Accuracy of activation times detected in simulated extracellular electrograms

Detection of local activation times is a basic operation in cardiac electrophysiological research and applied for several analysis techniques. Conduction velociry can be derermined by the diference of activation times at two positions divided by their spatial distance. In this work the accuracy of activation time detection was analyzed in a modeling study of papillary muscle surrounded by a bath. An electrophysiological model of the muscle was developed and a numerical simulation was performed. The simulation yielded spatiotemporal distributions of transmembrane and extracellular voltages, which were used to detect activation times. The study indicafed that the relationship between longitudinal distance of measurement position and detected nctivation time is mostly nonlineal; particularly at both ends of muscle. Thus, conduction velocity can be detected with a given accuracy only in a speciJic area in-between, which is defined by geometrical relationships.