Catheter Ablation of Atrial Fibrillation: Who? How?
How Good?John D. Day, M.D.
Director, Utah Cardiovascular Research Institute
Utah Heart Clinic Arrhythmia ServiceLDS Hospital
*Disclosure: No conflicts of interest, no relationships to disclose*
Atrial Fibrillation: Magnitude of the Problem
• 15-30% of all strokes from atrial fibrillation• Heart failure risk increased with atrial fibrillation• 2.5x mortality increase with atrial fibrillation
(Framingham data)• 1 in 4 people age 40 will develop Afib• No effective or safe medications for atrial fibrillation• Anti-arrhythmics may increase mortality or expose
patient to significant toxicities• Increasing risk factors: age, hypertension, heart
failure
JACC 2003;41:2185-2196, Circulation 2004;110:1042-1046
Ablation of Atrial Fibrillation
1. Mechanisms of Atrial Fibrillation2. Historical Approach to Catheter
Ablation of Atrial Fibrillation3. Our Approach to Catheter
Ablation of Atrial Fibrillation4. Future Directions
Mechanism: Wavelet Hypothesis
• Multiple wavelets – Moe and Abildskov 1959
• “Multiple independent reentrant wavelets are necessary to maintain fibrillation. These wavelets are always changing in position, shape, size and number with each successive excitation”
• Confirmed by animal/human mapping techniques
Moe, Am Heart J; 1959
Results• 94% of atrial
fibrillation triggers (premature atrial beats) arise from pulmonary veins
• Pulmonary Veins as source of atrial fibrillation (Winterberg, 1906)
New England Journal of Medicine 1998;339;659-666
RA LA
Why the Pulmonary Veins? Myocardial Tissue Lines the
Pulmonary Veins
Pulmonary vein lumen
Left Atrium
Pulmonary Vein Isolation 1998-Present
• Electrical isolation of pulmonary vein triggers (premature atrial beats)
• Success: 50-90%• Increased success without pulmonary
vein stenosis by isolating outside of vein (antrum)
• Evolution of Technique– Focal– Circumferential– Segmental– Antrum isolation
Mapping of Atrial Fibrillation Trigger to Left Upper Pulmonary
Vein
Sinus rhythm by EKG
Atrial fibrillation in pulmonary vein by Lasso catheter
A A A A A A A A A A A A AA A
A VSinus rhythm by left atrial recordings from coronary
sinusA V
Electrical Isolation of Pulmonary Vein
J Cardiovasc Electrophysiol 2003;14:150-153
Limitations of Pulmonary Vein Isolation: Pulmonary Vein
StenosisBefore Ablation
After Ablation
>50% reduction in ostium of left superior
pulmonary vein
2003: Wavelets and Pulmonary Vein Triggers
Both Important
Moe, Am Heart J; 1959
Convergence of Techniques:Pulmonary Vein Isolation and Left
Atrial Substrate Modification: 2003-Present
• Isolation of pulmonary veins (triggers) and modification of substrate both important (wavelet mechanism)
• New technique: left atrial ablation, wide area circumferential ablation, circumferential left atrial pulmonary vein ablation (Pappone, Morady, and others)
• Increased success by isolating/encircling outside of the pulmonary veins (pulmonary vein stenosis eliminated)
• Ongoing issue: Electrical isolation of pulmonary veins by Lasso catheter or anatomic lesion set with pulmonary vein conduction delay (no Lassovoltage reduction)
Circulation 2003;108:2355-2360,
Journal of the American College of Cardiology 2005;46:1060-1066
Ablation lesion Set Proposed by Morady in 2003 (based on Pappone approach):
• Anatomic ablation lesion set
• Success rate similar if pulmonary veins isolated by Lasso catheter versus voltage reduction with an anatomic approach (Lasso not used)
2004: Targeting Autonomic Inputs/Fractionated
Electrograms
Location of the Left Atrial Ganglionic Plexi
Heart Rhythm 2005;2:S11
Autonomic/Fractionated Electrogram Approach
Journal of the American College of Cardiology 2004;43:2044-2053
Lesion sets similar to the wide area pulmonary vein
circumerferential ablation approach!!!
New Paradigm for Atrial Fibrillation
Pulmonary Vein and Autonomic Triggers
MultipleWavelets
Electrical Remodeling
Substrate• Atrial Size• Fibrosis• Stretch
DrugsIn progression to persistent and permanent atrial fibrillation triggers become less important
Mortality and Morbidity with Atrial Fibrillation
Ablation• 1,171 consecutive patients referred for
ablation in Milan, Italy (January 1998 March 2001)
• 589 ablated versus 582 drug treated (1/3 amiodarone, 1/3 class Ic, 1/3 sotalol/class Ia)
• End-points: mortality, morbidity (heart failure/stroke), & quality of life (900 day follow-up)
Journal of the American College of Cardiology 2003;42:185-197
Pappone ApproachEach pulmonary vein encircled
(voltage reduction)
2 Posterior wall ablation lines
Mitral valve flutter ablation
lineRight atrial cavo-tricuspid isthmus
flutter line
Ablation versus Drug Success
Journal of the American College of Cardiology 2003;42:185-197
78%
37%
Mortality After AF Ablation
Journal of the American College of Cardiology 2003;42:185-197
Mortality After AF Ablation = Expected for Italian
Population
54% Mortality Reduction with
Ablation versus DrugAtrial Fibrillation mortality on
Drug Less than Expected Italian Mortality
Morbidity After AF Ablation
Journal of the American College of Cardiology 2003;42:185-197
hello
p<0.001
55% reduction in heart failure or stroke at 3 years in ablated patients versus drug treated
patients
Our Current Approach: 3D CT and CARTO Electroanatomic
Imaging
Our Results: LDS Hospital• 49 consecutive patients age 59±11 (Jan 1, 2004 –
October 1, 2004—now 300+)
• 7±3 months follow-up
• Drug refractory symptomatic atrial fibrillation (failed 2.3 ± 1.2 anti-arrhythmic drugs)
• 36 paroxysmal and 13 persistent atrial fibrillation
• LA size: 48 ± 8 mm, 16 with structural heart disease
• Follow-up: Pacemaker/ICD logs, Holter, event monitor
• Approach: Encircle pulmonary veins (end-point of voltage reduction), roof and mitral line, target autonomics and complex fractionated electrograms
12th World Congress of Cardiology, Vancouver 2005
Atrial Fibrillation Ablation Results:
LDS Hospital
92%
72%
0%
20%
40%
60%
80%
100%
Freedom from Atrial Fibrillation (4+ Months Out)
Atrial Fibrillation Free Atrial Fibrillation Free (no drugs)
n=49
12th World Congress of Cardiology, Vancouver 2005
Complications• 300+ cases now performed utilizing this
technique (2004-2005)• No strokes• 3 pericardial effusions requiring
pericardiocentesis (1%, experience related)
• 1 atrio-esophageal fistula*• 1 esophageal perforation*
– Successful temporary esophageal stenting– No long-term problems*Early in experience before ultrasound monitoring
12th International Congress of Cardiology, Vancouver 2005
New Achilles Heel: Potential Esophageal
Injury
Posterior LA Wall
Esophagus
Our Approach to Minimize Esophageal Risk: Intracardiac Echo Monitoring During
Radiofrequency Delivery and Esophageal Temperature Probes
Future Directions: Ultrasound/Cryo Isolation of
Pulmonary Veins?
Problem: “One size doesn’t fit all”
Robotic Approach to Ablations? Stereotaxis Magnetic Navigation?
Journal of the American College of Cardiology 2003;42:1952-1958
As most strokes from atrial fibrillation arise from the left
atrial appendage…Closure after ablation?
Final Points• Who?
– Ideal patient: Young, paroxysmal atrial fibrillation with no structural heart disease
– Success rate lower with permanent atrial fibrillation and structural heart disease
• How? 3 main “techniques” – All 3 with similar ablation lesion sets– Pulmonary vein isolation, wide area
circumferential ablation, Autonomic/fractionated electrograms
– Our approach: Integration of all 3 techniques
• How Good?– 80-90% success rate in experienced hands with
any technique