Resea ch A icle
A ial Dyssynch ony Measu ed by S ain Echoca diog aphy as a
Ma ke o P oa hy hmic Remodeling and Oxida i e S ess in
Ca diac Su ge y Pa ien s
F ancisco J. Sánchez ,
1,2
Vale ia A. Gonzalez,
3
Ma in Fa ando,
2
A iel O. Baigo ia Jaya ,
2
Ma ga i a Sego ia-Roldan ,
4
Lau a Ga cía-Mendí il ,
4
Lau a O do ás ,
4,5
Na alia J. P ado ,
6
Es he Pueyo ,
4,7
and Emiliano R. Diez
1,6
1
Depa men o Mo phophysiology, School o Medicine, Na ional Uni e si y o Cuyo, Cen o Uni e si a io, Mendoza 5500, A gen ina
2
Depa men o Ca dio ascula Su ge y, Clinic o Cuyo, Mendoza 5500, A gen ina
3
Depa men o Ca diology, Lagomaggio e Hospi al, Mendoza 5500, A gen ina
4
Biomedical Signal In e p e a ion and Compu a ional Simula ion (BSICoS), A agon Ins i u e o Enginee ing Resea ch (I3A),
Uni e si y o Za agoza Ins i u o de In es igación Sani a ia (IIS), Za agoza 50018, Spain
5
A agon Agency o Resea ch and De elopmen (ARAID), Za agoza 50018, Spain
6
Ins i u e o Expe imen al Medicine and Biology o Cuyo (IMBECU)-CONICET, Mendoza 5500, A gen ina
7
Biomedical Resea ch Ne wo king Cen e in Bioenginee ing, Bioma e ials and Nanomedicine (CIBER-BBN), Za agoza 50018, Spain
Co espondence should be add essed o Emiliano R. Diez; [email p o ec ed]
Recei ed 22 Sep embe 2020; Re ised 12 No embe 2020; Accep ed 20 No embe 2020; Published 30 Decembe 2020
Academic Edi o : Lau a Sa iani
Copy igh © 2020 F ancisco J. Sánchez e al. This is an open access a icle dis ibu ed unde he C ea i e Commons A ibu ion
License, which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is
p ope ly ci ed.
Aging leads o s uc u al and elec ophysiological changes ha inc ease he isk o pos ope a i e a ial a hy hmias; howe e ,
nonin asi e p eope a i e ma ke s o a ial p oa hy hmic condi ions a e s ill needed. This s udy is aimed a assessing whe he
in e a ial dyssynch ony de e mined using wo-dimensional speckle acking echoca diog aphy ela es o p oa hy hmic
s uc u al and unc ional emodeling. A coho o 45 pa ien s in sinus hy hm e e ed o ca diac su ge y was e alua ed by
echoca diog aphy and su ace elec oca diog am he day be o e he in e en ion. T ansmemb ane po en ial, connexin, and
po assium channel dis ibu ion, inflamma o y, and ni ooxida i e ma ke s we e measu ed om igh a ial issue ob ained om
pa ien s. A diffe ence g ea e han 40 milliseconds be ween igh and le a ial ee wall con ac ion confi med he p esence o
in e a ial dyssynch ony in 21 pa ien s. No diffe ence in ela ion wi h age, p e ious diseases, and 2-dimensional
echoca diog aphic findings as well as a e age alues o global longi udinal igh and le a ial s ain we e ound be ween
synch onic and dyssynch onic pa ien s. Pos ope a i e a ial fib illa ion incidence inc eased om 8.3% in he synch onic g oup
o 33.3% in he dyssynch onic ones. P wa e du a ion showed no diffe ence be ween g oups. Ac ion po en ials om
dyssynch onous pa ien s dec eased in ampli ude, maximal a e o depola iza ion, and hype pola ized. Du a ion a 30% o
epola iza ion inc eased, being ma kedly sho e a 90% o epola iza ion. Only he dyssynch onous g oup showed ea ly and
delayed a e depola iza ions. A ial issue o dyssynch onous pa ien s displayed la e aliza ion o connexin 40 and inc eased
connexin 43 exp ession and accumula ion o umo nec osis ac o -αin he in e cala ed disc. Tumo nec osis ac o -αdid no
colocalize, howe e , wi h la e alized connexin 40. Ni oxida i e ma ks and K
ATP
channels inc eased pe i ascula ly and in
myocy es. Ou esul s demons a e ha , as compa ed o a adi ional su ace elec oca diog am, he no el nonin asi e
echoca diog aphic e alua ion o in e a ial dyssynch ony p o ides a be e iden ifica ion o nonaged- ela ed p oa hy hmic
a ial emodeling wi h inc eased suscep ibili y o pos ope a i e a ial fib illa ion.
Hindawi
Oxida i e Medicine and Cellula Longe i y
Volume 2020, A icle ID 8895078, 14 pages
h ps://doi.o g/10.1155/2020/8895078
1. In oduc ion
A hy hmias usually complica e ca dio ascula su ge y, and
aging is he main isk ac o . A ial fib illa ion is he mos e-
quen sus ained a hy hmia wi h a peak o appea ance
be ween he second and fi h days o he pos ope a i e s ay
[1]. I s incidence p og essi ely inc eases om 18% in sexage-
na ians o 50% in oc ogena ians [2]. A hy hmic e en s a e
usually sel -limi ed, and ea men equen ly es o es sinus
hy hm. Howe e , pos ope a i e a ial fib illa ion (POAF)
p olongs hospi al s ay and inc eases he isk o s oke and
mo ali y [1].
A ial aging is an elusi e p ooxida i e and p oa hy hmic
condi ion. Oxida i e s ess, hype ad ene gic s a es, and
inflamma ion con ibu e o age- ela ed a ial emodeling,
bu hese issue al e a ions a e challenging o iden i y nonin-
asi ely [3, 4]. In his con ex , a ial enla gemen , s iffness,
and conduc ion blockade a e known isk ac o s, bu hey
a e p esen in only a ew pa ien s. The e o e, he mechanisms
in ol ed in he onse and pe pe ua ion o POAF a e difficul
o o esee [5]. Addi ionally, su ge y pe se acili a es a hy h-
mias due o ischemia- epe usion inju y, which inc eases he
p eexis ing oxida i e s ess s a e. The lack o ools o es ima e
he p oa hy hmic subs a e e idences he absence o p e en-
i e in e en ions.
S uc u e and unc ion o he bea ing hea can e eal
a ial hidden oxida ion and inflamma ion. Signs o issue
emodeling, be o e dila a ion, a ise om a ial dynamic
cyclic changes. New echoca diog aphic echniques like s ain
and s ain a e ep esen he magni ude and a e o myoca -
dial de o ma ion. S ain can eflec dis ensibili y and a ial
con ac ili y [6]. Nonmyocy ic cells and ex acellula ma ix
mainly affec dis ensibili y [7]. Ca diomyocy e s uc u e
and in e cellula communica ion de e mine con ac ile unc-
ion. Each a ial segmen ollows a ajec o y du ing he ca -
diac cycle ep esen a i e o he issue physiology [8].
Elec ical emodeling in ol es al e a ions in bo h myocy es
and nonmyocy ic cells, which mani es as con ac ile dyssyn-
ch ony in he echoca diog am, in a simila way as epo ed
o he en icles [9].
Gap junc ions in he hea p o ide low esis ance pa h-
ways o p opaga ing he ac ion po en ial ac oss he myoca -
dium, con ibu ing o elec ical coupling and signal
p opaga ion [10]. Al e a ion o ca diomyocy e gap junc ions
and hei main componen s, connexins (Cx), has been sug-
ges ed o con ibu e o he o ma ion o a hy hmias, includ-
ing a ial fib illa ion [11–13]. Accumula ing e idence also
sugges s ha inflamma ion and oxida i e s ess a e in ol ed
in a ial emodeling. De ec ion o p o ein 3-ni o y osine is
ega ded as a ma ke o ni ooxida i e s ess and is obse ed
especially in inflamma o y p ocesses. The eac ion o pe ox-
yni i e wi h y osine leads o he o ma ion o 3-
ni o y osine and p omo es p o ein, lipid, and DNA damage
[14, 15]. ATP- egula ed po assium channels (K
ATP
) a e well-
cha ac e ized me abolic and oxida i e senso s in ischemia/ -
epe usion a hy hmias and he e pos ula ed as an in e es ing
subs a e o POAF [16].
This s udy is aimed a assessing whe he in e a ial dys-
synch ony, de e mined by using wo-dimensional speckle
acking echoca diog aphy, ela es o p oa hy hmic s uc-
u al and unc ional emodeling o he a ia and whe he his
inc eases he suscep ibili y o POAF.
2. Ma e ials and Me hods
2.1. Subjec s and E hical Conside a ions. Pa ien s wi h co o-
na y a e y disease, ao ic s enosis, o he combina ion o
bo h pa hologies, scheduled o su ge y a he Depa men
o Ca diac Su ge y (Clinic o Cuyo, Mendoza, A gen ina),
we e p ospec i ely en olled be ween Janua y 2018 and
Ma ch 2020. Co ona y disease and ao ic al e s enosis
se e i y we e defined acco ding o cu en ESC Guidelines
o de e mine su ge y indica ion [17, 18]. All subjec s p o-
ided w i en in o med consen unde he esea ch p o ocol
app o ed by he E hics Commi ee o he Na ional Uni e si y
o Cuyo (Exp-Cuy: 22959/2017).
Clinical da a including age, gende , and his o y o p e i-
ous myoca dial in a c ion and hea ailu e was collec ed.
The p esence o p eope a i e a ial fib illa ion was de e -
mined acco ding o p e ious elec oca diog aphic epo s
o diagnosis in medical his o y. In o ma ion ega ding he
ollowing ca dio ascula isk ac o s was collec ed: hype en-
sion, dyslipidemia (low-densi y lipop o ein choles e ol abo e
100mg/dL o he use o lipid-lowe ing d ugs), smoking (cu -
en o any smoking habi in he pas en yea s), and diabe es
melli us (p e ious diagnosis o diabe es melli us o glyca ed
hemoglobin g ea e han 6.5%). The p eope a i e use o
medica ions was also documen ed.
2.2. Inclusion and Exclusion C i e ia. Pa ien s o e 18 yea s o
age in sinus hy hm wi h an indica ion o ca dio ascula su -
ge y ha ga e w i en in o med consen we e included in he
s udy. Exclusion c i e ia we e as ollows: indica ion o mi al
o icuspid al e epai o eplacemen , being olde han 80
yea s, his o y o p e ious a ial fib illa ion, p esence o mod-
e a e al ula disease o al ula p os hesis, his o y o con-
geni al ca diac abno mali ies o ca diac umo s, eme gency
su ge y, inabili y o p o ide in o med consen , and a no
en i ely de ec able le and igh a ial p ofile om he apical
ou -chambe iew du ing p eope a i e echoca diog aphy.
2.3. P eope a i e Elec oca diog am. Be o e su ge y, pa ien s
unde wen a 12-lead elec oca diog am (ECG) using he
Synch onous ECG so wa e V1.3.5. Measu emen in milli-
seconds o he P wa e and he PR segmen was pe o med
wi h he so wa e calipe . Acco ding o he cu en classifica-
ion, hese pa ien s we e e alua ed o he p esence o an
in e a ial conduc ion dis u bance called Bayes synd ome
[19]. The e a e wo majo ca ego ies o his synd ome: com-
ple e and incomple e, bo h based on P wa e du a ion and
mo phology in he 12-lead ECG.
2.4. Echoca diog aphy and A ial S ain. All pa ien s we e
imaged in a le la e al decubi us posi ion using ESAOTE
ul asound sys em equipmen (MyLab30Gold Ca dio ascu-
la ) wi h a 2-4 MHz/PA240 p obe. Two-dimensional speckle
acking s ain imaging was pe o med om he apical posi-
ion by an expe ienced echnician. The a e age ame a e o
analysis was 60-80 ames/s. Du ing a single b ea h-hold,
2 Oxida i e Medicine and Cellula Longe i y
h ee consecu i e ca diac cycles we e s o ed digi ally o off-
line analysis in he ou -, wo-, and h ee-chambe iew. The
en i e igh and le a iums we e ca e ully isualized o p e-
en walls’d opou .
Measu emen s ocused on e alua ing he indexed olume
o he le a ium and he a ea o he igh a ium. In he pa a-
s e nal long-axis o sho -axis iew, M-mode o he le en-
icle chambe was measu ed o diame e and wall hickness.
In he apical 4-chambe iew, he le en icle ejec ion ac-
ion was de e mined using he Simpson measu emen . Mi al
and icuspid inflows we e eco ded a he ip o he al e
leafle s. The peak eloci ies o ea ly and la e dias olic filling
wa es (E wa e and A wa e) and he E/A eloci y a io we e
measu ed. The e eloci y was ob ained by issue Dopple
a e aging he la e al and sep al mi al annulus alues and
he e wa e o he icuspid la e al wall. E/e’ alues we e
ob ained om bo h en icles.
S ain and s ain a e da ase s we e analyzed using a wall
mo ion acking so wa e (ESAOTE MyLab). In apical iews
(4-chambe , 3-chambe , and 2-chambe ), le a ial endoca -
dial bounda ies we e manually measu ed a he end-dias olic
phase. Righ a ia we e only egis e ed in he 4-chambe iew.
The alues o he ese oi , condui , and a ial con ac ion
s ain we e eco ded acco ding o he EACVI/ASE/Indus y
Task Fo ce o s anda dize de o ma ion imaging [20]. The
alues o s ain a e o he ese oi phase, he condui ,
and con ac ion phases we e also eco ded (Figu e 1). The
same was also done in 4 chambe s o he igh a ium. The
le a ium was subsequen ly di ided in o basal, medial, and
oo a ial segmen s. This de e mined a o al o 15 segmen s
o he le a ia when he 3 apical iews we e added. The
igh a ium was e alua ed simila ly, bu only he la e al seg-
men s we e aken in o accoun , adding 3 mo e segmen s,
hus making a o al o 18 segmen s. Sep al segmen s we e
conside ed as le a ia.
De o ma ion a e ime (DRT) was eco ded om he
beginning o he P wa e in he ECG o he maximum deflec-
ion o he a ial con ac ion in he s ain a e o each o he
segmen s, as indica ed in Figu es 1(a) and 1(e).
To de e mine in e a ial synch ony, an adap a ion o a ial
s ain was pe o med o e alua e he igh and le a ial walls
a he same ime. This new e alua ion was called “Omega”(ω)
because o he o m he s ain akes in he images. He e, he
maximal ime diffe ence be ween he s ain a e con ac ion
peaks o bo h igh and le a ial la e al walls was eco ded
(Figu e 2). Blinded analysis o he echoca diog ams was pe -
o med by wo independen esea che s (FJS and VAG).
2.5. A ial T ansmemb ane Po en ial. Righ a ium samples
aken in he ope a ing oom we e ans e ed wi hin 15 o
20 minu es o he labo a o y using a cold oxygena ed
Ringe - ype solu ion wi h albumin. Upon a i al, all samples
we e dissec ed in o smalle pieces, pinned a he bo om o a
pe usion chambe wi h he endoca dial su ace acing up,
and con inuously supe used wi h a modified K ebs–Hense-
lei solu ion con aining (in mM): 121 NaCl, 25 NaHCO
3
,
1.2 Na
2
HPO
4
, 5 KCl, 2 CaCl
2
, 1.2 MgSO
4
, and 11 glucose.
Once equilib a ed wi h 5% CO
2
in O
2
a 36:5±0:5
°
C, he
pH o he solu ion was 7:4±0:02.
The memb ane po en ial was eco ded wi h flexibly
moun ed glass mic oelec odes om subendoca dial abec-
ula a ial cells. Mic oelec odes we e filled wi h 3 mM KCl
and had esis ances o 10–15MΩ. A e 20 o 30 minu es o
s abiliza ion, we con inuously ob ained epica dial ansmem-
b ane po en ial using a cus om-made mic oelec ode ampli-
fie . The signals we e digi ized wi h an analog- o-digi al
con e e (NI PCI-6221; Na ional Ins umen s, Aus in,
Texas) and eco ded using LabView SignalExp ess 2.5
(Na ional Ins umen s, Aus in, Texas).
The ollowing p ope ies o he ansmemb ane po en-
ials we e quan ified: ac ion po en ial ampli ude, es ing
po en ial, maximum ups oke eloci y (ΔV/Δ max), and
ac ion po en ial du a ion a 30 and 90% o epola iza ion.
A hy hmic e en s and a hy hmogenic igge s we e e alu-
a ed by isual supe ision o he aces blindly ega ding
he pa ien ’s cha ac e is ics.
2.6. S uc u al, Inflamma o y, and Ni ooxida i e E alua ion
by Fluo escen Immunohis ochemis y. Pa o each a ial
sample was fixed in a 4% pa a o maldehyde solu ion o 1 h
a 4
°
C be o e embedding in pa affin blocks. Fi e-
mic ome e - hick issue sec ions we e s ained using he ol-
lowing p ima y an ibodies o label: abbi polyclonal an i-
Cx40 (Cx40 H-116, San a C uz, sc-28658, dilu ion 1:300),
abbi polyclonal an i-Cx43 (Cx43, Abcam, ab11370, dilu ion
1: 1000), abbi polyclonal an i-Ki 6.1 (Ki 6.1, The mo
Fishe , PA5-48354, dilu ion 1 :500), mouse monoclonal
an i-TNFα(TNFα52B83, San a C uz, sc-52746, dilu ion
1: 300), mouse monoclonal an ini o y osine (3-ni o y o-
sine, San a C uz, sc-32757, dilu ion 1 :200), and mouse
monoclonal an i-SERCA2a (ab2817 Abcam, dilu ion
1: 1000). Whea ge m agglu inin (WGA) conjuga ed o Alexa
Fluo 555 agains he ex acellula ma ix (W32464 The mo
Fishe , dilu ion 1 :500) and fluo escen ly conjuga ed F-ac in
agains he in acellula con en (ab112124 Abcam, dilu ion
1: 300). The seconda y an ibodies we e an i- abbi conju-
ga ed wi h Alexa Fluo 633 and an i-mouse labeled wi h he
Alexa Fluo 488 (Jackson ImmunoResea ch Labo a o ies
Inc., Wes G o e, PA, USA, dilu ion 1 :500). Images we e
acqui ed wi h a con ocal mic oscope Zeiss LSM 880 and
p ocessed wi h he Zen Blue 2.5 so wa e (Ca l Zeiss Mic os-
copy GmbH, 2018).
The maximum in ensi y p ojec ion o 20 o 40 z s acks
was used o analyze he la e aliza ion o connexins and he
in eg a ed op ical densi y (IOD). La e aliza ion was mea-
su ed wi h an open access au oma ed p og am designed by
ou g oup called MARTA [21]. This so wa e gene a es cell
masks, con ou s indi idual cells, and spli s he cells in o 4
ec angles o es ima e he la e al- o- o al a io o connexins.
The IOD quan ified he a ea (>3 pixels connec ed) mul iplied
by he a e age in ensi y using he so wa e ImageP oPlus 4.5,
2001 (Media Cybe ne ics, Inc., Rock ille, MD, USA). Values
o IOD measu ed o 18 pic u es pe immunofluo escence
channel we e g ouped a e he blinded analysis was com-
ple ed by wo independen esea che s (NJP and ERD), and
he esul s we e assigned o he co esponding g oups. The
alues o IOD a e ela i ely exp essed o he le el measu ed
in he synch onic g oup.
3Oxida i e Medicine and Cellula Longe i y
2.7. Pos ope a i e A ial Fib illa ion De ec ion. Con inuous
ECG moni o ing a e su ge y was pe o med in he ca dio-
ascula in ensi e ca e uni o 48–96 hou s o de ec any
new onse o a ial fib illa ion. A hy hmic e en s o a leas
1min leng h we e conside ed POAF when assessed by a
moni o ing sys em o using a 12-lead ECG in case o a symp-
oma ic episode ha equi ed in e en ion.
2.8. S a is ical Analysis. Quali a i e a iables a e exp essed as
numbe and pe cen age. Quan i a i e a iables a e exp essed
as mean ± s anda d de ia ion (SD) i hey a e no mally dis-
ibu ed and median wi h a ange i hey a e no no mally
dis ibu ed. Fo quali a i e da a, he chi-squa e es is used.
Fo nonno mally dis ibu ed da a, he Mann–Whi ney es s
a e used; o no mally dis ibu ed da a, he S uden - es is
used. The ecei e -ope a ing cha ac e is ic (ROC) cu e
analysis is pe o med o de e mine he cu off alue o a ial
a iables as p edic o s o POAF. The a ea unde he cu e
and 95% confidence in e al (CI) a e used o de e mine he
pa ame e s’inc emen al diagnos ic alue. Log- ank (Man el
Cox) es is used o assess he incidence o POAF. A p alue
below 0.05 was chosen as an indica i e o s a is ical signifi-
cance. The G aphPad P ism e sion 9.0.0, 2020 (G aphPad
So wa e, San Diego, CA, USA, h p://www.g aphpad.com)
was used o s a is ical analysis.
3. Resul s
3.1. Pos ope a i e A ial Fib illa ion, Pa ien Cha ac e is ics,
and Classifica ion ega ding In e a ial Synch ony. A o al
o 45 pa ien s we e included in he s udy. Fo y-one unde -
wen co ona y a e y bypass su ge y, h ee ao ic al e
eplacemen , and one combined su ge y. The mean age was
67:4±7:7yea s, and 69% we e male. No pa ien was unde
ea men wi h digi alis o an ia hy hmics.
This popula ion was di ided in o synch onic and dyssyn-
ch onic pa ien s based on he diffe ence be ween he ac i a-
ion o he la e al igh and le a ial walls de e mined om
he echoca diog am (Omega). This was used as a ac o
ela ed o he incidence o POAF. A ime diffe ence g ea e
han 40 milliseconds had a sensi i i y o 88.9% and a specific-
i y o 55.6% o iden i ying he a ial fib illa ion e en s, wi h
an a ea unde he cu e o 0.728 (95% CI 0.575-0.850)
(Figu e 3(a)).
Dyssynch onic pa ien s suffe ed om a highe incidence
o POAF. The median ime o a ial fib illa ion onse a e
su ge y was 2.5 days (Figu e 3(b)). All pa ien s eco e ed
sinus hy hm p io o discha ge om hospi al wi h he use
o in a enous amioda one. No elec ical ca dio e sion was
equi ed.
The ecei e -ope a ing cha ac e is ic cu e (ROC) o
a ial echoca diog aphic measu emen s had he ollowing
a eas unde he cu e and cu off alues: igh a ial a ea
0.796 (95% CI 0.650-0.902), cu off17.6cm
2
; le a ial olume
index 0.742 (95% CI 0.590-0.861), cu off29.86 mL/m
2
; le
a ia con ac ion s ain 0.645 (95% CI 0.488-0.782), cu off
15.4%; le a ial ese oi s ain 0.636 (95% CI 0.479-
0.774), cu off30.7%. A e adjus ing he igh a ial a ea, le
a ial olume index, le a ial ese oi s ain, and le a ia
con ac ion s ain o he cu off alues, acco ding o cu en
guidelines, only le a ial olume index emained as p edic-
o s o pos ope a i e a ial fib illa ion (a ea unde he cu e:
0.681 95% CI 0.525-0.812), bu he a ea unde he cu e was
lowe han he one ob ained wi h he in e a ial
Condui s ain
(𝜀CD)
Con ac ile
s ain (𝜀CD)
SR con ac ile
(SRc )
SR condui
(SRcd)
Rese oi
+30
+2
–10
0
–2
400 800 1200 1600 (ms)
R-R ga ing
DRT
A ial s ain (%)A ial s ain (1/s)
SR ese oi (SR )
s ain (𝜀R)
(a)
(b)
𝜀R
𝜀CD
33
22
11
0
0200 400
882 ms 600 800
𝜀CT
(c)
3
1.5
–1.5
–3
0
0200 400
882 ms 600 800
SR
SRcd
SRc
(d)
400
120 ms
600 800
DRT
(e)
B
Righ
a ia
Le
a ia
M
R
( )
Figu e 1: Two-dimensional a ial s ain cu es. (a) A ial s ain and s ain a e cu es and de e mina ion o a ial mechanics acco ding o an
R-R wa e- imed analysis. De o ma ion a e ime (DRT) is de e mined om he beginning o he P wa e in he elec oca diog am o he
maximum deflec ion o he s ain a e con ac ile phase (STc ). (b) Fou -chambe iew o speckle acking le a ial s ain. (c) A ial
s ain cu es. The whi e, dashed, and do ed line shows he a e age s ain cu e o he six segmen s o he a ia in ha iew. (d) A ial
s ain a e cu es. (e) De e mina ion o DRT in a segmen o le a ia. The measu emen ag eed wi h he scheme in (a). ( ) Schema ic
ou -chambe iew o how DRT can show he ac i a ion in ime o diffe en segmen s om bo h a ia. B: base segmen ; M: medium
segmen ; R: oo segmen .
4 Oxida i e Medicine and Cellula Longe i y
dyssynch ony [22–24]. These esul s suppo ed dyssyn-
ch ony as he g ouping a iable o he compa isons
h oughou he s udy.
Pa ien s in he synch onic and dyssynch onic g oups did
no show diffe ences in age, ype o su ge y, como bidi y, isk
ac o s, o ea men ecei ed be o e su ge y (Table 1). The
a e age pump ime o he pa ien s was 118 ± 39 minu es,
and he clamping ime was 75 ± 24 minu es, wi h no signifi-
can diffe ences be ween g oups. Du ing he s udy, he e
was only one dea h om a pa ien in he synch onic g oup.
3.2. A ial-Rela ed ECG. P wa e du a ion in he ECG was
125 ± 15 ms and 118 ± 12 ms in he synch onic and dyssyn-
ch onic g oups, espec i ely (p=0:128 by - es ). PR in e al
was longe in he synch onic g oup han in he dyssynch o-
nic g oup (179 ± 32 ms s. 160 ± 25 ms, espec i ely;
p=0:044 by Mann–Whi ney es ). No significan diffe ences
in Bayes synd ome incidence we e ound be ween g oups
(p=0:985).
3.3. Echoca diog aphy and A ial S ain. Rega ding gene al
da a om he echoca diog ams, he mean ejec ion ac ion
o he le en icle was 56:83 ± 15:36%. The mean indexed
olume o he le a ium was 30:78 ± 9:04 mL/m
2
, and he
a ea o he igh a ium was 16:20 ± 3:36 cm
2
. The E/e’ a io
o he le en icle showed a alue o 8:6±3:5, which indi-
ca ed end-dias ole p essu es a he no mal uppe limi in
mos pa ien s (Table 2). The e was no o he significan diffe -
ence be ween he g oups in echoca diog aphic findings,
excep o he le en icula index mass. The analysis o
he a ial speckle acking s ain showed no significan diffe -
ences be ween g oups in he de o ma ion a e imes co e-
sponding o he ac i a ion o any o he 18 a ial segmen s
(Table 3).
The es o he usual s ain analysis also showed no diffe -
ences be ween g oups (Table 4).
3.4. Ac ion Po en ials and P oa hy hmic T igge s. Ac ion
po en ials om dyssynch onous pa ien s dec eased by 3:9
±1:9mV in ampli ude and by 66 ± 13 V/s in he maximal
ups oke eloci y (Figu es 4(b) and 4(c)).
Du ing he beginning o he ups oke o he ac ion po en-
ial, we obse ed ha a segmen o he ascenden ac i a ion
had a li le nudge, like a oo ha delayed he maximal
ups oke occu ence. The es ing memb ane po en ial was
hype pola ized by 3:3±1:3mV in he a ial issue samples
om dyssynch onic pa ien s. The ac ion po en ial du a ion
a 30% o epola iza ion inc eased by 4:0±0:7ms bu ma k-
edly sho ened when measu ed a 90% o epola iza ion by
107 ± 12 ms. Only ac ion po en ials om synch onic pa ien s
displayed a pla eau and slow epola iza ion ypical o a s an-
da d a ial ac ion po en ial. Ea ly and delayed a e depola i-
za ions we e only obse ed in he dyssynch onic g oup.
3.5. A ial Remodeling, Inflamma ion, and Ni ooxida i e
S ess. Cx40 la e aliza ion inc eased by 9.81% (95% CI o di -
e ence 7.71-10.93) in samples om dyssynch onic pa ien s
wi h espec o synch onic ones (Figu e 5).
(a)
+2
–2
400 800 1200 1600 (ms)
A ial SR (1/s)
Synch ony ime
be ween la e al walls
(ms)
a
(b)
56 ms 30 ms
Righ
a ia
Righ
a ia
Le
a ia
Le
a ia
Dyssynch onic Synch onic
(c)
Dyssynch onic
1200 1500 1800 2100
56 ms –30 ms
2400 600 800 1000 1200 1400
Synch onic
(d)
Figu e 2: (a) Longi udinal s ain echoca diog aphy in a ou -chambe iew wi h he Omega (ω) adap a ion o he analysis echnique o ime
ac i a ion be ween la e al walls. Yellow and blue do s show he measu ed segmen o he la e al wall. (b) Measu emen echnique o de e mine
diffe ences be ween he ac i a ion ime o wo segmen s a he la e al a ial walls, om one maximal deflec ion s ain a e con ac ion o a
cu e o he same poin in he o he cu e. (c) Schema ic isualiza ion in a ou -chambe iew wi h an example o he de e mina ion o
ime diffe ence in ac i a ion be ween he la e al wall o he igh and le a ia. (d) Example o s ain a e om igh and le a ial walls in
synch onic and dyssynch onic pa ien s.
5Oxida i e Medicine and Cellula Longe i y

0
0 20 40 60 80 100
20
40
60
80
100
RAA
In e a ial dyssynch ony
LA𝜀R
LA𝜀CT
LAVi
100 - speci ici y
Sensi i i y
(a)
0246810
0
20
40
60
80
100
Days a e su ge y
Pos ope a i ea ial ib illa ion(%)
Dissynch onic
Synch onic
p = 0.0416
(b)
Figu e 3: Recei e -ope a ing cha ac e is ic cu es (ROC) o a ial fib illa ion incidence a e ca diac su ge y. (a) ROC cu es o igh a ial
a ea (RAA), in e a ial dyssynch ony, le a ial ese oi s ain (LAεR), le a ia con ac ion s ain (LAεCT), and le a ial olume index
(LAVi). (b) Pos ope a i e a ial fib illa ion incidence in pa ien s wi h synch onic and dyssynch onic ac i a ion o he igh and le a ial
la e al walls.
Table 1: Demog aphics and medica ion o pa ien s be o e su ge y.
Va iables Dyssynch onous (n=21) Synch onous (n=24)p alue
Demog aphics
Age in yea s (n)68 ± 9 67 ± 7 0.262
Pa ien sex (male) 15 (71.4) 16 (66.6) 0.731
Type o su ge y: co ona y 20 (95.2) 21 (87.5) 0.559
Co ona y disease 20 (95.2) 23 (95.8) 0.923
Diabe es melli us 13 (61.9) 10 (41.6) 0.175
Hype ension 20 (95.2) 22 (91.6) 0.632
Dyslipidemia 19 (90.5) 20 (83.3) 0.482
Dila ed ca diomyopa hy 4 (19.0) 1 (4.2) 0.113
Ch onic pulmona y obs uc i e disease 1 (4.8) 3 (12.5) 0.363
Ch onic enal ailu e 3 (14.3) 1 (4.2) 0.234
Obesi y 10 (47.6) 8 (33.3) 0.329
S oke 0 1 (4.2) 0.344
Hea ailu e in las mon h 3 (14.3) 5 (20.8) 0.567
Smoke 2 (9.5) 4 (16.6) 0.482
P esu gical medica ions
Aspi in use 21 (100) 24 (100) 1
βBlocke use 15 (71.4) 17 (70.8) 0.965
S a ins 20 (95.2) 24 (100) 0.280
ACEI o ARA 15 (71.5) 14 (58.3) 0.360
Spi onolac one o eple enone 5 (23.8) 2 (8.3) 0.153
Fu osemide 3 (14.3) 2 (8.3) 0.526
Da a a e exp essed as numbe and (%), unless o he wise indica ed. p alues a e calcula ed by K uskal-Wallis es o chi-squa e es . ACEI: angio ensin-
con e ing enzyme inhibi o s; ARA: angio ensin II, ype 1 ecep o an agonis s.
6 Oxida i e Medicine and Cellula Longe i y
This la e aliza ion was no colocalized wi h he inc eased
signal o umo nec osis ac o -α(TNFα) seen in he dyssyn-
ch onic g oup (Figu e 6). The TNFαwas mainly colocalized
wi h Cx40 close o he in e cala ed discs.
Ni o y osine is a ela i ely s able ma ke o ni oxida i e
s ess ha is o med by pe oxyni i e in e ac ion wi h y o-
sine. The ni o y osine signal was clea ly highe in he dys-
synch onic g oup, especially a ound he blood essels.
Howe e , i was diffusely obse ed in he issue and he
mic o ascula u e (Figu e 7). Cx43 inc eased in in e cala ed
discs and also la e alized 14.6% (95% CI o diffe ence
10.81-16.56) mo e in dyssynch onic pa ien s (Figu e 5), bu
bo h changes we e un ela ed o ni o y osine ma ks.
The exp ession o K
ATP
channels assessed by he de ec-
ion o i s po e- o ming uni Ki 6.1 inc eased in a ial myo-
cy es o dyssynch onic samples (Figu e 8). K
ATP
channels
usually agg ega ed a a ascula le el in images o bo h syn-
ch onic and dyssynch onic pa ien s. The ac ion po en ial
sho ening and he hype pola iza ion obse ed wi h he
mic oelec odes ag ees wi h inc eased exp ession o his
channel.
4. Discussion
Ou s udy ound ha in e a ial dyssynch ony assessed by
echoca diog aphy was associa ed wi h elec ical and s uc-
u al a ial emodeling and he incidence o pos ope a i e
a ial fib illa ion. The inno a i e measu emen in e a ial
dyssynch ony was sui able o es ima e nonin asi ely
ni ooxida i e and inflamma o y subs a e, as well as, an
elec ophysiological a hy hmogenic emodeling.
Table 2: Compa a i e echoca diog aphic measu emen s in bo h g oups.
Echoca diog aphic a iables Dyssynch onous Synch onous p alue
A ial index olume (mL/m
2
) 32.51 ±8.27 29.45 ±9.76 0.534
Righ a ial a ea (cm
2
) 17.07 ±3.54 15.57 ±3.13 0.694
Fey Simpson (%) 54.71 ±15.36 59.21 ±15.47 0.887
Mi al E wa e eloci y (cm/sec) 68.14 ±20.32 71.83 ±16.82 0.216
Mi al A wa e eloci y (cm/sec) 85.33 ±21.44 76.96 ±18.4 0.568
E/e a io LV 8.83 ±3.83 8.53 ±3.44 0.542
E/e a io RV 4.42 ±1.37 4.38 ±1.08 0.404
LV index mass (g/m
2
) 138.29 ±52.97 108.33 ±33.61 0.021
Da a a e exp ess as mean and SD. p alues a e analyzed by - es . LA: le a ia; RA: igh a ia; LVEF: le en icula ejec ion ac ion; LV: le en icle; RV:
igh en icle.
Table 3: De o ma ion a e ime pe segmen in bo h g oups.
De o ma ion a e ime Dyssynch onous Synch onous p alue
Le a ia
Base sep um segmen 138.95 ±44.43 142.46 ±39.48 0.780
Medium sep um segmen 146.57 ±40.89 136.54 ±30.11 0.350
Roo sep um segmen 157.76 ±47.46 134.46 ±30.11 0.078
Base la e al segmen 168.38 ±45.32 150.79 ±41.49 0.181
Medium la e al segmen 169.48 ±41.77 149.67 ±42.23 0.122
Roo la e al segmen 161.67 ±33.42 156.83 ±41.26 0.671
Base an e io segmen 151.71 ±43.26 155.67 ±34.38 0.734
Medium an e io segmen 154.05 ±41.87 154.54 ±35.02 0.966
Roo an e io segmen 157.05 ±41.48 151.67 ±49.59 0.697
Base in e io segmen 159.52 ±48.36 140.04 ±30.32 0.108
Medium in e io segmen 154.24 ±51.01 144.42 ±28.44 0.422
Roo in e io segmen 161.43 ±63.04 150.08 ±33.65 0.447
Base in e io la e al segmen 153.29 ±49.10 145.38 ±35.49 0.535
Medium in e io la e al segmen 150.90 ±44.43 148.04 ±31.73 0.803
Roo in e io la e al segmen 133.62 ±45.81 151.54 ±27.04 0.112
Righ a ia
Base la e al segmen 138.29 ±62.95 135.17 ±42.17 0.844
Medium la e al segmen 131.24 ±57.68 141.71 ±35.19 0.460
Roo la e al segmen 138.81 ±62.89 143.88 ±35.68 0.737
Da a a e exp essed as mean and SD. p alues o analysis by unpai ed - es .
7Oxida i e Medicine and Cellula Longe i y
4.1. A ial Dyssynch ony and Pos ope a i e A ial
Fib illa ion. In e a ial dyssynch ony is no a common isk
ac o o POAF. This is one o he fi s epo s o a p eope -
a i e indica o o p oa hy hmic issue emodeling. Rese oi
and con ac ile s ain o he le a ia ha e been p e iously
ela ed o he de elopmen o pa oxysmal and ch onic a ial
fib illa ion [25–27]. In his s udy, bo h we e below he e e -
ence alues ag eed in he clinical guidelines [22]. This indi-
ca es mo e igid a ia, wi h less pump unc ion, bu wi hou
adiffe ence be ween he wo g oups. One o he easons o
his absence o diffe ence could be he way in which he
pa ien s we e classified. We did no sepa a e he g oups
acco ding o he incidence o a ial fib illa ion bu o he
p esence o dyssynch ony de e mined by echoca diog am.
Ano he eason o ou pa ien s ha ing a be e pump and
ese oi unc ion is ha we did no include pa ien s wi h
mi al o icuspid al e disease known o ha ing la ge
a ial olumes, mo e igid a ia, and a clea endency o
de elop a ial fib illa ion. Also, one o ou exclusion c i e ia
was a p e ious his o y o a ial fib illa ion. We ound ha
in e a ial dyssynch ony was a be e p edic o o pos ope a-
i e a ial fib illa ion han o he a ial measu emen s.
A ial s uc u al and unc ional emodeling has many
causal ac o s such as oxida i e s ess, inflamma ion, fib osis,
and he no mal p ocess o aging. P e ious s udies ha e
shown ha le and igh a ial enla gemen p edic s pos op-
e a i e a ial fib illa ion [28, 29]. All ou pa ien s had le
a ial size below he cu off alues o a ial enla gemen .
Mo eo e , he a ial size was p ese ed in he dyssynch onic
pa ien s despi e he highe le en icle index mass and he
sligh ly educed condui s ain. Le en icula hype ophy
is associa ed wi h highe end-dias olic le en icula p es-
su es, explaining he diffe ence in he condui le a ial
s ain, bu o he ma ke s o ele a ed end-dias olic p essu es
like E/e’ ela ion showed no diffe ences. Righ a ial size
had no significan diffe ence be ween g oups bu was sligh ly
bigge in he dyssynch onic g oup.
E alua ing he ac i a ion o he diffe en segmen s o he
a ia did no show diffe ences be ween he wo g oups. This
suppo s he s anda diza ion guidelines ha ecommend
he longi udinal analysis o he a ia as a whole [22]. Addi-
ionally, segmen by segmen analysis akes a longe ime
and equi es a mo e expe ienced ope a o . Ne e heless, se -
e al s udies ha e al eady shown ha in a-a ial dyssyn-
ch ony is ela ed o a ial fib illa ion de elopmen [30, 31].
So, his analysis may be a use ul ool o he p edic ion o
a hy hmias. The omega app oach, p esen ed he e o he
fi s ime, is an adap a ion o he echnique ha no only
in oduces he e alua ion o he igh a ia bu i also educes
he ime o analysis. This acili a es he in e a ial dyssyn-
ch ony e alua ion wi h significan po en ial o a hy hmo-
genic subs a e iden ifica ion in he p eope a i e se ing.
S uc u al emodeling p oduces changes in a ial unc-
ion. These changes can be accele a ed in many disease p o-
cesses, like hype ension, diabe es melli us, and ischemic
hea disease. These changes can eflec modifica ions in
s uc u al p o eins ha p oduce a ial elec ical emodeling,
which, in u n, could be he cause o longe imes o a ial
mechanical ac i a ion. The esul s o ou s udy suppo ha
a ial dyssynch onic ac i a ion is ela ed o bo h elec ical
and s uc u al changes, wi hou an appa en influence o
o he isk ac o s.
4.2. A ial Dyssynch ony, Ac ion Po en ials, Connexins, and
K
ATP
Channels. Dyssynch onic pa ien s p esen ed abno mal-
i ies in he ups oke o he ac ion po en ials. In mul icellula
p epa a ions, bo h Na
+
channels and connexins con ibu e o
phase 0 o he ac ion po en ials. The oo and he delay in he
ups oke obse ed in dyssynch onic pa ien s ha e been p e-
iously associa ed wi h connexin al e a ions (see
Figu e 3(a)) [32]. Connexin exp ession, conduc ance, and
loca ion can influence he ini ial pa o he elec ical ac i a-
ion [33]. The la e aliza ion o Cx40 and Cx43 shown in
Figu e 5 could suppo hese findings a he beginning o
he ac ion po en ials. S ill, he concu en inc ease in Cx43
a he in e cala ed discs goes agains his idea, bu ag ees wi h
p e ious epo s ha educe he link wi h ac ion po en ial
mo phology [34]. The educed ampli ude and maximal a e
o depola iza ion indica e an impai men in he sodium cu -
en s. The e o e, bo h sodium channels and connexins can
Table 4: Compa a i e a ial s ain measu emen s in bo h g oups.
A ial s ain a iables Dyssynch onous Synch onous p alue
Rese oi LA s ain (%) 25.34 ±8.7 31.30 ±10.99 0.433
Condui LA s ain (%) 11.62 ±5.08 15.61 ±6.99 0.063
Con ac ile LA s ain (%) 14.58 ±5.8 16.37 ±5.57 0.963
S ain a e LA ese oi (1/s) 1.16 ±0.51 1.44 ±0.58 0.867
S ain a e LA condui (1/s) -1.13 ±0.60 1.63 ±1.45 0.419
S ain a e LA con ac ion (1/s) -1.01 ±0.61 -1.15 ±0.66 0.623
Rese oi RA s ain (%) 46.81 ±21.29 52.50 ±19.13 0.623
Condui RA s ain (%) 20.62 ±12.59 25.56 ±14.26 0.787
Con ac ile RA s ain (%) 17.92 ±13.19 26.73 ±14.69 0.598
S ain a e RA ese oi (1/s) 1.96 ±0.83 2.04 ±0.59 0.336
S ain a e RA condui (1/s) -1.52 ±1.02 -2.10 ±0.86 0.605
S ain a e RA con ac ion (1/s) -1.22 ±0.74 -1.68 ±1.31 0.080
Da a a e exp essed as mean and SD. p alue alues o analysis o - es . LA: le a ia; RA: igh a ia.
8 Oxida i e Medicine and Cellula Longe i y
con ibu e o in e a ial dyssynch ony because hey a e he
majo de e minan s o elec ical impulse p opaga ion
be ween ca diomyocy es.
K
ATP
channels could explain he ac ion po en ial sho -
ening and he hype pola iza ion, and hese ea u es can
wo sen unde s ess ul si ua ions like ischemia and epe u-
sion. Ou esul s b ing a new po en ial subs a e o he com-
plex elec ophysiology o he a ial issue. The subuni Ki 6.1
is an inwa d ec ifie cu en mainly exp essed in he ascu-
la u e [16]. He e, we epo he exp ession in human a ial
ca diomyocy es o dyssynch onic pa ien s. The ac i a ion o
hese channels educes he e ac o y pe iod, hus acili a ing
een an cu en s ha could lead o pos ope a i e a ial
fib illa ion. K
ATP
channels a e pa icula ly sensi i e o he
me abolic and oxida i e cellula condi ions [35]. In he con-
ex o ca dio ascula su ge y, hei p ope ies make hem
a ac i e candida es o po en ial p e en i e an ia hy hmic
he apies.
The a e depola iza ions obse ed in he dyssynch onic
g oup could be ela ed o al e a ions in calcium handling
and leaks om he sa coplasmic e iculum h ough he ya-
nodine ecep o s. These al e a ions ha e al eady been
desc ibed as associa ed wi h a mo e oxidized subs a e in
pa ien s unde going co ona y a e y bypass g a ing [36].
Dyssynch ony can p omo e s e ching o he cells du ing
he epola iza ion phase o sho ened ac ion po en ials, lead-
ing o mechanoelec ic eedback capable o ea ly a e depo-
la iza ion induc ion [37].
T ansmemb ane po en ial (mV)
Time (ms)
0 100 200 300 400 500
Synch onic
Dyssynch onic
–80
–60
–40
–20
0
20
40
(a)
0
20
40
100
120
Ampli ude (mV)
0
100
200
300
400
𝛥V/𝛥 max (V/s)
–80
–60
–40
–20
0
Res ing po en ial (mV)
*
Dyssynch onic Synch onic
Dyssynch onic Synch onic
Dyssynch onic Synch onic
Dyssynch onic Synch onic
0
5
10
15
20
25
Du a ion a 30% (ms)
0
100
200
300
400
Du a ion a 90% (ms)
⁎⁎
⁎
⁎
(b)
T ansmemb ane po en ial (mV)
–80
–60
–40
–20
0
20
40
(c)
Figu e 4: Ac ion po en ials and a hy hmic igge s in in e a ial dyssynch onic pa ien s. (a) A e aged ac ion po en ials om h ee diffe en
pa ien s om each g oup; (b) quan ifica ion o ac ion po en ial ampli ude, es ing memb ane po en ial, maximum ups oke eloci y
(ΔV/Δ max), and he ac ion po en ial du a ion a 30 and 90% o he epola iza ion om bo h g oups. ∗p<0:01 by - es ; (c)
a hy hmogenic igge s in 2 seconds aces om wo dyssynch onic pa ien s. The blue a ows ma k delayed a e depola iza ions, which
a e e y equen in dyssynch onous pa ien s. G een a owheads indica e igge ed e en s om ea ly a e depola iza ions.
9Oxida i e Medicine and Cellula Longe i y