A computer algorithm for determining local activation times in electrograms obtained during atrial fibrillation

A critical factor in analyzing the propagation of activation waves in the myocardium is the definition of local activation times (LAT) in the electrogram. The authors have formulated and tested a definition of LAT in bipolar electrograms applicable to atrial electrograms containing deflections with wide variation in complexity, e.g. those obtained during rapid, irregular atrial rhythm, i.e. atrial fibrillation. The definition, implemented as an algorithm in a computer program, consists of two parts: the first part identifies local activations in the electrogram and the second calculates the corresponding LAT using criteria that define the LAT as the median activation time of cells located between the bipolar electrodes