Clinical impac o de ib illa ion es ing a he ime
o implan able ca dio e e -de ib illa o inse ion
Claudio Hadid1, Felipe A ienza1, Bo is S asbe g2, Ángel A enal1,
Pablo Codne 2, Es eban González-To ecilla1, Tomás Da ino1,
Tama a Pe cal1, Jesús Almend al1, Me cedes O iz1, Raphael Ma ins3,
Nie es Ma inez-Alzamo a4, F ancisco Fe nandez A iles1
1Hospi al Gene al Uni e si a io G ego io Ma añón, Mad id, Spain
2Rabin Medical Cen e , Tel A i Uni e si y, Tel A i , Is ael
3CHU Nancy, F ance
4Uni e sidad Poli écnica de Valencia, Valencia, Spain
Abs ac
Backg ound: Ven icula ib illa ion is ou inely induced du ing implan able ca dio e e -
-de ib illa o inse ion o assess de ib illa o pe o mance, bu his s a egy is expe iencing
a p og essi e decline. We aimed o assess he e icacy o de ib illa o he apies and long- e m
ou come in a coho o pa ien s ha unde wen de ib illa o implan a ion wi h and wi hou
de ib illa ion es ing.
Me hods: Re ospec i e obse a ional se ies o consecu i e pa ien s unde going ini ial de i-
b illa o inse ion o gene a o eplacemen . We egis e ed spon aneous en icula a hy h-
mias incidence and he apy e icacy, and mo ali y.
Resul s: A o al o 545 pa ien s unde wen de ib illa o implan a ion (111 wi h and 434
wi hou de ib illa ion es ing). A e 19 ( ange 9–31) mon hs o ollow-up, he dea h a e pe
obse a ion yea (4% s. 4%; p = 0.91) and he a e o pa ien s wi h de ib illa o - ea ed en-
icula a hy hmic e en s pe obse a ion yea (wi h es : 10% s. wi hou es : 12%; p = 0.46)
we e simila . The gene alized es ima ing equa ions-adjus ed i s shock p obabili y o success
in pa ien s wi h es (95%; CI 88–100%) s. wi hou es (98%; CI 96–100%; p = 0.42) and
he p opo ion o success ul an i achyca dia he apies (wi h es : 87% s. wi hou es : 80%;
p = 0.35) we e simila be ween g oups. The e was no di e ence in he annualized a e o ailed
i s shock pe pa ien and pe shocked pa ien be ween g oups (5% s. 4%; p = 0.94).
Conclusions: In his obse a ional s udy, ha included an unselec ed popula ion o pa ien s
wi h a de ib illa o , no di e ence was ound in o e all mo ali y, i s shock e icacy and a e o
ailed shocks ega dless o whe he de ib illa ion es ing was pe o med o no . (Ca diol J 2015;
22, 3: 253–259)
Key wo ds: implan able ca dio e e -de ib illa o , de ib illa ion es ing,
en icula ib illa ion, de ib illa o shocks, mo ali y
253
www.ca diologyjou nal.o g
ORIGINAL ARTICLE
Ca diology Jou nal
2015, Vol. 22, No. 3, 253–259
DOI: 10.5603/CJ.a2014.0062
Copy igh © 2015 Via Medica
ISSN 1897–5593
Add ess o co espondence: Felipe A ienza, MD, PhD, Ca diology Depa men , Hospi al Gene al Uni e si a io G ego io
Ma añón, C/D Esque do, 46, 28007 Mad id, Spain, el: +34915868281, e-mail: [email p o ec ed]
Recei ed: 17.07.2014 Accep ed: 21.07.2014
In oduc ion
The assessmen o de ib illa ion e icacy has
long been he s anda d o ca e du ing implan able
ca dio e e -de ib illa o (ICD) inse ion, and is
ecommended by ICDs manu ac u e s and scien-
i ic guidelines [1, 2]. Howe e , his s a egy is
cu en ly being ques ioned due o he high p ob-
abili y o cu en de ices o success ully de ib il-
la e en icula a hy hmias, he low incidence o
spon aneous en icula ib illa ion (VF) (~10%)
and he high e icacy o dedica ed an i achyca dia
pacing (ATP) s a egies [2–8]. Mo eo e , de ib illa-
ion es ing (DT) is no wi hou a isk, and compli-
ca ions associa ed o VF induc ion, shock deli e y
and anes hesia may occu [2, 3, 9–12]. Fo all hese
easons, he p opo ion o pa ien s unde going any
ype o DT, especially among p ima y p e en ion
ICD implan a ion, is expe iencing a p og essi e
decline in ou ine clinical p ac ice [12–15]. The
p ospec i e, non- andomized SAFE-ICD s udy se-
lec ed cen e s acco ding o hei common p ac ice
o pe o ming o no pe o ming DT a implan a ion
and ound no di e en ou come be ween g oups [8].
Howe e , ha s udy only included de-no o implan s
and did no epo da a on ATP he apy.
The pu pose o he p esen s udy was o as-
sess he e icacy o ICD he apies (bo h shocks and
ATP) and long- e m clinical ou come in a coho
o consecu i e pa ien s, including de-no o implan s
and gene a o eplacemen s, ha unde wen ICD
implan a ion wi h (+) and wi hou (–) DT a he
ime o ICD inse ion.
Me hods
We e ospec i ely e iewed he eco ds
o a se ies o consecu i e pa ien s > 18 yea s
old, in whom an ICD had been implan ed in wo
e ia y-ca e eaching hospi als (Hospi al Gene al
Uni e si a io G ego io Ma añón and Rabin Medical
Cen e ) du ing a pe iod o 3 yea s, ollowing he
implemen a ion o a non-DT policy a ou ins i u-
ions. DT was ecommended in igh pec o al ICD
implan a ion, R wa e signal < 5 mV o no able
o be measu ed due o pacing, abandoned leads,
implan ed elec onic de ices, ch onic ea men
wi h amioda one and pa ien s wi h hype ophic
ca diomyopa hy o channelopa hies. Howe e , he
inal decision o es was le a he disc e ion o he
ope a o . In case any ype o DT was conside ed
necessa y de ib illa ion sa e y ma gin es ima ion
was ou inely pe o med [16]. In he DT+ g oup,
VF was induced by s anda d T-wa e shock o
a 50-Hz bu s . A p o ocol o 2 de ib illa ions a 10 J
below he maximum ou pu o he de ice was
applied wi h a 5-min es pe iod be ween VF in-
duc ions. I he i s shock ailed, bu he second
was success ul, he pa ien was also conside ed o
ha e adequa e DT. I he de ib illa ion a emp was
unsuccess ul ce ain s a egies we e adop ed o
o e come his si ua ion (i.e. igh en icula [RV]
lead eposi ioning) and he p o ocol was epea ed.
All pa ien s signed w i en in o med consen . All
spon aneous achya hy hmic episodes wi h ICD
s o ed elec og ams ha esul ed in en icula
he apies we e e iewed by wo independen ob-
se e s (C.H. and P.C.), o assess e icacy o he
deli e ed he apy. Disag eemen s we e esol ed
by consensus wi h a hi d obse e .
All ICD implan a ions we e pe o med a he
elec ophysiology labo a o y unde local anes hesia
and conscious seda ion. Only pec o al implan a-
ions wi h dual-coil shocking leads placed in he
RV apex we e included in he s udy. Pa ien s e-
cei ed high-ou pu (≥ 35 J) o s anda d ac i e can
de ices manu ac u ed by Med onic (Minneapolis,
MN, USA), Bos on Scien i ic (S . Paul, MN, USA)
o Bio onik (Be lin, Ge many). De ice p og am-
ming was pe o med acco ding o pa ien clinical
s a us and le a he disc e ion o he esponsible
physician, bu all shocks we e p og ammed a he
highes a ailable ou pu o he de ice. Howe e ,
a s anda dized ATP p og amming in he as en-
icula achyca dia (VT) zone was ecommended
in all pa ien s [17]. Pa ien s we e i s ollowed
3 mon hs a e de ice implan a ion and e e y
6 mon hs he ea e .
S a is ical analysis
We used an app oxima e no mal es o he
equali y o a es o sample size es ima ion, whe e
a o al o 111 pa ien s in he DT+ g oup and 434 in
he DT– g oup would be able o de ec an absolu e
e o in mo ali y a es o 0.06, wi h 80% s a is ical
powe and a signi icance le el o 5%. Con inuous
a iables we e assessed o no mali y using he
Wilk-Shapi o es . No mally dis ibu ed a iables
a e exp essed as mean ± s anda d de ia ion,
whe eas hose wi h nonpa ame ic dis ibu ion a e
p esen ed as median and in e qua ile ange (IQR).
Ca ego ical a iables a e epo ed as numbe and
pe cen age. Compa isons o no mal con inuous
baseline cha ac e is ics we e made using S uden ’s
- es . In case o non-no mally dis ibu ed con-
inuous a iables, nonpa ame ic es s we e used.
Compa isons o ca ego ical a ia bles we e done us-
ing he Fishe ’s exac es o c2 es , as app op ia e.
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Ca diology Jou nal 2015, Vol. 22, No. 3
Incidence a es o dea h and a hy hmic e en s
be ween he coho s o DT+ and DT– pa ien s
we e compa ed using an app oxima e no mal es
o he equali y o a es. The annualized a e o
each a hy hmic episode ype pe pa ien mon h
was calcula ed by di iding he o al numbe o
episodes by ype by mon hs o ollow-up o each
pa ien g oup (DT+ s. DT–), whe e he weigh
assigned o each pa ien is he p opo ion o o e all
ollow-up ha he pa ien con ibu ed o he agg e-
ga e ollow-up [7]. Annualized a es o e en s pe
pa ien in bo h coho s we e compa ed using he
Gene alized Linea Model (GLZM) and he Wald
c2 es . Gene alized es ima ing equa ions (GEE)
me hod was used o compa e he e icacy o ICD
he apies in he wo coho s, adjus ing o mul iple
episodes pe pa ien [18]. Kaplan-Meie su i al
cu es and log- ank es we e used o compa e su -
i al be ween bo h g oups. Fo s a is ical analysis
we used SPSS e sion 19.0 (SPSS Inc.; Chicago,
IL). All p obabili y (p) alues we e 2-sided and
s a is ical signi icance was es ablished a p < 0.05.
Resul s
We included 548 consecu i e pa ien s ha
ep esen he o al numbe o ICD implan s pe -
o med a he pa icipa ing cen e s du ing he
inclusion pe iod a each si e, including gene a o
eplacemen s. Pa ien s we e ollowed o a median
o 19 mon hs (IQR 9–31). Th ee (0.68%) pa ien s
could no be con ac ed and we e conside ed los
o ollow-up and excluded om analysis. Table 1
shows he clinical cha ac e is ics o pa ien s in-
cluded in he s udy. In 111 (20%) pa ien s, DT
was pe o med a he ime o ICD implan a ion.
DT+ pa ien s we e sligh ly younge , less likely o
ecei e a ca diac esynch oniza ion he apy wi h
de ib illa ion capabili ies (CRT-ICD) and mo e
likely o be ea ed wi h an ia hy hmic d ugs and
o ecei e a dual-chambe de ice. O he baseline
clinical cha ac e is ics we e compa able be ween
g oups.
Pa ien s’ clinical ou comes
Pa ien s in he DT+ g oup we e ollowed o
a longe pe iod han DT– pa ien s (32 [18–45] s.
15 [9–26] mon hs; p < 0.001). A e adjus ing he
e en a e by he ollow-up du a ion, he e was no
signi ican di e ence in he dea h a e pe obse a-
ion yea (DT+: 0.04 s. DT–: 0.04; p = 0.91) no
in he a e o pa ien s wi h en icula a hy hmic
e en s pe obse a ion yea (DT+: 0.10 s. DT–:
0.12; p = 0.46) (Table 2). Simila ly, he e was no
di e ence in he a e o pa ien s wi h VF pe ob-
se a ion yea and only a end owa ds a sligh ly
highe a e o pa ien s wi h VT pe obse a ion
yea in he DT– g oup.
Table 1. Pa ien s’ baseline cha ac e is ics.
Va iable DT+ (n = 111) DT– (n = 434) P
Age [yea s] 67 (54–74) 68 (59–76) 0.03*
Male 95 (86%) 360 (83%) 0.52**
Hea disease e iology:
Ischemic 80 (72%) 279 (64%) 0.12**
Dila ed ca diomyopa hy 12 (11%) 77 (18%) 0.08**
Channelopa hies 5 (4.5%) 10 (2.3%) 0.20**
Hype ophic ca diomyopa hy 6 (5.4%) 22 (5%) 0.88**
O he 8 (7%) 46 (10%) 0.28**
Ejec ion ac ion £ 0.35 69/111 (62%) 300/413 (73%) 0.16**
Indica ion seconda y p e en ion 69 (62%) 227 (52%) 0.08**
De no o ICD implan a ion 95 (86%) 349 (80%) 0.22**
Type o ICD: < 0.01**
Single chambe 72 (65%) 270 (62%) NS***
Dual chambe 21 (19%) 44 (10%) 0.01***
CRT-ICD 18 (16%) 120 (28%) 0.01***
An ia hy hmic d ug he apy (amioda one) 38 (34%) 95 (22%) 0.01**
Con inuous a iables a e exp essed as median and in e qua ile ange; *Mann-Whi ney U es . Sig 2-sided; **Pea son’s c2 es . Sig 2-sided;
***App oxima e no mal es o adjus ed esiduals. Sig. 2-sided; CRT-ICD — ca diac esynch oniza ion he apy wi h de ib illa ion capabili ies;
DT — de ib illa ion es ing; ICD — implan able ca dio e e -de ib illa o ; NS — no signi ican
www.ca diologyjou nal.o g 255
Claudio Hadid e al., ICD de ib illa ion es ing a implan
ICD he apy equency and e icacy
by DT g oup a implan
Du ing he ollow-up pe iod, 109 (20%) pa-
ien s expe ienced 449 en icula a hy hmic
episodes ha equi ed ICD he apy. The absolu e
p opo ion o shocked pa ien s was highe in he
DT+ g oup (22% s. 11%; p < 0.01). Howe e ,
a e adjus ing o he ollow-up du a ion, he e
was no di e ence in he annualized a e o pa ien s
ecei ing shocks o ATP he apies, be ween DT+
s. DT– g oups (Table 2).
As shown in Table 3, he e was no di e ence in
he GEE-adjus ed i s shock p obabili y o success
in pa ien s wi h DT+ (95%; CI 88–100%) s. DT–
(98%; CI 96–100%; p = 0.42). The p opo ion o
success ul ATP he apies was g ea e in he DT+
g oup, bu he di e ence was no signi ican (DT+:
87% s. DT–: 73%; p = NS).
Fi e pa ien s had a ailed app op ia e i s shock:
2 pa ien s in he DT+ g oup and 3 in he DT– g oup
(Table 4). This accoun s o 2.8% (5/179) o o al
app op ia e ICD shocks deli e ed in he s udy and
0.9% (5/545) o pa ien s ollowed in he s udy. A e
adjus ing o he di e ences in ollow-up du a ion,
he e was no di e ence be ween g oups in he an-
nualized a e o ailed i s shock pe pa ien (DT+:
0.01 s. DT–: < 0.01; p = 0.71) and pe shocked
pa ien (DT+: 0.05 s. DT–: 0.04; p = 0.94). Table 4
shows he clinical cha ac e is ics o pa ien s wi h
a ailed i s shock. In all cases, he second shock
success ully e mina ed he en icula a hy hmia.
Mo ali y
Fo y (7.3%) pa ien s died du ing he ollow-
-up: 13 in he DT+ g oup (6 non-sudden ca diac
Table 2. Pa ien s’ clinical ou comes du ing ollow-up.
Incidence a e (pa ien -yea obse a ion) DT+ (n = 11) DT– (n = 434) P
Dea h 0.04 0.04 0.91
Pa ien s wi h en icula a hy hmic e en s: 0.10 0.12 0.46
Pa ien s wi h en icula ib illa ion 0.08 0.05 0.16
Pa ien s wi h en icula achyca dia 0.05 0.09 0.07
Pa ien s wi h he apies: 0.10 0.12 0.46
Shock 0.08 0.07 0.69
An i achyca dia pacing 0.05 0.07 0.16
App oxima e no mal es o equali y o a es. Sig. 2-sided; DT — de ib illa ion es ing
Table 3. E icacy o app op ia e he apies o
en icula a hy hmias.
DT+
(n = 31)
DT–
(n = 78)
P
Success ul shocks 38 136
Failed shocks 2 3
Success ul shocks/
/shocks ±
95% 98% 0.42
Success ul ATP 79 196
Failed ATP 46 133
Success ul ATP/ATP ± 87% 80% 0.35
± Gene alized es ima ing equa ions adjus men o accoun o mul-
iple episodes; ATP — an i achyca dia pacing; DT — de ib illa ion
es ing
Table 4. Clinical cha ac e is ics o pa ien s wi h a ailed i s ICD shock.
Case Gende Age E iology EF De ice Indica ion:
P e en ion
DT E en Zone AAD 2nd ICD
shock
1 Male 70 Non-ischemic 0.15 CRT-ICD P ima y – M-VT VF Yes Success ul
2 Male 61 Ischemic 0.30 SC-ICD Seconda y – M-VT VF No Success ul
3 Male 60 Non-ischemic 0.20 SC-ICD Seconda y – P-VT VF No Success ul
4 Male 59 Ischemic 0.30 DC-ICD Seconda y + VF VF Yes Success ul
5 Male 65 Ischemic 0.25 SC-ICD Seconda y + VF VF Yes Success ul
ICD — implan able ca dio e e -de ib illa o ; EF — ejec ion ac ion; Zone — ICD de ec ion zone; AAD — an ia hy hmic d ug he apy;
SC-ICD — single-chambe ICD; DC-ICD — dual-chambe ICD; M-VT — monomo phic en icula achyca dia; P-VT — polymo phic en icula
achyca dia; VF — en icula ib illa ion
256 www.ca diologyjou nal.o g
Ca diology Jou nal 2015, Vol. 22, No. 3
dea hs; 4 non-ca diac dea hs; 2 sudden dea hs;
1 unknown cause) and 27 in he DT– g oup
(11 non-sudden ca diac dea h; 11 non-ca diac dea h;
2 elec ical s o m; 3 unknown causes). Pa ien s
dying due o elec ical s o m we e admi ed o
he hospi al wi h incessan en icula a hy hmia
ha was ea ed wi h mul iple app op ia e ICD dis-
cha ges ha e mina ed he episodes wi h he i s
shock in all ins ances, while he ICD was wo king
p ope ly. One sudden dea h in he DT+ g oup oc-
cu ed in 1 pa ien wi h hype ophic ca diomyo-
pa hy. Unknown dea hs we e non-sudden and no
shock deli e y occu ed. The e we e no dea hs
ela ed o de ice ailu e o mal unc ion.
Unadjus ed mo ali y a es we e highe in
pa ien s wi h (12%) s. wi hou DT (6.2%; p =
= 0.048). Howe e , a e adjus ing o he di e -
ences in ollow-up du a ion, he e was no di e ence
in he annualized a e o dea h in DT+ s. DT– pa-
ien s (Table 2). As shown in Figu e 1, he e we e
no signi ican di e ences in he obse ed su i al
a es be ween DT+ s. DT– pa ien s (p = 0.9).
Discussion
This obse a ional s udy in an unselec ed
popula ion o consecu i e pa ien s unde going
ICD implan a ion ound simila shock e icacy and
long- e m clinical ou come ega dless o whe he
DT was pe o med o no . The e o e, in ou s udy,
pe o ming DT did no p edic ICD pe o mance
and had no clinical impac du ing he ollow-up.
These esul s a e ep esen a i e o he o e all
popula ion o pa ien s cu en ly unde going all
ypes o ICD implan s a wo e ia y e e al
cen e s, o all kinds o ICD indica ions, including
ICD wi h CRT capabili ies and gene a o eplace-
men s. Finally, hese esul s a e ep esen a i e
o he clinical ou comes o he ansi ion om he
adi ional DT s a egy o he non-DT s a egy o
mos o he pa ien s.
Clinical impac o DT
ICD implan a ion is indica ed o educe all-
cause mo ali y in pa ien s a isk. In he p esen
s udy, we obse ed no di e ences in he o e all
mo ali y a es i espec i e o whe he DT was
pe o med o no . All-cause mo ali y a es we e
simila in he RAFT pilo ial [19], bu lowe han
lowe in o he s obse a ional o e ospec i e
s udies [8, 20, 21]. Di e ences in pa ien cha ac-
e is ics and ollow-up du a ion migh accoun o
hese appa en disc epancies. Ne e heless, none
o hese s udies we e powe ed o de ec ed di e -
ences in all-cause mo ali y and sudden ca diac
dea h. On he o he hand, in ag eemen wi h p io
s udies, he e was no di e ence be ween g oups
in he annualized a e o pa ien s wi h en icula
a hy hmic episodes and he annualized a e o
pa ien s ecei ing app op ia e shocks (8% s. 9%)
[19–21].
ICD he apy e icacy in DT+ s. DT–
pa ien s
The e icacy o ICD o success ully de ib illa e
induced VF a implan is conside ed an adequa e
su oga e o ICD e icacy du ing ollow-up [22]. In
he p esen s udy, i s shock e icacy was 97% and
Figu e 1. Kaplan-Meie es ima es o su i al in pa ien s wi h (DT+) and wi hou (DT–) de ib illa ion es ing.
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Claudio Hadid e al., ICD de ib illa ion es ing a implan

only 5 episodes equi ed a second shock o suc-
cess ully e mina e he a hy hmia, wi h no di e -
ences be ween DT+ (95%) s. DT– (98%) g oups.
This compa ison canno be assessed s a is ically
due o he small numbe o unsuccess ul shocks.
This a e o i s shock ailu e is in ag eemen o
ha epo ed o spon aneous VF in pa ien s wi h
DT (80–91%) o sa e y ma gin es ing (91%) a
ICD implan a ion [2, 4, 5]. Simila ly, a signi ican
p opo ion (80–87%) o VT/ as VT episodes we e
success ully ATP- e mina ed wi hou shock deli -
e y, ega dless o whe he DT was pe o med. This
is consis en wi h p e ious s udies showing ha
dedica ed ATP p og amming educe he need o
shocks o e mina e VT/VF in a subs an ial numbe
o pa ien s [7, 17, 23]. In addi ion, newe de ices
a e able o deli e ATP du ing ene gy cha ge when
ea ing a VF episode, in an a emp o e mina e
a as VT de ec ed in he VF zone [24, 25]. In e es -
ingly, we obse ed no i s shock ailu es ollowing
ine ec i e ATP he apies, bo h in DT+ and DT–
pa ien s, since all i s shocks we e p og ammed
a maximum ene gy [23].
P io s udies
P io e ospec i e [5, 20, 21], p ospec i e
obse a ional [8] and small andomized [19] s udies
ha e epo ed on he long- e m clinical ou come o
non- es ed s. pa ien s unde going DT, mos ly in
mixed popula ion o p ima y p e en ion and CRT-D
pa ien s. Despi e di e ences in design, pa ien s’
cha ac e is ics and ollow-up du a ion, ou esul s
a e in ag eemen wi h mos o hese s udies. Pi es
and Johnson [5] epo ed a e ospec i e analysis o
ICD pa ien s assigned o in aope a i e DT, limi ed
de ib illa ion sa e y ma gin es ing o no DT in
a non- andomized ashion, and ound no di e ence
in shocks e icacy and sudden dea h a e, bu
a highe o e all mo ali y in he non- es ed g oup.
Bianchi e al. [21] e ospec i ely compa ed he
clinical ou come o ICD ecipien s o p ima y
p e en ion om cen e s ha ou inely pe o med
DT o ha o pa ien s in whom no DT was pe -
o med, and ound no di e ence in o al mo ali y,
ca dio ascula mo ali y o sudden dea h a es
be ween hose g oups. Simila ly, no di e ences
in su i al ee o hea ansplan a ion o shock
e icacy we e ound in a e ospec i e s udy o
CRT-D pa ien s [20]. A small pilo sub-s udy o he
RAFT ial, compa ed pa ien s wi h and wi hou
DT in a andomized ashion and showed simila
ICD he apy e icacy bu a non-signi ican 2- old
inc eased all-cause mo ali y in pa ien s unde go-
ing DT [19]. In he la ges s udy epo ed o da e,
he SAFE-ICD s udy p ospec i ely ollowed 2,120
pa ien s om cen e s selec ed acco ding o hei
s anda d implan a ion p ac ice and ound a simila
long- e m ou come in pa ien s wi h DT s. wi hou
DT du ing de no o implan s, in e ms pe iope a i e
complica ions, ICD he apy e icacy and mo ali y
[8]. Despi e he smalle sample size, ou s udy
ag ees wi h he SAFE-ICD in hei p ospec i e,
non- andomized na u e, and he lack o ou come
di e ences be ween g oups. Howe e , in ou s udy,
no pa ien s we e excluded du ing he ec ui men
pe iod and all ypes o ICD implan s we e consid-
e ed, including gene a o eplacemen s. Thus, ou
s udy con i ms and u he expands he SAFE-ICD
s udy esul s in pa ien s ha mos likely ep esen
an unselec ed popula ion cu en ly unde going ICD
implan a ion wi h ega ds o age, gende , indica-
ion and de ice ype [14, 16]. Mo eo e , his is
he i s s udy o p o ide de ailed analyses o he
ou come o ICD he apies, bo h ATP and shocks,
showing a simila i s shock e icacy in pa ien s
ollowing ailed ATP he apy in pa ien s wi h and
wi hou DT a implan . Since ATP he apy ailu e
delays ime o shock and p olongs VF du a ion,
a lowe shock e icacy could ha e been expec ed in
his con ex [23, 26]. I is eassu ing o no e ha
in ou s udy, all VT/VF episodes ollowing ailed
ATP we e success ully con e ed when i s shock
was p og ammed a maximum ene gy, ega dless
DT was pe o med o no .
Limi a ions o he s udy
Ou s udy has se e al po en ial limi a ions.
This is a non- andomized e ospec i e s udy wi h
di e en ollow-up imes be ween g oups ha we e
adjus ed by calcula ing annualized e en a es. Se-
lec ion bias owa ds including pa ien s wi h lowe
DT h esholds in he non- es ed g oup canno be
excluded. Non- es ed pa ien s had lowe ejec ion
ac ion and his di e ence may explain he highe
a e o CRT implan a ion in his g oup. Second, as
only dual-coil ICD leads we e implan ed, ou ind-
ings should no be ex apola ed o pa ien s wi h
single-coil leads. Thi d, ICD p og amming was no
guided by he esul o DT in he es ed g oup and
i s shocks we e se a maximum ene gy in bo h
g oups. The emaining ICD pa ame e s se ings
we e le a he physicians’ disc e ion and we e no
a ailable o analyses. Ne e heless, he ecom-
mended ATP p og amming s a egy was able o
success ully e mina e a high p opo ion o ea ed
episodes in p e ious s udies [7, 17, 26]. Finally,
3 pa ien s died o unknown causes, bu wi nesses’ e-
po s easonably excluded a sudden cause o dea h.
258 www.ca diologyjou nal.o g
Ca diology Jou nal 2015, Vol. 22, No. 3
Conclusions
In his obse a ional s udy, ha included an
unselec ed popula ion o consecu i e pa ien s
unde going ICD implan a ion, pe o ming DT a
he ime o ICD inse ion was no associa ed wi h
imp o ed su i al, highe i s shock e icacy
p obabili y o lowe a e o ailed ICD shocks as
compa ed o he s a egy o wi hholding DT. Un il
he esul s o andomized clinical ials become
a ailable [22], he p esen s udy ques ions he need
o sys ema ically pe o ming DT in he majo i y
o pa ien s unde going ICD implan a ion.
Con lic o in e es : D A ienza and P o .
S asbe g a e on he Eu opean A iso y Boa d o
Med onic. The es o he au ho s ha e no con lic s
o in e es s o epo .
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Claudio Hadid e al., ICD de ib illa ion es ing a implan