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