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Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2804_Библиотеки_им_академика_М_И_Перельмана

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☆
DIAGNOSIS
ClinicalPresentation
Oftenproducesymptomsthatleadtopatientpresentationatoutpatientoracutecaresettings. Canbeassociatedwithsystemicillnessesinpatientsbeingevaluatedintheemergencydepartmentor beingtreatedintheinpatientsetting.
HISTORY
Symptomsgenerallyguideclinicaldecision-making. Dyspnea, angina, lightheadedness or syncope, and decreased level of consciousness are severe symptomsthatmandateurgentintervention. Symptoms thatreflectpoorleft ventricular(LV) function, such as dyspnea on exertion, orthopnea, paroxysmalnocturnaldyspnea,andlowerextremityswelling,arecriticaltoidentify. Palpitationsareacommonsymptomoftachyarrhythmias.Thepatternofonsetandterminationisuseful tosuggestthepresenceofaprimaryarrhythmia.
Suddenonsetandterminationofpalpitationsishighlysuggestiveofareentranttachyarrhythmia.
Terminationwithbreath-holdingorValsalvamaneuverissuggestiveofSVT. History or presence of structural heart disease (i.e., ischemic, nonischemic, or valvular cardiomyopathy)orendocrinopathy(i.e.,thyroiddisease,pheochromocytoma)shouldbedetermined. Historyoffamilialorcongenitalcausesofarrhythmiassuchashypertrophiccardiomyopathy(HCM), LQTS,orothercongenitalcardiacconditionsshouldbeascertained,aswell.
Hypertrophicobstructive cardiomyopathyis associated with atrial arrhythmias (primarilyatrial
fibrillation[AF])aswellasmalignantventriculararrhythmias.
Mitralvalveprolapseisassociatedwithsupraventricularandventriculararrhythmias.
Repaired congenital heart diseases, such as surgically corrected tetralogy of Fallot and d-
transposition of the great arteries with Mustard or Senning baffles, are substrates for ventricular
tachyarrhythmiaandSVTs,respectively. Medication and ingestion history(including over-the-counter drugs, herbal supplements, andillicit substances)shouldbetakentoassesspossiblecausallink.
PHYSICALEXAMINATION
If clinically stable, physical examination should focus on determining underlying cardiovascular abnormalitiesthatmaymakecertainrhythmsmoreorlesslikely. Signs of congestive heart failure (CHF), including elevated jugular venous pressure (JVP), pulmonary rales, peripheral edema, and S3 gallop, make the diagnosis of malignant ventricular
arrhythmiasmorelikely. Ifanarrhythmiaissustained,specialconsiderationsduringphysicalexaminationincludethefollowing:
Palpationofthepulsetoassessforrateandregularity.
Iftherhythmisirregularandtherateisapproximately150bpm,suspectatrialflutter(AFL)with 2:1block. Ifthepulseisirregularwithnopattern,suspectAF. Irregularpulsewithadiscerniblepattern(groupbeating)suggeststhepresenceofsecond-degree
heartblock. Presenceof“cannon”Awaves:RevealedoninspectionofJVP;reflectsatrialcontractionagainsta closedtricuspidvalve.
https://t.me/med1917
If irregular, may be suggestive of underlying atrioventricular (AV) dissociation and possible
presenceofVT.
Ifregularina1:1ratiowithperipheralpulse,thensuggestiveofanAVnodalreentranttachycardia
(AVNRT), AV reentrant tachycardia (AVRT), or a junctional tachycardia (JT), all leading to
retrogradeatrialactivationoccurringsimultaneouslywithventricularcontraction.
DiagnosticTesting
LABORATORIES
Serumelectrolytes,completebloodcount(CBC),thyroidfunctiontests,serumlevelofdigoxin(if applicable),andurinetoxicologyscreenshouldbeconsideredforallpatients.
ELECTROCARDIOGRAPHY
Twelve-leadECG,inthepresenceoftherhythmabnormalityandinnormalsinusrhythm(NSR),
isthemostusefulinitialdiagnostictest. Ifthepatientisclinicallystable,obtain12-leadECGandcontinuousrhythmstripwithleadsthatbest demonstrateatrialactivation(e.g.,V1,II,III,aVF).
ExamineECGforevidenceofconductionabnormalities,suchaspreexcitationorbundlebranchblock, orsignsofstructuralheartdiseasesuchaspriormyocardialinfarction(MI). Comparison of ECG obtained during arrhythmia with baseline can highlight subtle features ofQRS deflectionthatindicatesuperpositionofatrialandventriculardepolarization. Rhythm strip is useful to document response to interventions (e.g., vagal maneuvers, antiarrhythmic drugtherapy,orelectricalcardioversion).
IMAGING
CXRandtransthoracicechocardiogram(TTE)canhelpprovideevidenceofstructuralheartdisease thatmaymakeventriculararrhythmiasmorelikely.
OTHERDIAGNOSTICTESTING
ContinuousambulatoryECGmonitoring
Aidsinoutpatientdiagnosisoftachyarrhythmias. A 24- or 48-hour Holter monitor; useful for documenting arrhythmias that occur with sufficient frequency. Useful for assessment of patient’s heart rate response to daily activities or antiarrhythmic drug treatment. Correlationbetweenpatient-reportedsymptomsinatime-markeddiaryandheartrhythmrecordings iskeytodeterminingifsymptomsareattributabletoarrhythmia.
Eventrecorders
Weeks to months of ambulatory monitoring; useful for documenting symptomatic transient arrhythmiasthatoccurinfrequently. Looprecorder—wornbythepatientandcontinuouslyrecordsthecardiacrhythm.Whenactivatedby thepatientorviaautodetection,arhythmstripissavedwithseveralminutesofprecedingdata. Implantablelooprecorder(ILR)—SCmonitoringdeviceusedtoprovideanautomatedorpatient­activatedrecordingofsignificantarrhythmiceventsthatoccurveryinfrequentlyorforpatientswho areunabletoactivateexternalrecorders.
https://t.me/med1917
ExerciseECG
Usefulforstudyingexercise-inducedarrhythmiasorassessingsinusnoderesponsetoexercise.
Inpatienttelemetrymonitoring
Mainstay of surveillance monitoring during hospitalization for cardiac arrhythmia patients, especiallythosewhoareseriouslyillorexperiencinglife-threateningarrhythmias.
Electrophysiologystudy(EPS)
Invasive catheter-based procedure used to study susceptibility to arrhythmias or investigate the mechanismofaknownarrhythmia. EPScanbecombinedwithcatheterablationformanagementofmanyarrhythmias. CapabilityofEPStoinduceandstudyarrhythmiasishighestforreentrantmechanisms.
TREATMENT
Refertotreatmentofindividualtachyarrhythmiasforhemodynamicallyunstablepatientsandadvanced cardiaclifesupport(ACLS)algorithmfortachycardiasinAppendixC.
SupraventricularTachyarrhythmias
GENERALPRINCIPLES
SVTs—oftenrecurrent,rarelypersistent,andcanresultinvisitstoemergencydepartmentsandprimary carephysicianoffices. Alwaysbeginwithpromptassessmentofhemodynamicstabilityandclinicalstatus. Diagnostic and therapeuticdiscussion thatfollows is aimed athemodynamicallystable patients.Ifa patientisclinicallyunstablebasedonsignsandsymptoms,immediatelyproceedtocardioversionper ACLSguidelines.
Definition
TachyarrhythmiasthatrequireatrialorAVnodaltissueorbothfortheirinitiationandmaintenanceare termedSVT. TheQRScomplexinmostSVTsisnarrow(QRS<120ms). SVTscanpresentasawide-complextachycardia(QRS≥120ms)iftheyareaberrantlyconducted.
Classification
InitiallyclassifiedbyECGtohelpunderstandlikelyunderlyingarrhythmiamechanism. Diagnosticapproach,basedontheECG,issummarizedinFigure7-1.
https://t.me/med1917
Figure7-1  Diagnostic approach totachyarrhythmias.AF, atrial fibrillation;AFL,atrialflutter;AT,atrialtachycardia;AV,
atrioventricular; AVNRT, atrioventricular nodal reentrant tachycardia; AVRT, atrioventricular reentrant tachycardia; EAT,
ectopic atrialtachycardia;MAT,multifocalatrialtachycardia;O-AVRT,orthodromicAVRT;PAC,prematureatrialcomplex;
SANRT,sinoatrialnodalreentranttachycardia;ST,sinustachycardia;SVT,supraventriculartachyarrhythmia;VT,ventricular
tachycardia;WPW,Wolff–Parkinson–White.
Narrow QRS complex tachyarrhythmias can be divided into those requiring only atrial tissue for initiation andmaintenance (atrial tachycardia [AT], AF, and AFL) versus those that require the AV junctionforperpetuation(JT,AVNRT,andAVRT). ParoxysmalSVT—intermittentSVTotherthanAF,AFL,andmultifocalAT(MAT).
Epidemiology
TheestimatedprevalenceofparoxysmalSVTis2.25/1000,with anincidenceof35/100,000person­years.
1
Intheabsenceofstructuralheartdisease,SVTmostcommonlypresentsbetweenages12and30years.
1
WomenaretwiceaslikelytodevelopSVTasmen.
1
DIAGNOSIS
AF—most common narrow-complex tachycardia seen in the inpatient setting. AFL can often accompanyAF and is diagnosed one-tenth as often as AF, but first-time AFL is diagnosed twice as oftenastheparoxysmalSVTs.Remainingatrialtachyarrhythmiasarefarlesscommon.
2
MechanismofparoxysmalSVTissignificantlyinfluencedbygenderandage.
Irrespectiveofgender,AVRTtendstopresentatayoungerage(mostcommonlyinthefirst2decades oflife),whereasAVNRTandATtendtopresentmorecommonlylaterinlife.
2
ClinicalPresentation
https://t.me/med1917
ClinicalpresentationforSVTissimilartotachyarrhythmiasingeneralandhasbeenpreviouslyoutlined.
DifferentialDiagnosis
AF
Discussedasaseparatetopiclaterinthissection.
AFL
Adjustedforage,theincidenceinmenismorethan2.5timesthatofwomen.
3
AFL usuallypresentsasaregularrhythm butcanbe irregularlyirregularwhen associated with variableAVblock. Mechanism: Macroreentrant circuit usually within the right atrium around the perimeter of the tricuspid valve. This form of AFL is called “typical” AFL. Atrial rate is 250–350 bpm with conductiontoventriclethatisusuallynot1:1, butmostoften 2:1. (SVTwith regularventricular
rateof150bpmshouldraisesuspicionforAFL.)
Chronic AFL commonly coexists with AF and is associated with the same risk factors (obesity, hypertension[HTN],diabetesmellitus,andobstructivesleepapnea[OSA]). ECG:IntypicalAFL,a “sawtooth”patternbestvisualizedinleads II,III,andaVFwithnegative deflectionsinthoseleadsandeitherpositive,negative,orbiphasicatrialdeflectioninV1.
MAT
Irregularly irregular SVT generally seen in elderly hospitalized patients with multiple
comorbidities. Mostoftenassociatedwithchronicobstructivepulmonarydisease(COPD)andCHF. Alsoassociatedwithglucoseintolerance,hypokalemia,hypomagnesemia,drugs(e.g.,theophylline), andchronicrenalfailure. ECG:SVTwithatleastthreedistinctPwavemorphologies,generallybestvisualizedinleadsII, III,aVF,andV1.
Sinustachycardia
MostcommonmechanismoflongRPtachycardia. Usually,normal physiologic responsetohyperadrenergicstates(fever,pain,hypovolemia,anemia, hypoxia,etc.). Canbeinducedbyillicit(cocaine,amphetamines,methamphetamine)andprescription(theophylline, atropine,β-adrenergicagonists)drugs. Inappropriatesinustachycardiareferstopersistentlyelevatedrestingsinusrate(>100bpm)inthe absenceofidentifiablephysical,pathologic,orpharmacologicinfluence.
Ectopicatrialtachycardia(EAT)
EAT withvariable block canpresent as anirregularlyirregular rhythm andcanbe distinguished fromAFLbyanatrialrateof150–200bpm. EATwithvariableblockisassociatedwithdigoxintoxicity. Characterized byregular atrial activationpattern with Pwave morphologyoriginating outside the sinusnodecomplexresultinginlongRPtachycardia.
Mechanism:Enhancedautomaticity,triggeredactivity,andpossiblymicroreentry.
AVNRT
Reentrant rhythm requiring functional dissociation of the AV node into two pathways with both antegradeandretrogradeconductionthroughtheAVnode. Notcorrelatedwithstructuralheartdiseaseandcanoccuratanyage,withapredilectionformiddle
ageandfemalegender. TypicalAVNRT—majorcauseofshortRPtachycardia.
https://t.me/med1917
ECGappearancehascharacteristic“absentPwaves”becauseatrial activationis coincident
withtheQRScomplex.Commonly,atrialactivationcanoccuratterminalportionofQRStocreate
apseudo-r’(V1)orpseudo-s’(II)comparedwithsinusrhythm(SR)QRS.
ConductionoccursinanantegradefashiondowntheslowAVnodalpathwaywithretrograde
conductionoccurringbackupthefastpathway,manifestinginshortRPtachycardiabyECG. AtypicalAVNRT
Less common; antegrade conduction proceeds down a fast AV nodal pathway with retrograde
conductionupaslowAVnodalpathway,leadingtoalongRPtachycardia.
ECG:RetrogradePwaveinscribedwellafterQRScomplexinsecondhalfofRRinterval.
AVRT
Reentrant tachycardia with circuit consisting of the normal AV conduction system and accessory pathwaylinkingatrialandventriculartissues. OrthodromicAVRT—mostcommonAVRT,accountingforabout95%ofallAVRT.
Accessorypathway–mediated reentrant rhythm with antegrade conduction tothe ventricle down
theAVnodeandretrogradeconductiontotheatriumupanaccessoryor“bypass”tract,leadingto
shortRPtachycardia.
ECG: Retrograde Pwaves frequentlyseen after the QRS complexand usually distinguishable
fromtheQRS(i.e.,separatedby>70ms).
MostcommonmechanismofSVTinpatientswithWolff–Parkinson–White(WPW)syndromewho
have preexcitation(definedbyshort PR and a deltawave on upstrokeofQRS) present onSR
ECG.
Can occur without preexcitation when conduction through bypass tract occurs only during
tachycardiainretrogradefashion(“concealedpathway”).
Less commonly, retrograde conduction through the accessory pathway to the atrium proceeds
slowlyenoughforatrialactivationtooccurinthesecondhalfoftheRRinterval,leadingtoalong
RPtachycardia. Antidromic AVRT (A-AVRT): Occurs when conduction to the ventricle is down an accessory
bypasstractwithretrogradeconductionthroughtheAVnodeorsecondbypasstract.
ECG: QRSseems consistent withVT; however, the presence of preexcitation on the baseline
QRSshouldbediagnosticforWPWsyndrome.
A-AVRTisseenin<5%ofpatientswithWPWsyndrome.
JT
DuetoenhancedautomaticityofAVjunction.Electricalimpulsesconducttotheventricleandatrium simultaneously,similartotypicalAVNRT. RetrogradePwavesarefrequentlyconcealedwithintheQRScomplex. Uncommoninadults.Commoninyoungchildren,particularlyaftercardiacsurgery.
Sinoatrial(SA)nodalreentranttachycardia
ReentrantcircuitlocalizedatleastpartiallywithintheSAnode. Abruptonsetandtermination,triggeredbyprematureatrialcomplex. ECG:PwavemorphologyandaxisidenticaltonativesinusPwaveduringNSR.
TREATMENT
PleaserefertoTable7-1forgeneraltherapeuticapproachtocommonSVTs.
TABLE7-1
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TREATMENTOFCOMMONSUPRAVENTRICULARTACHYARRHYTHMIAS
Treatment Strategies
Atrialflutter (AFL)
AnticoagulationsimilartoAF;riskofthromboemboliccomplicationsis similar. RatecontrolwithsameagentsasAF. Ifhighlysymptomaticorratecontroldifficult,electricalorchemical cardioversionisappropriate. Ifpacemakerpresent,overdriveatrialpacingcanachievecardioversion. CatheterablationoftypicalrightAFLwithlong-termsuccessabove90% andrarecomplications.
Multifocalatrial tachycardia (MAT)
Therapytargetedattreatmentofunderlyingpathophysiologicprocess. Antiarrhythmic,ifsymptomaticrapidventricularresponse.Individualizeβ­adrenergicblockersversuscalciumchannelblockertherapy. DCcardioversionisnoteffective.
Sinus tachycardia (ST)
Therapytargetedattreatmentofunderlyingpathophysiologicprocess.
Ectopicatrial tachycardia (EAT)
Acutetherapy:Identifyandtreatprecipitatingfactorslikedigoxintoxicity;
ifhemodynamicallystable,thenβ-blockersandcalciumchannelblockers. Inrarecases,amiodarone,flecainide,orsotalol. Chronictherapy:Ratecontrolwithβ-adrenergicblockersandcalcium channelblockers.Ifunsuccessful,optionsincludecatheterablation(86% successrate),flecainide,propafenone,sotalol,oramiodarone.
AVnodal reentrant tachycardia (AVNRT)
Catheterablationhighlysuccessful(96%)buthastobeindividualizedto eachpatient. Ifmedicaltherapymoredesirable—β-adrenergicblockers,calciumchannel blockers,anddigoxin;thenconsiderpropafenone,flecainide,etc.
OrthodromicAV reentrant tachycardia(O­AVRT)
Acutetherapy:Vagalmaneuvers,adenosine,calciumchannelblockers.If
ineffective,thenprocainamideorβ-blockers. Chronicsuppressivetherapy:Catheterablationhighlysuccessful(95%) buthastobeindividualizedtoeachpatient.Ifmedicaltherapyismore desirableforprevention,flecainideandprocainamideareindicated.
AntidromicAV reentrant tachycardia(A­AVRT)
Acutetherapy:AvoidadenosineorotherAVnode–specificblocking
agents.Consideributilide,procainamide,orflecainide. Chronicsuppressivetherapy:Accessorypathwaycatheterablationis preferredandsuccessful(95%).Ifmedicaltherapydesired,consider flecainideandpropafenone.
AF,atrialfibrillation;AV,atrioventricular;DC,directcurrent.
AcutetreatmentofsymptomaticSVT—followACLSprotocolasoutlinedinAppendixC. Chronic treatment guided by severity of symptoms, as well as frequency and duration of recurrent
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events.
2
ManySVTscanbeterminatedbyAVnodalblockingagentsorvagaltechniques(Table7-2),whereas AF, AFL, andsome ATswillpersistdespitea slowing ofthe ventricularrate because ofpartial AV nodalblockade.
TABLE7-2
COMMONVAGALMANEUVERSANDADENOSINE
Preparation
a
Mechanism Dose/Duration/Details Toxicity Contraindication
Valsalva Describethe
procedure.
Vagal stimulation during relaxation phase.
Exhaleforcefully againstaclosed airwayforseveral secondsfollowedby relaxation.
Well tolerated.
Patientunableto follow commands.
Carotid sinus massage
Checkfor carotidbruits andhistory ofCVA;then placein recumbent positionwith neck extended.
Vagal stimulation.
First,applyenough pressuretosimplyfeel carotidpulsewithindex andmiddlefingers.If noeffect,thenuse rotatingmotionfor3– 5s.
Well tolerated. Riskof embolizing carotid plaque.
Never massage both carotids.
RecentTIAor strokeor ipsilateral significantcarotid arterystenosisor carotidartery bruit.
Adenosine Explainthe
potentialside effectstothe patient.
AVnodal blocking agent. Shortacting (serumhalf­life4– 8min).
Initial:6mgIVrapid bolusviaantecubital vein,followedby10– 30mLsalineflush.If desiredoreffectnot achieved,canrepeat 12mgfollowedby 12mgafter1-to2-min intervals. Centralvenousline:3 mgIVinitialdose.
Precipitate prolonged asystolein patients withsick sinus syndrome orsecond­orthird­degreeAV block.
Significant bronchospasm.
Atrioventricularnodalreentranttachycardia,atrioventricularreentranttachycardia,andmanyatrialtachycardiaswillterminatewith vagalmaneuversoradenosine,andinatrialflutter,theappearanceofflutterwaveformwillhelpdiagnosis.
Waterimmersion,eyeballpressure,coughing,gagging,deepbreathing,etc.,areotheralternativevagalmaneuvers. AV,atrioventricular;CVA,cerebrovascularaccident;TIA,transientischemicattack.
a
PatientsshouldbeundercontinuousECGmonitoringforeachoftheseprocedures.Toenhancediagnosticvalueofrhythmstrip,
useleadsV1andII(atrialactivity).
Radiofrequencyablation(RFA):Definitivecurewithhighsuccessratesrangingfrom80%to100% formanySVTsincludingAVNRT,accessorybypasstract–mediatedtachycardias,focalAT,andAFL.
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Complicationriskgenerally<3%forablationofcommonSVTs.Risksincludemajorbleeding,cardiac perforationortamponade,stroke,pulmonaryembolism,andcompleteheartblockrequiringpermanent pacemaker(PPM)implantation.
2
AtrialFibrillation
GENERALPRINCIPLES
Definition
Mostcommonsustainedcardiacarrhythmiaencounteredinclinicalpractice. Atrial tachyarrhythmia characterized by chaotic activation of the atria with loss of normal atrial mechanicalfunction. Twelve-lead ECG characterized by the absence of consistent P waves. Rapid, low-amplitude oscillationsorfibrillatorywavesnotedinbaselineofleadsthatbestdemonstrateatrialactivation(V1,
II,III,andaVF). VentricularresponsetoAFischaracteristicallyirregularand,often,rapidinthepresenceofintactAV conduction.
Classification
Fiveformsbasedonclinicalpresentation:firstoccurrence,paroxysmal,persistent,long-standing persistent,andpermanent.
Firstoccurrencemaybesymptomaticorasymptomatic.Spontaneousconversionrateishigh,measured at>60%inhospitalizedpatients. Paroxysmal—recurrentformofAFinwhichindividualepisodesare<7daysandusually<48hoursin duration. Persistent—recurrent form of AF in which individual episodes are >7 days in duration and may requireelectricalorchemicalcardioversiontoterminate.
Long-standingpersistent—AFfor>1year,stilldeemedmanageablewithcardioversionorRFA. Permanent—AF after failed attempts at electrical or chemical cardioversion, has been present for
morethan1year,orhasbeenacceptedduetocontraindicationsforcardioversionorlackofsymptoms.
Epidemiology
Mostcommonsustainedtachyarrhythmiaforwhichpatientsseektreatmentandmostlikelyetiologyfor irregularly irregular rhythm discovered on an inpatient ECG. Typically, a disease of the elderly, affecting>10%ofthoseaged>75years. Independent risk factors include advanced age, male gender, and comorbid presence of diabetes mellitusandcardiovasculardiseasessuchasCHF,valvularheartdisease,HTN,andpreviousMI.4Age <65years,obesity,andOSAareimportantriskfactorsfornew-onsetAF.
5
Followingcardiothoracicsurgery,AFoccursin20%–50%ofpatients.
6
Pathophysiology
PrecisemechanismsgivingrisetoAFarenotcompletelyunderstood. Initiationduetorapid,repetitive firing ofectopic focuswithinthe pulmonaryveinswith fibrillatory
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conductiontobodiesoftheatria. Maintenance likelyrequires multiple reentrant circuits varying inlocation and timing to explainthe self-perpetuatingcharacteristicofAF. Structuralandelectricalremodelingoftheleftatriumassociatedwithcardiovasculardiseasepromotes ectopic activity and heterogeneous conduction patterns that provide the substrate for AF. AF, when present,alsopromotesstructuralandelectricalremodelingintheatriathatstabilizestherhythm. Inflammation andfibrosis may play major role ininitiation and maintenance. Inflammatorymarkers, suchasinterleukin6andC-reactiveprotein(CRP),areincreasedinandcorrelatewithdurationofAF, successofcardioversion,andthrombogenesis.
Prevention
Lackofprospectiveclinicaldataexaminingthevalueofriskfactormodificationinthepreventionof non–postoperativeAF. SomedatasuggeststatinsmayreducerecurrentAFby61%,independentoflipid-loweringeffect.
7
Angiotensin-converting enzymeinhibitors (ACE-I)andangiotensinreceptorblockers (ARBs) shown to prevent atrial remodeling in animals via suppression of the renin–angiotensin system. A meta­analysisofpatientswithCHFandHTNtreatedwitheitherACE-IorARBhasdemonstratedreduction innew-onsetAFby20%–30%.
8
A number of pharmacologic and nonpharmacologic strategies have been evaluated to prevent postoperativeAF.Perioperativecontinuationofβ-adrenergicantagonists(β-blockers)hasshownto reducepostoperativeAFrates. Amiodarone, sotalol, magnesium,and omega-3 fatty acidsused in perioperativeperiodalsodemonstratedreductioninpostoperativeAF.
9
DIAGNOSIS
Diagnosedby12-leadECGwithstereotypicalpatternofirregularlyfluctuatingbaselinewithirregular, oftenrapid,ventricularrate(>100bpm). ImportanttodistinguishAFfromothertachycardiamechanismswithanirregularventricularresponse suchasMATandAFLwithvariableconduction.
ClinicalPresentation
Symptoms can range from nonexistent to nonspecific (fatigue) to severe (acute pulmonary edema, palpitations,angina,syncope). Symptoms usually secondary to rapid ventricular response (RVR) to AF rather than loss of atrial systole. However, patients with significant ventricular systolic or diastolic dysfunction can have symptomsdirectlyattributabletolossofatrialsystole. ProlongedtachycardiafromAFmayleadtotachycardia-inducedcardiomyopathy.
TREATMENT
Medical managementis directed atthree therapeuticgoals: (1) rate or(2) rhythm controland (3) preventionofthromboembolicevents.
Previous studies have shown there is no mortality benefit to a strategy aimed at maintaining SR.
10
Therefore,ratecontrolandmanagementofthromboembolicriskarepreferredstrategyinasymptomatic andminimallysymptomaticpatients.Rhythmcontrolisreservedforpatientswhoremainsymptomatic despitereasonableeffortsatratecontrol.
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