A new generic pacemaker code, derived from and compatible with the Revised ICHD Code, was proposed jointly by the North American Society of Pacing and Electrophysiology (NASPE) Mode Code Committee and the British Pacing and Electrophysiology Group (BPEG), and has been adopted by the NASPE Board of Trustees. It is abbreviated as the NBG (for "NASPE/BPEG Generic") Code, and was developed to permit extension of the generic-code concept to pacemakers whose escape rate is continuously controlled by monitoring some physiologic variable, rather than determined by fixed escape intervals measured from stimuli or sensed depolarizations, and to antitachyarrhythmia devices including cardioverters and defibrillators. The NASPE/BPEG Code incorporates an "R" in the fourth position to signify rate modulation (adaptive-rate pacing), and one of four letters in the fifth position to indicate the presence of antitachyarrhythmia-pacing capability or of cardioversion or defibrillation functions.