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Intraventricular Pressure Gradients in Heart Failure

Abstract

The aim of the present study was to characterize intraventricular pressure gradients (IVPGs) in an animal model of chronic heart failure. New Zealand rabbits were treated with doxorubicin (heart failure group, n=5) or saline (control group, n=5) and instrumented with pressure catheters placed in the apex and outflow-tract of left ventricle (LV) and with sonomicrometer crystals placed in the apex and base of the LV free wall. In heart failure animals, ventricular filling was delayed and slower when compared with control animals. Moreover, the physiological nonuniformity observed between apical and basal segments in normal hearts was abolished in failing hearts. Simultaneously, physiological IVPGs observed during normal ventricular filling were entirely lost in heart failure animals. During ventricular emptying physiological nonuniformity between apical and basal segments observed in control animals was also abolished in heart failure animals. In failing hearts minimal length occurred later and almost at same time both in apical and in basal myocardial segments. Simultaneously, the characteristic IVPG pattern observed in healthy hearts during systole, which promotes ventricular emptying, was not observed in failing hearts. The present study showed that diastolic IVPGs, a marker of normal ventricular filling, and systolic IVPGs, a marker of normal ventricular emptying, are abolished in heart failure.

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Intraventricular Pressure Gradients in Heart Failure

Author: Guerra, M,Bras Silva, C,Amorim, MJ,Moura, C,Bastos, P,Leite Moreira, AF
Year: 2013
Source: https://repositorio-aberto.up.pt/bitstream/10216/72892/2/47071.pdf
PHYSIOLOGICAL RESEARCH • ISSN 0862-8408 (p in ) • ISSN 1802-9973 (online)
© 2013 Ins i u e o Physiology . .i., Academy o Sciences o he Czech Republic, P ague, Czech Republic
Fax +420 241 062 164, e-mail: phys [email protected], www.biomed.cas.cz/physiol es
Physiol. Res. 62: 479-487, 2013
In a en icula P essu e G adien s in Hea Failu e
M. GUERRA1, C. BRÁS-SILVA1, M. J. AMORIM1, C. MOURA1, P. BASTOS1,
A. F. LEITE-MOREIRA1
1Depa men o Physiology and Ca dio ho acic Su ge y, Ca dio ascula R&D Uni , Facul y o
Medicine, Uni e si y o Po o, Po o, Po ugal
Recei ed Feb ua y 18, 2013
Accep ed July 4, 2013
On-line Sep embe 10, 2013
Summa y
The aim o he p esen s udy was o cha ac e ize in a en icula
p essu e g adien s (IVPGs) in an animal model o ch onic hea
ailu e. New Zealand abbi s we e ea ed wi h doxo ubicin (hea
ailu e g oup, n=5) o saline (con ol g oup, n=5) and
ins umen ed wi h p essu e ca he e s placed in he apex and
ou low- ac o le en icle (LV) and wi h sonomic ome e
c ys als placed in he apex and base o he LV ee wall. In hea
ailu e animals, en icula illing was delayed and slowe when
compa ed wi h con ol animals. Mo eo e , he physiological
nonuni o mi y obse ed be ween apical and basal segmen s in
no mal hea s was abolished in ailing hea s. Simul aneously,
physiological IVPGs obse ed du ing no mal en icula illing
we e en i ely los in hea ailu e animals. Du ing en icula
emp ying physiological nonuni o mi y be ween apical and basal
segmen s obse ed in con ol animals was also abolished in hea
ailu e animals. In ailing hea s minimal leng h occu ed la e
and almos a same ime bo h in apical and in basal myoca dial
segmen s. Simul aneously, he cha ac e is ic IVPG pa e n
obse ed in heal hy hea s du ing sys ole, which p omo es
en icula emp ying, was no obse ed in ailing hea s. The
p esen s udy showed ha dias olic IVPGs, a ma ke o no mal
en icula illing, and sys olic IVPGs, a ma ke o no mal
en icula emp ying, a e abolished in hea ailu e.
Key wo ds
In a en icula • G adien s • Hea ailu e • Dias ole • Sys ole •
Myoca dial segmen s
Co esponding au ho
A. F. Lei e-Mo ei a, Depa men o Physiology and Ca dio ho acic
Su ge y, Ca dio ascula R&D Uni , Facul y o Medicine, Uni e si y
o Po o, Alameda P o esso He nâni Mon ei o, 4200-319 Po o,
Po ugal. Fax: 00351225513646. E-mail: [email p o ec ed]
In oduc ion
Cou ois e al. (1988) desc ibed o he i s
ime, in a canine model, in a en icula p essu e
g adien s (IVPGs) du ing dias ole and la e showed ha
hese dias olic g adien s we e diminished by ischemia and
ela ed o sys olic unc ion (Cou ois e al. 1990).
Recen ly, we ex ended hose obse a ions also in an
animal model. We con i med no only he exis ence o
dias olic bu also sys olic IVPGs in he le en icle (LV)
and demons a ed, o he i s ime, ha hey a e
modula ed by physiological nonuni o mi y (B u sae e
al. 1987) be ween basal and apical myoca dial segmen s
(Gue a e al. 2013). Mo eo e , we showed ha dias olic
and sys olic IVPGs, a ma ke o no mal segmen al
unc ion, can be a enua ed, los en i ely o e en e e sed
when en icula emp ying is opposed by a e load
ele a ions o a e egional acu e ischemia (Gue a e al.
2013).
Fu he mo e, Fi s enbe g e al. (2008) showed
ha imp o emen s in LV sys olic and dias olic unc ion,
h ough su gical myoca dial e ascula iza ion in pa ien s
wi h ischemic ca diomyopa hy, co ela e di ec ly wi h he
eco e y o dias olic IVPGs. Ro ne e al. (2005) also
demons a ed ha dias olic IVPGs augmen a ion and LV
elaxa ion imp o emen wi h exe cise a e signi ican ly
impai ed in hea ailu e pa ien s. Howe e , sys olic and
dias olic IVPGs we e ne e ca e ully obse ed and
cha ac e ized, namely hei magni ude and hei beha io
in he p esence o sys olic and/o dias olic dys unc ion, in
ch onic models o hea ailu e (S ugaa d e al. 1993,
S eine e al. 2002).
In ac , he p ac ical alue o IVPGs in
480 Gue a e al. Vol. 62
unde s anding en icula pa hophysiology is enhanced
by he ecogni ion o i s gene al applicabili y and
quan i ica ion no only in acu e models, bu also in
ch onic models (De Boeck e al. 2005, Yo i e al.
2005a,b). Dias olic and sys olic IVPGs may e lec
in insic p ope ies and ch onic dys unc ion o he LV
and no only an acu e ans al ula low diso de
(Fi s enbe g e al. 2001, Gue a e al. 2011b). In his
se ing, he p esen s udy was conduc ed o cha ac e ize
dias olic and sys olic IVPGs in an animal model o
ch onic hea ailu e, and co ela e IVPGs wi h dias olic
and sys olic segmen al LV dys unc ion and
nonuni o mi y.
Me hods
The in es iga ion con o ms o he Guide o he
Ca e and Use o Labo a o y Animals published by he US
Na ional Ins i u es o Heal h (NIH publica ion no. 85-23,
Re ised 1996), and all animals ecei ed human ca e in
compliance wi h he Eu opean Con en ion on Animal
Ca e. S udy was also app o ed by he E hics Commi ee
o ou Uni e si y.
Ch onic hea ailu e model
A well-documen ed egimen was used o he
induc ion o hea ailu e due o doxo ubicin oxici y
(A nolda e al. 1985, B ás-Sil a e al. 2008). Adul male
New Zealand Whi e abbi s (O yc olagus cuniculus,
3.0±0.2 kg) ecei ed doxo ubicin ia a ma ginal ea ein
by bolus injec ion (1 mg/kg) wice weekly o 8 weeks
(n=5) ollowed by a washou pe iod o 1 week. Con ol
abbi s (n=5) ecei ed he ehicle (0.9 % saline) in
equi olume ic doses o e he same pe iod. All animals
we e e alua ed by echoca diog aphy a he beginning and
e e y wo weeks du ing he adminis a ion o doxo ubicin
o ehicle. Echoca diog aphic examina ion was
pe o med as p e iously desc ibed (Fon es-Sousa e al.
2009). B ie ly, he abbi s we e ligh ly anes he ized wi h
an in amuscula combina ion o ke amine hyd ochlo ide
(2 mg/kg) and mede omidine hyd ochlo ide (0.15 mg/kg),
being allowed o b ea h spon aneously. The animals we e
placed p one on a able wi h an a ea emo ed so ha he
ul asound p obe could be b ough om below and
placed on a sha ed a ea o he an e io ches wall.
The echoca diog ams we e ob ained using a 7.5 MHz
ansduce (Vi id 3 Gene al Elec ics echoca diog aph,
Po ugal) and he examina ion was pe o med om he
igh pa as e nal sho -axis iew. Two-dimensional
guided M-mode acings we e made jus below he mi al
al e a he le el o he papilla y muscles o
measu emen s o he le en icula in e nal diame e and
he le en icula wall was ee in dias ole and sys ole.
Th ee ep esen a i e cycles we e measu ed and a e aged
o each abbi a each ime poin . Analyzed pa ame e s
we e: hea a e, an e io and pos e io end-dias olic and
end-sys olic wall hickness, le en icula end-sys olic
and end-dias olic diame e s, and ac ional sho ening.
Expe imen al p epa a ion
Animal p epa a ion
The ins umen a ion o he animals o
hemodynamic s udies was pe o med one week a e he
las adminis a ion o he ehicle (n=5) o doxo ubicin
(n=5), espec i ely, as p e iously desc ibed (Lei e-
Mo ei a and Co eia-Pin o 2001). In summa y, animals
we e p emedica ed wi h ke amine hyd ochlo ide
(50 mg kg−1, I.M., Ke ala ®, P ize Limi ed) and xylazine
hyd ochlo ide (5 mg kg−1, I.M., Rompum®, Baye ).
A emo al ein was cannula ed, and a in a enous
solu ion con aining 20 meq KCl and 40 meq NaHCO3 in
500 ml o 0.9 % NaCl was adminis a ed a a a e o
8 ml kg−1 h−1 o compensa e o pe iope a i e luid losses.
A acheos omy was pe o med, and mechanical
en ila ion was ini ia ed (Ha a d Small Animal
Ven ila o , model 683), deli e ing oxygen-en iched ai .
Respi a o y a e and idal olume we e adjus ed o keep
a e ial blood gases and pH wi hin physiological limi s.
Gene al anes hesia was main ained by in a enous
in usion o midazolam (0.07 mg kg−1 h−1, Midazolam B.
B aun), en anil (0.003 mg kg−1 h
−1, Fen anil B. B aun)
and ecu onium (0.1 mg kg−1 h−1, No cu on®, O ganon)
o achie e adequa e dep h o anes hesia o absence o a
co neal e lex. A 20 gauge ca he e was inse ed in he
igh emo al a e y and connec ed o a p essu e
ansduce o moni o hea a e and a e ial p essu e and
o ob ain samples o blood gas analysis. The hea was
exposed by a median s e no omy, and he pe ica dium
was opened wide. A limb lead elec oca diog am be ween
he le leg elec ode and he igh a m elec ode (DII)
was eco ded h oughou . T ansien ao ic cons ic ions
we e pe o med by ab up ly occluding he ao a wi h a
silk su u e placed a ound he ascending ao a du ing he
dias ole sepa a ing wo hea bea s. This was achie ed by
pushing a plas ic ube agains he ao a wi h one hand
while pulling he silk su u e wi h he o he hand. Ao ic
cons ic ion was quickly eleased o a oid neu ohumo al
e lex changes in ca diac unc ion (Co eia-Pin o e al.
2013 IVPGs in Hea Failu e 481
2006). Peak sys olic p essu e o iso olume ic hea bea s,
which can be ob ained wi h ao ic occlusions, is a
sensi i e index o le en icula con ac ili y.
P essu e measu emen s
Two 3 F ench high- ideli y mic omanome e s
(SPR-524; Milla Ins umen s, Hous on, TX, USA) we e
inse ed h ough an apical punc u e wound in o he LV
ca i y. One was pulled ca e ully back owa ds he
endoca dium and secu ed in place wi h a pu se-s ing
su u e o measu e apical le en icula p essu e (LVP).
The o he was in oduced un il we could see he impac
om he ao ic al e on he p essu e ace. The ca he e
hen was pulled back 3 mm below he ao ic al e so ha
i was loca ed in he LV ou low ac o measu e basal
LVP. The p essu e ansduce s we e calib a ed agains a
me cu y column and ze oed a e s abiliza ion o 30 min
in a wa e ba h a body empe a u e. The ze o was se a
he le el o he igh a ium. Reco dings we e made wi h
espi a ion suspended a end expi a ion. Pa ame e s we e
con e ed online o digi al da a wi h a sampling
equency o 1 kHz. Le en icula p essu es we e
measu ed a end dias ole (LVPED), a p essu e nadi
(LVPmin) and a peak sys ole (LVPmax). Peak a es o LV
p essu e ise (dP/d max) and p essu e all (dP/d min), as
well as ime o dP/d min, we e also measu ed. Relaxa ion
a e was es ima ed wi h he ime cons an τ by i ing he
iso olume ic p essu e all o a monoexponen ial
unc ion. We eco ded he IVPG con inuously as apical
minus ou low- ac LVP. Peak and a e age (a ea di ided
by du a ion) IVPGs we e calcula ed du ing dias olic and
sys olic phases o he ca diac cycle.
Sonomic ome y
Regional en icula unc ion was measu ed wi h
wo pai s o ul asonic segmen leng h gauges implan ed
in he ci cum e en ial di ec ion o apical and basal le
en icula an e io midwall and connec ed o a
sonomic ome e ampli ie sys em (T i on Technology,
San Diego, CA, USA). A he end o he expe imen , he
animal was eu hanized by adminis a ion o an o e dose
o anes he ic agen s, and he posi ions o he c ys als and
mic omanome e s we e e i ied a pos mo em
examina ion. Segmen leng hs we e measu ed a he end
dias ole (ED leng h), a dP/d max and a mi al al e
opening (MVO). Minimal segmen leng h (Leng hmin)
was measu ed as he minimal leng h p eceding o
coinciding wi h peak –dP/d min. F ac ional sho ening was
calcula ed as he pe cen age segmen leng h change om
end dias ole o dP/d min.
Expe imen al p o ocol
A e comple e ins umen a ion, we allowed he
animal p epa a ion o s abilize o 30 min be o e he
beginning o he expe imen al p o ocol, which consis ed
in measu ing apex o ou low- ac p essu e g adien s and
apical and basal myoca dial segmen leng hs in con ol
and hea ailu e animals du ing baseline and a e loaded
hea bea s. The animals we e no paced, bu hea a e did
no a y signi ican ly du ing he expe imen al p o ocol.
S a is ical analysis
S a is ical analysis was pe o med using
SPSS 17.0 so wa e. G oup da a a e p esen ed as means ±
SEM and we e compa ed using wo-way ANOVA.
S uden -Newman-Keuls es was selec ed o pe o m
pai wise mul iple compa isons when signi ican
di e ences we e de ec ed. S a is ical signi icance was
assumed a a wo ailed alue o P<0.05.
Resul s
Ca diac hemodynamics and echoca diog aphy
The hemodynamic ea u es o he expe imen al
g oups a e summa ized in Table 1. In compa ison wi h
he con ol g oup, he hea ailu e g oup p esen ed a
lowe sys olic p essu e, dP/d max, peak sys olic
iso olume ic p essu e and ac ional sho enning. The
le en icula illing p essu e, as es ima ed by le
en icula end-dias olic p essu e, was inc eased in
ailing hea s, whe eas he dP/d min was dec eased and he
elaxa ion ime cons an τ was inc eased. Fu he mo e,
he echoca diog aphic e alua ion in he hea ailu e
g oup demons a ed a p og essi e inc ease o he
end-dias olic ( om 14.2±0.3 o 15.2±0.3 mm) and
end-sys olic ( om 9.9±0.2 o 11.1±0.3 mm) sho -axis
diame e s and a educ ion in ac ional sho ening ( om
32±1 o 26±1 %) and ejec ion ac ion ( om 64±1 o
56±2 %) o he le en icle. This was consis en wi h he
p esence o dila ed ca diomyopa hy and hea ailu e.
Mo eo e , in he p esen s udy he animals had clea
signs o hea ailu e such as u led hai , labo ed
en ila ion, asci es and pleu al e usion.
482 Gue a e al. Vol. 62
Table 1. Sys olic and dias olic pa ame e s in con ol and hea ailu e animals.
Con ol Hea ailu e
Apex Ou low ac Apex Ou low ac
LVPED (mm Hg) 3.3±0.2 3.2±0.3 3.9±0.2α 4.0±0.2α
dP/d max (mm Hg/s) 3791±667 3669±627 1187±182α 1103±155α
LVPmax (mm Hg) 80.7±4.6 80.8±4.7 49.1±5.5α 48.6±5.1α
dP/d min (mm Hg/s) -3598±664 -4631±564β -1070±241α -1098±234α
LVPISO (mm Hg/s) 148.9±9.2 149.7±9.8 84.6±13.5α 82.6±11.3α
Time o dP/d min (ms) 140±2 129±1β 191±11α 190±9α
LVPmin (mm Hg) 2.7±0.6 2.0±1.6 2.9±0.4 3.3±0.5
Time o LVPmin (ms) 214±8 231±4β 268±9α 272±7α
τ
(ms) 15.0±1.3 10.6±0.6β 30.4±1.9α 28.4±2.2α
ED leng h (mm) 6.90±0.33 7.35±0.89 7.33±0.54 7.82±1.22
Leng h a dP/d max (mm) 6.97±0.27 7.39±0.67 7.44±0.76 7.98±0.79
Leng hmin (mm) 5.89±0.34 6.28±0.78 6.92±1,38 6.72±1,64
Time o leng hmin (ms) 213±10 170±16β 268±86α 291±56α
Leng h a dP/d min (mm) 6.20±0.32 6.32±0.42 6.99±1.22 7.12±0.96
Leng h a MVO (mm) 6.00±0.20 6.22±0.23 6.78±0.98 6.98±1.43
F ac ional sho enning (%) 12.7±1.9 14.3±1.1 6.2±2.9α 7.9±1.3α
Hea a e (bpm) 170±11 181±7
α P<0.05 e sus no mal; β P<0.05 e sus apex. Abb e ia ions: LVPED, end dias olic le en icula p essu e; dP/d max, peak a e o le
en icula p essu e ise; LVPmax, peak sys olic le en icula p essu e; dP/d min, peak a e o le en icula p essu e all; LVPISO, peak
sys olic p essu e in a iso olume ic bea ; LVPmin, le en icula p essu e nadi ; τ, ime cons an o iso olume ic elaxa ion a e; ED
leng h, end dias olic segmen leng h; Leng hmin, minimal segmen leng h; MVO, mi al al e opening.
Table 2. Apex- o-ou low ac mean p essu e g adien s (in mm Hg) h oughou he ca diac cycle a baseline and du ing a e load
ele a ion in con ol and hea ailu e animals.
Dias ole Sys ole
Ea ly
dias ole
Ven icula
illing
A ial
con ac ion
Rapid
ejec ion
Slow
ejec ion
Con ol
Baseline -5.1±0.7 +3.4±0.2 +0.6±0.1 +0.5±0.1 -0.9±0.1
A e load -1.5±0.3α +3.7±0.2 +0.5±0.1 -0.8±0.1α -0.9±0.1
Hea ailu e
Baseline -0.5±0.1β +0.1±0.1β +0.4±0.1 +1.0±0.2 +0.7±0.2β
A e load -0.5±0.2β +0.1±0.2β +0.4±0.2 +2.3±0.3α,β +1.8±0.3α,β
α P<0.05 e sus baseline; β P<0.05 e sus con ol.
IVPGs changes in hea ailu e
Figu e 1 ep esen s le en icula apical and
ou low ac p essu es, as well as, simul aneous
eco ding o he apex- o-ou low ac IVPG along
ca diac cycle in wo ep esen a i e examples, one o a
no mal and one o a hea ailu e animal. Table 2
summa izes mean IVPGs h oughou he ca diac cycle in
con ol and hea ailu e animals du ing baseline and
a e loaded ca diac bea s.
In heal hy hea s o con ol animals, du ing he
apid phase o en icula illing, we eco ded a
–5.1±0.5 mm Hg IVPG om he ou low- ac o he
2013 IVPGs in Hea Failu e 483
apex. La e , when apical p essu e s a ed o ise, he
ou low- ac p essu e con inued o all, hus c ea ing a
+3.6±0.2 mm Hg apex o ou low- ac p essu e g adien .
Du ing sys ole we eco ded a biphasic IVPG pa e n,
mani es ed as a posi i e g adien (+0.6±0.1 mm Hg) om
apex o ou low- ac du ing apid ejec ion, which was
ollowed by a nega i e g adien om he ou low- ac
o he apex du ing he slow ejec ion phase
(–0.8±0.1 mm Hg).
Fig. 1. Le en icula apical (–––) and ou low ac (----) p essu es and simul aneous eco ding o apex- o-ou low ac IVPG (g ay)
along ca diac cycle in a ep esen a i e no mal s hea ailu e animal. No mal: Du ing dias ole we obse ed a signi ican ou low ac -
o-apex IVPG in he ea ly dias ole (a) and an apex- o-ou low ac IVPG in he la e dias ole (b); du ing ea ly sys ole we eco ded an
IVPG om apex- o-ou low (c) which in e s du ing la e sys ole (d). Hea Failu e: Dias olic IVPGs obse ed du ing no mal en icula
illing we e en i ely los in ailing hea s, while du ing sys ole we obse ed only one apex- o-ou low- ac g adien h oughou
en icula emp ying (
c
’).
In ailing en icles o hea ailu e animals,
dias olic en icula illing was delayed and slowe , as
indica ed by he inc ease in imes o apical and basal peak
dP/d min and o LVP nadi . Mo eo e , he nonuni o mi y
(measu ed as dis inc imings a which minimum leng h
was achie ed be ween di e en en icula segmen s
du ing ca diac cycle) obse ed be ween apical and basal
segmen s in heal hy hea s was abolished in hea ailu e.
In ac , as e ou low- ac elaxa ion (assessed by
dP/d min and by he ime cons an τ) obse ed in heal hy
hea s was no obse ed in ailing hea s whe e elaxa ion
occu ed a he same momen in he apex and in he
ou low- ac (Table 1, Time o LVPmin). Simul aneously,
dias olic IVPGs we e en i ely los in hea ailu e
animals, and no di e ences we e eco ded be ween
ou low- ac and apical LV p essu es du ing en icula
illing (Fig. 1, Hea Failu e). Du ing en icula
emp ying as e con ac ion o basal in compa ison o
apical myoca dial segmen s eco ded in heal hy hea s
(assessed by a sho e ime o minimal leng h o a simila
myoca dial sho ening) was also abolished in hea ailu e
animals. In ailing hea s minimal leng h occu ed la e
and almos a same ime bo h in apical and in basal
myoca dial segmen s (Table 1, Time o lengh min).
Simul aneously, he physiological biphasic IVPG pa e n
obse ed in heal hy hea s du ing sys ole was no
obse ed in ailing hea s (Fig. 1, Hea Failu e).
Addi ionally, he esponse o a e load ele a ion was also

484 Gue a e al. Vol. 62
dis inc in he ailing hea s, which may ep esen a
sensi i e indica o o LV con ac ili y impai men
(Table 2).
Discussion
The p esen s udy showed ha dias olic IVPGs,
a ma ke o no mal en icula illing, and sys olic
IVPGs, a ma ke o no mal en icula emp ying, a e
abolished in ailing hea s.
P e iously, we demons a ed ha dias olic and
sys olic IVPGs a e modula ed by physiological
nonuni o mi y be ween basal and apical myoca dial
segmen s and ha IVPGs can be a enua ed, los en i ely
o e en e e sed when en icula emp ying is opposed
by a e load ele a ions o a e egional acu e ischemia
(Gue a e al. 2013). So, we hypo hesized ha any
condi ion ha in e e es wi h he no mal segmen al
unc ion, such as ch onic hea ailu e, migh be expec ed
o al e he physiological IVPGs h oughou he ca diac
cycle. In ac , dila ed en icles a e poo suc ion pumps,
aspi a ing a ela i ely small olume in ea ly illing and
compensa ing wi h a ial con ac ion and a es ing
achyca dia o main ain ca diac ou pu (Li le 2005).
Heal hy en icles s o e g ea e amoun s o elas ic ene gy
du ing sys ole and a e he e o e mo e e ec i e suc ion
pumps du ing dias ole (Gilbe and Glan z 1989). In his
con ex , educed dias olic IVPGs a e he consequence no
only o a lowe impulse due o dep essed elas ic ecoil,
bu also o ela i ely highe dele e ious con ec i e o ces
and impai ed en icula elaxa ion, which ad e sely
a ec LV illing (Nikolic e al. 1995).
In ou animal model, he p og ession o ca diac
dys unc ion was moni o ed echoca diog aphically o
es ima e mo phologic and unc ional al e a ions du ing
he de elopmen o hea ailu e. Hemodynamic s udies
pe o med wo weeks a e he las adminis a ion o
doxo ubicin and he las echoca diog aphic e alua ion
clea ly showed he p esence o sys olic and dias olic
dys unc ion in hea ailu e animals. In compa ison wi h
he con ol g oup, he hea ailu e g oup p esen ed
signi ican ly lowe sys olic p essu es, dP/d max, peak
sys olic iso olume ic p essu es and ac ional
sho ening, consis en wi h he p esence o dila ed
ca diomyopa hy and hea ailu e. In ac , doxo ubicin is
an an h acycline widely used in cy os a ic ea men s
which causes a dose-dependen ca dio oxici y and hus
has been used o induce hea ailu e in a ious animal
species (Gomes e al. 2012). Doxo ubicin-induced
ca diomyopa hy is cha ac e ized by en icula wall
hinning and dila a ion, and dep essed sys olic and
dias olic unc ion accompanied by luid e en ion and by
neu ohumo al ac i a ion (Chekano 1999). A he ca diac
muscle le el, i p omo es in insic con ac ile dys unc ion
and educed con ac ile ese e. Fu he mo e,
doxo ubicin impai s ascula as well as endoca dial
endo helial unc ion and induces in lamma o y eac ions
in he hea , leading o h ombosis in he a ia and
myoca di is (Gaudin e al. 1993). Mul iple pa hways o
an h acycline-induced ca diac cellula inju y ha e been
p oposed such as he elease o ca dio oxic subs ances,
which subsequen ly accumula e in he ca diomyocy es,
he gene a ion o ee adical, lipid pe oxida ion, and
supp ession o DNA, RNA and p o ein syn hesis (Sawye
e al. 2010, Adão e al. 2013).
In he p esen s udy he animals had clea signs
o hea ailu e, which we e mo e compa ible wi h he
in asi e hemodynamic measu emen s han wi h he
mo e modes echoca diog aphic dep ession. As
echoca diog aphic eco dings we e pe o med e e y wo
weeks, he las echoca diog aphic e alua ion was ca ied
ou wo weeks be o e he hemodynamic measu emen s.
Gi en he apid p og ession o he disease a e six
weeks, his migh explain he di e en pheno ypes a he
wo dis inc ime poin s. Mo eo e , echoca diog aphy is
no a sensi i e me hod o de ec ing signi ican
di e ences o wall hickening in hese small hea s.
In hea ailu e animals, he no mal base- o-apex
IVPG obse ed du ing ea ly dias ole was en i ely
abolished, showing impai men o en icula illing. La e
dias olic apex- o-base IVPG was also los in ailing hea s
which may comp omise he beginning o nex en icula
emp ying. In ac , dias olic IVPGs migh be causally
ela ed o ecoil o en icula walls in conjunc ion wi h
elease o elas ic ene gy s o ed du ing he p e ious
sys ole, which gene a es suc ion and con ibu es o
no mal illing (Cou ois e al. 1990). In ca diomyopa hic
hea s, abno mal dias olic mo emen o dyskine ic
segmen s du ing iso olume ic elaxa ion could impa
some mo ion o blood pooled in he apical and an e io
egions o he en icle and hus con ibu e o he
al e a ion o he no mal dias olic IVPGs (Beppu e al.
1988, Delema e e al. 1988). Mo eo e , some elas ic
po en ial ene gy s o ed du ing sys ole could be
p ema u ely los du ing ea ly dias ole in ailing hea s
which may impai en icula illing and abolish no mal
ea ly and la e dias olic IVPGs (Smise h e al. 1998).
Thus, acu e o ch onic en icula dys unc ion, by
2013 IVPGs in Hea Failu e 485
diminishing he amoun o unc ional en icula
myoca dium a ailable o con ac ion and subsequen
elas ic ecoil in one egion o he en icle, should esul
in loss o diminu ion o he dias olic IVPG in ha egion
(Gue a e al. 2013).
Du ing sys ole, he no mal IVPG pa e n
obse ed in heal hy hea s, and cha ac e ized by an apex
o ou low- ac g adien du ing apid ejec ion ollowed
by an ou low- ac o apex g adien du ing he slow
ejec ion phase, was also los in ailing hea s. In no mal
hea s, sys olic IVPG pa e n pa allels he physiological
ao ic- en icula p essu e g adien s obse ed be ween
ao a and he LV wi h ao ic p essu e being lowe han
LV p essu e du ing apid ejec ion and highe du ing he
slow ejec ion phase. In hea ailu e animals,
physiological biphasic IVPGs du ing sys ole we e no
obse ed, which may impai no mal en icula
emp ying.
As a po en ial limi a ion, we mus acknowledge
ha he p esen s udy was pe o med in anes he ized
open-ches and open-pe ica dium animals wi h wo
p essu e ca he e s ied a he le el o he LV apex and wo
myoca dial segmen leng h gauges placed in he apex and
base o he LV ee wall. These manipula ions may
impai en icula con ac ili y, as well as, may al e
longi udinal unc ion and o sion he eby a ec ing apex
o base g adien s. We mus howe e unde sco e ha he
ca he e s and segmen leng h gauges a e a he lexible
and small, minimizing he nega i e impac on LV
unc ion. Mo eo e , as bo h g oups (hea ailu e and
con ol) we e submi ed o he same su gical
manipula ion such impac should ha e been simila ,
he e o e making i accep able o compa e IVPGs in he
wo g oups (Gue a e al. 2011a).
In conclusion, egional al e a ions in IVPGs
migh be an impo an ac o in he cha ac e is ic changes
ha occu in in a en icula low in speci ic ca diac
diso de s. IVPGs play a physiological ole in he heal hy
hea ha is los in pa hological condi ions, which may
con ibu e o and ep esen an ea ly sign o en icula
dys unc ion. In his way IVPGs eco ding and s udy may
gi e impo an no el insigh in o he comp ehension o
hea ailu e pa hophysiology. Mo eo e , ou indings
migh be ele an o be e unde s and he
pa hophysiology o doxo ubicin-induced ca diomyopa hy
so ha we can de elop e icien p o ec i e and/o
he apeu ic s a egies in pa ien s ea ed wi h his
chemo he apeu ic agen .
Con lic o In e es
The e is no con lic o in e es .
Acknowledgemen s
This wo k was suppo ed by a g an om he Po uguese
Founda ion o Science and Technology (FCT:
PEs -C/SAU/UI0051/2011; EXCL/BIM-MEC/055/2012
h ough Ca dio ascula R&D Uni ) and om he
Eu opean Commission (FP7-Heal h-2010; MEDIA-
261409). C. B.-S. is also suppo ed by g an s om he
Po uguese Founda ion o Science and Technology
(PTDC/SAU-FCT/100442/2008, COMPETE, FEDER
and Ciência 2008) and om he Uni e si y o
Po o/San ande To a.
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