Open AccessUndersensing by an ICD Due to Alternans of the Ventricular Electrogram
Author(s) -
Van Heuverswyn Frederic E.,
Timmers Liesbeth,
Stroobandt Roland X.,
Serge Barold S.
Publication year - 2013
Publication title -
annals of noninvasive electrocardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.494
H-Index - 48
eISSN - 1542-474X
pISSN - 1082-720X
DOI - 10.1111/j.1542-474x.2012.00521.x
Subject(s) - medicine , ventricular tachycardia , cardiology , defibrillation threshold , ventricular fibrillation , sustained ventricular tachycardia , defibrillation , qrs complex , implantable cardioverter defibrillator
Alternans of the ventricular electrogram (VEGM) during ventricular tachycardia (VT) is a rare cause of ventricular undersensing by an implantable cardioverter‐defibrillator (ICD). This report describes a patient with a St. Jude ICD who exhibited sustained monomorphic VT associated with surface QRS alternans, alternating cycle lengths, alternans of the VEGM causing intermittent undersensing of the smaller component, and intermittent 2:1 counting of ventricular intervals during 1:1 sensing in response to the ICD detection algorithm. VEGM undersensing was corrected noninvasively simply by programming the threshold start from 62.5% to 50% which increased the sensitivity based on the amplitude of the VEGM. This maneuver did not affect the satisfactory and stable defibrillation threshold.