Background:We conducted a multicenter study to evaluate mapping and ablation of ventricular fibrillation (VF) substrates or VF triggers in early repolarization syndromes (ERS) or J-wave syndrome (JWS). Methods: We studied 52 ERS patients (4 females; median age, 35 years) with recurrent VF episodes. Body-surface electrocardiographic imaging (ECGI) along with endocardial and epicardial electroanatomic mapping of both ventricles were performed during sinus rhythm and VF for localization of triggers, substrates, and drivers. Ablations were performed on:1) VF substrates defined as areas that had late depolarization abnormalities characterized by low voltage fractionated late potentials and 2) VF triggers. Results: Fifty-one of the 52 patients had detailed mapping which revealed two phenotypes: 1) Group 1 had late depolarization abnormalities predominantly at the right ventricular (RV) epicardium (n=40); and 2) Group 2 had no depolarization abnormalities (n=11). Group 1 can be subcategorized into 2 groups: Group 1A included 33 ERS patients with Brugada ECG pattern, and Group 1B included 7 ERS patients without Brugada ECG pattern. Late depolarization areas co-localize with VF driver areas. The anterior RV outflow tract (RVOT)/RV epicardium and the RV inferior epicardium are the major substrate sites for Group 1. The Purkinje network is the leading underlying VF trigger in Group 2 that had no substrates. Ablations were performed in 43 patients: 33 and 5 Group 1 patients had only VF substrate ablation and VF substrates plus VF trigger, respectively (mean 1.4 ± 0.6 sessions); 5 Group 2 patients and 1 without group classification had only Purkinje VF trigger ablation (mean 1.2 ± 0.4 sessions). Ablations were successful in reducing VF recurrences (p<0.0001). After follow-up of 31 ± 26 months, 39 (91%) had no VF recurrences. Conclusions: There are 2 phenotypes of ERS/JWS: 1) one with late depolarization abnormality as the underlying mechanism of high amplitude J-wave elevation that predominantly resides in the RVOT and RV inferolateral epicardium, serving as an excellent target for ablation; and 2) the other with pure ERS devoid of VF substrates, but with VF triggers that are associated with Purkinje sites. Ablation is effective in treating symptomatic ERS/JWS patients with frequent VF episodes. Non-Standard Abbreviations and AcronymsVF = Ventricular fibrillation. ERS = Early repolarization syndrome. BrS = Brugada syndrome JWS = J-wave syndrome RVOT = Right ventricular outflow tract RV = Right ventricle

BackgroundLocalizing the origin of outflow tract ventricular tachycardias (OTVT) is hindered by lack of accuracy of electrocardiographic (ECG) algorithms and infrequent spontaneous premature ventricular complexes (PVCs) during electrophysiological studies.ObjectivesTo prospectively assess the performance of noninvasive electrocardiographic mapping (ECM) in the pre-/periprocedural localization of OTVT origin to guide ablation and to compare the accuracy of ECM with that of published ECG algorithms.MethodsPatients with symptomatic OTVT/PVCs undergoing clinically indicated ablation were recruited. The OTVT/PVC origin was mapped preprocedurally by using ECM, and 3 published ECG algorithms were applied to the 12-lead ECG by 3 blinded electrophysiologists. Ablation was guided by using ECM. The OTVT/PVC origin was defined as the site where ablation caused arrhythmia suppression. Acute success was defined as abolition of ectopy after ablation. Medium-term success was defined as the abolition of symptoms and reduction of PVC to less than 1000 per day documented on Holter monitoring within 6 months.ResultsIn 24 patients (mean age 50 ± 18 years) recruited ECM successfully identified OTVT/PVC origin in 23/24 (96%) (right ventricular outflow tract, 18; left ventricular outflow tract, 6), sublocalizing correctly in 100% of this cohort. Acute ablation success was achieved in 100% of the cases with medium-term success in 22 of 24 patients. PVC burden reduced from 21,837 ± 23,241 to 1143 ± 4039 (P < .0001). ECG algorithms identified the correct chamber of origin in 50%–88% of the patients and sublocalized within the right ventricular outflow tract (septum vs free-wall) in 37%–58%.ConclusionsECM can accurately identify OTVT/PVC origin in the left and the right ventricle pre- and periprocedurally to guide catheter ablation with an accuracy superior to that of published ECG algorithms.

This prospective multicenter series shows a high success rate of ECM in accurately diagnosing the mechanism of AT and the location of focal arrhythmia. Intraprocedural use of the system and its application to atrial fibrillation mapping is under way.

The structural and/or functional abnormality of the cardiac electrovascular system is the most common cause of world mortality accounting for 29.0 % of deaths, followed by infectious diseases (16.2 %) and cancers (12.6 %) (WHO 2008 report).1 Abnormalities in the cardiac electrical system (arrhythmias and sudden death) and/or mechanical function (heart failure) constitute one of the major causes of disability and death, which heavily burden the health care systems across the globe. In cardiac electrophysiology and arrhythmias, several decades of research has led to the development of electrocardiographic imaging (ECGI), a novel three-dimensional (3D), 252-lead, body surface ECG-based, non-invasive epicardial imaging modality. This technique images potentials, electrograms and activation sequences (isochrones) on the epicardial surface of the heart. 2 This tool has been investigated in the normal cardiac electrophysiology and various tachyarrhythmic, conduction and anomalous depo-repolarisation disorders. It has been emerging as a tool of potentially higher clinical value than the 12-lead ECG in terms of sensitivity, specificity and accuracy in the diagnostic and therapeutic management of cardiac rhythm disorders.Here we describe the potential of this non-invasive mapping technique developed by Rudy 2 in identifying the sources of electrical disorders of the heart like atrial arrhythmias (premature atrial beat, atrial tachycardia, AbstractThe authors describe a novel three-dimensional, 252-lead electrocardiography (ECG) and computed tomography (CT)-based non-invasive cardiac imaging and mapping modality. This technique images potentials, electrograms and activation sequences (isochrones) on the epicardial surface of the heart. This tool has been investigated in the normal cardiac electrophysiology and various tachyarrhythmic, conduction and anomalous depo-repolarisation disorders. The clinical application of this system includes a wide range of electrical disorders like atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beat, ventricular tachycardia) and ventricular pre-excitation (Wolff-Parkinson-White syndrome). In addition, the system has been used in exploring abnormalities of the His-Purkinje conduction like the bundle branch block and intraventricular conduction disturbance and thereby useful in electrically treating the associated heart failure (cardiac resynchronisation). It has a potential role in furthering our understanding of abnormalities of ventricular action potential (depolarisation [Brugada syndrome and repolarisation], long QT and early repolarisation syndromes) and in evaluating the impact of drugs on His-Purkinje conduction and cardiac action potential.