HR-UK Meeting, Birmingham 2012

VT ablation .... When to do it?

John P. Bourke Consultant & Senior Lecturer in Cardiology

Academic Cardiology Unit Freeman Hospital

Putting the key elements of VT ablation together ...!

Are we even asking the right questions ..?

What are you trying to do for patients with VTAs ..? & How best to achieve it ..?

What are we trying to achieve by VT ablation..? ■ Terminate incessant VT..? ■ Reduce ICD shock frequency / Quality-of-life benefits...? ■ Reduce total arrhythmia episodes / reduce anti-arrhythmic medications..?

■ Avoid ICD implantation altogether / Abolish VT-substrate..? ■ Prolong survival / improve prognosis..?

If you haven’t decided beforehand what you were tying to achieve......

You will always be fudging your outcomes ..!?

VT aetiology & mechanism implications ..? Aetiology Structural Heart Ds

Conditions Post-infarction Cardiomyopathy (DCM/HCM/ARVC) Surgically scarred hearts (T-of-F) Cardiac sarcoidosis

Genetically determined ‘Primary electrical Ds’

Long-QT syndromes Short-QT syndrome Brugada syndrome Catecholaminergic polymorphic VT ‘Idiopathic VF’

‘Normal Heart’ VT

Right / left ventricular outflow tract VT Sinus of Valsalva VTs Mitral annular VT Fascicular VT (‘idiopathic’ LV-VT)

Heart Failure & VTAs

Failing LV of any aetiology ....

Mechanism / Nature Re-entry Sustained MMVT

Triggered automatic Loss or gain of function in Na+, K+, Ca2+ channels Ventricular fibrillation

Cyclic-AMP mediated triggered activity

Macro Re-entry Multiple mechanisms

Idiopathic Outflow Tract VTs Mechanism = Cyclic-AMP mediated triggered activity

Normal Heart VTs (RVOT-, LVOT-, Mitral annular- & ILV-VT)

If symptoms justify therapy ...

patients should be offered ablation ...

Cardiac ion channels, the Action potential & ‘Channelopathies’

Scar-related VT Mechanism = Re-entry

Post MI

DCM

ARVC

Where are critical parts of the circuits likely to be ...? ■ Post-infarction VT = endocardial usually

■

Cardiomyopathies - Dilated = endo +/- epi-cardial - Hypertrophic = intra-mural

- Cardiac sarcoidosis & = epicardial ARVC

Imaging the substrate beforehand ...

Multiple VTA-mechanisms in Heart Failure Pathological changes

Electrical changes promoting VT/VF

Arrhythmia mechanisms

Zipes & Jalife 5th Eds, Chapter 66, pg: 708

Forget the ‘one-man band’ approach ...!

VT-management is a team event ...!

- Electrophysiologist & team - ‘Intensivist’ / Anaesthetist & team - Heart failure / transplant team - PCI Cardiologist & team - Echo / CT / MR-imagers - Clinical Psychologist - Cardiac surgeon & team - Palliative care physician & team

Managing ‘troublesome’ VTAs successfully is a team effort ... Because ablation may not be appropriate or ‘enough’ ..! ■ Patient assessment – VT aetiology (underlying diagnosis) – VT context (incessant / ‘shock storm’ / high VT frequency / etc) – Pre-morbid LV-function (good, bad, very bad, ‘terminal’)

■ Does the patient need stabilization - Sedation / Ventilation/ ITU management / Anti-failure Rx or IABP-support

Is this primarily an arrhythmia problem or something else ..? ■ The ablation procedure - Access [vein and artery; endo- or endo- & epi-cardial; surgically-assisted access (hybrid)] - GA or sedation - Imaging pre- & intra-operatively(?)

■ The ablation ‘aftermath’ - ‘Joy & happiness unbounded ...’ - Repeat ablation(s) / ‘Flare-up’ of VTAs / Psychological recovery / Palliative care

Have you planned for procedural difficulties ...? ■ Arterial access to LV ..? - peripheral vascular disease, aortic aneurysms; low-output state

■ Venous access to LV ..? - enlarged RA and LA; difficult trans-septal; catheter reach to LV

■

Elderly with comorbidities ..? - tortuous iliac vessels; unfolded aortic arch; sclerotic aortic valve; sigmoid septum; CRF ..

■ Previous cardiac surgery ..? - coronary graft origins; little / no percutaneous epicardial access; valve replacements

■ Mapping & Ablation ..? - In SR, RV or Bi-ventricular paced rhythm (does it matter..?) - Large area of ablation required; Defining the core target; - Managing recurring ‘pulseless rhythms’; Procedure duration; Elements of EMD ...

What are your mapping strategies ..?

How extensive your ablation? Endocardial

No plan, no access, no map, no outcome audit ...

You might still have the occasional success ..?

But you’re just another part of the problem...!?

VT-Ablation .... What evidence so far..? Study

Design

N

End Point

Acute Success

Outcome

Thermo-cool VT ablation Multicentre trial (1)

Incessant VT(+) All VTs targeted CARTO-guided

231

Freedom from VT recurrence

All VT abolished 49%

No recurrence 53%

SMASH VT Trial

ICD + ablation vs ICD Incessant VT(-) Substrate ablation

Survival free from appropriate ICD Rx

NA

ICD + Ablation better p = 0.007 (all Rx) p = 0.003 (shocks) (at 22 + 5 months)

VT-recurrences

51 (81%)

Recurrences 49%

RCT - Prophylactic VT-ablation to prevent ICD Rx (2)

EURO-VT Study (multi-centre safety & efficacy study) (3)

VTACH Study (4) (Prospective open RCT of ICD alone vs ICD after ablation)

(post-MI)

128 (post-MI 20 prevention )

Incessant VT (+) ‘Pulseless’ VT (22%) CARTO-guided & irrigation tipped RF

(post-MI)

Stable VT LVEF < 50%

107

Analysis by EF > or < 30%

63

(post-MI) ICD + Ablation = 52 ICD alone = 55

(at six months)

(12 + 3 months)

-Time to VT recurrence - Estimated freedom from VT/VF at 2 yrs

---

18.6 vs 5.9 mths (p = 0.045)

47% vs 29%

(1) Stevenson WG, et al - Circulation 2008, 118:2773-82 (2) Reddy V, et al - N Engl J Med 2007, 357:2657-65 (3) Tanner H, et al - JCE 2010, 21:47-53. (4) Kuch KH, et al - Lancet 2010, 375:31-40

Acute versus longer-term success ..? Achieving durable & electrically intact linear lesions in 3D !!! Cooled RF or large electrode tips = larger / deeper lesions

Different ablation energy sources ?

Shock prevention in prognosis..? ■ Shock burden & increased mortality N=425; Seattle Heart Failure Model standardised; F-up: 41months Larsen GK, et al. Heart Rhythm 2011,8:1881-6

‘Shock-days’

HR

CI

p

1-5

1.30

0.88-1.94

= 0.19

6-10

2.22

1.21-4.08

< 0.01

> 10

3.66

1.86-7.19

< 0.01

Any shock vs No shock: 1.55 (CI:1.07-2.23) p = 0.02 ATP therapy – No effect on prognosis

■ Appropriate therapy but not inappropriate shocks predict survival in ICD-patients Dichtl W, et al. Clin Cardiol 2011, 34:433-6

What is your goal in VT ablation..? ■ Terminate incessant VT..?

√√

■ Reduce ICD shock frequency / Quality-of-life benefits...? √√ ■ Reduce total arrhythmia episodes / reduce anti-arrhythmic medications..? √ ■ Avoid ICD implantation altogether / Abolish VT-substrate..? √ & X

■ Prolong survival / improve prognosis..?X &??

Why has progress been so slow in VT ablation ...? ■ The ICD is seen as an end-point in management ..? ■ We don’t think VT-ablation really works ..? ■ Many ICD implanters are now ‘divorced’ from ablation teams ..? ■ It’s too complex & competing time-pressures ..? ■ Outcomes are too unpredictable ..? ■ Operator inexperience ..?

■ Inappropriate emphasis on an arrhythmia solution ..?

Experiences tend to reinforce our pre-conceptions ..! If you only undertake VT ablations when patients ...

..... are ‘in extremis but won’t die’ You will probably conclude

.... that it’s a waste of time & very stressful & I’m useless at it !

If you only undertake VT ablations when patients ...

..... can sustain VT sufficient to allow activation mapping You will probably conclude

.... that it always works, it’s a shame there are so few of them & you’re great!

A VT-ablation service needs to be prepared to offer ablation to all who are likely to benefit ...

Are we auditing our VT-ablation procedures ...? ■ What was my plan before I started ..? ■ How did my procedural plan work ‘on the day’ ..? ■ Did I achieve what I set out to do ..?

■ What was the outcome acutely & longer-term ..? ■ Were there any complications ..? ■ What lessons can I take forward to the next case ..? ■ If we’re that good or bad .. are case-selection criteria appropriate ..?

VT is not a unifying diagnosis ..! Can be the primary & only diagnosis Another aspect of a seriously damaged heart A pre-terminal sign …

One size really doesn’t fit all... Start with a plan ... Which may include ablation

If VT is really the problem, ablation should be offered much more routinely

Catheter ablation of VT is a team event not a one man show ..!!