Undersensing of ventricular fibrillation by a biventricular implantable cardioverter‐defibrillator: What is the cause and the troubleshooting?

Novel ventricular tachyarrhythmia detection enhancement detects undertreated life-threatening arrhythmias

“…As such, programming guidelines recommends faster detection rate cutoffs and longer detection times to reduce avoidable HV therapy. However, multiple reports have revealed that generic compliance with guideline directed ICD programming recommendations, with or without undersensing, may lead to delayed or in some instances even withholding delivery of the HV therapy [13][14][15]23 . Moreover, post-mortem studies suggest that mortality in ICD implanted patients can be due to undertreated ventricular tachyarrhythmias 13,18,24,25 .…”

“…Figure 1 provides an overview of the VFTA algorithm logic. The VFTA algorithm enhances traditional tachyarrhythmia detection by determining whether HV therapy needs to be accelerated at four different checkpoints during an episode: (1) the number of intervals to detect (ITD) for one of the tachyarrhythmia rate zone is fulfilled (VT and VF) and rhythm discriminators indicate VT (only for VT); (2) a pre-defined number of intervals (45) since the beginning of a potential tachyarrhythmia episode is passed without reaching ITD (the VFTA monitoring period); (3) the number of intervals to re-detect for one of the tachyarrhythmia rate zone is fulfilled; and (4) when a new potential tachyarrhythmia episode is detected within a pre-defined number of intervals (15) after the end of a previously diagnosed tachyarrhythmia episode (the VFTA post-episode monitoring period). While primary detection of tachyarrhythmia episodes uses primary near-field V-sense channel, the VFTA algorithm makes its determination based on two undersensing criteria that are continuously monitored on the secondary far-field sensing channel.…”

“…These findings led to a paradigm shift in ICD therapy programming away from more aggressive, shorter duration and slower arrhythmia detection to more conservative faster detection rate cutoffs and longer detection times 11,12 . Following these changes in recommended programming, several reports suggested that using generic programming of longer detection times and faster detection rates with or without device undersensing-may lead to delayed or undelivered therapy for PVT or VF, regardless of device manufacturer [13][14][15] .…”

“… 11 , 12 Following these changes in recommended programming, several reports suggested that using generic programming of longer detection times and faster detection rates—with or without device undersensing—may lead to delayed or undelivered therapy for PVT or VF, regardless of device manufacturer. 13 , 14 , 15 …”

Left ventricular sensing by cardiac resynchronization devices

“…18,19 The occurrence of puzzling frequent and irregular "LVinh" events may occur when there is stable RV pacing in association with LV sensing of rapidly occurring signals as in far-field atrial LV sensing of atrial fibrillation 3 or in the presence of ventricular fibrillation sensed only by the LV as in dissimilar rhythms. 21 The V-V interval was programmed to zero. The second As event initiated the AV delay, which was terminated by a RVp event.…”