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.