Download Catheter Ablation for VT

Post-Myocardial Infarction
Ventricular Tachycardia: should
catheter ablation be performed
before antiarrhythmic drug
therapy?
William G. Stevenson, M.D.
Brigham and Women’s Hospital
Boston, Ma
Disclosures: patent for a needle ablation catheter –
consigned to Brigham and Women’s Hospital
Ventricular Tachycardia and Ventricular Fibrillation
After Hospital Discharge from Myocardial
Infarction – Patients with depressed ventricular function
Sudden Death after Acute MI with ventricular dysfunction or
heart failure: Valiant trial
Solomon et al NEJM 2005; 352:2581.
Sustained Ventricular
arrhythmias in patients with
LVEF < 0.40 followed for 2 yrs
after myocardial infarction
CARISMA Study Thomsen et
al Circulation 2010; 122:1258
Sustained VT
3%
VF
2.7%
ICDs terminate VT or VF after it occurs:
Shocks or Antitachycardia Pacing (ATP)
ICD shock
C
Atrial
lead
VT
LV
lead
RV
lead
VT
Antitachycardia Pacing
The Rationale for Preventing VT – an ICD is
not enough
 ICD shocks reduce quality of life
 Spontaneous VT/VF is associated with increased
risk of death and heart failure
Moss et al. Circulation 2004;110:3760-3765
Poole JE et al. N Engl J Med 2008;359:1009-1017
SCD-HeFT: Spontaneous VT predicts
Increased Risk of Death
Poole JE et al. N Engl J Med 2008;359:1009-1017.
Heart failure + ischemic heart disease + ICD shock
37% one year survival
Episodes of VT/ VF predict increased mortality and
heart failure despite ICD therapy – MADIT II
Is VT a prognostic marker or directly
contribute to mortality and heart failure?
Moss et al. Circulation 2004;110:3760-3765
Need for Arrhythmia Management After ICD
placement
Secondary Prevention ICD
Recurrent VT: 40 – 60%
>3 shocks in 24 hrs: 20%
Primary Prevention ICD
Sustained VT - 5% year
Symptomatic VT
After ICD
Antiarrhythmic
Drugs
Catheter
Ablation
SCD-HeFT Bardy, G. H. et al. N Engl J Med 2005;352:225-237
MADIT II N Engl J Med 202;346:877
AVID VT storm, Exner et al Circ 2001;103:201
AVID Quality of life, Schron Circ 2002;105:589
OPTIC Trial – Drug therapy to reduce
recurrent VT in patients with ICDs
 412 patients receiving ICD
– spontaneous VT, or
– LVEF ≤40% and cardiac arrest or inducible VT/VF
 Randomized to
 b-blocker - sotalol - b-blocker and amiodarone
 Baseline characteristics
– 80% prior MI
– 71% spontaneous VT or VF / 29% inducible VT or VF
Connolly SJ. J Am Med Assoc. 2006;295:165-71
OPTIC Trial – Drug therapy to reduce
recurrent VT in patients with ICDs
Any VT (shock or ATP) at 1 Year
p<0.001
50%
p=NS
P< 0.001
45.0%
39.0%
40%
30%
20%
13.0%
10%
0%
b-blocker
Sotalol
b-Blocker
w/ Amiodarone
Connolly SJ. J Am Med Assoc. 2006;295:165-71
Optic TRIAL: Adverse Events of the 3 Treatment Assignments.
Drug discontinuation at 1 yr
5.3%
18.2%
23.5%
Connolly, S. J. et al. JAMA 2006;295:165-171
Amiodarone Toxicity
meta-analysis of trials for sudden death prevention
Piccini et al Eur H J 2009;30:1245
 Drug withdrawal in VT trials:
 Serious toxicities
– Lung
– Liver
– Thyroid
– Bradyarrhythmia
29%
2.9%
1.9%
3.6%
2.8%
ICD – Antiarrhythmic Drug Interactions
 Slower VT
– Impairs discrimination between sinus
tachycardia and VT
– Slower incessant VT
 Sinus slowing – increased ventricular pacing
 Effect on antitachycardia pacing (ATP) /
defibrillation efficacy
Catheter Ablation for VT: Approach and efficacy
depend on arrhythmia substrate
 Monomorphic VT s can be targeted for ablation
– Scar – related reentry
– Purkinje system – related VT
 Polymorphic VT – the initiating PVC can be
targeted for ablation if identifiable
– An option for rare patients with recurrent polymorphic
VT not due to acute ischemia / other treatable cause if
frequent PVCs are present
Post – Myocardial Infarction
Scars provide a stable substrate for
recurrent monomorphic VT
 repeated VT episodes occur over
years
 VT is inducible at EP study
 Drug efficacy is disappointing
– decreasing membrane currents
is usually insufficient to block
conduction and prevent reentry
Catheter ablation to interrupt reentry pathways
in areas of scar
Challenges:
 Areas of scar are often large
 Reentry circuits can be large
 Multiple potential reentry circuits
 Multiple VTs
 Hemodynamically unstable VT
Substrate guided ablation: mapping and ablation during stable
sinus rhythm for VTs that are hemodynamically unstable
Define Low Voltage
Ventricular Scar
Identify potential reentry
circuit channels based
on pace-mapping and
electrogram
characteristics
Ablation of reentry
circuit exits and
channels in the scar
RF Catheter Ablation Guided by Electroanatomic Mapping for
Recurrent VT After Myocardial Infarction
Stevenson et al Circulation 2008; 118: 2773
 CAD
- median LVEF 0.25
 Frequent VT failing therapy - 11 episodes in prior 6 months
Characteristics of induced VTs in 231 patients: median of 3 VTs/patient
Both
Mappable and
Unmappable*
38%
Mappable
Only
31%
Unmappable*
Only
31%
53% achieved primary endpoint: at 6 months no VT, or absence of
recurrence of incessant VT
Catheter Ablation Reduces VT Recurrences
6 months pre - ablation
6 months post - ablation
N = 142
Median 11.5 VT episodes
Median 0
P < 0.0001
>100
80
60
40
20
0
20
40
60
80 >100
Number of VT Events
Stevenson et al Circulation 2008
Procedure Complications
Thermocool Investigators, Circulation. 2008;118:2773.
Death
7
Perforation / MI
1
Uncontrollable VT
6
Non-fatal serious complications
27 in 24 pts
Stroke / peripheral embolism
0
Heart Failure
6
Increase in mitral regurgitation
1
Femoral bleeding / pseudoaneurysm
Others
(hematuria, HIT, sepsis, pericarditis, anemia,
incessant VT)
7/4
9
3%
7.3%
Ablation for VT late after Myocardial
Infarction
 Reduces ICD therapies in > 70% of patients
– Mortality 3%
• Most due to uncontrollable VT when the procedure fails
– Stroke 0 - 2.7%
– Vascular complications: 10%
• Femoral hematomas, pseudoaneurysms
Catheter ablation has been largely used only
after failure of antiarrhythmic drugs to
control recurrent VT
 Does early use of ablation improve outcomes?
– Lower risk of complications in less sick patients?
– Improve quality of life?
– Reduce heart failure hospitalizations?
– Extend surviva?
VTACH study – Kuck et al Lancet 2010
Randomized trial of ablation after first
hemodynamically tolerated VT post MI
Primary endpoint – time to recurrent VT
Survival free from cardiac hospitalization
Ablation reduced recurrent VT
Ablation reduced hospitalizations
Median time to recurrent VT:
Ablation - 18.6 months
Control - 5.9 months
VTACH study
Kuck et al Lancet 2010
Ablation
Control
p
SMASH VT: Is there benefit to prophylactic VT ablation
after one episode for ICD recipients with prior MI?
Reddy et al NEJM 2007
133 patients having ICD placed for VT
Randomized to substrate - guided ablation vs no ablation
Survival
Primary End Point:
Survival Free from ICD Therapy
Substrate guided ablation:
- Reduced VT
- No impact on mortality
- No negative impact on LV function on serial
echocardiograms
Procedure Complications in Early Use of VT
Ablation
Procedure Death
Major Complication
Vtach Trial
N = 52
Smash VT
N=64
0
0
2 /52
3/64
1- Myocardial Ischemia
1 Pericardial effusion
1 - TIA
1 – deep venous
thrombosus
1 – Heart Failure
exacerbation
SMASH VT
- no impact of VT ablation on LV function
Reddy et al NEJM 2007
Effect of Substrate Ablation on Ventricular Function
Reddy V et al. N Engl J Med 2007;357:2657-2665
Disclosures: None
Indications for Catheter Ablation of VT:
Patients with structural heart disease (including prior MI,
dilated cardiomyopathy, ARVC/D)
Recommended:
1. for symptomatic sustained monomorphic VT (SMVT), including VT
terminated by an ICD, that recurs despite drug therapy or when drugs
are not tolerated or not desired;
2. for control of incessant SMVT or VT storm that is not due to a transient
reversible cause;
Indications for Catheter Ablation of VT in Patients with
structural heart disease (including prior MI, dilated
cardiomyopathy, ARVC/D)
Should be considered:
1. one or more episodes of SMVT despite therapy with one or more AADs
2. recurrent SMVT due to prior MI with LV ejection fraction >.0.30 and
expectation for 1 year of survival; ablation is an acceptable alternative to
amiodarone therapy
3. For haemodynamically tolerated SMVT due to prior MI with reasonably
preserved LV ejection fraction (>.0.35) even if AADs have not failed
There was consensus among the
task force members that catheter ablation
for VT should generally be considered early
in the treatment of patients with recurrent
VT.
Heart Rhythm. 2009;6(6):886-933.
Europace. 2009;11(6):771-817.
Preventive Therapy for VT: An Individualized
Approach to Selecting Therapy
Catheter Ablation
Drug Therapy
 Skilled operator required
 Easy to implement
 Procedure risks
 Amiodarone reduces VT
 Can reduce / prevent VT
without ongoing toxicities
but has toxicities
requring monitoring
- Sotalol less effective
 Potential ICD / drug
interactions
Catheter Ablation before Antiarrhythmic Drug
An Individualized Approach
Catheter Ablation
Favored
Drug Therapy
Favored
 Monomorphic VT
 Polymorphic VT
 Experienced Center
 Experienced center
Available
 Acceptable procedure
risk
Incessant or very frequent
VT
 Increased risk for
drug toxicities
Not available
 Increased procedure
risk
 Patient preference
Thank You
VT Ablation Should be Considered Early in
the Course of Patients with Spontaneous VT
 Episodes of VT causing shocks decrease
quality of life and may contribute to mortality
 Ablation risks are acceptable
– No increase in mortality in SMASH VT
 Consensus of the EHRA/HRS Scientific
Statement on Catheter Ablation of VT
SMASH VT
- depressed LV function with “first episode of VT/VF”
Reddy et al NEJM 2007
Ablation
Control
67
66
92%
81%
VF
20%
16%
VT
47%
52%
Syncope + EPS
17%
25%
Recent VT/VF with ICD
16%
8%
LVEF
0.31
0.33
Beta-bl
94%
98%
Age (yrs)
Male
Index arrhythmia
SCD-HeFT: Spontaneous VT predicts
Increased Risk of Death
Shock Type
Hazard Ratio
 1 appropriate vs. none
5.68 (3.97-8.12)
p <0.001
Risk of
Death
≈ 6 times
increase
 1 inappropriate vs. none
1.98 (1.29-3.05)
p =0.002
≈ 2 times
increase
Both shock types vs. none
11.27 (6.70-18.94)
p <0.001
≈ 11 times
increase
Patients who receive a shock for VT or VF
had a 1 year mortality > 20%
with a median time to death of 6 – 7 months
Poole J. N Eng J Med 2008;359:1009-1017
VT – an ICD is not enough?
 VT / VF are markers for increased mortality in
patients with ICDs
– After an ICD detects an episode of VT or VF 1
year mortality exceeds 20% with a median time
to death of < 7 months
SCD-HeFT Poole J et al. NEJM 2008;359:1009
 Implications:
– Ongoing ventricular remodeling?
– Myocardial ischemia?
– Hemodynamic deterioration
Scars and VT – the future
 Anatomic characterization of scars to predict VT risk
 Modification of scars to treat arrhythmias
– Pharmacologic therapies
– Ablation
– Biologic therapies
Antiarrhythmic
Proarrhythmic
Mortality After VT Ablation
 Data are largely from a severely ill population
– Prior MI
– Depressed LV function, frequent heart failure
 Mortality after ablation is consistent with:
– Severity of disease
– Recurrent VT is a marker for increased mortality
 A focus on safety remains appropriate
 Clinical trials are needed to clarify the impact of ablation
on mortality
Ablation Efficacy and Outcomes Vary with heart
disease – but there is limited data for comparison
Prevents All
VT
Reduces VT
recurrences
Prospective
multicenter
data with >
50 pts
Myocardial Infarct
49 – 84%
>70%
Yes
Dilated
Cardiomyopathy
32 – 64%
Often
No
Sarcoidosis
38 – 56%
In some pts
No
Tetralogy of Fallot
>70%
No
ARVC
25% - 84%
Often
No
HCM
Reported
Reported
No