospitalNorthwell HealthBay Shore, NY2. Nassau University Medical CenterEast Meadow, NYFinancial support : none.Disclosures : Dr. Chinitz serves on the scientific advisory board for Biosense Webster and has received consulting fees
Abstract: After several years with sobering experiences with electrogram-based AF ablation approaches, Seitz et al present with the VX1 software a reliable tool to map and ablate spatio-temporal dispersion. The presented multicenter study in persistent AF patients was conducted in 1 expert and 7 satellite centers with a total of 17 operators, using the VX1 software to detect and subsequently ablate spatiotemporal dispersion. While the AF termination rate (88%) and the freedom from AF in 12 months FU (82%) was very encouraging, the VX1 software, using AI enhanced electrogram adjudication, achieved very similar results in all centers, regardless of the centre’s or the operator’s experience. Thus, the biggest criticism of electrogram-based ablation strategies, i.e. the lack of reproducibility in “non-expert” centers, seems to be finally addressed.
A 30-year-old man with a structurally normal heart was referred to us with a 2-year history of recurrent episodes of rapid paroxysmal palpitations. A few episodes required hospitalization and were terminated with intravenous diltiazem. During electrophysiology (EP) study done twice before in other hospitals, the patient was diagnosed as typical atrioventricular nodal reentrant tachycardia (AVNRT) and underwent radiofrequency ablation of the slow pathway. However, the episodes recurred. Because of the patient’s persistent symptoms, an EP study was performed again. Tachycardia was easily induced using atrial extrastimuli, ventricular extrastimuli and with rapid atrial pacing.
CT-imaging vs. high-density mapping in ischemic cardiomyopathy VT ablation: in whom do we trust?Thomas Fink, MD1, Vanessa Sciacca, MD1, Philipp Sommer, MD11Clinic for Electrophysiology, Herz- und Diabeteszentrum NRW, Ruhr-Universität Bochum, Bad Oeynhausen, Germany.Disclosures: PS is advisory board member of Abbott, Biosense Webster, Boston Scientific and Medtronic.Funding: (None)
Employing New Criteria for Confirmation of Conduction Pacing – Achieving True Left Bundle Branch Pacing May Be Harder Than Meets the EyeJoshua Sink, MD1, Nishant Verma, MD, MPH2Northwestern University, Feinberg School of Medicine, Department of Internal MedicineNorthwestern University, Feinberg School of Medicine, Division of CardiologyCorresponding Author:Nishant Verma, MD, MPH251 East Huron Street, Feinberg 8-503Chicago, IL [email protected]: NoneDisclosures: Dr. Sink has nothing to disclose. Dr. Verma receives speaker honoraria from Medtronic, Biotronik and Baylis Medical and consulting fees from Boston Scientific, Biosense Webster, AltaThera Pharmaceuticals and Knowledge 2 Practice.Word Count: 1200In recent years, conduction system pacing (CSP) has garnered significant attention from the electrophysiology (EP) community. This movement has been driven by the hypothesis that using the natural conduction system activation is desirable and clinically beneficial in patients with advanced conduction disease and ventricular desynchrony. Permanent His-bundle pacing (PHBP) is generally seen as the purest form of conduction system activation. (Figure 1) PHBP was first described over 20 years ago but the idea has attracted substantial investigative effort in recent years. When successfully achieved, His bundle pacing has been associated with reduction in mortality, reduction in heart failure (HF) admissions, and improvement in left ventricular (LV) function compared to right ventricular (RV) pacing.1 Despite this, consistent achievability in real-world practice remains limited due to a variety of factors including narrow anatomic targetability, lead stability, high pacing thresholds, low ventricular sensing, and inability to correct the QRS in bundle branch block.2Thus, while waiting for the next iteration of improved delivery techniques, pacing leads and programming algorithms,, alternative methods of conductive system pacing have emerged, with the potential to surmount the challenges described.Left bundle branch pacing (LBBP) has recently emerged as an alternative method of CSP. The technique was first described by Huang et al. in 2017 and has seen a momentous rise in interest since.3 In 2019, Huang et al. produced a user manual for a successful LBBP procedure, and in it they attempted to develop the first iteration of criteria for the confirmation of LBBP.4 Utilizing these criteria, or close variations of them, a number of studies were published afterwards that demonstrated preliminary safety, feasibility, and efficacy of LBBP.5,6,7 LBBP became an attractive alternative to His bundle pacing because of the lower thresholds, improved lead stability, and higher procedural success rates. When compared against RV pacing in patients requiring a high burden of pacing, LBBP has demonstrated reduced mortality, HF admissions, and need for upgrade to a BiV device.8 In a small, non-randomized patient sample, LBBP showed greater improvement in LV ejection fraction (EF) compared to BiV pacing.9 Most notably, perhaps, is the astonishing rate of lead placement success, with achievement rates reported as high as 98% in sizable studies.6Differences between the two forms of CSP were apparent from the beginning, including in the appropriate QRS morphology after a successful case. Unlike PHBP, LBBP did not reproduce the native QRS and the QRS duration was often greater than at baseline (Figure 2). The arena of LBBP underwent a notable shift in the Fall of 2021 when Wu et al. proposed new criteria to prove LBBP.10 In this study, they presented an exquisite display of fundamental electrophysiologic principles by using mapping catheters positioned on the His and LV septum during LBB lead placement. Through this painstaking work, they clarified the difference between true LBBP and left bundle branch area pacing (LBBAP), which can incorporate both LBBP and left ventricular septal pacing (LVSP). In their proposed framework, without the presence of a His or LV septum mapping catheter, output dependent QRS transition from non-selective (NS-LBBP) to selective-LBBP (S-LBBP) or LVSP is necessary to prove LBBP and had a sensitivity and specificity of 100%.The present study by Shimeno et al, published in the current issue of the Journal of Cardiovascular Electrophysiology , is the first known effort to document achievement rates of LBBP by utilizing the modified criteria proposed by Wu et al.11 The primary finding of the study is that achieving true LBBP with an acceptable pacing threshold is likely harder than previously realized. As expected, there was improvement after a learning curve, but even in the last third of patients enrolled, the achievement rate of LBBP was only 50%. This is dramatically lower than previously reported achievement rates using the original Huang et al. criteria, and it suggests that not all patients in the previously described studies were actually achieving true LBBP. An unknown subset of patients in these studies was likely only achieving LVSP. This is probably due to a prior reliance on indicators such as a paced right bundle branch block (RBBB) pattern, identification of an intrinsic LBB potential, and/or use of V6 R-wave peak time cutoffs (RWPT) without clear output-dependent QRS transition. It is also worth noting that a variety of RWPT cutoffs have been used seemingly arbitrarily as ‘evidence of LBBP’. This presents a major dilemma and highlights the need for a clear set of LBBP criteria to be defined by the collective EP community. Despite these caveats, many of these previous studies did not fully confirm LBBP in their patients, yet the outcomes from these studies were still clinically promising. This raises the obvious question, does obtaining true LBBP matter? Future studies will need to explore the differences in clinical outcomes between true LBBP and LVSP.Secondarily, Shimeno et al. have provided a useful tool in identifying that LBB potential to QRS-onset ≥ 22ms had a specificity of 98% in predicting LBBP.11 This target measure can help future operators ensure proximal enough engagement of the LBB conduction system. Additionally, the group took a close look at validating a RWPT cutoff time for the prediction of LBBP. Unfortunately, a RWPT cutoff of 68 ms (in non-LBBB patients), determined by the ROC curve, was not highly predictive. This runs contrary to previous reports by Wu et al. and Jastrzebski et al., which reported higher predictive value of RWPT cutoffs10,12 Looking at the data surrounding RWPT cutoffs as a collective, it likely should not be used as a primary metric for confirming LBBP due to imperfect sensitivity and specificity, but it may be an alternative if output dependent QRS transition or change in RWPT of ≥10 ms is not observed. Additionally, in the event that capture thresholds are similar between the LBB and the adjacent myocardium, programmed stimulation is an option to try to reveal a QRS transition by exploiting differences in refractory periods.This study also highlighted one of the unique complications of LBBP by demonstrating a high rate of septal perforation. Paradoxically, more perforations were seen with increased experience, likely highlighting that deeper penetration into the septum is often sought as operators become more familiar with the procedure. The long-term clinical implications of this complication are, thus far, unknown.Looking forward, clear guidelines for confirmation of LBBP need to be defined. This is necessary to ensure quality before undertaking multi-center randomized controlled trials to assess LBBP in comparison to current pacing methods. To date, Wu et al. seem to have provided the best framework to achieve this.10 That said, there are concerns given that this has only been validated in 30 patients (and only 9 with LBBB). In an ideal world, these criteria would be validated in a larger population, though the work to accomplish this would be meticulous given the current gold standard of using an LV septal mapping catheter to prove conduction system capture. Shimeno et al. should be congratulated for their effort in putting this framework to practice. In their work, they have demonstrated that achieving true LBBP as defined by Wu et al. may be harder than meets the eye, and this is very important in assessing the practicality of using LBBP as a widespread alternative to other pacing methods.References:Abdelrahman M, Subzposh FA, Beer D, et al. Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing. J Am Coll Cardiol . 2018;71(20):2319-2330. doi:10.1016/j.jacc.2018.02.048Zanon F, Abdelrahman M, Marcantoni L, et al. Long term performance and safety of His bundle pacing: A multicenter experience. J Cardiovasc Electrophysiol . 2019;30(9):1594-1601. doi:10.1111/jce.14063Huang W, Su L, Wu S, et al. A Novel Pacing Strategy With Low and Stable Output: Pacing the Left Bundle Branch Immediately Beyond the Conduction Block. Can J Cardiol . 2017;33(12):1736.e1-1736.e3. doi:10.1016/j.cjca.2017.09.013Huang W, Chen X, Su L, Wu S, Xia X, Vijayaraman P. A beginner’s guide to permanent left bundle branch pacing. Heart Rhythm . 2019;16(12):1791-1796. doi:10.1016/j.hrthm.2019.06.016Padala SK, Master VM, Terricabras M, et al. Initial Experience, Safety, and Feasibility of Left Bundle Branch Area Pacing: A Multicenter Prospective Study. JACC Clin Electrophysiol . 2020;6(14):1773-1782. doi:10.1016/j.jacep.2020.07.004Su L, Wang S, Wu S, et al. Long-Term Safety and Feasibility of Left Bundle Branch Pacing in a Large Single-Center Study. Circ Arrhythm Electrophysiol . 2021;14(2):e009261. doi:10.1161/CIRCEP.120.009261Huang W, Wu S, Vijayaraman P, et al. Cardiac Resynchronization Therapy in Patients With Nonischemic Cardiomyopathy Using Left Bundle Branch Pacing. JACC Clin Electrophysiol . 2020;6(7):849-858. doi:10.1016/j.jacep.2020.04.011Sharma PS, Patel NR, Ravi V, et al. Clinical outcomes of left bundle branch area pacing compared to right ventricular pacing: Results from the Geisinger-Rush Conduction System Pacing Registry. Heart Rhythm . 2022;19(1):3-11. doi:10.1016/j.hrthm.2021.08.033Wu S, Su L, Vijayaraman P, et al. Left Bundle Branch Pacing for Cardiac Resynchronization Therapy: Nonrandomized On-Treatment Comparison With His Bundle Pacing and Biventricular Pacing. Can J Cardiol . 2021;37(2):319-328. doi:10.1016/j.cjca.2020.04.037Wu S, Chen X, Wang S, et al. Evaluation of the Criteria to Distinguish Left Bundle Branch Pacing From Left Ventricular Septal Pacing. JACC Clin Electrophysiol . 2021;7(9):1166-1177. doi:10.1016/j.jacep.2021.02.018Shimeno K, Tamura S, Hayashi Y, et al. Achievement Rate and Learning Curve of Left Bundle Branch Capture in Left Bundle Branch Area Pacing Procedure Performed to Demonstrate Output-Dependent QRS Transition.J Cardiovasc Electrophysiol . 2022Jastrzębski M, Kiełbasa G, Curila K, et al. Physiology-based electrocardiographic criteria for left bundle branch capture. Heart Rhythm . 2021;18(6):935-943. doi:10.1016/j.hrthm.2021.02.021Figure LegendsFigure 1: Permanent His Bundle PacingPanel A: A 12-lead electrocardiogram (EKG) shows baseline conduction in a patient with exertional intolerance. The PR interval is markedly prolonged and, with exercise, this patient developed AV block. A permanent His-bundle pacemaker was implantedPanel B: An EKG demonstrating permanent His-bundle pacing in the same patient as panel A. Selective His-bundle capture results in reproduction of the intrinsic QRS complex.Figure 2: Non-Selective Left Bundle Branch PacingA 12-Lead electrocardiogram showing non-selective left bundle branch pacing. The paced QRS morphology is not a direct match for native conduction and the QRS duration is longer than at baseline. However, conduction system capture was confirmed with an output dependent QRS morphology change.FiguresFigure 1: Permanent His-Bundle Pacing
Title: Percutaneous Lead Extraction in Patients with Large Vegetations: Limiting our Aspirations.Robert D. Schaller, DO11The Section of Cardiac Electrophysiology, Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PennsylvaniaFunding: This work was supported in part by the Mark Marchlinski EP Research & Education FundKey words: Lead extraction, vegetation, pulmonary embolism, thrombus, aspirationDisclosures: NoneWord count: 1547Transvenous lead extraction (TLE) in the 1960’s involved orthopedic-style pulley systems that joined the exposed portion of the lead to progressively heavier weights hanging from the bed. Sustained tension on the lead was maintained until the patient experienced discomfort, ventricular arrhythmias, or noticeable resistance developed, and was maintained for minutes to days. The location of the lead within the chest was monitored with daily chest radiographs and the ensuingbang of the weight hitting the floor of the intensive care unit signified case conclusion; at which point the patient was assessed. Complications were erratic and included lead laceration and possible migration, injury to the tricuspid valve (TV), myocardial avulsion, tamponade, and death.1 Due to the immature nature of the procedure at that time, it was relegated to infectious indications including lead-related endocarditis, at that time referred to as “catheter fever”.Contemporary TLE has evolved into a highly refined practice with a multitude of tools and predictable results, and procedural indications that now span infection, venous occlusion, management of redundant leads, and access to magnetic resonance imaging.2Procedural imaging with computed tomography (CT) and real-time ultrasound-based tools have similarly changed the TLE experience with identification of adhesions, thrombi, vegetations, and complications.3 Large lead-related masses have historically caused angst due to the possibility of being sheared off by the extraction sheath and embolizing to the lung, and still represent a relative contraindication to percutaneous TLE.2In this issue of the Journal of Cardiovascular Electrophysiology , Giacopelli, et al.4 present the outcomes of 25 consecutive patients (mean age 64 years, 68% male) including 5 with pacemakers, 10 with implantable cardioverter-defibrillators, and 10 with cardiac resynchronization therapy devices, who underwent TLE with vegetations ≥10 mm on transesophageal echocardiography (TEE). Contrast-enhanced CT was performed before and after TLE with 18 (72%) patients showing subclinical pulmonary embolism (PE). Vegetation size (median of 17.5 mm and maximum of 30 mm) did not differ in those with and without PE (20.0 mm vs. 14.0 mm, p=0.116). Complete TLE success was achieved in all patients with 76% requiring advanced tools and 2 needing femoral snaring, and there were no significant procedural complications. In the group with pre-TLE PE, a post-TLE scan confirmed the presence of PE in only 14/18 (78%) and there were no patients with new PE formation. During a median follow-up period of 19.4 months, no re-infection of the new implanted systems was reported and there were 5 deaths (20%); with no differences between the groups. The authors concluded that subclinical PE was common in this clinical scenario but did not influence the complexity or safety of the procedure.Several aspects of this paper warrant comment. No data are reported on the size or location of the PEs nor the time between the first and second CT. It is possible that small PEs would not be identified on subsequent studies days after antibiotics had already been started. Patients also received acute and chronic anticoagulation if PE was identified, which in the setting of vegetations, is generally not indicated and could potentially lead to bleeding. The authors did not provide information regarding infectious pathogens or the timing of culture clearance, which could influence treatment. Additionally, it is unclear which patients received new CIED systems including the type and timing of reimplantation, which might influence subsequent infectious risk. A vascular occlusion balloon was not used in any patients in this report. While this tool is associated with a reduced risk of death in the setting of a superior vena cava laceration when used properly, it has also been shown to be thrombogenic during long dwell times,5 and use could impact post-operative CTs in future studies. Despite utilizing transthoracic echocardiography during TLE, neither TEE nor intracardiac echocardiography were used intraoperatively and thus no information regarding the precise location of the vegetations within the heart is known. Importantly, no information regarding the characteristics of the vegetations other than size was reported.Not all lead-related masses are created equal with two distinct sub-types previously described.6 The first is composed of thickened endocardium and fibrous tissue covering the leads and ultimately forming into connective tissue. These masses, commonly found on leads behind the TV, are caused by a vortical flow pattern leading to low shear stress on the lead surface and provoking neointimal hyperplasia,7 and range from small fibrous strands to large, smooth organized thrombus (Figure, left column). Despite their sterile nature, TLE in the setting of a large, mature thrombus could result in embolization and obstruction of the pulmonary artery resulting in symptomatic PE. The second type, frequently seen in the setting of infective endocarditis, is composed of inflammatory cells, platelets, adhesion molecules, fresh fibrin, and bacteria binding to coagulum and forming vegetations. They are typically longer, more likely to be multi-lobular, and commonly span several chambers of the heart (Figure, right column). These vegetations that are typically acute, with friable finger-like projections, characteristically break apart upon being sheared off during TLE, with reports showing low risk of symptomatic PE.8 Vegetations that are lobular, however, have been associated with worse outcomes.9Despite acute procedural success in the setting of lead-related vegetations, mortality rates at 1 year approach 25%.10 Indeed, despite successful TLE in this report, 20% of patients were dead at 1.5 years. Although complete understanding of the mechanism of these poor outcomes remains unknown, septic emboli, lung abscesses, and infected lead “ghosts” have been implicated.11 Vegetation removal prior to TLE has thus represented an appealing therapeutic option with reports of successful percutaneous aspiration prior to TLE showing promising results, albeit with unknown long-term benefit.12,13 Although the lack of new PEs after TLE in this report does not directly support the effort, cost, and added risk of such a strategy, “debulking” of infectious burden remains a tempting complementary treatment. Importantly, the acute safety of TLE with large vegetations in this study should not be extrapolated to chronic, large lead-related masses, which are more like to cause acute PE if embolized. While aspiration of these sterile masses prior to TLE is appealing from a procedural outcome perspective, their morphologic characteristics, and the imperfect, but evolving, aspiration sheaths currently available are limiting, and requires consideration of surgical extraction. Further advancements in aspiration catheter technology and the development of right ventricular outflow track filters might influence future management.TLE continues to represent the gold standard for the management of lead-related infection.2 Due to the extensive work of the pathfinders in the vanguard of procedural development, the sound of crashing weights has been supplanted by those that power advancing sheaths. Yet despite the safe and predictable nature of modern-day TLE, the sobering long-term mortality of patients with infectious indications remains out of proportion to acute procedural success. While infectious “debulking” continues to represent the most attractive and practical complementary option to address this incongruity, future studies should concentrate both on identification of mass characteristics that suggest success, as well as determining if long-term benefits exist above and beyond lead removal. However, if improvement in clinical outcomes that warrant this added cost and effort are not identified, we should likely limit our aspirations.