RF Ablation of Atrial Fibrillation in Valvular Heart Surgery Patients

Dubrava University HospitalZagreb, Croatiawww.kbd.hr

DEPARTMENT OF CARDIAC SURGERY

RF Ablation of Atrial RF Ablation of Atrial Fibrillation in Valvular Fibrillation in Valvular

Heart Surgery PatientsHeart Surgery Patients

Željko Sutlić

Dubrava University HospitalZagreb, Croatia

www.kbd.hr/kardkir

Department of Cardiac Surgery

IntroductionIntroduction

The incidence of chronic atrial fibrilation (AF) is age dependent:

1% of the general population

4% in pts > 60 years

7% in pts > 70 years

60-80 % in pts with significant mitral valve disease


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AF - TYPESAF - TYPES

paroxsismal AF

persistant AF

permanent AF


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Criteria for SuccessCriteria for Success

Sinus Rhythm

Absence of intermittent AF

Absence of atrial flutter

Atrial transport function

Restricted antiarrhythmic medication


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CriteriaCriteria

Indication for mitral valve repair/replacement or coronary artery disease

Chronic atrial fibrillation (>6 months)

Electrocardiographical confirmation of diagnosed chronic atrial fibrillation by 24 hour holter monitoring

EF > 30 %

Age: 18 – 80 years

Informed consent


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Atrial fibrillation in Patients Atrial fibrillation in Patients Undergoing Mitral Valve Surgery: Undergoing Mitral Valve Surgery: Why AF Surgery?Why AF Surgery?

Incidence of AF varies between 30 – 50%

Curative AF surgery can eliminate the need for anticoagulation by restoring sinus rhythm, particulary important in patients having valve repair

Rate of anticoagulation-related bleeding after mechanical valve surgery is between 0,3 to 4,9 events/ patient year

Bleeding rates with mitral bioprosthesesare less but stillsignificant (0,6 – 2,1 episodes/patient year) in part due to the need for anticoagulation for AF


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Atrial Fibrillation: Surgical TherapyAtrial Fibrillation: Surgical Therapy

Cox developed the Maze Procedure – first performed in 1987 at Barnes Jewish Hospital

High rate of surgical cure for atrial fibrillation (>90%) without antiarrhythmic therapy

Indications:Drug refractory AF

Arrhythmia intolerance

Recurrent thromboembolism


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Atrial fibrillation and Mitral Valve Atrial fibrillation and Mitral Valve DiseaseDisease

Should all patients with atrial fibrillation who are referred for mitral valve surgery undergo a concomitant Cox-Maze procedure?

Let's look at our long term surgical results in these patients!


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Cox-Maze III ProcedureCox-Maze III Procedure

Cox-Maze III first performed in 1988

Maze-like surgical incisions

Based on theory of multiple macro-reentrant circuits


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The Cox Maze Procedure:The Cox Maze Procedure:Evolution of the Surgical ApproachEvolution of the Surgical Approach

The Cox Maze I was abandoned because of a high incidence of chronotropic incompetence and pacemaker implantation

The Cox Maze II was replaced because of its' technical difficulty

The Cox Maze III has remained the gold standard since 1988 and has extraordinary long term efficacy


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The Cox-Maze Procedure:The Cox-Maze Procedure:Surgical ObjectivesSurgical Objectives

Cure of atrial fibrillation

Restoration of A-V synchrony

Preservation of atrial function

Discontinuation of anticoagulation and anti-arrhythmic drugs


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Cox-Maze III ProcedureCox-Maze III ProcedurePatient PopulationsPatient Populations

Lone atrial fibrillation

Atrial fibrillation in association with organic heart disease:

valvular heart disease

ischemic heart disease

Freedom form AF Freedom form AF All PatientsAll Patients

Cox JL. Surg Treat of AF, San Francisco, June 2003Cox JL. Surg Treat of AF, San Francisco, June 2003

Freedom from AF Freedom from AF LM versus CMLM versus CM

Cox JL. Surg Treat of AF, San Francisco, June 2003Cox JL. Surg Treat of AF, San Francisco, June 2003

Efficacy of Surgical Maze Procedure for Efficacy of Surgical Maze Procedure for Atrial FibrillationAtrial Fibrillation


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Cox-Maze III Procedure with Mitral Surgery: Cox-Maze III Procedure with Mitral Surgery: Washington University ExperienceWashington University Experience

65 consecutive patients between January 1988 – May 2003; mean follow-up = 3.6 years

Avarage duration AF: 5.2 years (0,5–28 years)

Paroxysmal AF: 41%

Operative mortality : 1/65 ( 1.5% )

Freedom from AF at 10 years: 97%

No late strokes!


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Advantages of the COX-MAZE III Advantages of the COX-MAZE III ProcedureProcedure

High cure rate (>90%)Proven long-term efficacyApplicable to both persistent and paroxysmal AFEliminates the late risk of stroke in a high risk populationRequires no additional devices except for a cryoprobe


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Shortcomings of the COX-MAZE III Shortcomings of the COX-MAZE III ProcedureProcedure

Requires cardiopulmonary bypass and an arrested heart

Adds to cross-clamp time

Few surgeons perform the operation due to its' complexity

Significant morbiditypacemaker requirement and left atrial dysfunction


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Cox-Maze III Procedure for AF Cox-Maze III Procedure for AF Postoperative ManagementPostoperative Management

DiureticsLasixSpironolactone

Coumadin3 monthsDiscontinue if in NSR

Anti-arrhythmic drugs2 monthsDiscontinue if in NSR

Postoperative sinus node dysfunction10 – 15 % of patientsWait 7-10 days before implanting pacemaker


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The Cox Maze Procedure:The Cox Maze Procedure:Goals of a Less Invasive ApproachGoals of a Less Invasive Approach

Preserve the high success rates of the Cox-Maze III procedure while decreasing its' morbiditySimplify and/or decrease the number of atrial incisions to shorten the procedure and increase its' adoption rate among surgeonsReplace surgical incisions with linear lines of ablation using various energy sources:

CryosurgeryRadiofrequencyMicrowaveLaserUltrasound


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Radiofrequency energyRadiofrequency energy

similar to electrocautery

very fast AC current

no depolarisation of the heart

monopolar or bipolar

irrigated or not irrigated (early)


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Dry vs- Irrigated Electrode Tissue Dry vs- Irrigated Electrode Tissue Heat DistributionHeat Distribution


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Complications of RF Ablation for Complications of RF Ablation for Atrial FibrillationAtrial Fibrillation

CVA

TIA

Tamponade

Aortic tear

Pulmonary vein stenosis

Damage to MV apparatus

Phrenic nerve injury

Coronary artery injury


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Surgical procedure (began on april Surgical procedure (began on april 2003)2003)

MVR and TVP 6 patients

MVR and CABG 1 patient

average aortic clamp time 94 ± 42 min

average pump time 124 ± 25 min


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Table 1. Clinical characteristics (n=7)Table 1. Clinical characteristics (n=7)Age (years) 58 (45-72)Male/femalePower p wave 25 W

< 3 years 53-6 years 1> 6 years 1

amjoderon 4atenolol 1

verapamil 1metildigoxin 1

DM (n) 1Arterial hypertension (n) 1Reoperation (n) 1Death (n) 1

AF duration

Antiarrhythmic drug tested

3/4


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Table 2. Echocardiographic variablesTable 2. Echocardiographic variablespreoperative

valuespostoperative

valuesanteroposterior LA diameter (mm)

49 (45-59) 47 (42-51)

mediolateral LA diameter (mm)

50 (50-52) 49 (48-55)

superinferior LA diameter (mm)

61 (60-69) 62(60-67)

anteroposterior RA diameter (mm)

40 (39-45) 38 (31-43)

mediolateral RA diameter (mm)

45 (42-56) 39 (31-45)

superinferior RA diameter (mm)

56 (52-60) 47 (45-52)

LVED (mm) 57 (50-64) 53 (48-64)

LVES (mm) 43 (38-47) 42 (37-48)

EF (%) 47 (45-51) 48 (41-56)


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Table 3. Single case (male, 58 years old, MVR + TVP)Table 3. Single case (male, 58 years old, MVR + TVP)

preoperative postoperative3 month

postoperativeanteroposterior LA diameter (mm)

45 47 45

mediolateral LA diameter (mm)

52 48 46

superinferior LA diameter (mm)

61 67 48

anteroposterior RA diameter (mm)

39 31 31

mediolateral RA diameter (mm)

45 45 34

superinferior RA diameter (mm)

56 52 48

LVED (mm) 64 52 55

LVES (mm) 47 39 35

EF (%) 51 49 65


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Surgery for Atrial Fibrillation:Surgery for Atrial Fibrillation:Established Facts and Surgical Established Facts and Surgical ApproachApproach

We have very effective, though invasive, operation with high success ratesPatients who are candidates for Cox Maze procedure should not be deprived of a curative, known procedure for a theoretical lesion set performed with unproven technologyNew procedures and technology should be subject to rigorous prospective clinical trialsNew lesion sets should be based on known mechanisms of atrial fibrillation


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Will There Be a Role for Surgery in Will There Be a Role for Surgery in the Future?the Future?

Yes, for the symptomatic patient:Who requires other concomitant cardiac surgical procedures

Coronary artery disease

Valvular heart disease

Congenital disease

With prior thromboembolic complications

For persistent and "permanent" atrial fibrillation

PossiblyWith paroxysmal atrial fibrillation if performed via minimally invasive techniques


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Catheter Ablation Techniques for Atrial Catheter Ablation Techniques for Atrial Fibrillation: ConclusionsFibrillation: Conclusions

Effective (60-80%) for drug refractory paroxysmal AF with pulmonary vein triggersTargets PV-LA junction, with linear line to MVA, possible linear lesion across Bachman's bundleProlonged procedures, requires transseptal access to the LALesions constrained by biophysical properties of tissueComplications approach 5%

TIA/CVAPulmonary vein stenosis Cardiac tamponadeAortic tear, coronary injury

One of multiple tools available


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Everything should be made Everything should be made as simple as possible. But as simple as possible. But

not simpler.not simpler.

Albert Einstein

RF Ablation of Atrial Fibrillation in Valvular Heart Surgery Patients

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