Digital filters for activation detection in unipolar cardiac electrograms

A limitation on the use of cardiac activation mapping is the inability to distinguish reliably between electrical activity occurring next to a sensing electrode and the effects of distant wavefronts. The authors modeled electrograms without local electrical activity by recordings in lesions created in canine epicardium by freezing, where, by definition, local electrical activity is not possible. Electrograms with local electrical activity were recorded in healthy myocardium. The authors present discriminators based on the frequency characteristics of unipolar electrograms. Different frequency bands were tested as discriminators and compared to the typically used first-derivative discriminator.<>