Review Article Supraventricular Arrhythmias after Thoracotomy: Is There a Role for Autonomic ...

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HindawiPublishingCorporation
AnesthesiologyResearchandPractice
Volume2013,ArticleID413985,12pages
http://dx.doi.org/10.1155/2013/413985
Review Article
Supraventricular Arrhythmias after Thoracotomy:
Is There a Role for Autonomic Imbalance?
GeorgeVretzakis,MarinaSimeoforidou,KonstantinosStamoulis,andMetaxiaBareka
AnesthesiologyClinic,UniversityHospitalofLarissa,41110Mezourlo,Greece
CorrespondenceshouldbeaddressedtoGeorgeVretzakis;[email protected]
Received27June2013;Revised23August2013;Accepted23August2013
AcademicEditor:S.Neustein
Copyright©2013GeorgeVretzakisetal. This is an open access article distributed under the Creative Commons Attribution
License,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperly
cited.
Supraventriculararrhythmiasarecommonrhythmdisturbancesfollowingpulmonarysurgery.Theoverallincidencevariesbetween
3.2%and30%intheliterature,whileatrialfibrillationisthemostcommonform.Thesearrhythmiasusuallyhaveanuneventful
clinical course and revert to normal sinus rhythm, usually before patent’s discharge from hospital. Their importance lies in
the immediate hemodynamic consequences, the potential for systemic embolization and the consequent long-term need for
prophylacticdrugadministration,andtheincreasedcostofhospitalization.Theirincidenceisprobablyrelatedtothemagnitude
of the performed operative procedure, occurring more frequently after pneumonectomy than after lobectomy. Investigators
believethatsurgicalfactors(irritationoftheatriaperseoronthegroundofchronicinflammationofagedatria),directinjury
to the anatomic structure of the autonomic nervous system in the thoracic cavity, and postthoracotomy pain may contribute
independentlyorinassociationwitheachothertothedevelopmentofthesearrhythmias.Thisreviewdiscussescurrentlyavailable
informationaboutthepotentialmechanismsandriskfactorsfortheserhythmdisturbances.Thediscussionisinparticularfocused
ontheroleofpostoperativepainanditsrelationtotheautonomicimbalance,inanattempttoavoidorminimizediscomfortwith
properanalgesiautilization.
1.Introduction the terms “thoracotomy,” “pulmonary resection,” “arrhyth-
mia,” “atrial fibrillation,” “heart rate variability,” and “pain.”
Variationsfromthenormalrhythmoftheheartbeat,encom- Thesearchwaslimitedtohumansandadultsandonlypubli-
passing abnormalities of rate, regularity, site of impulse cationswithatleastanEnglishabstractwereincluded.Pub-
origin,andsequenceofactivationarewell-documentedcom- lications without abstracts were excluded, except from case
plicationsfollowingthoracotomiesforsurgicaltreatmentof series and case reports. MEDLINE database was searched
intrathoracicpathology[1–10].Generally,theseperioperative usingPubMedadvancedsearchwiththefollowingstrategies:
arrhythmias are associated with longer hospital stay and (1)thoracotomyANDarrhythmia,149results;(2)pulmonary
highercost[8].Althoughnotwidelyaccepted,manyauthors resection AND arrhythmia, 86 results; (3) atrial fibrillation
believethatpatientsdevelopingpersistentorrecurrenttach- ANDpulmonaryresection,76results;(4)heartratevariability
yarrhythmias present a greater mortality and experience AND thoracotomy AND arrhythmia, 1 result; (5) thoraco-
morecomplicationsthanthosewhomaintainednormalsinus tomy AND pain AND arrhythmia, 12 results. All identified
rhythmsaftersurgery[1–3].Basedonanup-to-dateliterature citations that seemed relevant to our scope were reviewed.
review, this paper discusses currently available information Some citations were generated in common by the above-
about the potential mechanisms and risk factors for the mentionedstrategies.Initialconsiderationexcludedcitations
developmentoftheserhythmdisturbances. not focusing on the potential mechanisms for development
We searched for original articles, review articles, case of supraventricular arrhythmias after thoracotomy. We also
series or case reports, and editorials using the MEDLINE excluded citations dealing with preventive measures and
database (from January 2002 to September 2012) and the techniques and drug therapies. This search strategy yielded
CochraneCentralRegisterofControlledTrialsbycombining 32 articles. We expanded inclusion to the reference lists of
2 AnesthesiologyResearchandPractice
these articles, and finally 89 articles were found to be of overallincidenceof3.27%wasreportedforintraoperativeAF
relevance. The full texts of these original articles, review inaretrospectivereviewof10563medicalrecordsofpatients
articles,caseseries,casereports,andeditorialswereretrieved whounderwentlungoperations[11].Ingeneral,thereported
and examined. Finally, 84 articles were included in this incidenceofpostoperativeSAishigher,varyingfrom8.3to
narrativereview. 31.9% [1–10, 12, 13], peaking on the second [9, 13] or third
A number of factors have been identified as related to postoperative day [3]. In a prospective database including
higherriskfortheappearanceofpostthoracotomyarrhyth- 2588 patients the incidence of AF was 12.3% [14]. The
mias. In the literature, factors considered in favor for the percentage of patients developing postoperative arrhythmia
development of supraventricular arrhythmias are advanced ishigherafterpneumonectomycomparedtothatafterlobec-
age,malesex,historyofchronicobstructivepulmonarydis- tomy.Bilobectomyisoftenlistedwithpneumonectomy.The
ease (COPD), major resection especially right-sided, medi- incidence of tachyarrhythmias in nonanatomic resections
astinal dissection, and intrapericardial pneumonectomy. In (wedge resection) may range from almost null to approxi-
individual patients, preexisting cardiac disease, hypoxemia, mately10%andisverylowalsoinsegmentectomies[7,10].
hypercapnia, intraoperative fluid imbalance, hypotension, Esophagectomyisalsofollowedbyrhythmdisturbances[14–
andotherfactorsmayalsoberelatedtotheriskofarrhythmia. 16].Inaretrospectiveanalysisofaperiodgreaterthan10years
Little is known about the potential mechanisms that including 921 esophagectomies for cancer the incidence of
generate these arrhythmias. As it will be discussed in the AFwas22%[17].Hence,theoverallincidencevariesbetween
following,somedataexistthatitisinflammationinagedatria series,dependingonthepercentagesofthedifferenttypesof
that predisposes to arrhythmia in case of surgical irritation operationsandontheparticulartypesofarrhythmiaswhich
ordamage.Thecorrelationofectopicrhythmswithhypoxia, wereincludedforthecalculations.
hypercapnia,acidosis,andhyperphosphatemiaisalsonoted
bymanyresearchers.Asmostofthestudiesanalyzingtherisk
factorswereretrospectivelyperformedandtheeffectiveness 3.RiskFactors
ofperioperativeanalgesiacouldnotberevealed,verylittleis
knowndirectlyanddefinitivelyfortheroleofpain.Posttho- Inolderreports,genderandadvancedagewerenotreported
racotomypaindeservesextensivelycommentingfor,atleast, asimportantpredisposingfactorsfortachyarrhythmiasafter
fivereasons.Firstly,itissignificantandsometimesintolerable pulmonary resections [2, 5, 7]. The independent role of
ifuntreated.Asecondreasonisthattheonsetofarrhythmias these two factors was obscured by the different incidence
parallelswithpain.Athirdreasonisthatanalgesictreatment ofconcomitantcardiopulmonarydiseases.Malegenderand
with epidurally administered local anesthetics may result olderageareoftencorrelatedwithalongersmokinghistory
in significant decrease in the incidence of arrhythmias. and COPD and thus with a higher probability of impaired
Another reason comes from the fact that pain may cause oxygenationandcardiacdysfunction.Nevertheless,smoking
significant cardiac autonomic imbalance predisposing to history could not be identified as a predictor of AF in
arrhythmia due to increased sympathetic outflow. A fifth both pneumonectomy and lobectomy patients [10]. More
reasonfavoringarelationofpainandautonomicimbalance recently, male sex and advanced age were documented as
to postthoracotomy arrhythmias is the observation that, in strong clinical predictors for the appearance of SVT [3, 4,
most of the cases, arrhythmias show good clinical course 10, 13, 18, 19]. Aging causes degenerative and inflammatory
and recurrence of normal sinus rhythm as pain decreases. changesinatrialmyocardiumand,consequently,itleadsto
Although the impact of other analgesic modalities as the alterationsintheelectricalpropertiesoftheatria[20,21].In
intravenous administration of opioids on the autonomic addition,inanexperimentalsetting,olderanimalsdeveloped
systemisdifferent,informationabouttheirprophylacticrole significantlymoreepisodesofsupraventriculararrhythmias
ismissing.Finally,theroleofthedirectirritationorinjuryto afterpneumonectomythantheiryoungercounterparts[22].
theanatomicstructuresoftheautonomicsystemissuggested Ithasbeenreportedthatage>60yearswastheonlyindepen-
byanumberofinvestigators[10],buttheinformationonthis dentpreoperativeriskfactormoststronglyandconsistently
subjectisscarce. associatedwithpostoperativeAF[23].
Preoperativefunctiontestswererepeatedlyevaluatedand
presented no significant predictive value for the prediction
2.Incidence ofpostoperativecardiacfunctionandhemodynamicdistur-
bances[2,5,23,24].Manyauthorsagreedthattherewasno
The major rhythm disturbances after operations on pul- apparentassociationwithstandardpreoperativepulmonary
monary parenchyma, for malignancy or not, or other functiontestsandtheincidenceofpostoperativearrhythmia.
intrathoracic structures are atrial fibrillation (AF) (most Intworetrospectiveanalyses,FEV1(cut-offpointof50%[5]
commonly), supraventricular tachycardia (SVT), and atrial or2.0L[2])failedtoaffectsignificantlytheprevalenceofAF.
flutter.Mostofthestudiesdonotincludepatientswithpre- Nevertheless,theconceptofusingarbitrarycut-offvaluesfor
matureventricularcomplexesoratrialextrasystoles.Ventric- categorizingpatientsinclinicalstudieshasmanylimitations.
ular tachycardias were extremely uncommon in the studies It was recently shown that patients suffering from COPD
reviewed. developarrhythmiasinthepostoperativeperiodsignificantly
Supraventriculararrhythmias(SA)maybeseenthrough- more often than no COPD patients do. In a retrospective
out the whole perioperative period in these operations. An analysisof244patients,theincidenceofSVTandAFdiffered
AnesthesiologyResearchandPractice 3
significantlybetweenCOPD(FEV1 1.5L,48.37%)andnon- 4.PotentialMechanisms
COPD patients (FEV1 2.3L, 79.6%) [9, 19]. Furthermore,
Increased atrial ectopy, atrial premature contractions, and
thehistoryofchroniclungdiseasewasfoundindependently
acutelyincreasedheartratemayleadtoreentryofmultiple
predictiveofSVTinaseriesof4000patients[25].
small wavelets and initiate a paroxysm of atrioventricular
Conflicting data exist about the role of preoperative
nodaltachycardiaand/orAF[32].Ithasbeenobservedthat
hypoxemia on the incidence of postoperative supraven-
a greater preoperative heart rate (HR) was an independent
tricular arrhythmias. It is known from past research that
predictor of AF after cardiac operations, especially among
animalsthatweremadehypoxicdevelopedarrhythmiasand the elderly [22]. Atrial fibrosis or inflammation per se or
had hemorrhage of the conducting system [26] and that after an indirect atrial trauma during surgery presumably
ectopic rhythms correlate with hypoxia during operation provides the abnormal milieu for the development of SVT,
[27]. Hypoxia is known to cause changes in the electrical especially in the elderly [33] and during operations impli-
characteristicsofcardiacmusclethatcanleadtoarrhythmias cating major resections, interpericardial dissections, and
[28]. Nevertheless, a retrospective study showed that SpO2 pericardialhandling.Experimentalinformationissupportive
valueslessthan90%werenotsignificantlyassociatedtoSVTs for a relation between aging, inflammation, and postpneu-
[5].Morerecently,PaO2valuesshowednodifferencebetween monectomy supraventricular arrhythmias [34]. In the past,
patients with (PaO2 = 78.5mmHg) and without (PaO2 = atrialinflammationwasincludedamongtheproposedcauses
80.7mmHg) postoperative AF [10]. In disagreement with of arrhythmia by some authors [2]. Up to now, the data
about the role of inflammatory changes on the appearance
the above, other series documented significantly lower pre-
of post-thoracotomy tachyarrhythmias remain extremely
operative values of PaO2 in patients who developed tach-
scarce.Acutepericarditiswasconsideredaprimaryinitiator
yarrhythmias [7, 9]. Postoperatively, at the time of onset of
ofAFaftercardiacoperations,butthishasneverbeenproven
thiscomplication,patientsarenotnecessarilyinacondition
[35].
ofseverehypoxemia[2,7].
The role of direct injury to the autonomic cardiac
Most authors agree that the incidence of tachyarrhyth-
innervationduringthoracotomiesisspeculatedbyanumber
miasisrelatedtothemagnitudeoftheoperativeprocedure
of reports. The heart is innervated by both sympathetic
performed,occurringmorefrequentlyafterpneumonectomy
andparasympatheticfilaments,accompanyingthecoronary
than after lobectomy [2, 4, 5, 7, 10, 12, 29] (Table1). Major
arteries and their branches. Autonomic cardiac nerves may
resections are independently predictive of postoperative
be exposed, retracted, and injured during thoracic surgery.
arrhythmiasandperioperativemortality[9].Inaprospective
Injury to the parasympathetic branches of the sinoatrial
study with a small study population, patients developed
node may result in increased heart rate and decreased
postoperativearrhythmiasatalmostequalpercentages[16].
atrioventricularconduction.Surgicallyinducedalterationsin
The development of postoperative rhythm disturbances is
the efferent sympathetic outflow to the heart may account
not associated with the particular indication of surgery for postoperative cardiac arrhythmias. The anatomic loca-
(malignancy or not) and the underlying pathology. In 298 tion of cardiac plexus in the area between the aortic arch
patients,benigntumors,tuberculosis,andotherlungdiseases and the tracheal bifurcation makes it vulnerable to direct
represented the 27% of the indications for surgery. These damage, especially in thoracotomies implicating dissection
indications did not correlate significantly with the develop- of pulmonary hilum or sampling of nodes located in this
mentofpostoperativearrhythmias[5].Moreover,incaseof area.Meanwhile,thereisnodataconcerningpossibleimpulse
malignancy, the stage of lung cancer is also not associated generation at the site of surgical incision by the application
withtheincidenceofarrhythmia.Lungcancer,notbecauseof ofsurgicalinstrumentation,pressinganddeformingthoracic
itsmalignancy,butbecauseofitsassociationwithahistoryof wall structures, and by the partial removal of costa. It is
smokingandCOPD,orbecauseitrequiresamoreextensive unknownifsuchimpulsesreachsympatheticgangliaormore
lungresection,issometimesconsideredasariskfactorforthe central anatomic formations and return to the heart as an
onsetofpostoperativearrhythmia[6]. altered autonomic tone. Recently, in patients undergoing
sympathectomyforprimaryhyperhidrosis,withaminimally
Tachyarrhythmias occur more frequently in operations
invasiveendoscopictechnique,decreasedHRwasobserved
withintrapericardialdissectionsorpericardialhandlingand
postoperatively [36]. This clinical vagotonic image of the
in cases of postoperative interstitial or perihilar pulmonary
heartwasfurtherdocumentedasadecreaseinsympathetic
edema [2, 3, 24, 30]. The operational side may also play
activity by heart rate variability (HRV) analysis. In another
a role in the occurrence of postoperative arrhythmias.
report,patientswhounderwentvideo-assistedthoracoscopic
Many authors, comparing right and left pneumonectomies,
lobectomy for lung cancer were properly matched with
demonstratedahigherincidenceafterright-sidedprocedures
thoseundergoingopenthoracotomyandpostoperativeatrial
[3, 13]. Reported results from other investigators do not
fibrillation developed in comparable percentage of patients
confirmthisobservation[10].Postoperativehemorrhageand inbothgroups[37].Thissupportsthetheorythatautonomic
repeatthoracotomyarealsosignificantlyassociatedwithAF denervation may be responsible for the pathogenesis of
[5]. Finally, a relationship was suggested between previous postoperative SA. Finally, other anatomic regions may also
thoracic irradiation and the frequency of postthoracotomy play a role. It has been shown that pulmonary vasculature
cardiacrhythmdisturbances[31]. proximallytotheheartshowselectricalpropertieswhichcan
4 AnesthesiologyResearchandPractice
Table1:Associationbetweenpostoperativeheartratedisordersandthetypeoftheperformedsurgicalprocedure.
Percentagein Percentagein
Study Ref.no. Includedarrhythmias ∗ Overall
pneumonectomy lobectomy
Krowkaetal.1987 [2] TDR 23.6∗∗
DyszkiewiczandSkrzypczak1998 [5] AF 24.0 6.1 8.3
Curtisetal.1998 [6] SA 39.4 17.0 22.4
Ciriacoetal.2000 [7] SA 33.3 12.6 13.7
Sekineetal.2001 [9] SVT 31.9
Renaetal.2001 [10] SA 35.0 23.0 22.8
BarbetakisandVassiliadis2004 [12] SA 37.3 17.4 21.6
∗
Includingbilobectomy.
∗∗
Studyaddressingonlypneumonectomy.
TDRdenotestachydysrhythmia.
generateectopicbeats[38].Surgicalirritationordamageto balance. Nevertheless, HRV is only an indirect measure of
thiszonemayprobablybearrhythmogenic. autonomicinfluencesonthesinusnode,andthereforeinter-
The observation that a greater preoperative heart rate pretationconcerningtheexactmechanismofpostoperative
is an independent predictor of postoperative AF suggests a AFshouldbemadewithcaution[46].
relationofvagaltonewiththeappearanceofthesearrhyth- Denervatedheartsshowtypicallyhigherheartratesthan
mias. In fact, some believe that lower vagal tone stratifies innervated hearts and much reduced HRV with no definite
patients susceptible to AF [22]. Autonomic imbalance has spectralcomponents[47,48].Theabovementionedposttho-
been implicated as a possible trigger of postoperative AF. racotomy tachycardia, which is associated with decrements
Nevertheless, increased heart rate may also be attributed to in all HRV variables, could also be explained by “apraxic
increased sympathetic drive to the heart, and there is some surgical injuries” to both sympathetic and parasympathetic
controversy as to whether the imbalance in relation to the neuralfibres,leadingtoatemporarystateofdenervatedheart.
postthoracotomy arrhythmias is primarily vagal or sympa- Is an imbalance of heart’s autonomic system some-
theticinorigin[39,40].Asithasbeenshowninexperimental how present during thoracotomy? Findings about heart’s
models, AF may be produced from increased vagal tone autonomousnervoussystemduringesophagectomyorpul-
alone. Some hypothesize that the heightened background monary resections were demonstrated in patients operated
sympathetic tone helps promote AF with increased vagal without epidural anesthetic support [16]. After esophagec-
activity.Itisconceivablethatvagalreboundpromotesectopy tomyLF,HF,andtotal-frequencycomponentsofHRVwere
by shortening refractoriness in a heterogeneous matter and reduced, LF/HF ratio was increased. In the pulmonary
thattheincreasedbackgroundsympatheticactivitymaythen resectiongroup,declinedLFcomponentofHRV,reduction
promoteAF[41].TheadrenergicallyorvagallymediatedAF ofthetotal-frequencycomponentofHRV,decreasedLF/HF
in nonsurgical patients, which, in respect, is characterized ratio, and no significant change in HF were observed.
byanincreasingordecreasingHRbeforearrhythmiaonset, These results indicate decreased sympathetic outflow to the
may be interpreted differently in postoperative patients. A heart. Postoperatively, these patients presented increased
complexpostoperativeenvironmentthatconsistsofchanging heart rates, irrespective of the performed operation and
respiratory pattern, ensuing pain, application of various supraventriculararrhythmiasthatoccurredin15%ofthem.
analgesictechniques,includingcentralneuralblockade,and Morerecently,decreasedLFcomponentandincreasedLF/HF
the systemic circulation of swinging opioid concentrations ratio were demonstrated in patients undergoing thoracic
couldpossiblyaffect thearrhythmogenicitypotentialinthe surgery under high thoracic epidural analgesia (TEA) [49].
individualpatient. Theseresultsalsoindicatedecreasedsympatheticactivity,but
It is known that during normal sinus rhythm the time attributingitsolelytotheperformedthoracotomyisincorrect
interval between heartbeats is not stable. This beat-to-beat as TEA also may lead to similar HRV findings (see below).
oscillation of RR intervals around its mean value is heart Using HRV analysis, other investigators also showed that
rate variability. Measured and analyzed, this physiological thoracoscopic sympathectomy under general anesthesia is
phenomenon of cycle length variability represents a simple followedbybluntedcardiacsympatheticneuraldrivewhichis
and noninvasive electrocardiographic quantitative index of inagreementwithwhatisclinicallyexpected.Postoperatively,
the heart’s autonomous status [42–45]. A typical spectrum HRwasdecreased,andthe38patientsofthisstudydidnot
ofRRseriesischaracterizedbytwomainfrequencycompo- developarrhythmias[36].
nents,namely,thehigh-frequencycomponentofthepower Inaprospectivestudy,Holterrecordingswerecompared
spectrum(HF)andlow(LF).IngeneraltheHFcomponent between patients with postthoracotomy AF and matched
hasbeen thoughttoreflectprimarilyvagalactivitywhereas surgical controls without AF [50]. Patients developing AF
LFreflectsbothsympatheticandvagalactivity.TheratioofLF had a significant elevation of heart rate before developing
toHFpowerisoftenconsideredameasureofsympathovagal arrhythmia. The authors analyzed HRV data before the
AnesthesiologyResearchandPractice 5
onset of AF and found that both LF and HF powers were arrhythmias.Effective,clinicallyadequateanalgesiadoesnot
significantlygreaterthanthoseinthenonarrhythmiaperiods. preclude a pro- or antiarrhythmic effect. Although opi-
They also had significantly lower LF/HF ratio compared oidscanincreaseparasympatheticactivityandmaybalance
to controls. These data suggest that vagal activation in the heightenedsympathetictoneafteroperation,theyexhibitno
settingofsympatheticpredominancecontributesstronglyto effect on sympathetic drive. The effect of opioids on HRV
postoperative AF. This study differs in comparison to the variables is different than that of the epidurally adminis-
abovementioned studies, as it does not only demonstrate teredlocalanesthetics[60].Postoperativepatient-controlled
thechangesinautonomicstatusafterthoracicsurgery,when analgesia(PCA)withopioidswascomparedwithTEAafter
thereisanincreasedpossibilityforarrhythmiadevelopment, thoracicsurgeryundergeneralorcombinedgeneral/epidural
butitalsofocusesindetailontheautonomicalterationsthat anesthesia [61]. In this study, HRV analysis was not used.
precedetheonsetofarrhythmia.Thefindingsofthisstudyare TheincidenceofSVT,AF,andsupraventricularectopicbeats
comparabletodatainnonsurgicalpatientswhereRRinter- was lower in the opioid group (PCA). These results are in
vals decreased and frequency domain parameters of HRV disagreement with the findings of a similar study where
increased before AF onset [51]. In addition, time domain postoperative tachycardia was significantly less frequent in
parameters of HRV also increased in the study patients, theTEAgroup[49].Inthislaterstudy,HRVanalysisshowed
providing consistent data to suggest that vagal rebound or unchanged LF/HF ratio in the opioid-PCA group whereas
resurgence was occurring in addition to an elevation in it was significantly reduced in the TEA group. Similarly, in
sympathetictonebeforetheinitiationofpostoperativeAF. patients undergoing thoracotomy under combined general
Thoracotomiesarefollowedbysignificantpain.Thoracic and thoracic epidural analgesia with levobupivacaine, it
epidural anesthesia is regarded as the most reliable treat- was found that substitution of the local anesthetic on the
ment for postthoracotomy pain management [52, 53]. TEA 3rd postoperative day with patient-controlled intravenous
withadministrationoflocalanestheticsshowsaprophylac- morphine resulted in an increased LF component of the
tic effect on postoperative dysrhythmias after thoracotomy HRV [62]. Patients in the continued TEA group were free
[8, 54, 55]. These observations are somehow indicative ofpostoperativearrhythmias.Thisdifferenceinsympathetic
of a relationship between postthoracotomy pain and the outflowwasnotclinicallyapparentastherewasnodifference
appearanceofarrhythmiasduringthepostoperativeperiod. betweenthegroups(TEAwithlevobupivacaineversusmor-
Increasedsympatheticoutflowduetopostoperativepainmay phinePCAinthe3rdday)regardinghemodynamicvariables
be arrhythmogenic. Most authors have verified that TEA’s and pain visual scale. The authors concluded that the post-
analgesic effect associates with decreased sympathetic drive operativelydecreasedcardiacsympatheticoutflowcontinues
to the heart. For thoracotomies, high TEA (sensory block withepidurallocalanestheticsadministration,whereasitis
of C6-T6) is preferable as it is associated with minimal abolished by the change to intravenous patient-controlled
effectonsystemicvascularresistanceandmoreorlessstable morphine. Finally, two studies tested the impact of TEA
hemodynamics[56,57]. on postoperative AF in patients who underwent coronary
ItisknownthathighTEAdoesnotaltertheoverallreflex revascularization [63, 64]. In both, TEA showed no effect.
responsestoanumberofstimuliandisassociatedwithstable The lack of prophylaxis in the second study existed despite
hemodynamicsandpreservationofbaroreflexsensitivity.Ina asignificantreductioninsympatheticactivityassessedwith
studyincorporatingHRVanalysis,thedecreasedsympathetic HRVanalysis.Itseemsthattheunderlyingarrhythmogenic
outflow after TEA was associated with some withdrawal of mechanismsdiffersignificantlybetweenthoracicandcardiac
vagalactivity,asLF/HFratiowasincreased[57].Inthesame operations.
patients,inductiontogeneralanesthesia,laryngoscopy,and
tracheal intubation was also followed by increased LF/HF
ratio and the authors attributed this change to sympathetic 5.ClinicalSignificance
activation. In another study, with sensory block of C6-T6,
both low- and high-frequency spectral power remained Most commonly, the onset of supraventricular arrhyth-
unchanged. During tilting, the subjects showed attenuation mias follows the operation, not rarely complicating the
of the increase in heart rate, no change in absolute and period when patients regain consciousness. Intraoperative
fractionalLFandHFpower,andadecreaseinLF/HFratio incidence compared to postoperative is considerably lower.
which was attributed to preganglionic cardiac sympathetic The course of these arrhythmias varies. In the majority of
blockade [58]. The authors’ interpretation of these findings cases, patients leave the hospital in normal sinus rhythm
wassubsequentlycriticizedintheliterature[59].Finally,the or, in lower percentages, they are dismissed arrhythmic
combinedeffectofthoracotomyandTEAonHRVvariables but with good rate control under medication. However,
was demonstrated, suggesting autonomic imbalance and a significant percentage of patients undergoing thoracic
decreasedpostoperativesympatheticoutflow[49].Decreased surgery die in the hospital, and sometimes it is difficult to
HF and LF components and decreased LF/HF ratio were clear among other factors the role of arrhythmias for this
demonstrated early after surgery, with total HRV and HF outcome.Complicationssuch as atelectasis,pneumothorax,
increasing towards preoperative values whereas the LF/HF pneumonia, bronchopleural fistula, empyema, and acute
ratioremainedsignificantlylower. respiratory distress syndrome are not uncommon in the
More studies are needed to elucidate the role of anal- postoperative period, especially in patients with history
gesic therapies on the prophylaxis of postthoracotomy of COPD [9]. Recurrence of supraventricular arrhythmia
6 AnesthesiologyResearchandPractice
may be encountered when, in the course of postoperative threepatientsdevelopedARDSandtwoofthemdiedofthis
hospitalization, a respiratory complication occurs [13, 65]. complication [73, 74]. However, the dose of amiodarone in
Theimportanceofthepostthoracotomyarrhythmiasliesin thesepatientswasrelativelyhigh(1200mg/24hbeinggiven
theimmediatehemodynamicconsequences,thepotentialfor i.v.for3days).Inamorerecentbutretrospectiveandsmall
systemic embolization and the consequent long-term need study of 83 thoracic surgery patients, the incidence of AF
forprophylacticdrugadministration,andtheincreasedcost in the amiodarone group was 10%, significantly lower than
ofhospitalization.In28%of“arrhythmic”patientselevation controls(33%)withnocomplicationsforthedrug[75].The
of concentrations of cardiac enzymes was found, with or dose of amiodarone was far lower (200mg orally) in this
withoutelectrocardiographicsignsofmyocardialischemiaor study. Amiodarone effectively decreased the incidence of
infarction, and in 38% hypotension was observed [2]. Even postoperativearrhythmiasinanumberofothertrialswithout
when atrial fibrillation is a solitary complication, hospital serious side effects [7, 12, 65]. In a randomized study of
stayforthesepatientsislonger[13].Manyinvestigatorshave 130 thoracic surgery patients, a continuous infusion dose
stated that the patients who develop persistent or recurrent of 1050mg of amiodarone, given after anesthesia induction
tachyarrhythmiaspresentagreatermortalityandexperience for the next 24 hours, followed by oral administration of
more complications with longer hospitalization and higher 800mg for a maximum of 6 days, was proven effective for
coststhanthosewhomaintainednormalsinusrhythmsafter reducingtheincidenceofAFsignificantly[76].Theincidence
surgery[1–3,8,13]. of pulmonary complications or other adverse effects was
Prevention and treatment of postthoracotomy arrhyth- not different compared to controls, and, moreover, patients
mias is an important issue for the clinician. Nowadays, the belonging to the amiodarone group left intensive care unit
acceptance and wide postoperative use of analgesic tech- earlier. More recently, in a randomized controlled study of
niques with local anesthetics or opioids make it somehow 254patients,300mgofamiodaronewasgivenintravenously
unethical to perform prospective studies investigating the over 20 minutes immediately after surgery, and it was fol-
impactofpainontheironsetandclinicalsignificance.There lowed by an oral dose of 600mg twice daily during the
arenostudiesdirectlyrelatingpain,irrespectively,ifitexists first5postoperativedays.Thisschemeloweredsignificantly
intraoperativelyinahypnotizedpatient,duringemerge,orin the incidence of AF without increasing complications [77].
a fully awaken patient postoperatively, with the appearance In case that cardioversion is decided, for example, when
ofarrhythmias.However,the“antiarrhythmic”propertiesof AFpersistsandisfollowedbyhemodynamicconsequences,
a perioperative pain-free status are shown in many of the electrotherapy under amiodarone has more possibilities for
aforementioned studies [8, 54, 62]. Furthermore, data in conversionandpreservationofsinusrhythm[78].However,
thesereportsshowthathighTEAismoreprophylacticthan existingreviewsunderlinethefactthattheappropriatenessof
intravenousopioids. amiodaroneprophylaxisagainstpostthoracotomyAFisnot
Untilafewyearsago,theeffectivenessofantiarrhythmic thesameasinthecourseofcardiacsurgery[79].
prophylaxiswithdrugsinthecourseofthoracicoperations Otherprophylacticstrategiesincludetheadministration
wasdebatable[10,55].Somearekeentoreverseearlyatrial of beta-blockers (metoprolol and propranolol). However,
fibrillationbyelectricaldefibrillation([2],seealsoAppendix studies for antiarrhythmic prophylaxis with these drugs
A in [5]). Although this review is not focused on the suffer from small-sized populations, not clearly significant
preventive drug therapies, some results from the reviewed results, and that the patients experienced side effects [80,
literature are provided here and they are summarized in 81]. Existing reviews support the use of beta-blockers after
Table2. Existing reports vary in design, size of studied individualizationandwithhavingthepossibleadverseevents
population,andqualityofdata.Inthepast,digoxinwasfound in mind. Finally, as a link has been established between
ineffective for the prevention of AF in patients undergoing lowmagnesiumplasmaconcentrationandthegenerationof
avarietyofthoracicsurgeryprocedures[66–68].Twosmall arrhythmias, a prophylactic magnesium treatment has also
studies showed better results for flecainide and diltiazem beenproposed[82–84].
comparedtodigoxin[69,70].Flecainideversusplacebowas
foundeffectiveforthepreventionofAFwithnosideeffects
[71].Inarelativelystrongrandomizedstudyof330patients, 6.Conclusions
the prophylactic effect of diltiazem was evaluated [18]. The
studydemonstratedasignificantreductioninpostoperative Thoracic surgical interventions involving excision of lung
AF,withanincidenceof26%incontrolpatientswhichwas tissue are known to be associated with various forms
reduced to 14% in diltiazem patients, without significantly of supraventricular arrhythmias, most commonly AF. The
increasedadversereactionstodrugtreatment.Beyondatrial authors dealing with the subject have revealed certain
arrhythmias, calcium channel blockade is associated with a predisposing-precipitatingfactors,suchasage,malegender,
significantreductionintheincidenceofthenotverycommon pneumonectomy (especially right), bilobectomy, intraperi-
intheseoperationsventriculararrhythmias[72]. cardialprocedures,andCOPD.Astothepathophysiological
In a three-arm trial of verapamil, amiodarone, and backgroundofpost-thoracotomytachyarrhythmias,thereis
controls,thefirstdrugreducedtheincidenceofAFbutthis stillmuchtobeexplained.Autonomicnervoussystemdisor-
finding was lacking significance and, at the same time, a derstriggeredbothbyintraoperativesurgicalmanipulations
significantproportionofpatientsexperiencedbradycardiaor aswellasbypotentpainstimuli,seemtobeofcardinalimpor-
hypotension. The amiodarone arm was stopped early after tanceforthegenesisoftheaforementionedarrhythmias;the
AnesthesiologyResearchandPractice 7
nt
e
w
r
e
d n
kness ntsun ngulatio ng
udystrength/wea nly56.1%ofpatiengresectionoHoltermonitoriosamplesizecalc oHoltermonitori oltermonitoringmallstudy oltermonitoring,mallstudyoplaceboarm
St OluNN N Hs HsN
n
xi
o
g
Di r
a
myarrhythmias. ResultsIncidenceofarrhythmiaDigoxin29/64(45%)Control24/66(36%)NSOnedeathduetoarrestingroupIncidenceofarrhythmiaDigoxin29/58(50%)Control19/53(36%)NSOnedeathduetoarrestinDigoxingroupOutcomedefinedasneedtostartorincreaseantiarrhythmicdrugFlecainide0/14Placebo6/16(38%)significantSVTorcomplexventricularrhythmiaFlecainide1/15(7%)Digoxin7/15(47%)significant
o
ot
c
a
r
o
h s
postt atient 6466 5853 =1416 =1515
for ofp 𝑛=𝑛= 𝑛=𝑛= 𝑛e,𝑛= 𝑛e,𝑛=
ophylaxis Number Digoxin,Control, Digoxin,Control, FlecainidPlacebo, FlecainidDigoxin,
r
p
g
u
r
D
2:
Table dytype blindedCT blindedCT CT CT
u nR nR R R
St UP UP P P
(ref.no.) eetal.1990[66] eetal.1992[67] atetal.1989[71] atetal.1991[69]
Study Ritchi Ritchi Borge Borge
s
e
di
u
st
o
s
al
e
e
Drug Digoxin(s[69,70]) Flecainide
8 AnesthesiologyResearchandPractice
s,
n
o
nti
e
r v
Studystrength/weakness NoHoltermonitoring LowDiltiazemdose,Noplaceboarm Goodstudydesign,Holtemonitoring,samplesizecalculation,comparablesurgicalinterpoweranalysis
p m
u e
o z
milgr Diltia =1in up
ResultsIncidenceofAFVerapamil8/100(8%)Control15/99(15%)NS23%bradycardiaorhypotensioninVerapaIncidenceofAFDiltiazem5/35(14%)Digoxin11/35(31%)NSHypotension=2ptsingroup2nddegreeheartblockDigoxingroupIncidenceofAFDiltiazem25/167(14%)Control40/163(26%)significant3.59%inDiltiazemgrodevelopedhypotension(0.61%incontrol)
ontinued. patients 𝑛=100=99 𝑛=35=35 𝑛=167=163
Table2:C Numberof Verapamil,𝑛Control, Diltiazem,𝑛Digoxin, Diltiazem,𝑛Control,
d
e
d
n
pe ed ed bli
dyty blindCT blindCT uble-CT
u nR nR oR
St UP UP DP
]
3
7
[
6
9
9
al.,1 [70] [18]
ef.no.) ghemet al.1997 al.2000
udy(r nMie maret maret
St va A A
o
s
al
e
e
s
(
mil4]) m
7
a[ e
Drug Verapstudy Diliaz
AnesthesiologyResearchandPractice 9
d
e
v
s ei
Studystrength/weakness StudystoppedearlyduetocomplicationsHighdoseofAmiodaroneNoHoltermonitoring NorandomizationNoHoltermonitoringIncidenceofAFfromrecordLowdoseofAmiodarone NoHoltermonitoring ElectrocardiogramorHoltermonitoring,poweranalysis,intentiontotreatanalysis NoHoltermonitoringNopoweranalysisPatientsincontrolgrouprecDigoxin
p ol
ResultsIncidenceofAFAmiodarone1/32(3.1%)Verapamil0/32(0.0%)Control7/32(21.8%)(RCTreport)3/32ptsdevelopedARDSand2/32diedinAmiodaronegrou(RCTreport)6/55(11%)inAmiodaronegroupversus9/497(1.8%)incontrdevelopedARDS(cohortreport)IncidenceofAFAmiodarone3/31(9.7%)Control17/52(33%)SignificantIncidenceofAFAmiodarone9/65(13.8%)Control21/65(32.3%)SignificantShorterICUstayforAmiodaronegroupptsNodifferenceincomplicationsIncidenceofAFAmiodarone11/122(9%)Control38/120(31.6%)significantNosideeffectstracedtotheprophylacticregimeIncidenceofatrialtachyarrhythmiaMagnesium10/93(11%)control27/101(27%)Significant
nued. ents =55 e, =31 =65 0 =931
Table2:Conti Numberofpati 𝑛Amiodarone,NoAmiodaron𝑛=497 𝑛Amiodarone,𝑛=52control, 𝑛Amiodarone,𝑛=65control, Amiodarone,𝑛=122𝑛=12Control, 𝑛Magnesium,𝑛=10Control,
Studytype Retrospectivereviewofprospectivelycollecteddata Retrospectivecohortstudy PRCT Double-blinded-PRCT UnblindedPRCT
]
4
7
[
4
9 ]
Study(ref.no.) vanMieghemetal.19 Lanzaetal.2003[75] Tisdaleetal.2009[76 Riberetal.2012[77] Terzietal.1996[82]
e
n m
daro esiu
g o n
Dru Ami Mag
10 AnesthesiologyResearchandPractice
latter also explains the potential beneficial role of TEA in [11] D.H.Wu,M.Y.Xu,T.Mao,H.Cao,D.J.Wu,andY.F.Shen,
regard to prophylaxis against tachyarrhythmias. Heart rate “Riskfactorsforintraoperativeatrialfibrillation:aretrospective
variability consists of a useful, noninvasive diagnostic tool analysisof10,563lungoperationsinasinglecenter,”TheAnnals
thathasbeenrecruitedinordertoelucidatevariousaspects ofThoracicSurgery,vol.94,no.1,pp.193–197,2012.
of the related pathophysiology, showing that postoperative [12] N.BarbetakisandM.Vassiliadis,“Isamiodaroneasafeantiar-
tachyarrhythmiascanpartlybeattributedtoaperioperative rhythmictouseinsupraventriculartachyarrhythmiasafterlung
cancersurgery?”BMCSurgery,vol.4,article7,pp.1–6,2004.
disequilibriumbetweenthebasicvariantsoftheautonomic
system—the vagal and sympathetic ones. In regard to the [13] E.E.Roselli,S.C.Murthy,T.W.Riceetal.,“Atrialfibrillation
complicating lung cancer resection,” Journal of Thoracic and
prophylactic/therapeutic approach and in addition to the
CardiovascularSurgery,vol.130,no.2,pp.438–444,2005.
favourableeffectofTEA,mostauthorsagreethattheappli-
[14] A.A.Vaporciyan,A.M.Correa,D.C.Riceetal.,“Riskfactors
cation of pharmacological agents such as amiodarone and
associated with atrial fibrillation after noncardiac thoracic
beta or calcium channel blockers can either prevent or
surgery: analysis of 2588 patients,” Journal of Thoracic and
suppresstachyarrhythmiaswithhighratesofsuccess.Finally,
CardiovascularSurgery,vol.127,no.3,pp.779–786,2004.
the maintenance of a physiologic electrolytic balance with
[15] L.J.Kohman,J.A.Meyer,P.M.Ikins,andR.P.Oates,“Random
prompt correction of related deviations, especially the ones
versuspredictablerisksofmortalityafterthoracotomyforlung
affectingpotassiumandmagnesiumserumlevels,isanother
cancer,”JournalofThoracicandCardiovascularSurgery,vol.91,
waytoprotectourpatientsfromthistypeofpostthoracotomy no.4,pp.551–554,1986.
complications,whichcancostlivesifnotdealtwithproperly. [16] T. Kimura, T. Komatsu, J. Takezawa, and Y. Shimada, “Alter-
ationsinspectralcharacteristicsofheartratevariabilityasacor-
References relateofcardiacautonomicdysfunctionafteresophagectomyor
pulmonaryresection,”Anesthesiology,vol.84,no.5,pp.1068–
[1] F.M.MowryandE.W.ReynoldsJr.,“Cardiacrhythmdistur- 1076,1996.
bancescomplicatingresectionalsurgeryofthelung,”Annalsof [17] S.C.Murthy,S.Law,B.P.Whooley,A.Alexandrou,K.M.Chu,
InternalMedicine,vol.61,pp.688–695,1964. andJ.Wong,“Atrialfibrillationafteresophagectomyisamarker
[2] M. J. Krowka, P. C. Pairolero, and V. F. Trastek, “Cardiac forpostoperativemorbidityandmortality,”JournalofThoracic
dysrhythmiafollowingpneumonectomy:clinicalcorrelatesand andCardiovascularSurgery,vol.126,no.4,pp.1162–1167,2003.
prognosticsignificance,”Chest,vol.91,no.4,pp.490–495,1987. [18] D.Amar,N.Roistacher,V.W.Ruschetal.,“Effectsofdiltiazem
[3] D.H.HarpoleJr.,M.J.Liptay,M.M.DeCampJr.,S.J.Mentzer, prophylaxis on the incidence and clinical outcome of atrial
S. J. Swanson, and D. J. Sugarbaker, “Prospective analysis of arrhythmias after thoracic surgery,” Journal of Thoracic and
pneumonectomy:riskfactorsformajormorbidityandcardiac CardiovascularSurgery,vol.120,no.4,pp.790–798,2000.
dysrhythmias,”AnnalsofThoracicSurgery,vol.61,no.3,pp.977– [19] Y. Sekine, M. Behnia, and T. Fujisawa, “Impact of COPD on
982,1996. pulmonarycomplicationsandonlong-termsurvivalofpatients
[4] H.Asamura,T.Naruke,R.Tsuchiya,T.Goya,H.Kondo,and undergoingsurgeryforNSCLC,”LungCancer,vol.37,no.1,pp.
K. Suemasu, “What are the risk factors for arrhythmias after 95–101,2002.
thoracic operations? A retrospective multivariate analysis of [20] M.S.SpachandP.C.Dolber,“Relatingextracellularpotentials
267 consecutive thoracic operations,” Journal of Thoracic and and their derivatives to anisotropic propagation at a micro-
CardiovascularSurgery,vol.106,no.6,pp.1104–1110,1993. scopic level in human cardiac muscle: evidence for electrical
[5] W. Dyszkiewicz and M. Skrzypczak, “Atrial fibrillation after uncoupling of side-to-side fiber connections with increasing
surgeryofthelung:clinicalanalysisofriskfactors,”European age,”CirculationResearch,vol.58,no.3,pp.356–371,1986.
JournalofCardio-ThoracicSurgery,vol.13,no.6,pp.625–628, [21] M.A.Allessie,P.A.Boyden,A.J.Cammetal.,“Pathophysiology
1998. andpreventionofatrialfibrillation,”Circulation,vol.103,no.5,
[6] J.J.Curtis,B.M.Parker,C.A.McKenneyetal.,“Incidenceand pp.769–777,2001.
predictors of supraventricular dysrhythmias after pulmonary [22] D.Amar,H.Zhang,D.H.Y.Leung,N.Roistacher,andA.H.
resection,”AnnalsofThoracicSurgery,vol.66,no.5,pp.1766– Kadish,“Olderageisthestrongestpredictorofpostoperative
1771,1998. atrial fibrillation,” Anesthesiology, vol. 96, no. 2, pp. 352–356,
[7] P.Ciriaco,P.Mazzone,B.Canneto,andP.Zannini,“Supraven- 2002.
triculararrhythmiafollowinglungresectionfornon-smallcell [23] B.A.Keagy,G.R.Schorlemmer,andG.F.Murray,“Correlation
lung cancer and its treatment with amiodarone,” European ofpreoperativepulmonaryfunctiontestingwithclinicalcourse
JournalofCardio-ThoracicSurgery,vol.18,no.1,pp.12–16,2000. inpatientsafterpneumonectomy,”AnnalsofThoracicSurgery,
[8] T.Oka,Y.Ozawa,andY.Ohkubo,“Thoracicepiduralbupiva- vol.36,no.3,pp.253–257,1983.
caine attenuates supraventricular tachyarrhythmias after pul- [24] J.vonKnorring,M.Lepantalo,L.Lindgren,andO.Lindfors,
monaryresection,”AnesthesiaandAnalgesia,vol.93,no.2,pp. “Cardiacarrhythmiasandmyocardialischemiaafterthoraco-
253–259,2001. tomyforlungcancer,”AnnalsofThoracicSurgery,vol.53,no.4,
[9] Y.Sekine,K.A.Kesler,M.Behnia,J.Brooks-Brunn,E.Sekine, pp.642–647,1992.
and J. W. Brown, “COPD may increase the incidence of [25] C. A. Polanczyk, L. Goldman, E. R. Marcantonio, E. J. Orav,
refractory supraventricular arrhythmias following pulmonary andT.H.Lee,“Supraventriculararrhythmiainpatientshaving
resectionfornon-smallcelllungcancer,”Chest,vol.120,no.6, noncardiacsurgery:clinicalcorrelatesandeffectonlengthof
pp.1783–1790,2001. stay,”AnnalsofInternalMedicine,vol.129,no.4,pp.279–285,
[10] O.Rena,E.Papalia,A.Oliaroetal.,“Supraventriculararrhyth- 1998.
miasafterresectionsurgeryofthelung,”EuropeanJournalof [26] R.E.Clark,I.Christlieb,M.Sanmarco,R.Diaz-Perez,andJ.F.
Cardio-ThoracicSurgery,vol.20,no.4,pp.688–693,2001. Damman,“Relationshipofhypoxiatoarrhythmiaandcardiac