Julien Seitz et al. JACEP 2016;2:732-742 Validation of Our Manual Average CL Measurement Method In this example, we first converted the cycle length (CL) values in milliseconds to frequencies in hertz [frequency = (1/CL) • 1,000]. We then compared these values to the one obtained after offline treatment by fast Fourier transformation (Microsoft Excel 2007) of 100 automatic CARTO points (window of 2.5 s) in 10 patients. No statistical difference was observed between these 2 frequency measurement methods (p = 0.5). LAA = left atrial appendage; LSPV = left superior pulmonary vein. Julien Seitz et al. JACEP 2016;2:732-742 American College of Cardiology Foundation