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P U B L I S H E D B Y E L S E V I E R

Elevated Pacing Threshold Due toSubtotal Separation of PermanentPacemaker Header From Generator Casing

Theodore Maglione, MD,a,b Constancia Macatangay, MD,a,c George Thomas, MDa

P ermanent pacemakers represent the mainstayfor the management of symptomatic brady-cardia. Pacemaker system malfunctions are

rare and usually involve the pacemaker lead. We pre-sent a case of elevated right ventricular capturethreshold due to generator header bonding break-down in a Boston Scientific Insignia series pacemaker(Marlborough, Massachusetts).

A 71-year-old man presented with a past medicalhistory of squamous cell carcinoma involving thepiriformis sinus treated with chemoradiation therapyand radical neck dissection, hypothyroidism, periph-eral neuropathy, and alcohol abuse who had a dualchamber, pre-pectoral pacemaker implanted in 2003for sinus node dysfunction with syncope. The systemgenerator was an Insignia I Plus DR 1297 (BostonScientific), the right ventricular lead (RV) was a Gui-dant 4469 Fineline II Sterox EZ (Boston Scientific),and the right atrial lead (RA) was a Guidant 4470Fineline II Sterox EZ (Boston Scientific).

At the time of implantation, the patient had normalpacing thresholds in both the RA (0.60 V at 0.50 ms)and in the RV (0.60 V at 0.50 ms). During deviceclinical follow-up in 2014, he had stable lead param-eters in normal sinus rhythm but was noted to have

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From the aDivision of Cardiology, Weill Cornell University Medical Center, NbPresent address: Division of Cardiology, Rutgers–Robert Wood Johnson McPresent address: Cardiology, Bay View Physicians, Suffolk, Virginia. Dr. Tho

from Biotronik unrelated to the nature of this submission. All other authors h

to the contents of this paper to disclose.

All authors attest they are in compliance with human studies committees

stitutions and Food and Drug Administration guidelines, including patient co

the JACC: Clinical Electrophysiology author instructions page.

Manuscript received December 21, 2018; accepted January 22, 2019.

several episodes of ventricular high rates consistentwith ventricular failure to capture. In 2016, he wasagain found to have episodes of high ventricular ratesconsistent with failure to capture as well as a mar-ginal increase in his RV pacing threshold to 1.2 V at0.4 ms (Figure 1). At his most recent follow-up in late2017, the RV threshold was found to have increased to2.7 V at 0.40 ms and the battery was noted to be at theelective replacement interval (Figure 2). A chestradiograph did not show any apparent compromise inlead integrity or change in lead position. Given theincreasing RV threshold with episodes of failure tocapture, there was concern for a lead fracture. Thedecision was made to extract the RV lead extractionand implant a cardiac magnetic resonance imagingconditional system.

On presentation, device interrogation showed afurther increase in RV capture threshold to 3.3 V at0.4 ms. Cine imaging was performed, which did notdemonstrate evidence of lead fracture or malpositionof the pins within the header. An incision was carrieddown to the capsule and the existing generator wasremoved without difficulty. Inspection of the gener-ator showed subtotal separation of the header fromthe rest of the casing (Figure 3). Both leads were

https://doi.org/10.1016/j.jacep.2019.01.018

ew York Presbyterian Hospital, New York, New York;

edical School, New Brunswick, New Jersey; and the

mas has received research grants and consulting fees

ave reported that they have no relationships relevant

and animal welfare regulations of the authors’ in-

nsent where appropriate. For more information, visit

FIGURE 1 Device Interrogation Findings

Arrhythmia logbook (left) and example of ventricular high rate episodes (right) due to ventricular failure to capture.

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disconnected from the generator and when testedthrough the pacing system analyzer were found tohave normal thresholds, sensing, and impedance.Gross visual inspection of the proximal leads found

FIGURE 2 Device Lead Trends

Right atrial (RA) (left panel) and right ventricular (RV) (right panel) lea

extraction, the pre-operative RV threshold further increased to 3.3 V at

no evidence of structural compromise. The decisionwas made to abort the prior planned RV lead extrac-tion as the subtotal header separation was believed toaccount for the increased RV thresholds. The leads

d trends since device implantation. Of note, at the time of planned

0.4 ms.

FIGURE 3 Intraoperative Imaging

Intraoperative images demonstrating subtotal separation of the header from the titanium casing in multiple views.

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were connected to a new generator (Accolade MRI DRL311, Boston Scientific) and found to have normalthresholds; RA threshold 0.4 V at 0.5 ms and RVthreshold 1.0 V at 0.5 ms. The patient recovered welland was discharged the following day with stable leadparameters.

Pacemaker lead failure can be classified into acuteand chronic phases. Failure immediately after im-plantation or in the perioperative period can often beascribed to lead dislodgement or air trapped in theheader (1). Historically, short-term lead failure wasalso due to local inflammatory processes at the lead-tissue interface, but this has largely been mitigatedwith the advent of steroid-eluting tips (2). Whendealing with suspected lead failure months to yearsfollowing device implantation, one must considerinsulation breach, lead fracture, lead-lead interac-tion, and exit block due to tip calcification as possiblecauses (1). Putative lead failure may not be due todevice malfunction at all, but rather may beexplained by a change in the myocardial substrateitself; either from an infiltrative process or scarring,electrolyte disturbance, or from medication changes(3,4). In our patient, the only lead parameter changewas an increase in RV capture threshold. Sensing andimpedance remained stable throughout devicefollow-up.

The first case of header separation in a permanentpacemaker as a cause of device malfunction wasdescribed by Mellert et al. (5) in a dual-chamber,subpectoral Medtronic Elite 7075 device (Minneap-olis, Minnesota). Since that time there have beennumerous reports of Boston Scientific implantablecardioverter-defibrillator header separation resultingin inappropriate device therapy or function (6,7). In2009, Boston Scientific issued a class 2 device recallfor subpectorally implanted Cognis cardiac resynch-ronization therapy devices and Teligen implantablecardioverter-defibrillators due to a potential weak-ening of the bond between the header and casing (8).However, a review of the MAUDE (Manufacturer andUser Facility Device Experience) database did notreveal any prior occurrences of this event in Insigniamodels.

We therefore present the first reported case ofelevated RV capture threshold due to generatorheader bonding breakdown in a Boston Scientific In-signia series pacemaker.

ADDRESS FOR CORRESPONDENCE: Dr. TheodoreMaglione, Division of Cardiology, Rutgers–RobertWood Johnson Medical School, 125 Paterson Street,MEB #578A, New Brunswick, New Jersey 08901.E-mail: maglioth@rutgers.edu.

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RE F E RENCE S

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4. Dohrmann ML, Goldschlager NF. Myocardialstimulation threshold in patients with cardiacpacemakers: effect of physiologic variables,

pharmacologic agents, and lead electrodes. Car-diol Clin 1985;3:527–37.

5. Mellert F, Esmailzadeh B, Schneider C, et al. Anunusual case of pacemaker failure: completedisconnection of connector block and battery of asubpectorally implanted dual chamber pacemaker.Pacing Clin Electrophysiol 2002;25:509–10.

6. Aryana A, O’Neill PG, Charn KK. Subtotal sepa-ration of implantable cardioverter-defibrillatorheader from the casing mimicking an atrial leadfracture. J Innov Card Rhythm Manag 2013;4:1300–1.

7. Kumar S, Weiss R, Amin A, Houmsse M. Recur-rent inappropriate ICD shocks: header bondingmalfunction in Guidant Vitality device. J InnovCard Rhythm Manag 2015;6:1900–4.

8. U.S. Food and Drug Administration. Class 2Device Recall Boston Scientific Corporation.December 1, 2009. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfres/res.cfm?id¼87000. Accessed March 23, 2018.

KEY WORDS elevated pacing threshold,pacemaker malfunction