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Catheter AblationCatheter Ablation
in the Treatment ofin the Treatment ofAtrial FibrillationAtrial Fibrillation
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First described in
1903 by Hering
Most common
sustained arrhythmia
Atrial FibrillationAtrial Fibrillation
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Atrial fibrillation accountsAtrial fibrillation accounts
for 1/3 of all patientfor 1/3 of all patient
dischargesdischarges
with arrhythmia aswith arrhythmia as
principal diagnosisprincipal diagnosis
2% VF
Baily D. J Am Coll Cardiol. 1992;19(3):41A.
34%
Atrial
Fibrillation
18%
Unspecified
6%
PSVT
6%PVCs
4%
Atrial
Flutter
9%
SSS
8%
ConductionDisease
3% SCD
10% VT
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Atrial FibrillationAtrial Fibrillation
What is Atrial Fibrillation?
Chaotic circular impulses in the atria
Several reentrant circuits moving simultaneouslyAtrial rates
300 to 600 beats per minute
Ventricular rates regulated by the AV node Irregularly irregular due to partial depolarization of AV
node
Results in loss of AV synchrony 20% to 30% decrease in cardiac output
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Incidence and PrevalenceIncidence and Prevalence
Prevalence increases with age
4.8 % in the 70-79 age group
Increases to
8.8% in the 80-89 age group
During the next 7-8 years, the number of
people over the age of 80 is expected toquadruple
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Atrial Fibrillation Demographics by AgeAtrial Fibrillation Demographics by Age
Adapted from Feinberg WM. Arch Intern Med. 1995;155:469-473.
U.S. population
Population with
atrial fibrillation
Age, yr
95
U.S. population
x 1000
Population with AF
x 1000
30,000
20,000
10,000
0
500
400
300
200
100
0
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Stages of Atrial FibrillationStages of Atrial Fibrillation
Paroxysmal
Persistent
Permanent
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Stages of Atrial FibrillationStages of Atrial Fibrillation
Paroxysmal (23% of AF population)
Self limiting
Spontaneous conversion to sinus rhythm within 24 hrsafter onset is common
Once the duration exceeds 24 hrs, the likelihood of
conversion decreases
After one week of persistent arrhythmia, spontaneousconversion is rare
30% of these patients develop Persistent AF
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Stages of Atrial FibrillationStages of Atrial Fibrillation
Persistent (38% of AF population)
Requires intervention to restore normal rhythm
Cardioversion Electrical or Chemical (drugs)
Can lead to electrophysical and structural changes
in the myocardium (remodeling) that can lead to
Permanent AF
AF with duration of greater than 7 days rarely
spontaneously converts
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Stages of Atrial FibrillationStages of Atrial Fibrillation
Permanent (39% of AF population)Unable to convert Electrical or Chemical (drugs)
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Mechanisms of AFMechanisms of AF
Theories of the mechanism of AF involve
2 main processes:
- Enhanced automaticity in one or several rapidly
depolarizing foci
- Reentry involving one or more circuits
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Mechanisms Contributing to AF
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Mechanisms of AFMechanisms of AF
Rapidly firing atrial foci, located in one or
several pulmonary veins (PVs), can initiate AFin susceptible patients
Foci also can occur in RA and infrequently inthe superior vena cava or coronary sinus
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Pulmonary Vein MyocardialPulmonary Vein Myocardial
SleevesSleeves
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Factors Involved in the Pathogenesis of AFFactors Involved in the Pathogenesis of AF
Studies in man have shown that increased inhomogeneity ofrefractory periods and conduction velocity is present in AF
patients.
Structural changes in atrial tissue may be one of the underlyingfactors for dispersion of refractoriness in AF.
Other factors involved in the induction or maintenance of AF
include premature beats, the interaction with the autonomicnervous system, atrial stretch, anisotropic conduction, and theaging process, vein of Marshall.
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Mechanisms contributing to AFMechanisms contributing to AF
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Atrial Fibrillation: Clinical ProblemsAtrial Fibrillation: Clinical Problems
Embolism and stroke (presumably due to LA clot)
Acute hospitalization with onset of symptoms
Anticoagulation, especially in older patients (> 75 yr.)
Congestive heart failure
Loss of AV synchrony
Loss of atrial kick
Rate-related cardiomyopathy due to rapid and irregular ventricularresponse
Rate-related atrial myopathy and dilatation
Chronic symptoms and reduced sense of well-being
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Therapeutic Approaches toTherapeutic Approaches to
Atrial FibrillationAtrial Fibrillation
Anticoagulation
Antiarrhythmic suppression
Control of ventricular response
Pharmacologic
Catheter modification/ablation of AV node
Curative procedures
Catheter ablation
Surgery (maze)
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Disadvantages
High recurrence rate
High long-term cost
Non-curative
Adverse effects
Potential proarrhythmia
Antiarrhythmic Therapy for Atrial FibrillationAntiarrhythmic Therapy for Atrial Fibrillation
Advantages
High efficacy for some
patients, at least
initially
(< 50% of all patients)
Low initial cost
Noninvasive
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Antiarrhythmic SuppressionAntiarrhythmic Suppression
DrugsConversion of AF
Class 1A (decrease conduction velocity, increase refractoryperiods of cardiac tissue, suppress automaticity)
Quinidine
Procainamide
Class III (decrease conduction velocity, increase refractoryperiods of cardiac tissue, suppress automaticity)
Amiodarone
Sotalol
Ibutilide (Corvert)
Dofetilide
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Antiarrhythmic SuppressionAntiarrhythmic Suppression
Drugs
Maintenance of normal rhythm
Class 1A
Class III
Class 1C (decrease conduction velocity)
Flecainide
Propafenone
Drug choice depends upon patients underlying
heart disease
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Nonpharmacological Approaches toNonpharmacological Approaches to
Atrial FibrillationAtrial Fibrillation
1. Pacemaker therapy
2. AblationAblation
3. Surgery
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RF Ablation TechniquesRF Ablation Techniques
A)A) Focal ablation of PV (Pulmonary vein) triggersFocal ablation of PV (Pulmonary vein) triggers
B)B) Segmental PV isolationSegmental PV isolation
C)C) Wide Area Circumferential AblationWide Area Circumferential Ablation
D)D) Ablation of Fractionated Complex ElectrogramsAblation of Fractionated Complex Electrograms
E) Targeted ablation of ganglionated autonomic plexi in theepicardial fat pads
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Focal Ablation of TriggersFocal Ablation of Triggers
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Focal AblationFocal Ablationof Atrial Fibrillationof Atrial Fibrillation
95% of foci are located within a pulmonary
vein ( PV).
Focal sources of AF may be found in the RA,
LA, coronary sinus, superior vena cava or vein of
Marshall.Haissaguerre M, Jais P, Shah DC, et al. Spontaneous initiation of atrial fibrillation by ectopic
beats originating in the pulmonary veins. N Engl J Med 1998;339:65966.
Chen SA, et. al: Initiation of atrial fibrillation by ectopic beats originating from the pulmonary
veins: Electrophysiologic characteristics, pharmacologic responses, and effects of
radiofrequency ablation. Circulation 1999;100:1879-1886.
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Pulmonary Vein Spike DischargesPulmonary Vein Spike Discharges
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Pulmonary Vein Spike DischargesPulmonary Vein Spike Discharges
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Initiation of AF by PV DischargesInitiation of AF by PV Discharges
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PV potentials
PV Potentials
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PV Potentials
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PV Potential on 6-10
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PV potentials
disappeared
during
radiofrequency
currentapplication
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Loss of PV Potentials
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Focal Ablation of Pulmonary VeinsFocal Ablation of Pulmonary VeinsComplicationsComplications
The most common complications associated with thefocal ablation of the PVs are pericardial effusion(
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PV Stenosis
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PV Stenosis
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Multi-slice CT Endocardial View
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PV StentingPV Stenting
T d I t di hTamponade: Intra cardiac echo
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Tamponade: Intra-cardiac echoTamponade: Intra-cardiac echo
The incidence of perforation during ablation of the left atrium is relatively low
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Segmental PV IsolationSegmental PV Isolation
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Segmental PV IsolationSegmental PV Isolation
Limitations associated with focal ablation have
prompted the development of other techniques foreliminating the PV arrhythmias.
Anatomically PV isolation has significant advantages
over focal ablation.
L S i l C th t
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Lasso or Spiral Catheters
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Dissociation of the
PV potential aftersuccessful isolation
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Segmental Ostial Pulmonary VeinSegmental Ostial Pulmonary Vein
IsolationIsolation
The initial experience with segmental ostial
ablation of PVs guided by PV potentials is
encouraging, with a long-term success rate of 90%
in patients with paroxysmal AF
Minimal risk of PV stenosis when the power of
radiofrequency energy applications is limited to 30W.
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Wide Area CircumferentialWide Area Circumferential
AblationAblation
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Circumferential AblationCircumferential Ablation
It is an anatomic approach in which circumferential lines ofblock are created using 3D maps ( Carto, NavX..) around the
ostia of PVs for isolation of PVs from LA.
Additional linear lesion from LIPV to mitral annulus for
preventing LA incisional tachycardia ( 2%).
Additional linear lesions (posterior, roof, right isthmus.)
may be created deepening on operators preference.
Pappone C, et al. Atrial electroanatomic remodeling after circumferential radiofrequency
pulmonary vein ablation: efficacy of an anatomic approach in a large cohort of patients
with atrial fibrillation. Circulation 2001;104:25392544.
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NavX MapNavX Map
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Anatomical Reconstruction of LAAnatomical Reconstruction of LA
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Circumferential AblationCircumferential Ablation
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Circumferential AblationCircumferential AblationCarto MapCarto Map
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Circumferential AblationCircumferential Ablation
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Circumferential AblationCircumferential Ablation
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Circumferential AblationCircumferential Ablation
Magnetic Resonance Image Electroanatomic Map
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Magnetic Resonance Image Electroanatomic Map
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Circumferential AblationCircumferential Ablation
Effective in both paroxysmal and chronic AF
(81%, 76%) Bipolar amplitude < 0.1 mv inside and aroundBipolar amplitude < 0.1 mv inside and around
the lesion may be acceptable for showing PVthe lesion may be acceptable for showing PV
isolation.isolation.
Post Circ mferential PV ablation
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Post Circumferential PV ablation
BipolarBipolar
amplitudeamplitude< 0.1 mv< 0.1 mv
inside theinside the
lesionlesion
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Mitral Isthmus LineMitral Isthmus Line
The addition of mitral isthmus line to the PVdisconnection may allow a significant improvement ofsinus rhythm maintenance rate, particularly in patientswith persistent AF, without the risk for major
complications.
J Cardiovasc Electrophysiol, Vol.
16, pp. 1150-1156, November 2005
C li ti t f ll i i f ti lC li ti t f ll i i f ti l
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Complication rates following circumferentialComplication rates following circumferential
pulmonary vein ablationpulmonary vein ablation
Death 0%
Pericardial effusion 0.1%
Stroke 0.03% Transient ischemic attack 0.2%
Tamponade 0.1%
Atrio-esophageal fistula 0.03% Pulmonary vein stenosis 0%
Incisional left atrial tachycardia 6%
Phrenic nerve injury
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Topographic
Variability of theEsophageal Left
Atrial Relation
CT
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CT
reconstruction
of the LA, the
pulmonary
veins, and theesophagus
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Topographic Variability of the
Esophageal Left Atrial Relation
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Phrenic Nerve Injury
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Phrenic Nerve Injury
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Ablation of Fractionated ElectrogramsAblation of Fractionated Electrograms
Hypothesis being that these are consistent sites whereHypothesis being that these are consistent sites wherefibrillating wavefronts turn or split.fibrillating wavefronts turn or split.
By ablating these areas the propagating randomBy ablating these areas the propagating randomwavefronts are progressively restricted until the atriawavefronts are progressively restricted until the atriacan no longer support AF.can no longer support AF.
Nademanee demonstrated 70% freedom from AFNademanee demonstrated 70% freedom from AFfollowing a single procedure for permanent AFfollowing a single procedure for permanent AF
patients.patients.
Nademanee K, et al. A new approach for catheter ablation of atrial fibrillation: mapping of the
electrophysiologic substrate. J Am Coll Cardiol 2004;43:204453.
Segmental Ablation vs CircumferentialSegmental Ablation vs Circumferential
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Segmental Ablation vs. CircumferentialSegmental Ablation vs. Circumferential
Ablation?Ablation?
Is either of the two ablation strategies superior to the other?
Oral et al. showed that, during the 6 months following a singlecatheter procedure, Circumferential Ablation was associated witha significantly better outcome with no differences between thetwo ablation strategies in the complication rates.
Schmitt et al. reported opposite results to those of Oral et al.
The opposite results in the two studies were obtained because ofthe large variability in the success rate observed in patientsundergoing Circumferential Ablation (88 vs. 47%) while thesuccess rates in patients undergoing Segmental Ablationremained unchanged (67 vs. 71%).
Integrated ApproachIntegrated Approach
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Integrated ApproachIntegrated Approach
Journal of Cardiovascular Electrophysiology Vol. 16, No. 12, Dec. 2005
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Frequently Asked QuestionFrequently Asked Question
Who is currently a candidate forAF ablation?
Patient selection criteriaPatient selection criteria
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Patient selection criteriaPatient selection criteria
Inclusion criteria At least one monthly episode of persistent symptomatic AF or At least one weekly episode of paroxysmal AF or
Permanent AF
And
At least one failed trial of antiarrhythmic drugs or More than one antiarrhythmic drug to control symptoms
Exclusion criteria NYHA functional class IV
Age > 80 years
Contraindications to anticoagulation
Presence of cardiac thrombus
Left atrial diameter 65 mm
Life expectancy < 1 year
Thyroid dysfunction
Recent updates Patients with mitral and/or aortic metallic prosthetic valves are
not excluded Previous repair of atrial septal defects is not an absolute contraindication
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Frequently Asked QuestionFrequently Asked Question
AF ablation for asymptomaticindividuals?
Asymptomatic PatientsAsymptomatic Patients
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Asymptomatic PatientsAsymptomatic Patients
To date there is no evidence that treatment of AF byablation improves mortality, although there are uncontrolled
data suggesting that this may be the case.
Therefore, asymptomatic patients should not be offeredcurative ablation of AF, except in the case of those patients
undergoing cardiac surgery who may benefit from surgical
ablation of their AF as an adjunctive procedure.
There is also evidence that patients with heart failure have
significant improvements in left ventricular function
following successful catheter ablation of AF.
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ConclusionConclusion
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ConclusionConclusion
For many patients with a previously untreatable heartrhythm, ablation has dramatically improved their symptomsby restoring and maintaining sinus rhythm.
Preliminary randomized studies of catheter ablation of AF
provide evidence that ablation (with or without concurrentanti-arrhythmic drug use) effectively improves maintenanceof sinus rhythm when compared with current anti-arrhythmicdrugs.
Although prognostic and quality of life data from long termrandomized trials of catheter ablation for AF are still inpreparation, the non-randomized data comparing ablation tocontinued medical treatment suggests a strong benefit from
ablation.
Tehran Arrhythmia CenterTehran Arrhythmia Center
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WWW.IranEP.orgWWW.IranEP.org
[email protected]@IranEP.org
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