Takashi Nitta
Cardiovascular Surgery, Nippon Medical SchoolTokyo, JAPAN
Map-Guided Ablation of Non-ischemic VT
Declaration of Interestnothing
Catheter Ablation of Non-ischemic VT
4 Tokuda M, Stevenson WG, et al. Circ Arrhythm Electrophysiol. 2012;5:992-1000
DCM, 119, 53%
Valvular, 34, 15%
ARVC, 37, 16%
Congenital, 16, 7%
Sarcoidosis, 13, 6% HCM, 7, 3%
Surgery for Non-ischemic VT
5
Number of patients (2000-2017) 34
Age (range, median; year) 1-79, 59
Gender (male : female) 27:7
LVEF (%) 49±11
Indication for Surgery
Refractory VT 34 (100%)
Incessant VT/ICD shocks (storm) 11 (32%)
Cardiac Tumor 6
Heart Failure 2
HCM, 16, 47%Other CM, 8, 23%
Cardiac Tumor, 6, 18%
Post-OP for CHD, 2, 6%
ARVC, 1, 3%Sarcoidosis, 1, 3%
Underlying Heart Disease (n=34)
Preoperative Therapies
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Preoperative TherapiesAnti-arrhythmic Drugs 34 (100%)
Number of drugs (range, median) 1-8, 3Defibrillators 17 (52%)
ICD/CRTD/WCD 14/2/1RFCA (endo- or epicardial) 28 (85%)
Number of sessions (range, median) 1-8, 2Epicardial ablation 9 (27%)
What is difficult in Catheter Ablation of VT in HCM patients?
1. Epicardial or intramural focus or substrate
2. Thick myocardium that hampers transmural ablation
3. Epicardial fat that diminishes ablation energy conducting to myocardium
4. A focus adjacent to or beneath the major coronary vessels
Surgical Strategy and Procedures
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Map-guided procedure in all (N=34)Preoperative endo- and epicardial mappingIntraoperative mapping (N=30, 88%)
Surgical Procedure1. HCM (N=16), Other cardiomyopathy (N=8)
Transmural cryothermia at VT focus or substrate
2. Cardiac tumor (N=6) Resection of tumor with cryoablation (N=4) Encircling cryo-isolation of tumor (N=2)
Intraoperative Electro-anatomical Mapping (CARTO)
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Location pad
Effective magnetic FieldCatheter electrode
Nitta T, et al. Ann Thorac Surg 2012;93:1285-8.
LV Thickness at VT focus in HCM Patients
10TTE (short axis view of LV base)
15.2±1.5 mm(N=7)
0
5
10
15
20
RF Cryothermia(Nitrous oxide)
Epi and Endocardial Bi-directional Ablation Required
VT Focus
How to Create a Transmural Lesion
LV Apex Cryoprobes
Simultaneous Epi- and Endocardial Cryoablation through a Ventriculotomy
Endocardial Cryoablation through an Aortotomy to avoid a ventriculotomy
Asc. Ao
Cryoprobe
LV Summit VT
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Originates from high lateral LV bounded by LAD, LCX, and AIV
Epicardial ablation is hampered by1. Major coronary vessels
2. Thick LV mass
3. Thick epicardial fat
AIV: Anterior Interventricular Vein
A 31-year-old man with palpitation Clinical Course
• First episode of palpitation developed in 2009.1 at the age of 24 and underwent endocardial catheter ablation of VT.
• In 2016.4, the VT recurred and he underwent 2nd session of endocardial ablation with partial success. Sustained VT was suppressed by oral beta-blocker and amiodarone, but PVC bigeminy continued for all day.
No particular family history or past history Normal Echocardiogram and normal CAG
Sustained VT and PVC Bigeminy
Inf. Axis + RBBB MorphologyHR =220 bpm
CAG and Pace Map from Distal CSPVC
Distal CS Pacing
RAO
LMTLAD
LCX
CS
AIV
AIV: Anterior Interventricular Vein
Intra-OP Epicardial Activation Maps
RAO LAO
Earliest activation site
1. Taping LAD and LCX proximally
2. Removal of fat over VT origin using ultrasonic scalpel
3. Cryothermia directly applied at the VT origin for 2 mins at -60℃
Dissection of Coronary Arteries and Epicardial Fat followed by Epicardial Cryoablation
1. LV endocardial cryoablation across the aortic valve
2. The ablation site was directed by the needle punctured at the epicardial earliest activation site.
Cryothermia at the LV Endocardium just underneath the Epicardial Earliest Activation Site
LADLCX
AIV
RCCLCC
What is Essential in Surgical Ablation of VT in HCM Patient?
1. Three-dimensional localization of focus or substrate
2. Transmural ablation
3. Avoidance of injuries to the major coronary vessels
Case 2 (HCM VT)
74-year-old male patient
Undergone 2 sessions of endocardial RFCA and implanted with an ICD for refractory VT associated with HCM.
Chemical ablation with intra-coronary alcohol was performed for incessant VT with frequent ICD shocks (VT storm).
Referred for surgical treatment of recurrent VT.
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Two morphologies of VT
III
aVF
V5
III
V2
aVRaVL
V4
V6
V1
V3
TCL:400msecLBBB + inferior axis
VT #1 VT #2
TCL:320msecRBBB + inferior axis21
Pre-OP Epicardial Voltage MappingLAO cranial LPO cranial
PA
RVOT
Ao
LADMA
LCXOM
Ao
22
VT #1 VT #2
Pre-OP Epicardial Activation Mapping
LAD
RVOT
PA
Ao
LCX
MA
23
LAD
OM
VT #1 VT #2
Intra-OP Epicardial Activation Mapping
LADRVOT
PA
Ao LPO
LAD
LCX
LAAOM
LCA
Epicardial cryoablation after removing fat tissue using the Harmonic scalpel
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Cryoprobe
LV Apex
LAD
LCX
LAD
LCXPA
LV Summit VT: Location of Focus
26
⑧⑦
⑥
②③
③
④
④⑤ ①
Survival after Surgery for Non-ischemic VT (N=34)
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Months after Surgery
0
0.2
0.4
0.6
0.8
1
0 12 24 36 48 60 72 84 96 108120132144156168180
No operative deathOne late death (CHF) 16 months post-OP
Freedom from Clinical and Non-clinical VT
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0
0.2
0.4
0.6
0.8
1
0 1825 3650Days after Surgery
0
0.2
0.4
0.6
0.8
1
0 30 60 90
Clinical VT in 2 Non-clinical VT in 4
Summary1. Refractory VTs associated with cardiomyopathy, cardiac
tumors, or others are indicated for surgery and the results are satisfactory.
2. Pre- and intra-operative mapping is essential for precise and three-dimensional localization of VT substrate and successful surgical ablation.
3. Transmural ablation with epi- and endocardial cryothermia is crucial to ablate intramural substrate.
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