Map-Guided Ablation of Non-ischemic VT. Takashi Nitta Cardiovascular Surgery, Nippon Medical School Tokyo, JAPAN

Transcription

1 Map-Guided Ablation of Non-ischemic VT Takashi Nitta Cardiovascular Surgery, Nippon Medical School Tokyo, JAPAN

2 nothing Declaration of Interest

3 Catheter Ablation of Non-ischemic VT Sarcoidosis, 13, 6% HCM, 7, 3% Congenital, 16, 7% ARVC, 37, 16% DCM, 119, 53% Valvular, 34, 15% 4 Tokuda M, Stevenson WG, et al. Circ Arrhythm Electrophysiol. 2012;5:

4 Surgery for Non-ischemic VT Underlying Heart Disease (n=34) ARVC, 1, 3% Post-OP for CHD, Sarcoidosis, 1, 3% 2, 6% Cardiac Tumor, 6, 18% Other CM, 8, 23% HCM, 16, 47% Number of patients ( ) 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 5

5 Preoperative Therapies Preoperative Therapies Anti-arrhythmic Drugs 34 (100%) Number of drugs (range, median) 1-8, 3 Defibrillators 17 (52%) ICD/CRTD/WCD 14/2/1 RFCA (endo- or epicardial) 28 (85%) Number of sessions (range, median) 1-8, 2 Epicardial ablation 9 (27%) 6

6 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

7 Surgical Strategy and Procedures Map-guided procedure in all (N=34) Preoperative endo- and epicardial mapping Intraoperative mapping (N=30, 88%) Surgical Procedure 1. HCM (N=16), Other cardiomyopathy (N=8) Transmural cryothermia at VT focus or substrate 8 2. Cardiac tumor (N=6) Resection of tumor with cryoablation (N=4) Encircling cryo-isolation of tumor (N=2)

8 Intraoperative Electro-anatomical Mapping (CARTO) Effective magnetic Field Catheter electrode Location pad 9 Nitta T, et al. Ann Thorac Surg 2012;93:

9 LV Thickness at VT focus in HCM Patients Epi and Endocardial Bi-directional Ablation Required 20 VT Focus ±1.5 mm (N=7) TTE (short axis view of LV base) 0 RF Cryothermia (Nitrous oxide)

10 How to Create a Transmural Lesion Asc. Ao LV Apex Cryoprobes Cryoprobe Simultaneous Epi- and Endocardial Cryoablation through a Ventriculotomy Endocardial Cryoablation through an Aortotomy to avoid a ventriculotomy

11 LV Summit VT Originates from high lateral LV bounded by LAD, LCX, and AIV Epicardial ablation is hampered by 1. Major coronary vessels 2. Thick LV mass 3. Thick epicardial fat 12 AIV: Anterior Interventricular Vein

12 A 31-year-old man with palpitation Clinical Course First episode of palpitation developed in at the age of 24 and underwent endocardial catheter ablation of VT. In , the VT recurred and he underwent 2 nd 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

13 Sustained VT and PVC Bigeminy HR =220 bpm Inf. Axis + RBBB Morphology

14 RAO CAG and Pace Map from Distal CS Distal CS Pacing PVC LMT LCX AIV LAD CS AIV: Anterior Interventricular Vein

15 Intra-OP Epicardial Activation Maps RAO LAO Earliest activation site

16 Dissection of Coronary Arteries and Epicardial Fat followed by Epicardial Cryoablation 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

17 Cryothermia at the LV Endocardium just underneath the Epicardial Earliest Activation Site LCX AIV LAD LCC RCC 1. LV endocardial cryoablation across the aortic valve 2. The ablation site was directed by the needle punctured at the epicardial earliest activation site.

18 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

19 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. 20

20 21 Two morphologies of VT VT #1 VT #2 TCL:400msec LBBB + inferior axis I II III avr avl avf V1 V2 V3 V4 V5 V6 TCL:320msec RBBB + inferior axis

21 Pre-OP Epicardial Voltage Mapping LAO cranial LPO cranial Ao Ao PA RVOT LAD OM LCX MA 22

22 Pre-OP Epicardial Activation Mapping VT #1 VT #2 Ao PA RVOT LAD MA LAD OM LCX 23

23 Intra-OP Epicardial Activation Mapping VT #1 VT #2 Ao LPO PA RVOT LAD LAD LCA LAA OM LCX

24 Epicardial cryoablation after removing fat tissue using the Harmonic scalpel LCX PA LCX LAD Cryoprobe LAD 25 LV Apex

25 LV Summit VT: Location of Focus

26 Survival after Surgery for Non-ischemic VT (N=34) No operative death One late death (CHF) 16 months post-op Months after Surgery

27 Freedom from Clinical and Non-clinical VT Clinical VT in 2 Non-clinical VT in Days after Surgery

28 Summary 1. 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. 29