Catheter Ablation of Atrial Fibrillation in Patients with Prosthetic Mitral Valve

Catheter Ablation of Atrial Fibrillation in Patients with Prosthetic Mitral Valve Luigi Di Biase, MD, PhD, FHRS Senior Researcher Texas Cardiac Arrhythmia Institute at St. David s Medical Center, Austin, Texas, USA; Adjunct Professor Department of Biomedical Engineering, University of Texas, Austin, Texas, USA; Assistant Professor Department of Cardiology, University of Foggia, Foggia, Italy Email: dibbia@gmail.com

General Considerations During the past decade, catheter ablation of atrial fibrillation has progressed rapidly. As experience and technique have evolved, patient selection criteria for this ablative procedure have expanded. Initially, this procedure was performed only in young patients with structurally normal hearts with paroxysmal atrial fibrillation refractory to multiple antiarrhythmic medications. As the techniques for ablation have been refined, nowdays it is available to a larger segment of the population.

AF Catheter Ablation: Question Is the ablation of atrial fibrillation feasible, safe and efficacious in patient with mechanical valve?

Challenges for AF ablation in Patients with Mechanical Valve Higher Risk for TIA/ Stroke due to Warfarin discontinuation and bridge with low weight molecular heparin Higher rate of focal atrial tachycardia Higher Risk for Major bleeding due to more aggressive anticoagulation in the case of warfarin discontinuation Potential Higher Risk for catheter entrapment with damage to the valve Harder Transeptal access due to plane distortion and fibrotic septum.

TIA ( left sided weakness) with ACT 220 ( lacunar infarcts at CT) Femoral Pseudoaneurism Aborted because of difficult transeptal access

Abs, ACC 2011

Abs, HRS 2011

Methods Conventional and CARTO mappings were applied A 3.5mm open irrigated-tip catheter was used for ablation Ablation strategies: Group 1 (N=45): standard PVAI extended to the LA posterior wall. Group 2 (N=64): in addition to strategy used in Group 1, an isoproterenol challenge up to 30µg/min was performed and trigger activities arising from extra-pv foci were abolished. Procedure endpoint : complete PVAI (for both Groups 1 and 2) as well as elimination of all potential trigger sites (for Group 2)

Results All patients (51 males; age 62±10yrs) underwent the procedure successfully LA=50.1±10mm; EF=50.1±13% INR on the day of ablation was 2.6±0.3 2 groin hematomas and 2 pericardial effusions in Group 2; 63/64 (98.4%) patient in Group 2 had extra-pv triggers

Results At 1-year follow up, 39 (61%) patients in Group 2 and 7 (15%) patients in Group 1 were in SR off AAD with single procedure (P<0.0001). 85% of patients in Group 1 underwent redo ablation due to early recurrence of AF. Very late recurrence (32±4 months) was observed in 12 (19%) patients in Group 2 and consisted of focal atrial tachycardia in 9 and atypical atrial flutter in 3 patients, which were treated successfully with repeat ablation.

Abs, HRS 2011

Ablation Goals Maximize Success Reduce complications

Worldwide Survey on the Methods, Efficacy, and Safety of Catheter Ablation for Human Atrial Fibrillation Cappato, Circulation 2005 Complication rate: 3,9% Deaths: 0,1% Cappato, 2008

AF Catheter Ablation: Considerations Targets and techniques

Foci Triggering Atrial Fibrillation 25% 45% 9% 16% 94% Haïssaguerre M et al. NEJM 1998; 339: 659-66

PV Triggers initiating AF LA LAA * PV

AF Catheter Ablation Strategies Exit (Os) Focal Antrum More Proximal ablation: The PV Antrum

Distal PV Isolation PV electrical Antrum Isolation

ICE Guided Antrum Identification

Double LASSO Approach Arentz et al Circulation 2007 Verma, Natale Circulation 2005

Paroxysmal Atrial Fibrillation

Paroxysmal AF

Typical lesion set in patients with Paroxysmal AF

Long-Standing Persistent Atrial Fibrillation

Typical lesion set in patients with long standing persistent AF

LAA isolation was performed by placement of the circular catheter at the ostium of the LAA guided by ICE. Lesions were delivered targeting the earliest electrical activation on the circular mapping catheter.

A C

Increasing Complexity of AF Ablation Sinus Rhythm Organized Atrial Arrhythmias NonPV Sources Atrial Fibrillation Left Atrial Lines Isthmus/Roof/Antrum 86 82 2 PVs 3 PVs 4 PVs 70 50 1 PV RA Lines 11 1994 2002 Time

Strokes/TIA

Char within the left atrium

Group 1: Ablation with an 8-mm catheter off warfarin Group 2: Ablation with an open irrigated catheter off warfarin Group 3: Ablation with an open irrigated catheter on warfarin Di Biase et al. Circulation 2010; 121: 2550-6

Anticoagulation Protocol: Flow Chart

Periprocedural Stroke and Management of Major Bleeding Complications in Patients Undergoing AF Catheter Ablation The Impact of Periprocedural Therapeutic INR Di Biase et al. Circulation 2010; 121: 2550-6

Transeptal access

Right Atrium

Considerations for AF Transseptals For the circular mapping catheter a more anterior stick is better

Considerations for AF Transseptals For the ablation catheter a more inferior and posterior approach is better

Electrocautery

RF Energy or Electrocautery For Transseptal

AF Catheter Ablation in patients with prosthetic valve Final Considerations In high volume centers, AF ablation in patient with prosthetic valve is as safe and efficacious as in patients with native valves. Beyond more extensive ablation, a higher number of extra PV triggers is present in these patients that should be targeted in addition to PVAI and posterior wall isolation. This is relevant to increase the long term success. Focal atrial tachycardia seems the most common very late arrhythmia recurrence. Anticoagulation protocol without Coumadin discontinuation,caution during transeptal access with the use of ICE and 3D mapping systems and extreme caution during catheter manipulation are useful suggestion to minimize complications.