Rationale for Key EGM Selection
For each transmission, the key EGM selection rules select up to 3 EGMs per day of each arrhythmia type. The limit of 3 EGMs/day, according to the arrhythmia-specific prioritization criteria described in the methods section, resulted in an optimal balance of maximal EGM burden reduction with minimal TP day reduction. For AF, the EGMs with the fastest mean rate, longest duration, and 2nd longest duration were selected, as faster mean ventricular rates and longer durations are both more likely to be associated with true episodes, as recently reported in a similar study11, and more likely to be clinically valuable. For tachycardia, the EGMs with the fastest maximum rate, longest duration, and 2nd longest duration were selected by the same rationale.
For bradycardia, the EGMs with fastest minimum rate, longest duration, and 2nd longest duration were selected. Although including the fastest bradycardia episode may seem counterintuitive, bradycardia episodes with a faster minimum rate are less likely to be false positive detections due to R-wave undersensing, which commonly results from suboptimal implant orientation or sensing threshold programming. For pause, the EGMs with the shortest duration, longest duration, and 2nd longest duration were selected by the same rationale. Although longer pause episodes may be more clinically actionable, shorter pause episodes are less likely to be false positive detections due to R-wave undersensing, so a balanced approach was taken. It is important to note that, although bradycardia episodes with fastest minimum rates were selected, all such episodes must still exhibit rates slower than the programmed bradycardia detection threshold to be recorded. Likewise, although the shortest duration pause episodes were selected, all such episodes must still exhibit pause durations beyond the programmed pause detection threshold to be recorded.