Evaluation of the multiple frequency distribution of conduction block in atrial fibrillation

A software program has been developed to evaluate the relationship between functional reentry (multiple frequency distribution) and conduction block (slow conduction velocity) in atria fibrillation (AF). This methodology improvement was designed to extract the activation time of AF automatically, calculate the mean cycle length for each record, evaluate conduction velocity, and analyze the frequency distribution by the short time Fourier transform (STFT) for studying the spatial relationship between electrical reentry and the conduction block. The electric potential of eight canines with electrically-induced AF were recorded using unipolar electrode 15×8 mapping array on the right atrium epicardium. These data were used in the reconstruction of isochronal map, the mapping of excitation delay, and the mapping of functional reentry for every cycling time. The data indicated that the electrical activation was "stopped" by the block band. The screening of multi-frequency channels at the same cycling time shown in functional reentry mapping has illustrated that the iso-velocity contour was enveloped by a collection of channels with multiple-frequency distribution.