AFib Management and the Role of Catheter Ablation

1
AFib Management and the Role of Catheter Ablation
2
Slide Kit Structure

• Section I. AFib Overview
• Section II. Clinical Management of AFib
• Section III. Catheter Ablation for the Treatment
  of AFib

3
Section IAFib Overview
4
Atrial fibrillation

• Atrial fibrillation (AFib) is a common disease
  that causes the upper chambers of the heart
  (atria) to beat rapidly and in an uncontrolled
  manner (fibrillation).
• Uncoordinated, rapid beating of the atria affects
  the flow of blood through the heart, causing an
  irregular pulse and sometimes a sensation of
  fluttering in the chest.

5
Classification of AFib Subtypes
Levy S, et al. Europace (2003) 5 119
6
Prevalence of AFib

• General population-based prevalence
• 0.95

ATRIA study
2.5
Olmsted County study
Go AS, et al. JAMA (2001) 285 2370
Miyasaka Y, et al. Circulation (2006) 114 119
7
Prevalence of AFib in the General Population in
USA and EU

• ATRIA Olmsted

USA 2.8 million 7.4 million
(? 300 million inhabitants)
EU 4.3 million 11.4 million
(? 456 million inhabitants of 25 member states)
8
Prevalence of AFib
Olmsted County study
15.9
15.2
16
14.3
14
13.1
11.7
12
10.2
12.1
11.7
10
8.9
11.1
Projected number of persons with AF (millions)
7.7
10.3
8
9.4
6.7
5.9
8.4
5.1
6
7.5
6.8
6.1
5.6
4
5.1
2
0
2000
2005
2010
2015
2020
2030
2025
2035
2040
2045
2050
Year
Miyasaka Y, et al. Circulation (2006) 114 119
9
Incidence of AFib in the General Population
Gender Differences
Olmsted County study
Observational period 20 years
Men 0.49 Women 0.28 Ratio men
to women 1.86
Miyasaka Y, et al. Circulation (2006) 114 119
10
Principal Reasons for Increasing Incidence and
Prevalence of AFib

• The population is aging rapidly, increasing the
  pool of people most at risk of developing AFib
• Survival from underlying conditions closely
  associated with AFib, such as hypertension,
  coronary heart disease and heart failure, is also
  increasing
• According to the Olmsted County study, the
  increase is also related to the increasing
  population
• These figures may also be significantly
  under-estimated because they do not take into
  account asymptomatic AFib (25 of cases in
  Olmsted survey)

Miyasaka Y, et al. Circulation (2006) 114
119 Steinberg JS, et al. Heart (2004) 90 239
11
AFib has an Impact on All Aspects of QoL
SF-36 quality of life scores in AFib patients and
healthy subjects
Healthy controls(n47)
AFib patients(n152)
SF-36 scale
plt0.001
Dorian P, et al. J Am Coll Cardiol (2000) 36 1303
12
Risk Factors for AFib
ATRIA study
Characteristic
(n17,974)
Baseline characteristics of 17,974 adults with
diagnosed AFib,July 1, 1996-December 31, 1997
Go AS, et al. JAMA (2001) 285 2370
13
AFib is Responsible for 15-20 of all Strokes

• AFib is responsible for a 5-fold increase in the
  risk of ischaemic stroke

12
8
Cumulative stroke incidence ()
Men AFib
Women AFib
Men AFib-
Women AFib-
4
0
2
4
1
5
3
2
4
1
5
3
Years of follow-up
Wolf PA, et al. Stroke (1991) 22 983 Go AS, et
al. JAMA (2001) 285 2370 Friberg J, et al. Am J
Cardiol (2004) 94 889
14
Increased Risk of Cardiovascular Events
Death or hospitalization in individuals with CV
event(s) after 20 years
Men
Women
100
89
80
66
60
At least one CV event ()
45
40
27
20
0
AFib
No AFib
AFib
No AFib
Stewart S, et al. Am J Med (2002) 113 359
15
Mortality Associated with AFib
Framingham Heart Study, n5209
80
60
Men AFib
Women AFib
Mortality during follow-up ()
40
Men AFib-
Women AFib-
20
0
2
0
10
9
8
7
6
4
1
5
3
Follow-up (y)
Benjamin EJ, et al. Circulation (1998) 98 946
16
Incremental AFib Healthcare Costs

• UK costs for AFib in 1995 vs. 2000

• 1995 Direct cost of AFib in the UK between 244
  and 531 million (0.61.2 of overall health care
  expenditure)
• 2000 459 million direct cost double that in
  1995 (0.92.4 of NHS expenditure)

Cost of heart failureadmission
50
Cost of strokeadmission
48
5.1
warfarin use
10 admission
7.4
10 community-based care
5.6
Base cost of AFin 2000
700
600
500
400
300
200
100
0
Total health care expenditure ( million)
Base cost of associated conditions and procedures
Incremental cost of AFib
Base cost of AFib
Stewart S, et al. Heart (2004) 90 286
17
Major Costs in Treatment of AFib
COCAF Study
6
2
8
52
Hospitalizations
9
Drugs
Consultations
Further investigations
Paramedical procedures
Loss of work
23
Le Heuzey JY, et al. Am Heart J (2004) 147121
18
Cost of AFib (Europe)
FIRE study

• 4507 consecutive patients with AFib/flutter
  admitted to ER enrolled in FIRE study (1.5 of
  all ER admissions)
• 61.9 of AFib/flutter patients were hospitalized
  (3.3 of all hospitalizations)
• Mean hospital stay 76 days

Santini M, et al. Ital Heart J (2004) 5 205
19
The Burden of AFib

• AFib is responsible for significant economic and
  healthcare costs
• Hospitalization costs
• Drug treatment
• Treatment of AFib-associated co-morbidities and
  complications
• The health and economic impact will increase with
  the increasing prevalence and incidence of AFib
• AFib, owing to its epidemiology, morbidity, and
  mortality, represents a significant health
  problem with important social and economic
  implications that needs greater attention and
  allocation of more resources

20
Section IIClinical Management of AFib
21
Primary Therapeutic Aims in AFib

• Restore and maintain sinus rhythm whenever
  possible
• Prevent thromboembolic events
• In order to
• Reduce symptoms and improve QoL
• Minimize impact of AFib on cardiac performance
• Reduce risk of stroke
• Minimize cardiac remodelling

ACC/AHA/ESC 2006 Guidelines for the Management of
Patients With Atrial Fibrillation J Am Coll
Cardiol (2006) 48 854
22
Treatment Options for AFib

• Cardioversion
• Pharmacological
• Electrical
• Drugs to prevent AFib
• Antiarrhythmic drugs
• Non-antiarrhythmic drugs
• Drugs to control ventricular rate
• Drugs to reduce thromboembolic risk
• Non-pharmacological options
• Electrical devices (implantable pacemaker and
  defibrillator)
• AV node ablation and pacemaker implantation
  (ablate pace)
• Catheter ablation
• Surgery (Maze, mini-Maze)

23
Recurrence Following Cardioversion AFFIRM Study
AFFIRM most recurrences occur within 2 monthsof
cardioversion
100
80
60
Patients with AF Recurrence ()
40
Log rank statistic 58.62 plt0.0001
20
0
0
1
2
3
4
5
6
Time (years)
N, Events ()
Raitt MN, et al. Am Heart J (2006) 151 390
24
Amiodarone to Prevent Recurrence of AFib
CTAF Study mean follow-up 16 months
100
plt0.001
80
60
Patients without AFib ()
40
Sotalol
Propafenone
20
Amiodarone
0
0
100
200
300
400
500
600
Follow-up (days)
Roy D, et al. N Engl J Med (2000) 342 913
25
Effectiveness of Current AADs

• Even with the most effective AAD, such as
  amiodarone, long-term efficacy is low
• 50 or less at 1 year

26
Non-Pharmacological Treatment Options for AFib

• Pacemakers not curative and must be worn for life
• Surgical procedures may be effective but are not
  a practical solution for the millions of
  sufferers of AFib
• Catheter ablation is potentially curative

Surgery
Electrophysiological
Devices
Pacemaker(single or dual chamber) Internal
atrialdefibrillators
Catheter ablation AV node ablation
Maze procedure Modified Maze (mini-Maze)
ACC/AHA/ESC 2006 Guidelines for the Management of
Patients With Atrial Fibrillation J Am Coll
Cardiol (2006) 48 854
27
Management of AFib - Summary

• Current antiarrhythmic drug therapies are not
  highly effective in maintaining sinus rhythm and
  generally have poor outcomes
• high recurrence rates
• adverse effects and high discontinuation rate
• A potentially curative therapy for AFib is
  desirable

28
Section IIICatheter Ablation for the Treatment
of AFib
29
Catheter Ablation

• Uses a series of long, thin wires (catheters)
  that are inserted through an artery or a vein and
  then guided through to the heart.
• One of the catheters is then used to localise the
  source of the abnormal electrical signals and
  another then delivers high energy waves that
  neutralise (ablate) abnormal areas.
• Using catheters to reach the heart is a common
  approach to treat a range of heart conditions and
  is much less invasive than surgical treatments.

30
Landmarks in Catheter Ablation Techniques
Technique
Publication date
31
1998 Ablation of PV Foci
Spontaneous Initiation of Atrial Fibrillation by
Ectopic Beats Originating in the Pulmonary
Veins Haïssaguerre, M, Jaïs, P, Shah, DC, et
al. N Engl J Med (1998) 339 659

• Pivotal study identifying the pulmonary veins as
  a major source of ectopic electrical activity
• Radiofrequency ablation of ectopic foci was
  associated with a 62 success rate (absence of
  recurrence at 8 ? 6m follow-up)

32
A Combination of Techniques may now be used
Depending on the Type of AFib
AFib
Substrate - Atrial tissue
Trigger - Ectopic Foci
Autonomic Nervous System
PV non-PV Foci Ablation, PV Isolation
CFAEs Ablation Linear Lesions (e.g. mitral
isthmus, roof)
Vagal Denervation (parasympathetic ganglia
ablation)
33
Cardiac Imaging Techniques

• Electroanatomical mapping
• CARTO / CARTOMERGE
• Fluoroscopy
• Angiography
• Intracardiac echography
• Cardiac spiral CT
• Cardiac MRI

34
CARTO System

• Localization of catheter to within 1 mm
• Increase safety margin during ablation

• 3D-electroanatomic maps (CARTO) showing ablation
  points encircling PVs

35
PV Antrum Isolation Guided by CARTOMERGE Image
Integration Software Module
Courtesy of Professor Antonio Raviele, Mestre,
Italy
36
Catheter Visualization under Fluoroscopic Guidance
Ablation catheter
LASSO
LAO
RAO
37
Efficacy and Safety of Catheter Ablation
38
Meta-analysis of Catheter Ablation
Paroxysmal AF
Patients
6-month cure
Ablation method
SHD
6-months OK
Cure (by each authors criteria) means no further
AFib 6 months after the procedure in the absence
of AAD. OK means improvement (fewer episodes, no
episodes with previously ineffective AAD). SHD
indicates structural heart disease.
Fisher JD, et al. PACE (2006) 29 523
39
Worldwide Survey on Efficacy and Safety of
Catheter Ablation for AFib

• Total success rate 76
• Of 8745 patients
• 27.3 required 1 procedure
• 52.0 asymptomatic without drugs
• 23.9 asymptomatic with an AAD within lt1 yr
• Outcome may vary between centres

Cappato R, et al. Circulation (2005) 111 1100
40
Improved Survival with Ablation vs Drug Treatment

• 589 ablated patients compared with 582 on AADs

Pappone C, et al. J Am Coll Cardiol (2003) 42 185
41
More AFib-free Patients with Catheter Ablation vs
Drug Treatment
100
80
60
AFib-freesurvival probability ()
Ablation Group
40
Medical Group
20
0
0
300
200
100
Follow-up (days)
No. at risk
282
135
217
589
479
507
379
Ablation
Medical
207
97
141
582
354
456
277
Pappone C, et al. J Am Coll Cardiol (2003) 42 185
42
Randomised Clinical Trials of Catheter Ablation

• RF ablation vs AAD as first-line treatment for
  AFib
• Wazni OM et al. JAMA (2005) 293 2634-2640
• Catheter ablation in drug-refractory AFib
• Stabile G et al. Eur Heart J (2006) 27 216-221
• Circumferential PV ablation for chronic AFib
• Oral H et al. N Engl J Med (2006) 354 934-941

43
RF Ablation vs Antiarrhythmic Drugs as First-line
Therapy

• Patients randomised to receive ablation (n33) or
  AADs (n37) AFib-free Survival

1.0
0.8
0.6
AFib.free survival
PVI Group
0.4
Antiarrhythmic DrugGroup
0.2
0
0
300
200
100
Follow-up (days)
Wazni OM, et al. JAMA (2005) 293 2634
44
Catheter Ablation vs. AADs Alone in
Drug-refractory AFib
AADs plus ablation (n68) or AADs alone (n69)
1 year follow-up
Ablation Group
100
Medical Group
80
60
AFib-free survival ()
40
20
0
0
12
9
5
11
10
8
7
6
4
3
2
1
Months
Stabile G, et al. Eur Heart J (2006) 27 216
45
Randomized Controlled Trial of Amiodarone
Cardioversion Catheter Ablation
Amiodarone cardioversion (n69) vs. amiodarone
cardioversion plus PV ablation (n77)
100
Circumferentialpulmonary-vein ablation
Control
80
60
Sinus rhythm ()
40
20
0
12
11
10
9
8
7
6
5
4
3
2
1
Months
Oral H, et al. N Engl J Med (2006) 354 9
46
Catheter Ablation is Successful in the Long Term
No ERAF
1.0
ERAF
0.8
0.6
Freedom from Recurrent AFib
0.4
0.2
0
0
12
10
8
6
4
2
Months after PV isolation
Oral H, et al. J Am Coll Cardiol (2002) 40 100
47
Complications Reported by Leading Centres
Major complications with pulmonary vein
ablationin 1039 patients (6 series)
Events(n)
Range in studies()
Rate()
Complication
Verma A Natale A Circulation (2005) 112 1214
48
Cost EffectivenessAnalyses of Catheter Ablation
49
Catheter Ablation May Be More Cost-effective than
Pharmacological Therapy
After 5 years, the cost of RF ablation was below
that of medical management and further diverged
thereafter
118 patients with symptomatic,drug-refractory
AFib
1.52 0.71 ablation procedures
32 weeks
Catheter ablation
Pharmacological treatment
4715 followed by 445/year
1590/year
Weerasooriya R, et al. Pacing Clin Electrophysiol
(2003) 26 292
50
Differences in Hospital Visits and Costs with and
without Catheter Ablation
Although the initial cost of ablation is high,
after ablation, utilization of healthcare
resources is significantly reduced
No ablation
Catheter ablation
Goldberg A, et al. J Interv Card Electrophysiol
(2003) 8 59
51
Catheter Ablation Cost-Effective in Patients at
High Risk of Stroke
Model to compare the cost-effectiveness of left
atrial catheter ablation (LACA), amiodarone, and
rate control therapy in the management of AFib
The use of LACA may be cost-effective in
patients with AFib at moderate risk for stroke
This model did not find it to be cost-effective
in low-risk patients. Conclusions Cost-effective
in patients at moderate or high risk of stroke
Chan DP, et al. J Am Coll Cardiol (2006) 47 2513
52
Current Guidelines and Summary
53
Current ACC/AHA/ESC Guidelines
RecurrentParoxysmal AF
Minimal orno symptoms
Disabling symptomsin AF
Anticoagulation and rate control as needed
Anticoagulation and rate control as needed
No drug for preventionof AF
AAD therapy
AF ablation if AADtreatment fails
ACC/AHA/ESC 2006 Guidelines for the Management of
Patients With Atrial Fibrillation J Am Coll
Cardiol (2006) 48 854
54
Recent Commentary
Why Ablation for AFib might be Considered
First-Line Therapy for Some Patients
Current therapies, especially AAM, not onlyare
ineffective but also pose a threat to patientQoL
and even longevity. In the hands of experienced
operators, AF ablation is an effective, safe, and
established treatment for AF that offers an
excellent chance for a lasting cure unlike
other therapies, ablation tackles AF at its
electrophysiological origin.
Verma A Natale A Circulation (2005) 112 1214
55
Summary of catheter ablation (I)

• Catheter ablation for AFib has undergone
  significant methodological and technical
  revolution since its initial appearance two
  decades ago
• Discovery that PVs are a major source of ectopic
  triggers was pivotal in determining efficacy of
  procedure
• Significant technological advances in catheters
  and imaging are further improving the efficiency
  of catheter ablation
• 3D reconstructions of actual left atrial PV
  anatomy using CT, MRI, or intracardiac echography
  enables ever more accurate placement of lesions

56
Summary of catheter ablation

• High success rate
• Improves survival, cardiac function and freedom
  from recurrence
• New data from RCTs confirm benefits
• Safe, with a risk comparable to other low-risk,
  routine interventions
• Cost effective compared to standard
  pharmacological therapy, at least in patients at
  moderate thromboembolic risk