Batra, Anjan S

Berdjis, Farhouch

McCanta, Anthony C

Morchi, Gira S

Starr, Joanne P

Tuozo, Froilan

English

eScholarship - University of California

UC IrvineUC Irvine Previously Published WorksTitleImplantation of a leadless pacemaker in a pediatric patient with congenital heart diseasePermalinkhttps://escholarship.org/uc/item/4t23s8bvJournalHeartRhythm Case Reports, 4(11)ISSN2214-0271AuthorsMcCanta, Anthony CMorchi, Gira STuozo, Froilanet al.Publication Date2018-11-01DOI10.1016/j.hrcr.2018.07.012Copyright InformationThis work is made available under the terms of a Creative Commons Attribution License, availalbe at https://creativecommons.org/licenses/by/4.0/ Peer reviewedeScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaImplantation of a leadless pacemaker in a pediatricpatient with congenital heart diseaseAnthony C. McCanta, MD, FHRS,*† Gira S. Morchi, MD,*† Froilan Tuozo, NP,*†Farhouch Berdjis, MD,* Joanne P. Starr, MD,*† Anjan S. Batra, MD, FHRS*†From the *Heart Institute, Children’s Hospital Orange County, Orange, California, and †University ofCalifornia Irvine, Pediatric CardioPulmonary Center, Orange, California.IntroductionPatients with congenital heart disease (CHD) and significantpostoperative atrioventricular (AV) nodal injury frequentlyrequire lifelong backup pacing. However, lifelong pacingin this population is complicated primarily by lead-related is-sues. Pacing leads in pediatric patients with CHD fail earlierand at higher rates than leads in adults with structurallynormal hearts for both epicardial and endocardial leads.1 So-matic growth and the vigorous activity of pediatric patientslead to higher rates of fracture and dislodgment. Surgicalrepair requiring exogenous materials, including bioprostheticvalves and patches, places transvenous pacing leads in pa-tients with CHD at higher risk for infection; this necessitatesextraction procedures for lead removal, which carry up to 2%risk of serious complications, including death.2,3Transvenous leads carry significant risk of venousthrombosis and occlusion over the life of pediatric patientsand thus have a profound effect in CHD patients who mayrequire frequent venous access for interventional cardiaccatheterization procedures, including balloon angioplasty ofpulmonary arteries (PAs) and transcatheter pulmonaryvalve implantation. For these reasons, leadless pacing canbe a valuable intervention to minimize the lifelongcomplications of epicardial or transvenous pacing inpediatric patients with CHD.Case reportA 12-year-old, 37-kg girl with a history of repaired tetralogyof Fallot with pulmonary atresia and postoperative high-grade heart block status post epicardial pacemaker placementat 5 months was referred to the pediatric electrophysiologydepartment for epicardial pacemaker lead fracture. Thepatient was asymptomatic, with first-degree heart block andKEYWORDS Congenital heart disease; Leadless pacemaker; Pediatrics;Tetralogy of Fallot; Transcatheter pacing system(Heart Rhythm Case Reports 2018;4:506–509)Address reprint requests and correspondence: Dr Anthony C. McCanta,CHOC Children’s Specialists, 505 South Main Street, Suite 200, Orange,CA 92868. E-mail address: amccanta@choc.org.2214-0271/© 2018 Heart Rhythm Society. Published by Elsevier Inc. This is an opunder the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4right bundle branch block at baseline and documentedsecond-degree type II heart block at night. Based on theunpredictability of recurrence of postoperative heart blockin patients with CHD4,5 and the continued occasional high-grade heart block, implantation of a new VVI pacing systemwas recommended.Because the patient had previously undergone 4 sternoto-mies for surgical repairs, including central shunt placementand unifocalization of the PAs at age 3 weeks, completerepair with right ventricle to pulmonary artery (RV-PA)conduit and closure of ventricular septal defect at age 5months, which was complicated by complete heart blockrequiring placement of an epicardial dual-chamber pace-maker 5 days after the repair, and pulmonary valve replace-ment at age 18 months, placement of a new epicardialpacing system was not recommended by the cardiac surgeryteam. The patient was referred for a transvenous pacingsystem. After discussion with the referring cardiologist andthe patient’s parents, and after careful consideration of therisks of lifelong transvenous pacing compared to the risksof a large-bore (23F) delivery sheath in the femoral vein,possible cardiac perforation and/or pericardial effusion, andthe many potential unknown or unreported risks of leadlesspacing (eg, multiple abandoned devices within the ventricle,possible need for surgical retrieval or extraction), transcath-eter leadless pacing (Micra Transcatheter Pacing System,Medtronic, Minneapolis, MN) was offered to the patient.While under general anesthesia, the patient underwent adiagnostic right and left heart catheterization to confirmnormal hemodynamics, minimal stenosis of the RV-PAconduit, and normal PA pressures. She then underwent elec-trophysiological study to confirm the absence of sustainedventricular arrhythmias and supraventricular tachycardia.After a right femoral venogram was performed to rule outsignificant stenosis of the common femoral vein, iliac vein,and inferior vena cava, serial dilations of the right femoralvein were performed with 12F, 16F, 18F, 20F, and 22F hy-drophilic dilators. The proprietary 23F sheath was thenplaced over a wire and advanced to the middle of the rightatrium. The delivery catheter was advanced through thesheath, and the sheath was withdrawn into the inferior venaen access article.0/).https://doi.org/10.1016/j.hrcr.2018.07.012KEY TEACHING POINTS Postoperative atrioventricular (AV) nodal injuryfrequently necessitates lifelong backup pacing inpatients with repaired congenital heart diseasebecause of the unpredictability of late recurrence ofAV nodal block. Permanent pacing in pediatric and congenital heartdisease patients requires careful consideration of thecumulative risks of pacemaker implant techniquesover the entire course of the patient’s life. Leadless pacing via a transcatheter pacing system isfeasible in pediatric patients with repairedcongenital heart disease and minimizes the lifelongburden of pacing by eliminating lead-relatedcomplications.Figure 1 Leadless pacemaker implant final position. Biplane fluoroscopyof leadless pacemaker in the right ventricle with fractured atrial and ventric-ular epicardial leads, surgical clips, and sternal wires. The intracardiac echo-cardiogram catheter is seen in the right atrium advanced through theproprietary 23F delivery sheath from the right femoral venous approach.McCanta et al Leadless Pacemaker in a Pediatric Patient With CHD 507cava below the level of the diaphragm. The delivery catheterwas deflected across the tricuspid valve into the RV. Contrastinjection through the catheter under biplane fluoroscopyconfirmed the septal and apical location of the catheter.The pacing system was exposed from the catheter and im-planted onto the RV septum. The catheter was withdrawn,and control was maintained on the pacemaker using the su-ture adhered to the distal ring. Initial implant parameterswere suboptimal, with pacing threshold .2.0 V at 0.24 ms,sensed R waves ,5 mV, and pacing impedance ,500 U.The pacing system was recaptured with the delivery catheter,and the delivery system was repositioned. Again, suboptimalimplant parameters were achieved, and the device was recap-tured and repositioned. Ultimately, the device required repo-sitioning 7 times before acceptable implant parameters wereachieved: pacing threshold of 1.25 V at 0.24 ms, sensed Rwave of 4.4 mV, and pacing impedance of 480 U. The deliv-ery sheath was removed, and intracardiac echocardiographywas used to visualize the pacing system in the RV(Figure 1). The delivery sheath was removed, and hemostasiswas maintained with 2 vascular closure devices (PerCloseProglide, Abbott Vascular, Abbott Park, IL) placed withthe assistance of interventional cardiology. The existingpacemaker generator in the right upper abdomen wasremoved, and the epicardial leads were capped with the assis-tance of cardiothoracic surgery.The patient was admitted overnight. A pacemaker interro-gation performed the following day revealed a mild increasein pacing threshold to 2.6 V at 0.24 ms and 2.0 V at 0.4 ms,with mild decrease in R-wave sensing to 4.2 mV but stablepacing impedance of 480 U. Chest radiograph and transtho-racic echocardiogram confirmed stable device position. Afterdiscussion with the device manufacturer, the decision wasmade to not reposition the device but to follow the thresholdclosely on an outpatient basis, and the patient was dischargedhome.The pacing threshold continued to rise during outpatientfollow-up, reaching a maximum pacing threshold of 3.25 Vat 0.24 ms 2 weeks after implant despite stable appearanceon chest radiograph, and stable R-wave sensing and imped-ance. Over the next 10 weeks, the pacing threshold steadilydecreased. Three months after implant, the pacing thresholdwas 2.0 V at 0.24 ms, with R-wave sensing of 6.0 mV andpacing impedance of 490 U. At 9-month follow-up, pacingparameters remain stable, and the patient is paced approxi-mately 1% of the time.DiscussionLeadless transcatheter pacing systems have been studiedextensively in adults with structurally normal hearts in bothEurope and the United States.6,7 These systems havedemonstrated low complication rates at both implantationand throughout short- to mid-term follow-up.8,9 However,implantation of a leadless transcatheter pacing system in aFigure 2 Biplane right ventriculogram showing heavily trabeculated rightventricle with right ventricle to pulmonary artery conduit extending from themid-anterior right ventricle.Figure 3 Postimplant intracardiac echocardiogram showing the leadlesspacemaker in an apical location inferior to the takeoff of the right ventricleto pulmonary artery conduit.508 Heart Rhythm Case Reports, Vol 4, No 11, November 2018pediatric patient or a patient with significant CHD had notpreviously been described before this case of implantationof the Micra Transcatheter Pacing System in a 12-year-oldgirl with tetralogy of Fallot.The decision to implant this device rather than a transve-nous pacing system or an epicardial pacing system was basedon long-term complications. Because the life expectancy ofpatients with tetralogy of Fallot and other significant CHDscontinues to increase, approaching that of people withoutCHD, the expectation of lifelong pacing in such individualsmeans that our 12-year-old patient potentially could requirerare, intermittent pacing for 60–70 years. Thus, consideringthe lifelong complications of pacing becomes crucial to ex-tending the patient’s lifespan.Pacing in pediatric patients and patients with CHD is asso-ciated with higher complication rates than pacing in adultswith structurally normal hearts.10,11 Lead-related complica-tions remain the most significant, with lead failure rates ashigh as 15% over mid- to long-term follow-up.1 Venousthrombosis and endovascular infection are other long-termrisks of transvenous pacing systems. Even in ideal situationswithout immediate complications, lead performance deterio-rates over time. Therefore, a young patient with transvenousleads is likely to experience deterioration in lead performanceand possibly lead failure at some point over the life course,and the physician caring for the patient must decide betweenlead extraction and abandonment.12 The rate of major com-plications from lead extraction procedures, including majorvascular injury, remains high in pediatric and CHD pa-tients.13 By eliminating the primary instrument of complica-tions, leadless pacemakers are well suited to meet the pacingdemands of many pediatric patients with CHD who requireintermittent pacing because of surgically created conductionsystem disease.As part of the preprocedural discussion with the familyand informed consent to perform this procedure for the firsttime at our institution, we acknowledged that data on thelong-term performance of the device and its potential long-term complications are lacking compared to traditionalapproaches, and that complications may present that havenot previously been described. We also discussed future pac-ing strategies for the patient, which may include transvenouspacing to provide DDD pacing or cardiac resynchronizationtherapy if the patient were to develop indications for eithertreatment. Regarding the abandonment of this leadless pace-maker and/or multiple leadless systems in the RV, we dis-cussed with our patient that she is likely to require at least1 other cardiac surgery for RV-PA conduit replacement inadolescence or young adulthood before transvenous pulmo-nary valve replacement, at which time the abandoneddevice(s) could be retrieved by a cardiothoracic surgeon.Regarding the implant technique, an RV angiogram per-formed before implantation as part of planning the cardiaccatheterization was helpful in determining the trueMcCanta et al Leadless Pacemaker in a Pediatric Patient With CHD 509ventricular dimensions (Figure 2). In addition, intracardiacechocardiography, which was used as part of the electrophys-iological study, was helpful in evaluating the position of thedevice in relation to the takeoff of the RV-PA conduit(Figure 3).Many of the sites sampled within the RV had suboptimallead parameters despite multiple deployments. Similarly, theparameters worsened over the first several weeks before theystabilized. However, knowing that improvement in subopti-mal pacing thresholds in patients with the Micra systemhad been studied and described, our implant was not reposi-tioned after the initial procedure. Fortunately, our experienceis similar to that of Piccini and colleagues,14 showingimprovement of the threshold by 1 month and 6 months.Although the exact cause of the suboptimal parameters isnot known, the patient had undergone cardiopulmonarybypass 3 times during her staged repair of tetralogy of Fallot,all of which had the potential for endocardial ischemia. RVhypertrophy with thick trabeculations defines tetralogy ofFallot, and contact of the distal electrode may have beenaltered by its positioning within trabeculations. Fortunately,the parameters returned to an acceptable range, and the de-vice did not need to be retrieved or repositioned.ConclusionThis case demonstrates the feasibility of implanting a leadlesspacemaker in a 12-year-old, 37-kg patient with tetralogy ofFallot. To our knowledge, this is among the first transcatheterpacemaker implants reported in a pediatric patient with sig-nificant CHD. Despite challenges in finding an optimalimplant site possibly because of factors specific to repairedtetralogy of Fallot, such as a history of endocardial ischemiafrom bypass and thick trabeculations of the RV, the implantwas successful, without procedural complications and withadequate pacing parameters. By eliminating the lead-relatedcomplications of endovascular pacing, leadless pacing offersan excellent option for young patients with CHD in need oflifelong pacing.References1. Fortescue EB, Berul CI, Cecchin F, Walsh EP, Triedman JK, Alexander ME.Patient, procedural, and hardware factors associated with pacemaker lead failuresin pediatrics and congenital heart disease. Heart Rhythm 2004;1:150–159.2. Maytin M, Jones SO, Epstein LM. Long-term mortality after transvenous leadextraction. Circ Arrhythm Electrophysiol 2012;5:252–257.3. Brunner MP, Cronin EM, Wazni O, Baranowski B, Saliba WI, Sabik JF,Lindsay BD, Wilkoff BL, Tarakji KG. Outcomes of patients requiring emergentsurgical or endovascular intervention for catastrophic complications during trans-venous lead extraction. Heart Rhythm 2014;11:419–425.4. Aziz PF, Serwer GA, Bradley DJ, LaPage MJ, Hirsch JC, Bove EL, Ohye RG,Dick M 2nd. Pattern of recovery for transient complete heart block after openheart surgery for congenital heart disease: duration alone predicts risk of late com-plete heart block. Pediatr Cardiol 2013;34:999–1005.5. Gross GJ, Chiu CC, Hamilton RM, Kirsh JA, Stephenson EA. Natural history ofpostoperative heart block in congenital heart disease: implications for pacingintervention. Heart Rhythm 2006;3:601–604.6. Reynolds D, Duray GZ, Omar R, et al. A leadless intracardiac transcatheter pac-ing system. N Engl J Med 2016;374:533–541.7. Ritter P, Duray GZ, Zhang S, Narasimhan C, Soejima K, Omar R, Laager V,Stromberg K, Williams E, Reynolds D. The rationale and design of the MicraTranscatheter Pacing Study: safety and efficacy of a novel miniaturizedpacemaker. Europace 2015;17:807–813.8. Roberts PR, Clementy N, Al Samadi F, et al. A leadless pacemaker in thereal-world setting: the Micra Transcatheter Pacing System Post-Approval Regis-try. Heart Rhythm 2017;14:1375–1379.9. Soejima K, Asano T, Ishikawa T, et al. Performance of leadless pacemaker inJapanese patients vs. rest of the world. Circ J 2017;81:1589–1595.10. Chaouki AS, Spar DS, Khoury PR, Anderson JB, Knilans TK, Morales DL,Czosek RJ. Risk factors for complications in the implantation of epicardial pace-makers in neonates and infants. Heart Rhythm 2017;14:206–210.11. Sachweh JS, Vazquez-Jimenez JF, Schondube FA, Daebrtiz SH, Dorge H,Muhler EG, Messmer BJ. Twenty years experience with pediatric pacing: epicar-dial and transvenous stimulation. Eur J Cardiothorac Surg 2000;17:455–461.12. McCanta AC, Schaffer MS, Collins KK. Pediatric and Adult Congenital Endocar-dial Lead Extraction or Abandonment Decision (PACELEAD) survey of leadmanagement. Pacing Clin Electrophysiol 2011;34:1621–1627.13. Cecchin F, Atallah J, Walsh EP, Triedman JK, Alexander ME, Berul CI. Leadextraction in pediatric and congenital heart disease patients. Circ ArrhythmElectrophysiol 2010;3:437–444.14. Piccini JP, Stromberg K, Jackson KP, et al. Long-term outcome in leadless Micratranscatheter pacemakers with elevated thresholds at implantation: results fromthe Micra Transcatheter Pacing System Global Clinical Trial. Heart Rhythm2017;14:685–691.

Implantation of a leadless pacemaker in a pediatric patient with congenital heart disease

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Implantation of a leadless pacemaker in a pediatric patient with congenital heart disease.

Implantation of a leadless pacemaker in a pediatric patient with congenital heart disease.

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