Ablation in Atrial Fibrillation - PDF of Slides.pdf · 1 Ablation of Atrial Fibrillation Emile...
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Ablation of Atrial FibrillationEmile Daoud, M.D.
Clinical Professor of MedicineDirector, Electrophysiology Section
Ross Heart HospitalOhio State University Medical Center
Atrial Fibrillation
Rapid and Irregular
Normal Sinus RhythmRight & Left Atria
Electrograms During AFSurface, Right & Left Atria
Right Atrium
Surface
Organized
Disorganized
Left Atrium
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Canadian Trial of AFMedications Rarely Provide
Long Term Efficacy1yr
50% of pts at 1 year still have
Atrial Fibrillation
Drug-Induced Proarrhythmia - Torsade
Just Say No to Drugs
Poor Efficacy and Excessive Side Effects
Beginnings of Curative Ablation for Atrial Fibrillation• Minneapolis Feb 1999• Haisseguerra – Bordeaux, France• “Pulmonary Vein Isolation”
Designed a circular catheter to map the pulmonary veinsAtrial muscle bundles span the transition zone from the pulmonary veins into the atria – trigger for AFib
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Pulmonary Vein AnatomyStructure-Function Substrate for
Ectopy
Low & high power magnification of PV muscle bundles
• Heart attack victims atBordeaux hospital are beinggiven two glasses of wine aday during their stay.
• Patients on the cardiac wardare being encouraged toenjoy a daily tipple to cuttheir risk of further heartproblems.
First in the US to perform PV Isolation
Hospital Gives Patients Wine
Left Atrium
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Pulmonary Veins Pulmonary
Veins
Left Atrium
Pulmonary Veins Pulmonary
Veins
Left Atrium
Ablation of Pulmonary Vein Muscle Bundles Identified By A Circular Mapping Catheter
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Ablation of Pulmonary Vein Muscle Bundles Identified By A Circular Mapping Catheter
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Circular Mapping & Ablation CatheterRight Pulmonary Vein
Case Study• 62 yo WF, H/O PAF with increasing
frequency and duration, 3– 4 episodes / wk.• Sx: Extreme fatigue, palpitations• PMHx: AF for 5 yrs; Multiple CV’s; HTN;
LVEF 40%; LA size 48mm• Failed AA therapy: Beta blockers, sotalol,
propafenone and amiodarone x 4 mos.
Sinus with PAC’s
Nonconducted & Conducted PV EctopyCircular Catheter in RSPV
RA
PV
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Spontaneous PAC-Induced AF Recorded With Circular
Catheter in RSPV
RA
PV
Atrial Pacing Post-CVRSPV - LA Dissociation
RA
PV
PV Potentials from LSPV
RA
PV
Final RF Site for LSPVRA
PV
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Goal: PV ElectricalEntrance & Exit BlockPre-RF Post-RF
∗∗
∗
Why Does Atrial Fibrillation Spontaneously Stop in Some Patients But Requires an
Electrical Shock in Others?
• Moe’s Wavelet theory
• Once a trigger (often from PV source) initiates AF, multiple wandering waves of depolarization are created, called wavelets
• These wavelets occur simultaneously and account for irregularity
• “Mother” waves give rise to “daughter”wavelets…together this process leads to persistent AF
• Rate-related adverse atrial remodeling
• Acute ChangesShortening of refractory periodsHeterogeneous refractory periodsFunctional conduction blockCalcium loading alters contractilityAlteration of atrial hemodynamics
• Chronic ChangesAltered mitochondrial functionAltered ion channel functionAltered expression of atrial myocyte proteinsAccelerated atrial fibrosis and apoptosis
What Sustains Wavelets and Thus AF?“AF Begets AF”
For Persistent AFNot just merely a TRIGGER problem• Rate-related changes result in pathologic
changes in atrial musculaturePV isolation alone provides low successRF ablation therefore must approach more than just the PV’s, but also the atrial musculature
• Since the strategy for ablation of persistent AF is to target the atrium as well as the PV’s, defining and navigating the LA anatomy becomes critical
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AortaEsophagus
Left Ventricle
Left Atrium & PV’s
Pulmonary Artery
Left Common PV
Right Middle PV
Right Superior PV
Right Inferior PV
Atrial appendage
Sup. branch
Inf. branch
Left Common Ostium
Atrial appendage
Anterior aspect of LA
Posterior aspect of
LA
Opening of atrial appendage
Red Circular Tags = Ablation Site
Final Lesion Set Isolation of the PV’s + Linear Connecting Ablation Lines
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Case Study• 58 yo Male, H/O persistent AF for 4
years• Failed sotalol, flecainide and
amiodarone• Sx: Extreme fatigue, palpitations• LVEF: 45%, LA Size 52mm• Referred for RFA AV node
Atrial Fibrillation
After RFA in LAII
RA-19, 20
RA-17, 18
RA-15, 16
RA-13,14
LA-5, 6
LA-3, 4
LA-2, 1
CS -LA
RA
Organized Activity in LA
“The AF Driver”Disorganized Fractionated
Signals = Wavelet
Organization of AF With RFA in RA
II
ABLATION
RA-19, 20
RA-15, 16
RA-13,14
LA-5, 6
LA-3, 4
LA-2, 1
RA-17, 18
RA-11, 12
RA-9, 10
RA-7, 8
RA
CS -LA
Organization during RFA at areas of micro-reentry
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Termination of AFBy RFA of “AF Driver”
Ablation of Areas of Microreentry
RA
II
RA-19, 20
RA-15, 16
RA-13,14
LA-5, 6
LA-3, 4
LA-2, 1
RA-17, 18
RA-11, 12
RA-9, 10
RA-7, 8
ABLATION
CS -LA
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Candidates for Catheter Ablation for Atrial Fibrillation• Patients with symptomatic AFib & failed 1
Class I or III antiarrhythmic medication (ACC/AHA Guidelines)
• Other considerations:AFib controlled with drug therapy but pt does not want to continue with life-long medical therapy / excessive side effectsDesire to eliminate anticoagulation
• Cornerstone of Catheter Ablation of AFib….Isolation of PV’s
Paroxysmal – Circular catheter guidancePersistent – Circumferential Ablation around each PV ± Linear ablation
• >1800 Procedures• All comers 86% cure at 1 year
91% paroxysmal83% permanent / persistent
• 1.35 procedures / pt• Complications 1.8%
OSU RFA Experience
Factors Associated with Successful AFib Ablation• Paroxysmal rather than Persistent AFib• Absence of LA enlargement• History of AFib < 5 years• Lower Body Mass Index
• Not Age
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Worldwide Registry:Complications Associated with
Curative Ablation for AF (n = 8,745)
516 (5.9%)Total 4 (0.05%)Death71 (0.81%)Other morbidities
10 (0.11%)Phrenic nerve injury / diaphragmatic paralysis
82 (0.94%)Cerebrovascular accident / transient ischemic attack
100 (1.14%)Vascular access complications107 (1.22%)Cardiac tamponade142 (1.63%)Clinically important PV stenosis
Number of Patients (%)Type of Complication
“If we pull this off, we’ll eat like kings.”
AF Cure
New Technologies for the Ablation of Atrial Fibrillation
John D. Hummel, M.D.Ohio State University Electrophysiology
Current State of CurativeAFib Ablation
• Total Patients > 1000 (65% Persis. AF)• Table Time ~ 4 hours• Expected success @ 1yr
≈ 75% after first procedure≈ 87% after second procedure
• Complications ≈ 1-2%Tamponade – 0.6%Pulmonary vein stenosis – 0.6%TIA / CVA – 0.5%Esophageal-LA fistula - 0Groin Bleeding / Hematoma(Last 200 pts complications < 1%)
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Atrial Fibrillation: Ablation vs Drug Rx.
Ablation87% successPV stenosisAE fistula TIA/CVA
Drug Rx.40% successProarrhythmiaEnd Organ Toxicity
No Free Lunch
PV stenosis
AE fistula
Torsades
New Technology to Increase Efficacy and Decrease Risk of
Complications• Catheter Navigation/Mapping
MagneticRoboticUltrasound
• Energy SourcesHigh Intensity Focused Ultrasound (HIFU)Cryoablation
• RF Energy Delivery:PV MeshLasso RF DeliveryClosed vs. Irrigated RF catheters
• Left Atrial Appendage Closure
Conventional Ablation: Limitations
• Power output limited due tooverheating of the ablation electrodeand the adjacent tissue
• Dependent on cavitary cooling –cavitary cooling is pulsatile,dependent on cardiac output andvaries in different parts of the heart.
Areas of thick tissue
Areas of low cavitary cooling
Coagulum formation due to highelectrode and electrode-tissueinterface temperatures
4mm, Temperature control mode
Irrigated (Cool Tip) Ablation Tissue Heating
• Active cooling• Lowers the temperature of
the ablation electrode and adjacent tissue
• Allows higher levels of power output, and results in a larger lesion.
• There are two types of irrigation technologies :
Closed loopOpen loop
Nakagawa et al. Circulation 1995,91:2264-73
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Irrigation TechnologyOpen Loop Irrigation
ExternalCooling
Thermocouple
•Irrigation fluid flows through tinyholes around the electrode tip. •The irrigation fluid is in directcontact with both the ablationelectrode and the surroundingtissue surface. •Directly cools the electrodetissue interface
Higher power delivery Higher perforation riskBubble riskFluid LoadEndocardial sparing
InternalCooling
Irrigation TechnologyClosed Loop Irrigation
Thermocouple
•Irrigation fluid is not released intothe blood thus no volume overload,bubble risk
•2 lumens for the internal circulation:
One bringing fluid to the tip
Other removing fluid from tip
•Irrigation fluid does not directly coolthe electrode-tissue interface
Lower power delivered due to lesscooling of ET interface
Higher Char Risk
Afib Ablation=TransseptalPuncture
Ablation Frontier PVAC Catheter in LSPV
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II
Pair 1
Pair 2
Pair 3Pair 4
Pair 5
Pre
II
Pair 1
Pair 2
Pair 3
Pair 4Pair 5
Post
LIPV RF Ablation
3 Spline Catheter – SeptalPositioning
LA Roof and Floor Ablation Sites
Stereotactic Navigation
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Automatic Catheter Access to Right Inferior Pulmonary Vein
Pre-Programmed Atrial Reconstruction and Linear Ablation
Accunav Fan Segmentation of LA With MRI Registration
Cartosound
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Esophagus near LIPV
Effect of Cryothermyon Cells
Cryo Applications to Complete PVI
Each Cryo Marker= 4mm
Arctic Front® Cardiac CryoAblation Catheter
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HIFU AblationRSPV LSPV
HIFU RFALSPV Baseline Recordings
III
V1Map 1,2Map 2,3Map 3,4Map 4,5Map 5,6
A PVP
HIFU RFALSPV Recordings During RFA
III
V1Map 1,2Map 2,3Map 3,4Map 4,5
Map 5,6
Isolated PVP
APVP A A
Implant Face Distal to Ostium
Barbs Engage LAA Wall
WATCHMAN® LAA Filter System
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Current State of New Technologies
1. Cool Tip technology currently in use with new designs in trials
2. Circular Ablative Tool in Trials3. Cryo focal approved, Balloon under Review
by FDA4. HIFU on Hold5. LA closure under FDA review (in trials)6. Magnetic Navigation in Use7. Ultrasound Registration in Use