Treating Atrial Fibrillation

Richard SchillingSt Bartholomew's Hospital, Queen Marys University of London

AF burdenFraminghamLifetime risk of developing AF = 25%Mortality: SMR =1.9 1.5 NHS audit1% of budget spent on AF - 688, 000, 000 in 2000Quality of life Symptoms of AFSide effects of medication

Benjamin, E. J. et al. "Impact of atrial fibrillation on the risk of death: the Framingham Heart Study." Circulation 98.10 (1998): 946-52.Stewart, S. et al. "Cost of an emerging epidemic: an economic analysis of atrial fibrillation in the UK." Heart 90.3 (2004): 286-92

ATRIAL FIBRILLATIONIncidenceFraminghamHeart Study

Nice guidance for management of AFIssued on June 2006Aimed to give a UK based simple guidance on management of AFAttempts to be evidence basedAnd applicable to the majority of patients

Key aims of managementDiagnosis - everyone with irregular pulse gets ECGIdentify secondary causes (thyroid, hypertension, valve disease)Treatment Stroke preventionRate controlRhythm control where appropriate

DiagnosisAF can only be diagnosed on an ECG recorded during symptoms/signsEven asymptomatic patients should have an ECGConsider 24 hour to 7 day Holter if intermittent (depending on frequency)Or ask patient to attend A+E during symptoms and get a copy of ECG

InvestigationTFTEchoIf youngIf rhythm control strategyIf unsure of stroke riskIf structural heart disease suspected

Stroke preventionWarfarin (INR 2-3)Aspirin

Rate control vs rhythm controlRACEMortality 22.6% vs 17.2%39% vs 10% in SR AFFIRMMortality 23.8% vs 21.3 % hospitalisation Side effectsSR has a prognostic benefit

Rhythm control - problemCardioversion and drugs maintains SR in 42% at one year (amiodarone)Side effects require stopping amiodarone in 25%Anticoagulation stopped too early

Treatment decision tree

Advantages of Warfarin over Aspirin

Advantages of Warfarin over Aspirin

rhythm vs rate control

Persistent AF rate controlSpecialist referral

Rhythm control

Rate control vs Rhythm controlAF is dangerousSR is better and confers mortality benefit Conventional therapies are poor at maintaining SR The population is aging

What specialist treatments are available?Antiarrhythmic drugsPacemakerCatheter ablationSurgical ablation

AV node ablation and pacing

AV node ablation and pacinghides the AFEasy to perform (99%) successNo atrial transport (turbo)Pacing dependent (LBBB)No going backRefuge of the elderly and desperate

The first curative procedure MazeJL Cox et al 1991

Why does the maze work?

Radiofrequency Ablation CatheterLesion cross-section

How is RF energy applied

RFA Lesion - Macroscopic

Atrial fibrillation originates in the left atrium

Mechanisms for AF

Target PV triggerLIMITED BY:Absence of spontaneous ectopyMultiple triggers

Focal AF: RFA to disconnect PV potential

Continuous circular lesions

Catheter ablation in permanent AFEarley et al. Heart 2005MV31/41(76%) in SR at 8.4 mths

The electroanatomical approachThe anatomy is very stylisedAccurate lesion location is very dependent on experience

CT integrationTrue 3-dimensional anatomy with catheter localisation

Creating 3 landmark pairs

LPV locations of interest

LPV internal view

Does this have a clinical effect?LUPVLAALLPVAblation lines

Isolation of LPVs during AF

Practicalities of curative AF ablationPre op - CT few weeks pre-opTOE on dayACT >300 during procedureProcedure time 2-3 hours PAF/ 3-4 hours PersistentPost-op echoWarfarin loading on night of procedureContinues for 3 months if low riskEnoxaparin day after until INR>2

Case Control Study of 3-D mapping vs CT integration105 patients6 month follow up7 day holter at 3 monthsSimilar operator profile and experience

AF ablation results

Freedom from AT/AFoff medication at 6 month follow upCT integration(n = 53)3D mapping(n = 52)P value

Complications of AF ablation2% pericardial effusion/tamponade3% Femoral haematoma

RecurrenceUsually occurs

How does ablation compare to drugs?

Ablation vs drugs

Does ablation improve prognosis?Pappone et al circulation 2001

AblationN=589MedicalN=582Death3883Adverse events54117

Complications of AF ablation

AF ablation is good for your garden

AF ablation for heart failurePatients with EF

Preliminary results2 pts recurrence after ablation awaiting redo6pts improved >1 NYHA5% EF after 1 month

Who should have AF ablationSymptomatic (incl heart failure?)Persistent AF for

Limitations of AF ablationHigh volume does make a differenceRedos are commonTarrif does not reflect costSerious complications are increasingly rare but do occurTeam work is critical

ConclusionAF is commonPriorities for treatment now clearly definedCure is now possible but at a costThe lost tribe of AF sufferers now have hopeThe epidemic may have a solutionwww.londonafcentre.com

One can never overstate the enormity of the problem that AF pesents to cliniciansData from Frammingham has shown us that 1in 4 people over the age of 40 will develop AF. And once standardising for all other factors it is ass with an increased mortalityA recent economic analysis published in heart this year estimatedbased on 1995 figuresQuality of life .

First descrip by JL Cox et al from the united state in 1991 as surgical treatment of AF

It involed multiple sugical incisions in both atria to produre electrical barrier prevent re-entry circuit.

Howevere the procedure is performed on bypass and

The procedure has been fine-tuned in subsequent years.The success rate is operator dependent.

From Dr. Cox seriers on 164 patients the reported 100% in restoring sinus rhytm and 7% of those patient require anti-arrhytmic therapy afterward

Having said that because this procedure required mutiple atriotomy, it increases the cardiopulmonary bypass time.

The epicardial Maze one the otherhand is done off bypass. And perhaps this is an alternative technique which need to be investigated.