Not so Safe(ty) Mode
Safety mode can be triggered by a bit flip.
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A bit flip is a phenomenon where a single bit in a computer’s memory changes its value, causing data corruption, system crashes, or security vulnerabilities
Triggers include cosmic rays, software issues, EMI, manufacturing defects, aging of hardware and overclocking
-Hardware malfunction: may not be able to be reset (device will need replacement)
-External event: usually can be programmed back to desired settings.
May result in
-Deactivation of ICD therapies
-VVI mode (no RR, loss of AV synchrony is previously DDD)
-Unipolar high output pacing (large pacing spikes)
-Unipolar and max sensitivity (0.1mV) – easily resulting in pacing inhibition
Mode switched to VVI 70 unipolar pacing and sensing
with max sensitivity (.1mV) resulting in oversensing of any muscle artefact and pacing inhibtiion
Mode switched from VVIR 60 (bipolar sensing/pacing) to VVI 70 unipolar pacing and sensing
with max sensitivity (.1mV) resulting in grosse oversensing of any muscle artefact and pacing inhibtiion
Mode switched from DDD 60-120 with search AV algorithm resulting in <1% ventricular pacing (bipolar sensing/pacing) to VVI 70 unipolar pacing and sensing
ICD therapies turned OFF and home monitoring turned OFF