Characteristics of Induced Ventricular Fibrillation Cycle Length in Symptomatic Brugada Syndrome Patients

Background: Limited information is available on the ventricular fibrillation (VF) spectrum in Brugada syndrome (BS) patients. We clarified differences in the VF cycle length (CL) using fast-Fourier transformation (FFT) analysis in symptomatic and asymptomatic BS patients. Methods and Results: VF was induced by pacing from the right ventricular (RV) apex and/or RV outflow tract (RVOT) for >8s. A 4096-point FFT analysis of results from 28 male BS patients (51.1 +/- 13.7 years old) was performed. Dominant frequency (DF) from phases 1 (4s) to 6 was obtained at 2-s intervals. The average DF from surface and intracardiac electrograms (ECG: DFECG; ICE: DFICE,, respectively) was compared between symptomatic and asymptomatic patients. Symptomatic patients had a significantly shorter effective refractory period at a CL of 600 ms at the RVOT than asymptomatic patients. DFECG significantly increased with phase (5.64 +/- 0.32 Hz in phase 1 to 6.16 +/- 0.52 Hz in phase 6) and was significantly higher in symptomatic patients than in asymptomatic patients. DFECG had the same characteristics as DFECG. Conclusions: Induced VF in BS patients can be characterized using FFT analysis. Our data support the hypothesis that symptomatic patients have a significantly shorter VF CL than asymptomatic patients. (Circ J 2012; 76: 624-633)