The Value of Redundancy in Chronic BipolarPacemaker Electrode Systems

UAVID R, HOLMES. JR,, BERNARD [. OERSH, CLARHN'CH SHIJB, [AMESn. MALONEY, and JOHN" MERIDETHl''ron"i t h e t ) i ^ ' i s i o n ul ( ' . a r ( i i n \ " a s r u l a r D i s c M s o s .iriii h i l e n i a l M c d i n i n i ' , M t U ' o (Cl in ic anc i \ 1 a y o

I ' i K n u i t i l i n n , Ku i :h i ! s ! t ' r , M i n n i i s n t a

HOLMES, D.H, /R.. KJ \I... The value of redunduncv in chronic bipolar pacemnkorelectrode s y s f o m s . Bipolar p a c i n g s y s t e m s . h e ( ; a u s e of (he p r e s e n c e (if t w o i n t r a -• xirdiav ulectrodes. provide lead redundancy. This allows conversion of bipolor tounipolar pacfnu or !he reversoJ of lend polarity. During !J 3-yvMr period, this redun-dancy was utilized in 34 I13.7''^yi of 248 patien!s with chronic hipoiur lead systems'iunrig iiillow-uj) paeemaker surgerx'. Df the 34 poii'f^nts, eiecJive pulsf! generaiorchange was ihf.^ most frequen! in(ijcation for surger\' (23 pufienfs) and in this groupreihinihiiicy was used mast often to select t h i ' lead auiii'^aration with th<- h i g h e s i H -:vave amplitude and lowest s t i n n i l d f i o n lhr(^sho/f i , fir !o s o l v e fhe p r o b l e m of vve/d(if'focf.s !si the f:onf)('r;tor p i n s o r ira.y(.H.l insulation. The remaining 11 patienls under-i\e.nt surger) for pacemaker s y s t e m m a l f u n c t i o n ( jnd m this group rethmdancv wtisused fo ti\-oid fhe nefid fnr lead r epos i t ion ing or plfjcement of a new caiheier sy'stern,Leuii redun!ianf ;y in those patients in w h o m hi'polor piicing hos beA-;n seleciedpro\-)dos flexi!jili!\" at thf: h'nie of Oiiddiontd pf jcemeker surgery , ami its use jn(J\' oh-vintf: the rioeti for a ci innge in C(jthe!er syslejTi whr-n sfimuliilion ihrosholds am ex-i:ossi'v"o, wire IrorAion is irieparal)le. or hif)ol(ir sens ing signals ore ino(i(u/ua;eIPM:K. Vni 3, fuly-/\ngust, 19801

leaii reda.nd<incy. bipoltn' e l ec t rodes , b ipo la r jxici/jg, lend pfi/tir/tv

i b i ipolar and bij)olar l ead sys tems a r e both fre- o ther difff ' rences. in [)arUcnliir the va lue f)f l eadijuently used in [permanent c a r d i a c [")acing. e l e c t rode r e d u n d a n c y , wh ich ailovvs for conver -Seiecl ion of e i the r s\',stem invoK'es consitiiH'a- sion of b ipo la r lo uni[)olar [lacing or the r eve r sa ltioii oi niuUi[i!e factors b e c a u s e ea!:h has ach^an- of lead polar i ty . Al though redundancN" wou ld ap-{,\g()s anf] disafK'antagi!8, Al though a t t en t ion has p e a r to he an a d v a n t a g e oi' b ipo la r hnuis . t h e r e isliecn paif! lo cer ta in ilifl'erence.s in the two types l imi ted in fo rmat ion on its c l inical value.'""" Th isol sys tems, for exain[)le, pacemaker - induc fn l refsori df icuments our ut i l iza t ion of this t 'ealure\ eulr if :ular fil'ir i l lat ion. ' local skfdetal musc le in pal i en Is w i t h c h r o n i c b i p o l a r (di"M:trfides t imula t ion , sens ing fit' thf in t raf ;ard iac signal.-' systnuis-an(! art ifact ampl ih! fh^ ' less has btjen paifl to

Materials and Miithotls

T h e rf 'Ciiri ls of a l l p a t i e n t s w i t h [ ) r ( ^ e x i s t i n g' ' " " ' - • ' . < ' ' ' ' • p u l s f ! g e n e r a t o r s a n d c h r f ) n i c b i p o l a r l e a d

A . l i h ' c - s ( c r r c j i r n i l s i ) n v i n R I i n h T i P ; i , I r , \ ' 1 . i ) , , I ) i \ ' i ^ n i n u ! ,• i r . 1 ,, . 1 •• \r . H - d i c v . L s ' : i l , i i - D i s f M s i ' s iiiifl l i i b ' n i i i t M i ' d i m c \ U i \ n s y s t e m s [iU | H a c n t o r m f i r e t h a n ,i m o n t h s ) w h oe l i i ' i . ' , R tMi i ! ' ' ; t iT , Mi imi^ '^o! , ! riTiiHM, t ' . s . A u n d e r w e n t a t i d i t i o n a l p a c e m a k e r s u r g e r y f r f j m

:um I'ACI-:, \'^

Kia)['\'DAN(:Y IK !ilP()L,AR PACHMAKi-H i'LI-CFKODES

S e p t e m b e r 1971! lo S o p t e m b e r 1979 vveti'rnviovved. Patients r(K]uiring load repositioningor pliic:(Mii(int of a new cathcti'r vver(! excludoci.After (hnsn exclusions, there wore 248 patifmts(luring this :i-ynar period in whom the {ixi.sHnjbipniar electrode was utihi^ed. The rociirds (ifthese patients wfjre iinalyzed with regard to ihf;frccjuency and indi(;ati[in for iitihzing the in-hor<int reiiiindancy in the bip(dar hiad system.

Resulls

Of the 24i5 patients, 214 underwent roopfM'a-tion and placfMnent of a new pulse grmc^ratorwithout any nhange in load configuration. Leadrcdunrlancy was uti!iz(Ki in the rr^maining 34{rA.V'i ). In the '•]4 patients, the rni)s{ common in-dication f(ir surgfM-y was pulse-generator d(!ple-tiori or inanui'aclurer advisory [23 patient.s|(Table I). The remaining 11 patients underw*entsurgery for pacemaker-system malfunclion. OfIhe 34 patients, 2H had transvenous l(;ad systemsand 8 had ejiicardial leads,*

Croup ]-—Pdtients !'ndergo/ng KlofiiveOe.nnrutor Chtinge for Manufacturer Advisory orF.nd-nf-Life Indicators

Of the 23 patients in whom the major indica-tion for reoperation was battery depletion ormanufacturer advisory, 20 had had no pre-operative evidence of pacing or sensingmalfunction. Of the remaining 3 palients. 1 hadhad in addition rare failure to sense and 1 hadintermittent diaphragmatic .stimulation. Thefinal [)atient had a hipolar lead sysiem with aunipolar pulse generator and had intermittf-ntlof:al muscle sHmulation. In thes(! patients, therare failure to sense intermittent dia[)hragmaticstiniidalion and locnl niusele stimulalion werenot felt to be significant clinical [)roblems-

In these 23 patients, the pre-existing eledrodehad been in place for a mtian of 4.3 years. At thetime of reoperalion, thresholds wfn-e measuredat O.fi or 0.8 ms pulse widfh depending on

; I c a i i s , M i u t c t Kns. 6 !n : i , ('.917, nHlH. fi^iOl, o r liM

Tabie I.

Preoperative indications tor Surgery

IndicationNo. of

Palienta

Elective pulse-generator changePacemaker maHunction

Failure to paceSensing malfunctionFailure to pace and sense

23115

33

manufacturer specifications using a 5311(1 Med-tronic PSA analyzer. R-wave amplitude wa.s alsomeasured with a 5300 Medtronic PSA anaKzer.Ten patients (Table Ii) had ac:ceptable bipolarchronic stimulation thr(!sholds (< 3.r) Vj, RiMhin-dancy was utilized in these palients and th(! leaciconfiguration was (;hang(Ml because anothercombination (either reversed j)olarity or uni-polar pacing) provided im[)roved an(] lowerstimulation thresholds and thus a higher marginof safety. An additional 4 patienls had chronichipolar stimulation thresholds that wen; >3,ri Vand were considered lo be unacceptable Inthese patienls, the system was converleci lo jni-polar pacing or the polarity was revers<!<tbecause with unipolar pacing or reversal ofpolarity th(! thresholds w'ere founcl to be Imverand accej)table (< 3.5 V]. Redundancy wasutilized in 8 of the remaining 9 patients tn in-

Table n.

indications for Use of Redundancy in 23 PatientsUndergoing Elective Pulse-Generator Change

IndicationNo. ol

Patients

Selection of pacing combination with loweststimulation thresholds (initial stimulationthreshold acceptable)

Selection of pacing combination with loweststimulation thresholds [initial stimulationthresholds unsatisfactory > 3.5 V)

Frayed connector or loose connector pinImproved sensing characteristicsDiaphragmatic stimulationLocal skeletal muscle stimulation

Vo

(;|-,RSi Al

i:r(;a,sn K-vviivn a m p l i t u d e (3 patifinl.s) bf^caii.sn

tht! f inding of we ld defec is wi th loose ci inneci

p ins or f rayed insu la t ion [4 pa t ients ) or

u i imina to d iaphra j jma t i c s t imula t ion (1 pati(in

hi MK; final pa t i en t , re t l i in i lancy was u!i]iz(Ml

e l i m i n a h ' Ihe intiM'mittent local m u s c l e sliinul

lion ihal was iissociaSefl with the p r ev inus use

ii un ipo l a r g e n e r a t o r wi th ihe b ipo la r le

syslern. In this pa t i en t , (ho p a n n m a k e r syste

w a s c h a n g e d to a b i p o l a r g e n e r a t o r wi

of tho iucal musc le s l imi i la t ion.

Patients f 'nder^fi ing /\fJ(fifionn/

.Surppr\' for Pocomuker-Sys! '?!!!

i',le\'eii p a t i e n t s hacl p a c e m a k e r

fTahle I | . Of thosn I 1 pa t i en t s , thi^ most f r equen t

mal func t ion was ftiilure to pact; senoni la r \ lo

eii-ctrode f rac ture (dociimenteci in two and as-

siuneil in \hv. (Hher on \hi'. ha.sis nf i n t i n i t r

i n i p e d a n c e in one (;on(iuct(ui or ('xi! block

('i'ai;)le 111]. In these 11 pa t i en t s , r e d u n d a n c ) ' u as

uti!izf"!(i in an attc^npl to S O | \ T the malfunct ion

and to avoici the noerl for p l a c o m c n l of a new-

cat hfMer or r epos i t ion ing of the pro-exis l ing

ca thc le r , Tho \>M\d sys tem in those j ial ionls had

h(!(ni in p l ace for a nuuin of 4.5 \ e a r s lii all II

pa t i en t s , the lead sys tem was c o n v e r h ' d tn iiiii-

[ifilar pac ing .

Dur ing the m e a n follow up of 9.8 months , 2 of

tho M j)ationls o p e r a t e d on for pace!n<iko?

ina]lynt; t ion [(>roup 1I| r e ip i i r ed add i t iona l sur-

gory (la 'Vj bocau.so the app l i ca l ion of redui i

d a n c \ ' fai led to resul t in a long-iorm s(ilulioii to

iho cl inical pac ing p r o b l e m . T h e first of these 2

pa t i en t s ini t iai ly had failiiro to pace . His systoni

Table III.

Indications for Use of Redundancy in 11 Patients UndergoingAdditional Surgery for Pacemaker Malfunction

Indication

Stimulation thirestiolds > 3,5 Viead fractureInsulation breakLow H-wave amplitude and clinical

sensing matfunction

No. otPatients

A

31

w a s c o n v e r t e d to t h e u n i p o l a r moch^ b e c a u s e of

a n i n s u i a f i o n b r e a k , O n e w e e k l a t e r h i ; h a d

f a i l u r e lo p a c e aj^ain, S u h s e ( ] n ( i n l s u r g e r y r e -

v o a l e d f r a c t u r e s of b o t h c o n d u c t o r s a n d a n e w

!(;ad w a s p l a c e d . T h e s e c o n d lif tbes«» 2 p a t i e n t s

u n d e r w e n ( s u r g e r y i o r fa i l i i r< ' !o s e n s e , T b e

H\ s t e m w a s c o n \ ' e r t ( ; d to a u n i p o J a r m o d e

h i u j a u s e of i h e f i n r l i ug of a n i m p n n ' e d K w a \ ' e

w i t h t h i s c o n f i g u r a t i o n . P o s t o p e r a l i \ ' i ' ] \ \ h o w -

ex e r . s h e c o n t i n u e d to l i a \ e f a i l u r e to s e n s e a n d

a ri(^\v b i p o l a r e l e c t r o d e w a s [)laciHl, A n a d -

dilHiT'iai t h i r d j j a t i e n i w h o ( u i g n i a l l y u n d e r w i ' i i t

r e n [ i f ; r a t i o n for a n eii^'Ctix e p u l s e g f U i e r a t o r

i : h a n g e ( ( i r (5up I) r e q u i i ' e i l f u r t h e r surgt ' ! -y Al

t h e l i m e ol i n i l i a l r ( ? p l a c ( n i ) e n t t l ic s y s l c m w a s

con \ ' ( » r ! ed lo t h e un i j )o i r ) r m o d e b e c a u s e in\<- of

d i e l e a d s w a s f r a y e d A l t e r s u r g e r y , ' h e paliiMil

h a d t h e n e u ' o n s e t of a l n l o n i i n a ! w a l l s l i m u i a l i i u T

w h i c h w a s feit lo bo s e c o i i d a i A lo Ihe l e a d c o u -

f i g u r a l i o n of b e r s \ ' s l e m , S u h s e i p i o n t K , s l ie

u n H e r w f r U p l a c e m e n t of a n e w b i [ )o la i ' ! r a n s

D i s c i i s s i o n

R e d u n d a n c y , tin? a h i l i i y lo r e v e r s e [ l o l a r i t y or

c o n \ ' e i 1 fi 'oni b i p o l a r lo u n i p o l a r p a c i n g in orc lc i '

to i m p r o v e [ l a c i n g a n d s e n s i n g c h a r a ( J i ; r i s t i c s , is

n n i ( | i H ' io b i p o l a r p a r : i n g . It c a n h e u t i l i z e d in

s e v e r f i l w a y s : In p a l i e n t s u n d e r g o i n g i d e c l i v e

b a t t e r y - p a c k c b a n g e [o r g e n e r a t o r d r j)hM ion

w i t h o u l e \ ' i i ! e n c e of a i n otb(U' m a l h m c l i o n , il

a l l o w s s e l e c t i o n of th(^ (;I<M;tro(i(i sws t inn i h a t l i as

t h e l o w e s t s t i m u l a t i o n t h r e s h o l d a n d t h o h i g h e s t

R A v a v e a m p l i t u i l e a n d t h f ; r o f o r o thf! b i g h c s l

s a f o K ' m a i g i n , ln a d d i t i o n to u t i l i z i n g t h e tdoc -

t r o d o s y s t e m w i t h t h e i o w e s t t b r r j s h o l d , in i h o s e

c i r r : u m s ! a n c e s in w l i J c h a d a p t e j - s a r e no t r o a i i i h '

a v a i l a b l e or i h e (;r)nnfactors a n - f o i i n d lo Ix*

fra>i ' ( l o r a r e d a m a g e d at surgcMA. I h e ro iUin-

d a i i c \ f a c i l i t a t e s c o n t i n u o d u s e af \h<', e x i s t i n g

c a t h e t e i ' w i t h o u t th i ; n o e d l o r s p l i c i n g , R e d u n -

d , i n c \ ' a l s o c a n b e u t i l i z e d for s o l v i n g t d i n i c i d

p a c i n g p r o b l e m s in p a t i e n t s w i t h p a c ( ; m a k e r '

s y s l e m m a l f u n c t i o n . T h i s w a s u t i l i z e d in 11

p a t i e n t s u n d e r g o i n g s u r g e r y fo r a p a c e m a k e r -

s \ s t e m f a i b i r o , T b e m o s l f r iMpien ! p r o c i ' i l u i ' e in

t b i s s i t u a t i o n is c o n v e r s i o n f r o m b i p o l a r to u n i -

p o h i r p a c i n g to o b t a i n a{le(]\iat(» p a c i n g t h r e s h

Ui\\ - •\\tU.U'- VM'M. \ ni

Ri-;[)H.\I)AM(;Y IN BiPOLAR PACEMAKER HLF:CTKOL)KS

iiid.s or Io improve the sensing characleri .stics (ifthf; sysletn. Thi.s may hn of parfi(;nhir impor-\:\nt:G in pa l ien ls with ep ica rd ia l lead sy.sfemsand load f rac tures thai a re irre[)ar;i!ile.

1'herp are polonlial prohifmis in ulil izing therfMliirKiancy of (he b ipolar sy.stcm. If Iho indica-tion for fjonvnrsion is wi re iracturf;. tho rnmain-in> loiid may be more likely io f racture becausethii s ame local strosse.s r ema in . If lh(5 p(!!arity ofIlic svstom is mornly rover.s(;d !)ut Ihe systimiil.self rf jmain.s b i p o l a r , ( h e r o art,' o t i i o rihnoret ical p rob iems wiiich ri-late to the flif-lerc i ice in n l ec tmdo desiiiii. In most hi|}f)larsystems, fh( j)roximal e loc l rode is largor andthus ihe oiirrnnt densi ty will he lower anil ihes t i m u l a t i o n t h r e s h o l d s hi^yher. Thi e s h o i d smoasurod at convers ion . h()W(*Vi'r, a re rJirnnicand if ai:coptahlo shfinld remain 8taiih^'' In 2 oithe 11 pa t ien ts operatiMl on for p a c e m a k e rmalfin-iction in ihe present seri(is, the ,ipphi;a-

lion of r e d u n d a n c y failed to resul t in asolution It) the clinical pac ing prohlorn.

T h e r e a rc advan tages and d i sadvan tages toi)()th bi!)f)l<!r and un ipo la r pacing. O n c e soleotei!,a pa r t i cu la r lead system m\ist he ut i l ized in anoptimal way. In pa t i en i s in w h o m bipolar pacingh a s h e e n prev ious ly se lec ted , tho potent ia l va lueol" redundanf :y should he appret : ia tod. It a l lowsthe phys ic ian to select the opt imal pacinjj modeat the t ime of e lec t ive pulse-j.!enerator chan^thUs use may e l imina te the need f(ir a ohans^e in(dironic lead sys tems in ins tances in whii h thepacin^J and sens ing charac te r i s t i cs of ihe pace-m a k e r system ha\-e changed with t ime andslimuhit ion ih reshokis a re excess ive r-r u'ii'ef rac ture is irre[)a^ai)h^ An a t tempt U) utilize [hisre t i imdancy is par t icuhi r ly impor tant in [latieiifswith ep ica rd ia ! lead .systems if implan ta t ion ofnew leads involves the risk of gene ra l anes-

Refnroncos

I . P r e s t o n . T . A . : A n o f h i i s l i i n u l n l i n n ds a c o i s r o fI H i n f i m n k o r - i d d u c i u i v n n U ' i c u h i r f i i i r i l l i i n o n , .Aiji; / ( ^ r i r i /.. Hfi:;if;(), i f j7; i .

1 . l ) e ( : , i } ) r i o . V \ , llurzi^li^r. P . , a n d i M i r n i n n , S . : Ai . o n i p i n ' i s o i i o f u n i [ ) o i a r a n d l i i p o h i r r l n ( ; t r i i > ; r a i i i sl o r o a i ' d i a c p . i c c m a k f j r s m i s i n j ; , (Arnilatinn.,~3(i:7r)\). 1977.

; i i-"nrm<!n, S , , T n i i j o i n r a n d b i p o l a r p . i i : i i i ^ S ( n n i i -

Am4, i- ' i iniiHii . S,: ( ;ar t i i<i( : [ l acm.u a n d

A i i a l y s i . s of j i a c p i n a k e r n i i t l f i n i c i

it4::i7B. 1977

n. K a n t r o w i ! / , A . . R u h i M i f i r i ' . M , . a m i \V<ij.s7(,/.uk. U"

n o i i i p h c a l i n n s of p o r i n a i i i i n ! h -ans \ 'on( ) i i . s j iao t

n i a k n r t h e r a [ ) v . In H J . T . T h a l i ' n |!-,(i,!: P r . ( - m i -

inps nt lhi> tVlii internalionul <S\;ii/K)siun; oi: Cur-i l n u : P a c i n g . A s . s f n . T h e N n l h t i r l . i m l s , V a n ( n r i . i n n^ S i n n i p i t n y [! V . t ' ) 7 : i , p . 2A<1

(i^ y . n U . I ' . M , , i - r a i i k , i i . A , . Z a r s k > , L , R , \ , , l . i n r i U h a l ,A - l . a i ^ i l H o l g a r d , . A , H , . L o n ^ t ; l f ; r i n r h ^ c i r j i :s t u i i u i a f i o n n l t h o h o n r ! f o r S l o k p s - A d d n ; - . i h sn a . s i ' , A n n S u i O . . . 1 5 - l \ i 3 l ) . i l t P L

7 . H a r ' n h l , H . S , . a n d ( i a i d n i a , j j , : r . n l u r o i t f ( i f i n . u u ip a c o n i a k o r i r o n i i o v v - \ o N a y c h i | ) o l a r \ ( ' ! i l r i i : u l a i 'I ' l f c t r t i i j r a i n s / . A A J . A . 2 \ 5 . 9 2 ' \ . \ 9 7 ] .

H, ] - ' n r m . i n , S . , t l u r / i i l e r . 1 ' . , , i n t i M c h r a . K C s i ' t i j a f ,p a c n i L ' a i K J [ i a c i M n a k i ^ r s , I \ " , T h r e s h o l d i d L d r d i a c. • ^ t i r n u i a h n i i . A n ) . U r n r S /,, 9 4 - n r ) , l ! ) 7 ~

A u u n s I