Inappropriate ventricular fibrillation annotation and defibrillator discharge despite the same tachycardia cycle length in ventricular tachycardia‐1 zone in an Abbott defibrillator – What is the mechanism?

Abstract

Newer devices incorporate advanced algorithms to have more accurate delivery of implantable cardioverter‐defibrillator (ICD) therapy. Newer models of Abbott Implantable cardioverter‐defibrillators like Gallant and Entrant have a new ventricular fibrillation (VF) therapy assurance algorithm. This algorithm has a proven role in avoiding under‐detection of VF where some of the smaller electrograms are under‐sensed. We report a case of ventricular fibrillation therapy assurance (VFTA) algorithm malfunction in a 48‐year‐old lady having single chamber Entrant Implantable cardioverter‐defibrillator, where the patient received inappropriate therapies. The VFTA algorithm eventually had to be turned off.

Real-world use of a novel ventricular tachyarrhythmia detection algorithm: A case report

“…The VFTA algorithm has been evaluated retrospectively on 564,353 recorded ventricular tachycardia arrhythmia electrograms from 20,000 devices, and it would have led to a new or earlier HVT in 0.27% (53/20,000) of devices with an increase of inappropriate HVT in 0.07% (14/20,000) devices 8 ; however, to our knowledge, VFTA has not yet been evaluated in prospective clinical trials. One case report 9 described VFTA activation leading to HVT in a monomorphic ventricular tachycardia episode that would has not been treated without VFTA because the arrhythmia rate was lower than the treatment zone cutoffs. The authors suggested the therapy in that case could be inappropriate, but some programming changes could also improve the algorithm’s specificity.…”