Key EGM Selection Criteria
Each arrhythmia episode was characterized by the episode duration and representative rate, defined as follows. The episode duration was defined as the time from device detection to end-of-episode for AF, tachycardia, and bradycardia episodes; and the duration of the pause itself for pause episodes. The representative rate was defined as the mean ventricular rate over the entire episode (i.e., mean rate, number of ventricular beats divided by AF episode duration) for AF; the minimum R-R interval during the episode (i.e., maximum rate) for tachycardia; and the maximum R-R interval during the episode (i.e., minimum rate) for bradycardia.
For each arrhythmia type, up to 3 “key EGMs” per day (starting at 12 AM in the patient’s local time zone) were prioritized for review, as follows. For AF, the EGMs with the fastest mean rate, longest duration, and 2nd longest duration were selected. For tachycardia, the EGMs with the fastest maximum rate, longest duration, and 2nd longest duration were selected. For bradycardia, the EGMs with the fastest minimum rate, longest duration, and 2nd longest duration were selected. For pause, the EGMs with the shortest duration, longest duration, and 2nd longest duration were selected.
If 3 or fewer EGMs of one arrhythmia type were detected on a particular day, all of those EGMs would be prioritized for review. Exceptions include cases in which a single EGM satisfies more than one criterion; in such cases, fewer than 3 EGMs may be prioritized for review. For example, if there were 3 AF EGMs on a single day, but one EGM had both the fastest mean rate and the longest duration, only 2 EGMs would be selected for transmission. Patient-initiated “symptom” EGMs were not impacted by the prioritization rules, and all symptom EGMs were prioritized for review.