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

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    Compared to ischemic cardiomyopathy, pts with nonischemic cardiomyopathy have smaller endocardial scar areas (often with a patchy distribution and preferential localization adjacent to the mitral valve) and fewer fractionated electrograms and isolated diastolic potentials However there appears to be more extensive epicardial scarring An epicardial origin is seen in > 25% of pts idiopathic nonischemic cardiomyopathy and < 10% in pts with remote MI and ARVC Potential scar related VT circuits Scar related VT - etiology Stevenson, WG et al Circulation 2007:2750-2760 Indications for ablation in the scar related VT pts    Pts with recurrent symptomatic VT not well controlled with drug therapy or failed drug therapy Pts with tachycardia cardiomyopathy Pts with recurrent ICD discharges Clinical considerations before VT ablation  Documented VT – stable or unstable    Ischemic vs nonischemic etiology – need for epicardial Pre-procedure assessment     12 lead ECG, ICD EGM LVEF, LV thrombus Artificial valves Scar imaging Tolerance for procedure       Sedation risks 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 MRI     Delayed enhance MRI Circ AE 2013 Zeppenfeld CT Echo Intracardiac echo 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 • V3-4 Q or qS –Apical site • V4-6 R – Basal site • Lead I - distinguish Left vs right • Narrow vs wide QRS • Notching of QRS 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         Widen QRS duration Broad pseudo delta wave> 34ms Broad RS complex Intrinsicoid deflection > 85 ms Maximum deflection index > 0.55 QS in I and aVL 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 • Endocardial – Retrograde aortic – Transeptal • Epicardial • Navigation systems • Remote magnetic - Stereotaxis • Advance mapping systems – – – – CARTO Navx Noncontact balloon Rhythmia 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 AP view Early activation Very late activation Double ventricular potentials noted Conclusion     Radiofrequency catheter ablation can be considered in patients with scar related ventricular tachycardia which is not suppressed by drugs or occurs frequently in patients with an ICD New technologies will further improve the results of VT ablation There is significant improvement in QOL and reduction in ICD therapy Whether mortality is improved needs to be proven Join APHRS Visit our new website at www.aphrs.org • • • Fresh design New functionality Exclusive contents ... Induce VT before ablation Further mapping and ablation strategy  Depends on type of inducible VT - Stable vs unstable VT/ VF Mapping of stable scar related VT  Mapping of substrate  Voltage mapping. .. cardiomyopathy and < 10% in pts with remote MI and ARVC Potential scar related VT circuits Scar related VT - etiology Stevenson, WG et al Circulation 2007:2750-2760 Indications for ablation in the scar related. .. 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,