Postgraduate Medical Journal (1989), 65, 98- 102

Transvenous pacemaker electrodes placed unintentionally inthe left ventricle: three cases

S.J. Winner and N.A. Boon*

Department ofCardiovascular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK.

Summary: Three patients are described in whom pacemaker electrodes were unintentionally placedwithin the left ventricle, followed by considerable delay before the error was recognized. In two casestemporary pacemaker wires were inserted into the subclavian artery and passed along a retrograde course.One patient required urgent surgery for acute arterial obstruction on removal ofthe wire. In the third case,a permanent wire was inserted correctly into a vein but traversed the atrial septum, probably via a patentforamen ovale, to enter the left ventricle. Twelve lead electrocardiograms in all three patients showedpaced complexes with right bundle branch block configuration. This appearance should raise suspicion thatthe pacemaker electrode might be in the left ventricle, in which case its position should be defined by chestradiographs (including a lateral view) and echocardiography.

Introduction

We report three patients in whom pacemaker elect-rodes were unintentionally placed within the leftventricle, followed by considerable delay before theerror was recognized.

Case reports

Patient I

A 70 year old woman was admitted to hospitalfollowing several episodes of syncope. A 24-hourelectrocardiogram (ECG) showed sinus rhythm, withpassages of 2: 1 atrioventricular block, and periods ofsinus arrest up to three seconds in duration. Atemporary pacing wire was inserted via a right supra-clavicular approach. She remained well, and wastransferred to the Regional Cardiac Centre 5 dayslater. A twelve lead ECG showed paced beats withright bundle branch block configuration. A postero-anterior (PA) chest radiograph showed that thepacemaker wire followed an odd course, with the tip inan abnormally lateral position within the cardiacshadow. A permanent pacemaker was implanted onthe next day, and immediately afterwards the tem-porary wire was withdrawn.

Post-operatively, the right brachial pulse weakened,and the forearm became cool. It was then recognizedthat the tip of the temporary pacemaker had beenplaced in the left ventricle, via the right subclavianartery and aorta, and that removal of the wire hadcaused traumatic occlusion of the artery. An arterio-gram (Figure 1) demonstrated occlusion of the rightsubclavian artery, which tapered from a point justdistal to the origin of the vertebral artery; collateralvessels from around the shoulder joint filled theaxillary artery. The brachial artery was also occluded,with appearances suggesting an embolus at the mid-point of the humerus.

Figure 1 Patient 1: arteriogram showing occlusion oftheright subclavian artery following withdrawal of thetemporary pacemaker wire.

i) The Fellowship of Postgraduate Medicine, 1989

Correspondence and present address: S.J. Winner, M.A.,M.B., B.Chir., M.R.C.P., University Division of GeriatricMedicine, The Radcliffe Infirmary, Oxford OX2 6HE.*Present address: Department of Cardiology, RoyalInfirmary of Edinburgh, Edinburgh EH3 9YW, UK.Accepted: 17 August 1988

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CLINICAL REPORTS 99

Despite therapy with intravenous heparin, paraes-thesiae and reduced sensation developed in the rightforearm, and the brachial and radial pulses disap-peared. Urgent surgery was undertaken. The rightsubclavian artery was found to be thrombosed, withintimal damage. An end-to-end goretex graft wasinserted between the subclavian and axillary arteries,and distal thrombus was extracted using a Fogartyembolectomy catheter. Initial progress was satisfac-tory, and she was symptom-free with good peripheral

RHYTHM STRIP: II25 mm/sec: 1 cm/mV

pulses. However, 16 months later she reportedischaemic symptoms on exercising the right arm, andthe peripheral pulses were no longer palpable. Archaortography demonstrated occlusion of the graft.Further surgery is under consideration.

Patient 2

An 80 year old man was admitted to hospital followingthe acute onset of breathlessness, confusion, and

Figure 2 Patient 2: twelve lead electrocardiograms. (a) Temporary pacemaker in the left ventricle, paced beats withright bundle branch block pattern. (b) Two days later, permanent pacemaker in the right ventricle, paced beats with leftbundle branch block pattern.

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100 CLINICAL REPORTS

impaired vision on looking to the left. Examinationrevealed bradycardia and left homonymoushemianopia; an ECG showed complete heart block. Atemporary pacemaker was inserted via a left infrac-lavicular approach, after attempts to insert a wire fromthe right side had failed.

Six days later he was transferred to the RegionalCardiac Centre. An ECG showed paced beats withright bundle branch block configuration (Figure 2).Antero-posterior and lateral chest radiographappearances (Figure 3) suggested that the tip of thepacemaker was in the left ventricle. On the next day, apermanent pacemaker was implanted. X-ray screeningduring this procedure.confirmed that the temporarywire lay within the left ventricle. After consultationwith a vascular surgeon, the temporary wire waswithdrawn. Arterial bleeding occurred at the skinpuncture site, and was controlled by pressure. Therewas temporary loss of the left brachial and radialpulses; the former returned in 5 minutes, the latterafter 60 minutes. A cranial computed tomographic(CT) scan showed a slightly haemorrhagic infarct inthe right temporo-occipital region, with a matureinfarct in the left posterior frontal region, and others inthe basal ganglia on both sides. His confusion rapidlyresolved, and the hemianopia showed some improve-ment.

Patient 3

A 72 year old woman was admitted to hospital with a5-week history of dizzy spells, and five episodes of lossof consciousness. Five years previously, she had beennoted to have transient complete heart block, duringan episode ofmyocarditis attributed to viral infection.An ECG showed sinus rhythm with first degree heartblock, and frequent short-lived episodes of completeheart block. A temporary pacemaker was inserted andshe was transferred to the Regional Cardiac Centre.A permanent pacemaker wire was inserted via a

cut-down to the left cephalic vein, with a pacingthreshold of 0.7 volts. The temporary wire wasremoved. Two days later, she suffered sudden andtransient loss of consciousness when attempting tostand up after using a commode. There were noabnormal physical signs, her pacemaker was found tobe functioning satisfactorily, and the episode wasattributed to vaso-vagal syncope. She remained welluntil one year later, when she was admitted to hospitalwith left subclavian vein thrombosis, confirmed byvenography. This was treated successfully with in-travenous streptokinase, followed by heparin, andoral anticoagulation with warfarin.Two years after permanent pacemaker insertion,

her radiographs were examined in the course of aresearch project. The permanent pacemaker wirefollowed an abnormal route after entering the right

Figure 3 Patient 2: (a) antero-posterior and (b) lateralchest radiographs showing temporary pacemaker elect-rode placed in the left ventricle via the left subclavianartery.

atrium, consistent with passing across the atrial sep-tum, through the mitral valve and into the leftventricle. The patient was reviewed and found to bewell. An ECG showed paced complexes with completeright bundle branch block configuration. Two-dimensional echocardiography (Figure 4) confirmedthat the wire ran across the atrial septum and themitral valve, and lay with its tip in the left ventricle.Apart from this abnormal position, pacemaker func-tion was normal. Withdrawal of the wire was notattempted, for fear of precipitating systemicembolism. She has remained well, on long-term war-farin therapy.

Discussion

In each of these patients, a pacemaker electrodeintended for the right ventricle was placed in the lef

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Figure 4 Patient 3: two-dimensional echocardiogram. (a) Parasternal short axis view. (b) Subcostal four chamberview. Ao, aorta. RA, right atrium. LA, left atrium. LV, left ventricle. Arrows point to pacemaker wire, seen in (a)passing across the inter-atrial septum, probably via a patent foramen ovale, and in (b) passing from LA to LV.

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102 CLINICAL REPORTS

ventricle, and the error was not appreciated at the timeofthe procedure. In two patients, the subclavian arterywas mistaken for the vein, and a temporary pacemakerwire was passed along a retrograde course through theartery, the aorta, and the aortic valve. We are notaware of any published reports of similar cases.Puncture of the subclavian artery is the most frequentcomplication of attempted subclavian veincatheterization, occurring in approximately 3% ofattempts, but in most cases the operator isimmediately aware of the error.'Our first case (Patient 1) was diagnosed only when

'routine' withdrawal of the intra-arterial temporarywire led to catastrophic acute arterial obstruction. Theincreased awareness resulting from this episode prob-ably contributed to the prompt diagnosis ofthe secondcase (Patient 2), who was admitted 2 years later. Onthis occasion, withdrawal of the wire did not give riseto complications apart from temporary loss ofperipheral pulses, attributed to arterial spasm ratherthan embolism. This might not have been noticed inthe absence of specific monitoring. Some of thecerebral infarcts shown on this patient's cranial CTscan may have been caused by thrombotic emboliarising from the wire. However, homonymoushemianopia was noted before insertion of the temp-orary pacemaker, and other causes were implicated,including cerebral ischaemia during periods of ex-treme bradycardia or asystole complicating his com-plete heart block.

In the third patient, a permanent wire was insertedcorrectly into a vein and advanced to the right atrium,but then traversed the atrial septum, probably via apatent foramen ovale, to enter the left ventricle. Theforamen ovale remains a potential opening, valvularor 'probe patent', in a quarter ofthe adult population.2

Two similar cases have been reported previously.Friable debris was seen on the wire at surgical removalin one, and amaurosis fugax was the presentingsymptom in the other.3'4 This potential complicationof permanent transvenous pacemaker insertion is notwell known, and was not mentioned in a recentreview.5Our patient was diagnosed when a research project

prompted detailed scrutiny of the chest radiographs.Warfarin therapy prescribed for her venous throm-bosis may have prevented systemic emboli fromarising. None of the clinical events in this case can beattributed unequivocally to the misplaced wire, andthis 'benign' course suggests the possibility that theremay be other as yet unrecognized patients withpermanent pacemaker electrodes in the left ventricle.

Pacing with an intracardiac electrode near the apexof the right ventricle commonly produces QRS com-plexes on an electrocardiogram which resemble leftbundle branch block.6'7 In all three of our patients, atwelve lead ECG showed paced beats with theconfiguration of complete right bundle branch block.Although this is an occasional finding with a rightventricular electrode,7'8 such appearances should sug-gest the possibility that the pacemaker tip hasinadvertently been inserted into the left ventricle. Itsposition should be defined by PA and lateral chestradiographs, with echocardiography where approp-riate.

AcknowledgementsWe are grateful to Professor P. Sleight for allowing us toreport on patients under his care, and to Dr C. Woodham forradiological advice.

References

1. Sznajder, J.I., Zveibil, F.R., Bitternan, H., Weiner, P. &Bursztein, S. Central vein catheerization. Failure andcomplication rates by three percutaneous approaches.Arch Intern Med 1986, 146: 259-261.

2. Hagen, P.T., Scholz, D.G. &'Edwards, W.D. Incidenceand size of patent foramen ovale during the first 10decades of life: an autopsy study of 965 normal hearts.Mayo Clin Proc 1984, 59: 17-20.

3. Judson, P.L., Moore, T.B., Swank, M. & Ashworth, H.E.Two-dimensional echocardiograms of a transvenous leftventricular pacing catheter. Chest 1981, 80: 228-230.

4. Schiavone, W.A., Castle, L.W., Salcedo, E. & Graor, R.Amaurosis fugax in a patient with a left ventricularendocardial pacemaker. Pace 1984, 7: 288-292.

5. Phibbs, B. & Marriott, H.J.L. Complications of perma-nent transvenous pacing. N Engl J Med 1985, 312:1428-1432.

6. Goldman, M.J. Principles ofClinical Electrocardiography.Lange Medical Publications, California, 1979, p. 303.

7. Barold, S.S., Narula, O.S., Javier, R.P., Linhart, J.W.,Lister, J.W. & Samet, P. Significance of right bundle-branch block patterns during pervenous ventricular pac-ing. Br Heart J 1969, 31: 285-290.

8. Mower, M.M., Aranaga, C.E. & Tabatznik, B. Unusualpatterns of conduction produced by pacemaker stimuli.Am Heart J 1967, 74: 24-28.

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