Novel CineECG Derived From Standard 12-Lead ECG Enables Right Ventricle Outflow Tract Localization of Electrical Substrate in Patients With Brugada Syndrome

BACKGROUND-In Brugada Syndrome (BrS), diagnosed in presence of a spontaneous or Ajmaline-induced type-1 pattern, ventricular arrhythmias originate from the right ventricle outflow tract (RVOT). We developed a novel CineECG method, obtained by inverse electrocardiogram (iECG) from standard 12-lead ECG, to localize the electrical activity pathway in BrS patients. METHODS-The CineECG enabled the temporo-spatial localization of the ECG waveforms, deriving the mean temporo-spatial isochrone (mTSI) from standard 12-lead ECG. The study sample includeda) 15 spontaneous BrS patients, and b) 18 Ajmaline-induced BrS patients (at baseline and after Ajmaline), in whom epicardial potential duration maps (PDM) were available; c) 17 type-3 BrS pattern patients not showing type-1 BrS pattern after Ajmaline (Ajmaline- negative); d) 47 normal subjects; e) 18 right bundle branch block (RBBB) patients. According to CineECG algorithm, each ECG was classified as “Normal”, “Brugada”, “RBBB”, or “Undetermined”. RESULTS-In spontaneous or Ajmaline-induced BrS patients, CineECG localized the terminal mTSI forces in the RVOT, congruent with the arrhythmogenic substrate location detected by epicardial PDMs. The RVOT location was never observed in normal, RBBB, or Ajmaline- negative patients. In most Ajmaline-induced BrS patients (78%), the RVOT location was already evident at baseline. The CineECG classified all normal subjects and Ajmaline-negative patients at baseline as “Normal” or “Undetermined”, all RBBB patients as “RBBB”, while all spontaneous and Ajmaline-induced BrS patients as “Brugada”. Compared to standard 12-lead ECG, CineECG at baseline had a 100% positive predictive value and 81% negative predictive value in predicting Ajmaline-test results. CONCLUSIONS-In spontaneous and Ajmaline-induced BrS patients, the CineECG localized the late QRS activity in the RVOT, a phenomenon never observed in normal, RBBB, or Ajmaline- negative patients. The possibility to identify the RVOT as the location of the arrhythmogenic substrate by the non-invasive CineECG, based on the standard 12-lead ECG, opens new prospective for diagnosing BrS patients.