Normalization of increasing shocking coil impedance with full output synchronized shock

Abstract

AbstractIntroductionImpedance is a crucial parameter in cardiovascular implantable electronic devices (CIEDs). Clinically, most CIEDs measure impedance using low voltage sub‐threshold measurement (LVSM). Although the LVSM of shock impedance (LVSM‐SI) is generally comparable with high voltage shock impedance (HVSI), LVSM‐SI might be inaccurate if peri‐lead tissue degeneration occurs.Methods and ResultsWe present a case of elevated LVSM‐SI occurring 8 years post‐lead implantation, possibly attributed to encapsulation of the right ventricular lead coil. After 0.1 J shock was delivered, a full output synchronized shock was administered to measure HVSI, revealing a normal value. Furthermore, LVSM‐SI was normalized and maintained within the normal range during long‐term follow‐up.ConclusionOur findings suggest conducting a full‐output synchronized shock test to assess HVSI when abnormal LVSM‐SI is detected in the remote phase post‐ICD implantation, which may be considered to help normalize LVSM shock impedance.