Key result
Inappropriate 200 ms PVAB triggers atrial undersensing and unnecessary ICD shock during atrial flutter.
Case Report (n=1)
Inappropriate programming of post-ventricular atrial blanking can lead to atrial undersensing during atrial flutter, resulting in unnecessary and potentially proarrhythmic ICD therapies.
May trigger inappropriate shocks in AFL; leaves open need for refined VT discrimination algorithms in dual-chamber ICDs.
A 55-year-old lady with non-ischemic cardiomyopathy (NICM) was referred for multiple implantable cardioverter defibrillator (ICD) shocks. Stored electrograms (EGM) revealed atrial flutter (AFL) with A > V. Morphology match was good and RR-intervals were irregular. Despite all these, the dual-chamber-ICD (Abbott medical) classified this as ventricular tachycardia (VT-2) via V > A algorithm where it did not analyze morphology/stability and delivered therapy. Anti-tachycardia-pacing (ATP) was delivered which induced a true VT (rate in VF-zone) and immediate shock was delivered. It was hence appropriate but an 'unnecessary' shock. The offender was found to be an inappropriately programmed long post-ventricular atrial-blanking (PVAB) of 200 ms which led to undersensing of several atrial electrograms, falsely making V > A during a clear AFL.
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Bera et al. (2022) conducted a case report in Non-ischemic cardiomyopathy (n=1). Inappropriately programmed long post-ventricular atrial-blanking (PVAB) was evaluated on Unnecessary defibrillator discharge. Inappropriately programmed long post-ventricular atrial-blanking of 200 ms led to atrial undersensing and an unnecessary defibrillator shock during atrial flutter.
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