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AtrialFlutterAuthor:LawrenceRosenthal,MD,PhD,FACC,FHRSChiefEditor:JeffreyNRottman,MDmore...

Updated:Mar27,2014

PracticeEssentialsAtrialflutterisacardiacarrhythmiacharacterizedbyatrialratesof240400beats/minandsomedegreeofatrioventricular(AV)nodeconductionblock.Forthemostpart,morbidityandmortalityareduetocomplicationsofrate(eg,syncopeandcongestiveheartfailure[CHF]).Seetheimagebelow.

Anatomyofclassiccounterclockwiseatrialflutter.Thisdemonstratesobliqueviewofrightatriumandshowssomecrucialstructures.Isthmusoftissueresponsibleforatrialflutterisseenanteriortocoronarysinusorifice.Eustachianridgeispartofcristaterminalisthatseparatesroughenedpartofrightatriumfromsmoothseptalpartofrightatrium.

Signsandsymptoms

Signsandsymptomsinpatientswithatrialfluttertypicallyreflectdecreasedcardiacoutputasaresultoftherapidventricularrate.Typicalsymptomsincludethefollowing:

PalpitationsFatigueorpoorexercisetoleranceMilddyspneaPresyncope

Lesscommonsymptomsincludeangina,profounddyspnea,orsyncope.Tachycardiamayormaynotbepresent,dependingonthedegreeofAVblockassociatedwiththeatrialflutteractivity.

Physicalfindingsincludethefollowing:

Theheartrateisoftenapproximately150beats/minbecauseofa2:1AVblockThepulsemayberegularorslightlyirregularHypotensionispossible,butnormalbloodpressureismorecommonlyobserved

Otherpointsinthephysicalexaminationareasfollows:

PalpatetheneckandthyroidglandforgoiterEvaluatetheneckforjugularvenousdistentionAuscultatethelungsforralesorcracklesAuscultatetheheartforextraheartsoundsandmurmursPalpatethepointofmaximumimpulseonthechestwallAssessthelowerextremitiesforedemaorimpairedperfusion

Ifembolizationhasoccurredfromintermittentatrialflutter,findingsarerelatedtobrainorperipheralvascularinvolvement.Othercomplicationsofatrialfluttermayincludethefollowing:

CHFSeverebradycardiaMyocardialraterelatedischemia

SeePresentationformoredetail.

Diagnosis

Thefollowingtechniquesaidinthediagnosisofatrialflutter:

ECGThisisanessentialdiagnosticmodalityforthisconditionVagalmaneuversThesecanbehelpfulindeterminingtheunderlyingatrialrhythmifflutterwavesarenotseenwellAdenosineThiscanbehelpfulinthediagnosisofatrialflutterbytransientlyblockingtheAVnodeExercisetestingThiscanbeutilizedtoidentifyexerciseinducedatrialfibrillationandtoevaluateischemicheartdiseaseHoltermonitorThiscanbeusedtohelpidentifyarrhythmiasinpatientswithnonspecificsymptoms,toidentifytriggers,andtodetectassociatedatrialarrhythmias

Transthoracicechocardiography(TTE)isthepreferredmodalityforevaluatingatrialflutter.Itcanevaluaterightandleftatrialsize,aswellasthesizeandfunctionoftherightandleftventricles,andthisinformationfacilitates

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diagnosisofvalvularheartdisease,leftventricularhypertrophy(LVH),andpericardialdisease.

SeeWorkupformoredetail.

Management

Generaltreatmentgoalsforsymptomaticatrialflutteraresimilartothoseforatrialfibrillation.Theyincludethefollowing:

ControlofventricularrateThiscanbeachievedwithdrugsthatblocktheAVnodeintravenous(IV)calciumchannelblockers(eg,verapamilanddiltiazem)orbetablockerscanbeused,followedbyinitiationoforalagentsRestorationofsinusrhythmThiscanbedonebymeansofelectricalorpharmacologiccardioversionorRFAsuccessfulablationreducesoreliminatestheneedforlongtermanticoagulationandantiarrhythmicmedicationsPreventionofrecurrentepisodesordecreaseintheirfrequencyordurationIngeneral,theuseofantiarrhythmicdrugsinatrialflutterissimilartothatinatrialfibrillationPreventionofthromboemboliccomplicationsAdequateanticoagulation,asrecommendedbytheAmericanCollegeofChestPhysicians,hasbeenshowntodecreasethromboemboliccomplicationsinpatientswithchronicatrialflutterandinpatientsundergoingcardioversionMinimizationofadverseeffectsfromtherapyBecauseatrialflutterisanonfatalarrhythmia,carefullyassesstherisksandbenefitsofdrugtherapy,especiallywithantiarrhythmicagents

SeeTreatmentandMedicationformoredetail.

BackgroundAtrialflutterisacardiacarrhythmiacharacterizedbyatrialratesof240400beats/min,usuallywithsomedegreeofatrioventricular(AV)nodeconductionblock.Inthemostcommonformofatrialflutter(typeIatrialflutter),electrocardiography(ECG)demonstratesanegativesawtoothpatterninleadsII,III,andaVF.

TypeI(typicalorclassic)atrialflutterinvolvesasinglereentrantcircuitwithcircusactivationintherightatriumaroundthetricuspidvalveannulus.Thecircuitmostoftentravelsinacounterclockwisedirection.TypeII(atypical)atrialflutterfollowsadifferentcircuititmayinvolvetherightortheleftatrium.(SeePathophysiology.)

Atrialflutterisassociatedwithavarietyofcardiacdisorders.Inmoststudies,approximately60%ofpatientswithatrialflutterhavecoronaryarterydisease(CAD)orhypertensiveheartdisease30%havenounderlyingcardiacdisease.Uncommonformsofatrialflutterhavebeennotedduringlongtermfollowupinasmanyas26%ofpatientswithsurgicalcorrectionofcongenitalcardiacanomalies.(SeeEtiology.)

Symptomsinpatientswithatrialfluttertypicallyreflectdecreasedcardiacoutputasaresultoftherapidventricularrate.Themostcommonsymptomispalpitations.Othersymptomsincludefatigue,dyspnea,andchestpain.(SeePresentation.)ECGisessentialinmakingthediagnosis.Transthoracicechocardiography(TTE)isthepreferredmodalityforevaluatingatrialflutter.(SeeWorkup.)

Interveningtocontroltheventricularresponserateortoreturnthepatienttosinusrhythmisimportant.Considerimmediateelectricalcardioversionforpatientswhoarehemodynamicallyunstable.ConsidercatheterbasedablationasfirstlinetherapyinpatientswithtypeItypicalatrialflutteriftheyarereasonablecandidates.Ablationisusuallydoneasanelectiveprocedurehowever,itcanalsobedonewhenthepatientisinatrialflutter.(SeeTreatment.)

Atrialflutterissimilartoatrialfibrillationinmanyrespects(eg,underlyingdisease,predisposingfactors,complications,andmedicalmanagement),andsomepatientshavebothatrialflutterandatrialfibrillation.However,theunderlyingmechanismofatrialfluttermakesthisarrhythmiaamenabletocurewithpercutaneouscatheterbasedtechniques.

PathophysiologyInhumans,themostcommonformofatrialflutter(typeI)involvesasinglereentrantcircuitwithcircusactivationintherightatriumaroundthetricuspidvalveannulus(mostofteninacounterclockwisedirection),withanareaofslowconductionlocatedbetweenthetricuspidvalveannulusandthecoronarysinusostium(subeustachianisthmus).A3dimensionalelectroanatomicmapoftypeIatrialflutterisshowninthevideobelow.

3DimensionalelectroanatomicmapoftypeIatrialflutter.Colorsprogressfrombluetoredtowhiteandrepresentrelativeconductiontimeinrightatrium(earlytolate).Ablationline(reddots)hasbeencreatedontricuspidridgeextendingtoinferiorvenacava.Thisinterruptsfluttercircuit.RAA=rightatrialappendageCSO=coronarysinusosIVC=inferiorvenacavaTV=tricuspidvalveannulus.

Animalmodelshavebeenusedtodemonstratethatananatomicblock(surgicallycreated)orafunctionalblockofconductionbetweenthesuperiorvenacavaandtheinferiorvenacava,similartothecristaterminalisinthehumanrightatrium,iskeytoinitiatingandmaintainingthearrhythmia.

Thecristaterminalisactsasanotheranatomicconductionbarrier,similartothelineofconductionblockbetweenthe2venaecavaerequiredintheanimalmodel.Theorificesofbothvenaecavae,theeustachianridge,thecoronarysinusorifice,andthetricuspidannuluscompletethebarrierforthereentrycircuit(seetheimagebelow).TypeIatrialflutterisoftenreferredtoasisthmusdependentflutter.Usually,therhythmisduetoreentry,thereisanexcitablegap,andtherhythmcanbeentrained.

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Anatomyofclassiccounterclockwiseatrialflutter.Thisdemonstratesobliqueviewofrightatriumandshowssomecrucialstructures.Isthmusoftissueresponsibleforatrialflutterisseenanteriortocoronarysinusorifice.Eustachianridgeispartofcristaterminalisthatseparatesroughenedpartofrightatriumfromsmoothseptalpartofrightatrium.

TypeIcounterclockwiseatrialflutterhascaudocranialactivation(ie,activationcounterclockwisearoundthetricuspidvalveannuluswhenviewedintheleftanteroobliquefluoroscopicview)oftheatrialseptum(seetheimagebelow).

TypeIcounterclockwiseatrialflutter.This3dimensionalelectroanatomicmapoftricuspidvalveandrightatriumshowsactivationpatterndisplayedincolorformat.Redisearlyandblueislate,relativetofixedpointintime.Activationtravelsincounterclockwisedirection.

TypeIatrialfluttercanalsohavetheoppositeactivationsequence(ie,clockwiseactivationaroundthetricuspidvalveannulus).Clockwiseatrialflutterismuchlesscommon.Whentheelectricactivitymovesinaclockwisedirection,theECGwillshowpositiveflutterwavesinleadsII,III,andaVFandmayappearsomewhatsinusoidal.ThisarrhythmiaisstillconsideredtypeI,isthmusdependentflutteritisusuallycalledreversetypicalatrialflutter.

TypeII(atypical)atrialfluttersarelessextensivelystudiedandelectroanatomicallycharacterized.Atypicalatrialfluttersmayoriginatefromtherightatrium,asaresultofsurgicalscars(ie,incisionalreentry),orfromtheleftatrium,specificallythepulmonaryveins(ie,focalreentry)ormitralannulus(seetheimagebelow).Leftatrialflutteriscommonafterincompleteleftatriallinearablationprocedures(foratrialfibrillation).Thus,tricuspidisthmusdependencyisnotaprerequisitefortypeIIatrialflutter.

Atypicalleftatrialflutter.

EtiologyAtrialflutterisassociatedwithavarietyofcardiacdisorders.Inmoststudies,approximately30%ofpatientswithatrialflutterhaveCAD,30%havehypertensiveheartdisease,and30%havenounderlyingcardiacdisease.Rheumaticheartdisease,congenitalheartdisease,pericarditis,andcardiomyopathymayalsoleadtoatrialflutter.Rarely,mitralvalveprolapseoracutemyocardialinfarction(MI)hasbeenassociatedwithatrialflutter.

Inaddition,thefollowingconditionsarealsoassociatedwithatrialflutter:

HypoxiaChronicobstructivepulmonarydisease(COPD)PulmonaryembolismHyperthyroidismPheochromocytomaDiabetesElectrolyteimbalanceAlcoholconsumptionObesityDigitalistoxicityMyotonicdystrophyinchildhood(rare)[1]

Atrialfluttermaybeasequelaofopenheartsurgery.Aftercardiacsurgery,atrialfluttermaybereentrantasaresultofnaturalbarriers,atrialincisions,andscar.Somepatientsdevelopatypicalleftatrialflutterafterpulmonaryveinisolationforatrialfibrillation.

Althoughtherearenoclearlydefinedgeneticconditionsthatcauseatrialflutter,inmanycasesthereislikelyanunderlyinggeneticsusceptibilitytoacquiringit.Genomewideassociationstudies(GWAS)haveidentifiedgenesassociatedwithatrialflutter.[2]

ThePITX2(pairedlikehomeodomain2)geneonchromosomelocus4q25isknowntoplayamajorroleinleftrightasymmetryoftheheartandhasbeenfoundtohaveastrongassociationwithatrialfibrillation[3]andanevenstrongerassociationwithtypicalatrialflutter.[4]Therearenotyetanyclinicallyavailablegeneticteststhatcanidentifypersonsatincreasedriskforatrialflutter.

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Epidemiology

UnitedStatesstatistics

Atrialflutterismuchlesscommonthanatrialfibrillation.OfthepatientsadmittedtoUShospitalswithadiagnosisofsupraventriculartachycardiabetween1985and1990,77%hadatrialfibrillationand10%hadatrialflutter.Onthebasisofastudyofpatientsreferredtotertiarycarecenters,theincidenceofatrialflutterintheUnitedStatesisestimatedtobeapproximately200,000newcasesperyear.[5]

Sexandagerelateddemographics

Inastudyof100patientswithatrialflutter,75%weremen.Inanotherstudyperformedatatertiarycarestudy,atrialflutterwas2.5timesmorecommoninmen.

Patientswithatrialflutter,aswithatrialfibrillation,tendtobeolderadults.Inonestudy,theaverageagewas64years.Theprevalenceofatrialfibrillationincreaseswithage,asfollows:

2535years:23casesper1000population5564years:3090casesper1000population6590years:5090casesper1000population

PrognosisTheprognosisforatrialflutterdependsonthepatientsunderlyingmedicalcondition.Anyprolongedatrialarrhythmiacancauseatachycardiainducedcardiomyopathy.Interveningtocontroltheventricularresponserateortoreturnthepatienttosinusrhythmisimportant.Thrombusformationintheleftatriumhasbeendescribedinpatientswithatrialflutter(021%).Thromboemboliccomplicationshavealsobeendescribed.[6]

BecauseoftheconductionpropertiesoftheAVnode,manypeoplewithatrialflutterwillhaveafasterventricularresponsethanthosewithatrialfibrillation.Theheartrateisoftenmoredifficulttocontrolwithatrialflutterthanwithatrialfibrillation,becauseofincreasedconcealedconductioninthosewithatrialfibrillation.

Forthemostpart,morbidityandmortalityresultfromcomplicationsofrate(eg,syncopeandcongestiveheartfailure[CHF]).Inpatientswithatrialflutter,theriskofembolicoccurrencesapproachesthatseeninatrialfibrillation.PatientswithWolffParkinsonWhitesyndromewhodevelopatrialfluttercandeveloplifethreateningventricularresponsesandthereforeshouldbeconsideredforcatheterablationoftheiraccessorybypasstract.

DatafromtheFraminghamstudysuggestthatpatientswithatrialfibrillationdonotliveaslongaspatientswithoutatrialfibrillation(ie,controlsubjects).Nodataareavailableonatrialflutter.

TheprognosisforpatientswithtypeIatrialflutterwhoundergocatheterablationisexcellent,withaverylowrecurrencerate.Thepictureisnotasclearforpatientswithbothatrialflutterandatrialfibrillation.Somereportshavedocumentedfewerepisodesofatrialfibrillationaftersuccessfulflutterablationothershavenot.Itispossiblethatatrialfibrillationmaybemoreresponsivetoantiarrhythmicagentsafteratrialflutterhasbeeneliminated.

Bohnenetalperformedaprospectivestudytoassesstheincidenceandpredictorsofmajorcomplicationsfromcontemporarycatheterablationprocedures.[7]Majorcomplicationratesrangedfrom0.8%(supraventriculartachycardia)to6%(ventriculartachycardiaassociatedwithstructuralheartdisease),dependingontheablationprocedureperformed.Renalinsufficiencywastheonlyindependentpredictorofamajorcomplication.

NumerousreportsindicatethatpatientswithatrialfibrillationwhoaregivenclassICantiarrhythmicagentsmayconverttoatrialflutterwithfasterventricularrates.Thus,patientsreceivingtypeICagents(eg,flecainide)shouldalsoreceiveanAVnodeblockingdrugsuchasabetablockerorcalciumchannelblocker.Inpatientswithbothatrialfibrillationandatrialflutter,therelativeriskfordevelopmentofstrokeis4.1%incomparisonwithcontrolsubjects.[8]

PatientEducationPatienteducationregardingmedicationsanddietisimportant.Patientstakingwarfarinshouldavoidmakingmajorchangesintheirdietuntiltheyhaveconsultedwiththeirhealthcareproviders.Specifically,asuddenchangeintheconsumptionofgreenleafyvegetables,whicharesourcesofvitaminK,canaffectcoagulationinpatientstakingwarfarin,whichinhibitsvitaminKsynthesis.Thiseducationisnotneededwithnewerdrugsthatavoidthesedrugdrugordrugfoodinteractions.

Forpatienteducationinformation,seetheHeartHealthCenter,aswellasAtrialFlutter,HeartRhythmDisorders,Stroke,SupraventricularTachycardia,andPalpitations.

ContributorInformationandDisclosuresAuthorLawrenceRosenthal,MD,PhD,FACC,FHRSAssociateProfessorofMedicine,Director,SectionofCardiacPacingandElectrophysiology,DirectorofEPFellowshipProgram,DivisionofCardiovascularDisease,UniversityofMassachusettsMemorialMedicalCenter

LawrenceRosenthal,MD,PhD,FACC,FHRSisamemberofthefollowingmedicalsocieties:AmericanCollegeofCardiology,AmericanHeartAssociation,andMassachusettsMedicalSociety

Disclosure:Nothingtodisclose.

Coauthor(s)CynthiaAnneEnnis,DOAssistantProfessor,UniversityofMassachusettsMedicalCenter

Disclosure:Nothingtodisclose.

ChiefEditorJeffreyNRottman,MDProfessorofMedicineandPharmacology,VanderbiltUniversitySchoolofMedicine

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Chief,DepartmentofCardiology,NashvilleVeteransAffairsMedicalCenter

JeffreyNRottman,MDisamemberofthefollowingmedicalsocieties:AmericanHeartAssociationandNorthAmericanSocietyofPacingandElectrophysiology

Disclosure:Nothingtodisclose.

AdditionalContributorsBrianOlshansky,MDProfessorofMedicine,DepartmentofInternalMedicine,UniversityofIowaCollegeofMedicine

BrianOlshansky,MDisamemberofthefollowingmedicalsocieties:AmericanCollegeofCardiology,AmericanHeartAssociation,CardiacElectrophysiologySociety,andHeartRhythmSociety

Disclosure:Guidant/BostonScientificHonorariaSpeakingandteachingMedtronicHonorariaSpeakingandteachingGuidant/BostonScientificConsultingfeeConsulting

FranciscoTalavera,PharmD,PhDAdjunctAssistantProfessor,UniversityofNebraskaMedicalCenterCollegeofPharmacyEditorinChief,MedscapeDrugReference

Disclosure:MedscapeSalaryEmployment

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