An ICD processing system for acquiring breathing pattern signals from intracardiac electrograms obtained from implantable cardiac devices. The system may include both an implantable ICD device and an external processing system. Both the ICD module and the external processing system processing data to generate a representation for the respiration rate for a patient using intracardiac electrogram data obtained by the ICD device. The ICD module and the external processing module communicate with each other to pass collected patient data from the ICD module to the external processing system. The ICD module and the external processing module process the electrogram data to obtain an processed data representation of the respiration data which is used to estimate the respiration rate.