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Three perspectives of cardiac electrical activity.

This article discusses three different perspectives of the electrical activity of the human heart based on three types of electrocardiographic recordings: the Surface ECG, the Subcutaneous ECG, and the Intracardiac Electrogram. Although all three types of recordings are generated by the same electrical activity, namely, the depolarization and repolarization of cardiac cells, the recordings have similarities and differences with regard to method of deployment, duration of implant, duration of recording, maximum long-term storage capacity, signal strength, and susceptibility to electrical noise. The article discusses the similarities and differences among the three types of recordings, as well as the engineering and clinical consequences of these similarities and differences. However, as the consequences include both advantages and disadvantages, the choice of any particular type of recording is eventually dependent on the user.