INNOVATIVE COLLECTIONS

CLINICAL DECISION MAKING

Pacing Output Failure After ElectrocauteryDuring Pulse Generator Replacement1RANGADHAM NAGARAKANTI, MD, 1,2SATISH R. RAJ, MD, MSCI, FACC, FHRS and1,2JEFFREY N. ROTTMAN, MD

1Departments of Medicine and 2Pharmacology, Nashville VA Medical Center of the Tennessee Valley Health Systems,

Vanderbilt University School of Medicine, Nashville, TN

ABSTRACT. We report two cases of device malfunction with loss of pacing output duringroutine device generator replacement surgery after using electrocautery. These devices were nearingor had just reached the elective replacement indicator (ERI). Most current devices are relativelyrobust during electrocautery, although manufacturers warn of potential damage to the device.Device–electrocautery interactions, and these warnings, vary by manufacturer, and no specificguidelines/recommendations currently exist that specify the expected behavior of the device and thecorrective measures needed with electrocautery. Current monitoring strategies for device(pacemaker and defibrillator) battery depletion include ERI and end of life (EOL). ERI results inpredictable changes in device function, and allows programming of devices that can decrease therisks associated with electrocautery. However, those programming changes were not protective inthe cases described. More detailed information regarding device-specific risks with electrocautery,including the specific testing performed, would be useful. Electrocautery should be avoided inpacemaker-dependent patients with generators subject to output circuit failure, such as thosedescribed here.

KEYWORDS. arrhythmia, cardiac devices, electrocautery, generator replacement.

ISSN 2156-3977 (print)ISSN 2156-3993 (online)

’ 2012 Innovations in Cardiac

Rhythm Management

Introduction

Pacemaker and implantable cardioverter-defibrillator(ICD) generators differ in their behavior as they approachbattery depletion. All devices are intended to maintainsupport for basic pacemaker function when the batteryvoltage approaches ERI. In devices from most manufac-turers, ERI disables rate response and some diagnosticfeatures, and the mode of pacing may change (e.g. DDD toVVI mode). With a further decrease in voltage to the endof life (EOL) threshold, correct pacemaker function cannotbe reliably supported. Manufacturers currently recom-mend replacement of pacemaker and ICD pulse gen-

erators within 3 months of reaching ERI. The expectationis that ERI provides a period of normal and safe pa-cemaker function, providing a window for a typicalgenerator replacement procedure.

Electrocautery is often used to obtain hemostasis duringpacemaker and/or ICD generator changes. No univer-sally-applicable guidelines or recommendations currentlyexist regarding the expected change in pacemaker/ICDbehavior. Manufacturers generically describe the poten-tial damage to the pulse generator (Table 1). However,most clinical experience suggests that surgical electro-cautery causes little or no damage to current devicesystems. A recent evaluation showed only rare cases ofapplication of unipolar electrocautery in close proximityof the device causing electromagnetic interference (EMI),resulting in inappropriate sensing and no permanentdamage.1 In a pacemaker-dependent patient, devices areoften programmed to an asynchronous or triggered modeto pre-empt inhibition of pacing output and the tachy-cardia detection mode temporarily deactivated for adefibrillator.2

Dr. Rottman has reported he has received support for the CardiacArrhythmia Fellowship program from Medtronic Inc., St. JudeMedical, Boston Scientific Inc., and Biotronik Corporation.Manuscript received April 22, 2012, final version accepted May 21,2012.Address correspondence to: Jeffrey N. Rottman, MD, Division ofCardiovascular Medicine Departments of Medicine & Pharmacology,5209 Medical Center East, 1215 21st Avenue South Nashville, TN,37212-8802. E-mail: Jeff.rottman@vanderbilt.edu

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We report two cases of loss of pacemaker outputduring an elective pulse generator replacement with useof electrocautery when the battery voltage was eithergreater than or at ERI, but not in EOL. Both of these casesoccurred with St. Jude Medical (St. Paul, MN) devices.These cases are discussed in the context of electrocauteryinteraction with implanted devices.

Case 1

A 73-year-old male with history of hypertension, chronicobstructive pulmonary disease, sick sinus syndrome,complete heart block, and non-ischemic cardiomyopathywith left bundle branch block underwent a cardiacresynchronization therapy defibrillator device (CRT-D)implantation. His St. Jude Frontier II Model 5586 device(atrial lead, Guidant Model 4244 SN; RV lead, GuidantModel 4088; and LV lead St. Jude Model 1056) implantedin January 2007 approached ERI in November 2011with a battery voltage of 2.53V (ERI voltage 2.50V andEOL voltage 2.20V). His underlying rhythm was sinusbradycardia with complete heart block. All the leads hadstable impedances, and pacing and sensing thresholds.He was electively admitted for generator replacement 2weeks later. Prior to starting the procedure, the devicewas programmed to the ventricular asynchronouspacing (VOO) mode because of the patient’s underlyingpacemaker dependence (Figure 1a). Battery voltage atthis time remained within the ERI window. All leadswere programmed to bipolar pacing.

The prior incision was sharply opened and the devicewas freed from adhesions in the capsule using electro-cautery. Electrocautery was stopped prior to reaching thegenerator. When the generator was removed from thepocket, pacing output was suddenly lost with loss ofpacing (Figure 1b). Pacing output did not resume whenthe pacemaker generator was replaced in the pocket.Temporary pacing was emergently instituted using aunipolar connection with the header set screw (Figure 1c);the positive alligator clamp was attached to the surgicalwound retractor, and the negative clamp was attached to ahex wrench that made contact with the set screw to the

distal right ventricular (RV) electrode via the headergrommet. The old generator was disconnected from theleads, and the lead analyzer was used to provide bridgingpacemaker support. The leads were functioning correctlyand were transferred to the new generator. The newgenerator and leads were returned to the pocket, and thefunction of new generator and leads were satisfactory andconsistent with the previously measured values.

Repeat interrogation of the old generator confirmedthat the old generator was at ERI and not EOL. Thedevice was not noted to be in noise reversion mode, andno error parameters were identified. It was returned tothe manufacturer for further evaluation, particularlybecause of the unexplained pacemaker output failure.No additional analysis has been reported at this time.

Case 2

A 79-year-old male with history of hypertension, coronaryartery disease, and complete heart block underwent adual-chamber pacemaker implantation with a St. JudeIntegrity DR Model 5366 (atrial lead, St. Jude Model 1488;RV lead, St. Jude Model 1488) in January 2004. InNovember 2011, the device was near ERI with a batteryvoltage of 2.67V (ERI voltage 2.50V and EOL voltage2.20V), and he was electively admitted for generatorreplacement because of impended travel to areas withoutreliable device follow-up. His underlying rhythm wassinus bradycardia with complete heart block. All pacingleads demonstrated stable pacing and sensing thresholdsand pacing impedances. The device was programmed toasynchronous VOO mode due to the patient’s underlyingpacemaker dependence prior to the generator replacement(Figure 2a). While the device was being freed from theadhesions in the pocket (using electrocautery), there wassudden decrease in heart rate, to a pacemaker deliveredoutput rate of 30bpm (Figure 2b), corresponding to half ofthe previously programmed rate. The device was quicklyremoved from the pocket and the ventricular lead wasdisconnected from header and connected to the leadanalyzer with restoration of ventricular pacing. The atriallead was then disconnected from the old generator. Both

Table 1: Management of electrocautery with implantable cardiac devices

Manufacturer recommendations Med3 SJM4,5 BT6 BS7,8 Sor9,10

Program pacemaker to asynchronous mode (VOO/AOO/DOO) X X XTurn off antitachycardia pacing (ATP) and shock therapies

with the defibrillatorX X X X X

Use bipolar electrocautery system if possible X X X XUse short, intermittent, and irregular bursts at the lowest feasible energy X XPlace the ground plate as far as possible from the device and

lead system (at least 6 inches (15.2 cm)X X X X X

Keep temporary pacing and defibrillation equipment available. X XAvoidance of electrocautery (") X X X X XAfter the procedure, perform assessment of the device X X

" Med: Medtronic; SJM: St. Jude Medical; BT: Biotronik; BS: Boston Scientific; Sor: Sorin.Specific manufacturer statements in their respective field manuals/guides: Med, ‘‘Avoid direct contact with the implanted

device or leads.’’ SJM, ‘‘Do not use electrocautery in the vicinity of an implanted device.’’ BT: ‘‘Electrocautery should never beperformed within 6 inches of an implanted pulse generator or lead.’’ BS, ‘‘Avoid direct contact with the pulse generator orleads.’’ Sor, ‘‘Electrocautery should not be used.’’

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leads were found to be functioning correctly and weretransferred to the new generator. The new generator andleads were returned to the pocket, and the function of thenew generator and leads were verified and were stable.The old generator was returned to the manufacturer forevaluation, with note made of the pacemaker outputfailure of a device that had not yet reached ERI or EOL.

Discussion

Predictable pacemaker behavior is necessary for appropriatemanagement decisions and this is particularly important inpacemaker-dependent patients. Electrocautery is commonlyused during pulse generator replacement. Although nouniversal guidelines or recommendations currently exist,most manufacturers and standard texts suggest predictabledevice (pacemaker, defibrillator) behavior after voltagedecline to ERI, and recommend elective pulse generatorreplacement after the battery voltage reaches ERI. Multiplemanufacturer manuals vaguely caution that electrocauterycan result in abnormal device behaviors such as reprogram-ming, inhibition, or fall back to magnet mode. The common

recommendations from these manufacturers are to usebipolar cautery, place the cautery groundplate/electrodefarther away from device as possible, and use shortintermittent bursts of pacing at permissible low energylevels (Table 1).4–11 A review from 1986 of electrocauteryinteraction with pacing devices ultimately recommendedagainst use of electrocautery when possible.12

In general, current devices appear to be more robustto cautery interactions, and catastrophic consequencesfrom the cautery are rare; with current technology, themost common problem encountered is reversion toreset/magnet mode.13 With defibrillators, the tachycardiadetection mode is temporarily inactivated prior to cauteryas spurious detection of ventricular fibrillation is com-mon. Furthermore, performing the replacement proce-dure when the devices are still in ERI status allows thespecified programming changes, and is usually thoughtto provide additional protection. However, these casesclearly reflect device-specific differences in the potentialfor and the consequences of cautery-induced devicemalfunction.

We described two cases of pacing output failure. Onewas a pacemaker and the other one was a defibrillator

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Figure 1: Case 1: 73 year-old male undergoing pulse generator replacement of his cardiac resynchronization therapydefibrillator device at ERI threshold Panel A: Asynchronous VOO mode at 60 bpm prior to pulse generator replacementprocedure; Panel B: Loss of pacing output with electrocautery use; Panel C: Initiation of temporary pacing with using unipolarconnection with the header set screw.

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914 The Journal of Innovations in Cardiac Rhythm Management, August 2012

with different circuit platform by design. Both proce-dures were elective generator replacements as the devicebattery voltage has reached or was approaching ERI. Asa routine practice in our laboratory during generatorreplacements, electrocautery was used during both theseprocedures. Standard precautions were taken, such asreprogramming to asynchronous mode for both devices,and tachycardia therapies were turned off for thedefibrillator prior to cautery use. During both proce-dures, there was sudden pacing output failure requiringimmediate measures as described in the cases to restoreventricular pacing. The device platforms are fundamen-tally different between these devices, but the analogoutput circuit design may be similar. ICDs differ im-portantly from pacemakers in not reverting to unipolarmode under noise conditions; thus, in an ICD the failureto pace after electrical noise generally is not due to anincomplete shoulder return circuit.

There are multiple means by which cautery caninterfere with pacemaker function. Oversensing of thecautery electrical activity can inhibit paced output, butthis inhibition should stop with the cessation of electro-cautery. Devices programmed to asynchronous modeshould be immune to this inhibition. Cautery can triggernoise reversion, and this may reprogram pacemakeroutput polarity to unipolar mode. When a unipolardevice is removed from the pocket, the current returnpath for pacing is interrupted, and effective pacing canbe lost. However, recreating this return path shouldrestore pacing, and ICD systems do not typically changeRV pace polarity. This mechanism therefore cannotexplain the output changes noted in these two cases,

and noise reversion was not observed on deviceinterrogation. Indirect coupling of radiofrequencyenergy, including cautery, to the leads can result in achanged lead–tissue interface, but the absence of anychange in lead parameters when attached to the newgenerator argues against this mechanism here. The likelymechanism in both of these cases was direct damage to theoutput circuit with complete (Case 1) or partial (Case 2)loss of effective output. The only effective response inthis circumstance is to provide an alternative source ofpacing energy prior to transfer of the leads to anunaffected generator. This is similar to a report from1992 in which output failure in a Medtronic pulsegenerator after electrocautery is detailed.14

Complete loss of output in response to electrocauteryin generators at or before ERI status is now very unusual.A St. Jude Technical Service memorandum15 describedthe estimated frequency of ‘‘circuit damage leading toerratic function or loss of pacing’’ as ‘‘rare.’’ The twocases described here occurred in rapid succession. Thetemporal juxtaposition of these two cases suggests that itmay be less rare than anticipated, and suggests thatshared output circuit design features may predispose tothis problem. The findings observed cannot be attributedto the unreliable device function that may be expectedafter transition from ERI to EOL.

16

We accordinglyrecommend that cautery is avoided during generatorreplacement in pacemaker-dependent patients withdevices in these St. Jude Medical generator families.

It would be beneficial for manufacturers to moreaccurately describe the range of behaviors that may beexpected with their specific devices in response to

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Figure 2: Case 2: 79 year-old male undergoing pulse generator replacement of his dual chamber pacemaker before reachingERI Panel A: Asynchronous VOO mode at 60 bpm prior to pulse generator replacement procedure; Panel B: Sudden decrease inpacing output rate and heart rate to 30 bpm with electrocautery. Pacing output remained inhibited for several seconds afterthe electrocautery was discontinued.

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cautery, the specific testing that has been performed, andthe frequency and predisposing factors to this behavior.Finally, with the availability of alternative coagulationand cutting instruments such as the ‘‘cold knife’’ and‘‘Plasma Blade,’’

17,18

the device-dependent characteristics ofthese alternative technologies should also be evaluated andreported.

Conclusion

Catastrophic output failure in response to electrocauterycan be observed with devices currently requiringgenerator replacement, and is not necessarily preventedby performing the replacement procedure during earlyERI status or by programming to asynchronous pacingmode. Certain devices may be especially prone to thismode of failure, and cautery should be avoided duringreplacement procedures with devices where this mode offailure has been reported. More complete disclosure ofelectrocautery interaction and testing would be desirablefor optimizing procedural aspects of cardiac rhythmdevice management.

References

1. Cheng A, Nazarian S, Spragg DD, et al. Effects of surgicaland endoscopic electrocautery on modern-day permanentpacemaker and implantable cardioverter-defibrillator sys-tems. Heart Rhythm 2007; 4:154–160.

2. American Society of Anesthesiologists Task Force onPerioperative Management of Patients with Cardiac RhythmManagement Devices. Practice advisory for the perioperativemanagement of patients with cardiac rhythm managementdevices: pacemakers and implantable cardioverter-defibrilla-tors. Anesthesiology 2005; 103:186–198.

3. Zipes DP, Jalife J. Cardiac Electrophysiology: From Cell toBedside. 5th ed. Philadelphia: Saunders; 2009: 992 and 1020.

4. Medtronic Adapta/Versa/Sensia Pacemaker CauteryLabeling – Pacemaker Reference Guide, 2006.

5. St. Jude Medical Accent and Anthem User’s Manual, 2009.6. St. Jude Current, Fortify, Promote, and Unify User’s

Manual, 2010.7. Biotronik Evia Technical Manual, 2011.8. Boston Scientific Altrua pacemaker System Guide, 2009.9. Boston Scientific Contak defibrillator System Guide, 2008.

10. Sorin Reply DR Implant Manual, 2010.11. Sorin Paradym defibrillator Implant Manual, 2009.12. Levine PA, Balady GJ, Lazar HL, Belott PH, Roberts AJ.

Electrocautery and pacemakers: management of the pacedpatient subject to electrocautery. Ann Thorac Surg 1986; 41:313–317.

13. Roman-Gonzalez J, Hyberger LK, Hayes DL. Is electro-cautery still a clinically significant problem with contem-porary technology? (abstract) Pacing Clin Electrophysiol 2001;24:709.

14. Mangar D, Atlas GM, Kane PB. Electrocautery-inducedpacemaker malfunction during surgery. Can J Anaesth 1991;38:616–618.

15. Effects of Electrocautery on St. Jude Medical ImplantableCardiac Pacemakers, Rev 11/08, Technical Services.

16. Aaarons D, Mower M, Veltri E. Use of the electivereplacement indicator in predicting time of automaticimplantable cardioverter-defibrillator battery depletion.Pacing Clin Electrophysiol 1989; 12:1724–1728.

17. Dane C, Dane B, Cetin A, Erginbas M. Haemostasis aftercold-knife conisation: a randomised prospective trial com-paring cerclage suture versus electro-cauterization. AustN Z J Obstet Gynaecol 2008; 48:343–347.

18. Loh SA, Carlson GA, Chang EI, Huang E, Palanker D,Gurtner GC. Comparative healing of surgical incisionscreated by the PEAK PlasmaBlade, conventional electrosur-gery, and a scalpel. Plast Reconstr Surg 2009; 124:1849–1859.

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