Identification and Ablation of Epicardial VT Yi-Gang Li, MD Xinhua Hospital, Shanghai Jiaotong University

When to go epicardially Identification of Epicardial VT When to go epicardially Present clinical data Previous history Surface ECG during VT Mapping data Cardiac Image

When to go epicardially ? Present clinical data Echocardiography: -- LV thrombus if their anticoagulation can be safely interrupted for the procedure 1 Daniels DV, et al. Circulation 2006

Frequency of Epicardial Origin Presence of SHD Chagas’s disease - 36% of a series of 138 VT pts1 Non-ischemic SHD - 25%-45%1,2,3 Ischemic SHD - 1/3 P subepicardial reentry circuits4 -- Posterolateral MI 4,5 -- Aneurism related VT 1 Sosa E, et al. JCE 2005. 2 Hsia HH, et al. Circulation 2003, 3 Soejima, et al. JACC, 2004. 4 Svenson, et al. JACC 1990. 5 Berruezo et al. Circulation 2004.

Frequency of Epicardial Origin Presence of SHD AVRT – 5-10%? Other (“Idiopathic” LV aneurysm, sarcoid, noncompaction) - Idiopathic LVOTVT(12%-30%) - LV epicardium (1/3) – perivascular1 Absence of SHD 1 Daniels DV, et al. Circulation 2006

When to go epicardially Previous history Previous failed VT ablation attempt 1 - Select truly epicardial VTs Suc. rate 150 VT ablation Pts Incessant VT: 19 Pts(12.7%) Endo abl. 10 Pts (53%) Epi abl. 8 Pts (42%) Suc. Rate: 95% 1 Brugada et al, JACC 2003;41:2036–2043 ESC 2008

Identification of Epicardial VT Mapping data in presence of SHD Mapping data inability to identify the reentry circuit isthmus on the endocardium by entrainment mapping Identification of a focal point of earliest endocardial activation, entrainment indicates an exit or outer loop site, but abl. fails to interrupt VT

Identification of Epicardial VT Mapping data in absence of SHD (LVOT?) Mapping data within CS and accessible LV branches suggest an epicardial VT circuit or focus

ECG Recognition of the Epicardial Origin of VT Analysis of ECG pattern in (A): 14 successful epicardial VT ablation after failed endocardial approach, (B): 27 successful endocardial VT ablation, (C): 28 additional VTs that could not be ablated from the endocardium Four distinct intervals of ventricular activation were measured: the pseudo-delta wave: from the earliest ventricular activation to the earliest fast deflection in any precordial lead the intrinsicoid deflection time: interval measured from the earliest ventricular activation to the peak of the R wave in V2. the shortest RS complex: interval measured from the earliest ventricular activation to the nadir of the first S wave in any precordial lead. (4) the QRS complex: earliest ventricular activation to the offset of QRS in the precordial leads. Berruezo A. Circ 2004;109:1842

Groups A & C (unsuccessful endocardial ablation) showed longer intrinsicoid deflection in V2, slurred initial part of QRS (pseudo  wave) vs Group B (endocardially ablated VT)

ECG Characteristics of VTs (msec) Group A (n=14) Group B (n=27) Group C (n=28) Pseudo-delta wave 43±9 16±9 42±9 Intrinsicoid deflection 97±21 65±15 98±14 Shortest RS interval 149±39 91±20 132±30 QRS complex 217±24 174±37 195±27 Group C vs B, group A vs B, P<0.05. Group A vs C, P=NS VTs from epicardial origin (groups A & C) showed a significantly longer pseudo-delta wave, intrinsicoid deflection, and RS complex duration compared to VT with endocardial origin (group B). Identification of Epicardial Origin of VT Sensitivity Specificity Pseudo-delta wave ≥ 34 ms 83% 95% intrinsicoid deflection ≥ 85 ms 87% 90% RS complex duration ≥ 121 ms 76% 85% Berruezo A. Circ 2004;109:1842

ECG Recognition of the Epicardial Origin of VT PDI=A/QRS Hachiya H, et al. Circulation 2010;74:256-261

ECG Recognition of the Epicardial Origin of VT Hachiya H, et al. Circulation 2010;74:256-261

Hachiya H, et al. Circulation 2010;74:256-261

ECG Recognition of the Epicardial Origin of VT Hachiya H, et al. Circulation 2010;74:256-261

Valles E, et al. Circulation 2010;3:63-71 MDI= IDT(Shortest)/QRSd Valles E, et al. Circulation 2010;3:63-71

Epi vs End. Pace maps Valles E, et al. Circulation 2010;3:63-71

Valles E, et al. Circulation 2010;3:63-71

Epi vs End. VT Morphology Valles E, et al. Circulation 2010;3:63-71

11 Pts, 21 VTs from basal superior or lateral origin ECG Recognition of the Epicardial Origin of VT 11 Pts, 21 VTs from basal superior or lateral origin Valles E, et al. Circulation 2010;3:63-71

Ablation of Epicardial VT

Ablation of Epicardial VT Sosa E, Scanavacca M. JCE 2005;16:449–452

Mapping of Epicardial VT Mapping of the epicardium can be performed using fluoroscopy and/or CARTO system. Areas of infarction or scar have low amplitude electrograms similar to findings during endocardial mapping. Epicardial fat may create low amplitude regions. - Inability to capture during epicardial pacing - High pacing tresholds: Epicardial fat; difficult catheter stability

Mapping and Ablation of Epicardial VT Mapping using conventional or Navi-Star Catheter (Biosense-Webster) Internally or externally irrigated catheter can be used for RF ablation to avoid high impedance Power limit of 50 W with temperature limit of 45ºC, infusion rate of 17 ml/min and duration of 110 sec Aspiration of pericardial fluid after 5 RF applications to prevent fluid accumulation

Ablation of Epicardial VT Pts [n] Acute suc.rate [%] Late suc. Rate complication Sosa 1 14 39 100 Schweikert ² 30 71 97 Brugada ³ 10 80 90 Soejima 4 28 73 54 Sosa: 14 ICM; FU 14 months. Schweikert: 6 ICM, 3 DCM, 15 NH. FU success auch wenn PVC weniger. Brugada: 8 ICM, 1 DCM, 1 ILVT. FU 18 months. 1 J Am Coll Cardiol 2000;35:1442–9; 2 Circulation 2003;108:1329-1335; 3 J Am Coll Cardiol 2003;41:2036–43, 4 J Am Coll Cardiol 2004;43:1834–42

QRS=180 ms CL=585 ms

Ablation of Epicardial VT

Complications Phrenic nerve injury Pacing shoud be performed before energy delivery to indenify phrenic nerve capture, indicating where ablation might cause diaphragmatic paralysis. phrenic nerve injury can be avoided by: - interposing a sheath,baloon, or even air in the pericardium between the abl. Site and the nerve.

Complications Coronary nerve injury - Coronary angiography before RF ablation - Requiring a minimum of 4 mm between epicardial coronary vessels and the ablation catheter. - the catheter is not touching the vessel at any point of cardiac cycle Pericartitis - mild, limited duration, often responds well to anti-inflammatory medication

Problems in epicardial ablation Epicardial mapping will not prevent all VT abl. failures. - Tachycardia circuits can originate from deep within the ventricular septum/myocardium, may require transcoronary ethanol ablation, or irrigated needle catheters. Ablaion can be limmited by - epicardial fat, - proximity to coronary arteries and other other stuctures

Conclusion Epicardial VT can be identify by previous history, present clinical data and surface ECG Mapping data and cardiac Image facilitate VT ablation Epicardial VT is rare, but it can be either focal or macroreentry Epicardial catheter techniques expand the options for investigating and treating VT

Thank You！