Catheter ablation of scar related VT significant challenges for operators and role of 3d electroanatomic mapping

Catheter ablation of recurrent scar-related ventricular tachycardia using electroanatomical mapping and irrigated ablation technology: results of the prospective multicenter Euro-VT-stud

Catheter Ablation of scar related VT: significant challenges for

operators and role of 3D electroanatomic mapping

Dr TEO Wee Siong

MBBS (S’pore), M Med (Int Med), FAMS, MRCP (UK), FRCP (Edin), FACC, FHRS

President, APHRS

Mt Elizabeth Hospital, Singapore

Senior Advisor, Electrophysiology & Pacing

Department of Cardiology National Heart Centre, Singapore

Size and site of scar

a patchy distribution and preferential localization adjacent to

the mitral valve) and fewer fractionated electrograms and

isolated diastolic potentials

nonischemic cardiomyopathy and < 10% in pts with remote

MI and ARVC

Potential scar related VT circuits

Stevenson, WG et al Circulation 2007:2750-2760

Scar related VT - etiology

Indications for ablation in the scar related VT pts

with drug therapy or failed drug therapy

Clinical considerations before VT ablation

 Documented VT – stable or unstable

 12 lead ECG, ICD EGM

 Ischemic vs nonischemic etiology – need for epicardial

 Potential for hemodynamic instability

 Risk of fluid overload and heart faioure

 Potential ischemia

 Potential for incessant VT

 Need for hemodynamic support

Identification of scar prior to EP study

ECG localization

• RBBB vs LBBB VT

– RBBB suggests LV free wall

– LBBB suggest RV or septum

• Superior vs Inferior axis

– II, III and AVF negative suggest inferior site

• Precordial transition

– Apex actually is anteriorly located in the

coronal section of the heart and is thus at V4-5

ECG suggesting Epicardial origin

 VTs that originate in the subepicardium generally produces a longer

QRS duration and slower QRS upstrokes in the precordial leads

compared to those with an endocardial exit

 May be less reliable in pts with heart disease

Berruezo A, Mont L, Nava S et al

Electrocardiiograqphic recognition of the epicardial origin of ventricular tachycardias

Circulation 2004;109:1842-1847

Mapping technique and systems

• Remote magnetic - Stereotaxis

• Advance mapping systems

– CARTO

– Navx

– Noncontact balloon

– Rhythmia

Catheter ablation of recurrent scar-related ventricular tachycardia using electroanatomical mapping and irrigated ablation technology: results of the prospective multicenter Euro-VT-study

Tanner H et al J Cardiovasc Electrophysiol 2010;21(1):47-53

Techniques for VT scar Mapping and ablation

• Begin by Substrate mapping during sinus rhythm

– Voltage and scar mapping, electrical unexcitable scar – Electrogram mapping

– Pre-systolic, mid-diastolic, late potentials – Low amplitude fragmented potentials, continuous electrical activity

• Induce VT

• Stable or unstable

Techniques for VT scar Mapping and ablation

Stable VT

 Activation mapping

– Endocardial localization for earliest activation

 Electrogram mapping

– Pre-systolic, mid-diastolic, fragmented potentials,

continuous electrical activity

 Entrainment mapping

 Pace mapping

Unstable VT

 Pace map for possible isthmus

 Map for Late potentials

Substrate Mapping

channels

Mapping of substrate – during sinus rhythm or pacing

Identification of scars

Voltage defined scar

• defined by voltage mapping

– Scar < 0.5 mv

– Border zone 0.5-1.5

– Normal > 1.5

Electrical unexcitable scar

• defined by pacing threshold

• Unipolar pace from standard 4 mm tip ablation catheter

threshold > 10 mA (pulse width 2 ms)

Late abnormal ventricular activation

(LAVA) mapping and ablation

suggested areas of scar

Late potentials

Induce VT before ablation

Further mapping and ablation strategy

Mapping of stable scar related VT

 Mapping of substrate

 Voltage mapping

 looking for scars, channels/isthmus

 Electrogram mapping

 low amplitude, fragmented, diastolic, double potentials, late potentials

 Mapping of VT circuit substrate

Map to identify exit, entry, central isthmus/channel, inner loop, outer loop, bystander sites by:

 Activation mapping

 Entrainment mapping

 Pacemapping

EGM mapping during stable VT

large portion of the CL of the tachycardia

Electrogram mapping in sinus

VT activation mapping

 Electroanatomical map with CARTO

 ESI Balloon noncontact mapping

 Contact mapping with Navx

Entrainment Mapping

Entrainment mapping during VT

Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review Wissner E, Stevenson WG, Kuck KH Eur HJ 2012;33:1440-50

Wilber DJ Catheter ablation of ventricular tachycardia: Two decades of progress Heart Rhythm 2008;5:S59-S63

Entrainment mapping

Pace-mapping of stable VT

Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review Wissner E, Stevenson WG, Kuck KH Eur HJ 2012;33:1440-50

Pace mapping

QRS morphologies and axis

Ablation strategies for scar related VT

Ablation of Stable scar related VT

within critical isthmus for stable reentrant VT

of mapped VT circuit

voltage mapping

ablation – elimination of LAVAs

Target sites for Stable VT ablation

 Candidate sites for ablation

 Scar border zone

 Adjacent to unexcitable scar

 QRS morphology – fusion or concealed fusion

 PPI < tachy CL + 30 ms (at the ablation catheter)

Ablation of Scar related unstable VT -

Ablation techniques for substrate ablation

Approach to Ablation of Unmappable Ventricular Arrhythmias Juan Fernández-Armenta, Diego Penela, Juan Acosta, David Andreu, Antonio Berruezo, Card Electrophysiol Clin 7 (2015) 527–537

Substrate ablation – Ablation along

borderzone of scar

Electrogram potential guided substrate

modification abaltion

electrograms separated by > 50 ms during sinus

rhythm or RV paing

noninducibility of clinically documented VT

Electrogram guided substrate based VT ablation

Scar Homogenization

Scar dechanneling

Approach to Ablation of Unmappable Ventricular Arrhythmias

Juan Fernández-Armenta, Diego Penela, Juan Acosta, David Andreu, Antonio Berruezo, Card Electrophysiol Clin 7 (2015) 527–537

Endpoints of substrate ablation

demonstrated by pacing

Conversion to electrical

unexcitable scar

Catheter ablation of recurrent scar-related ventricular tachycardia using electroanatomical mapping and irrigated ablation technology: results of the prospective multicenter Euro-VT-study

Tanner H et al J Cardiovasc Electrophysiol 2010;21(1):47-53

End-points and outcomes

Recent advances in ablation of ventricular tachycardia associated with structural heart disease: overcoming the challenges of functional and fixed barriers Riccardo Proietti, Jean-Francois Roux, and Vidal Essebag Curr Opin Cardiol 2016, 31:64–71

FT case

• Fallot’s Tetralogy repair in 1969

• Recurrent VT which first started in 1998 He had ICD inserted on 11 July 1998 He had remained relatively well while on Sotalol 80 mg bd

• Had recurrent VT requiring shocks and hence underwent an electrophysiological study and catheter ablation in 2002 Remained relatively well till 2006 when he had rapid VT which was appropriately detected by the device and treated

• Valvuloplasty for pulmonary infundibular stenosis

• Replacement of ICD in January 2010

Incessant VT (VT #1)

VT #1 – Voltage map – AP view

VT #1 – activation map with ablation points noted

Diastolic potentials

Diastolic potential

Concealed entrainment

Termination of VT #1 by RF #2

Induction of VT #2

Concealed entrainment VT #2

VT #2

Termination of VT #2

Spike potentials seen in SR before complete ablation and block

Sinus map showing block across linear ablation line from scar to TV

Early activation

Very late activation

Double ventricular potentials noted

AP view

Conclusion

patients with scar related ventricular tachycardia which

is not suppressed by drugs or occurs frequently in

patients with an ICD

VT ablation

reduction in ICD therapy