CE-454611-1 ISOLATED HIGH SHOCK IMPEDANCE DUE TO CALCIFIED POCKET AND THE MANAGEMENT

Impedance is the ratio of voltage to current in an electrical circuit. The most common causes high shock impedance are lead conductor fracture and calcification often associated with malfunction. We present first two cases isolated from pocket which function normal. Case 1: A 73-year-old male ICM, EF 10%, LBBB, sever COPD Boston biventricular (BiV) ICD 2013 that normalized EF. Shock slowly rose 70 Ω 122 2019 189 2021. Lead extraction a new system was considered at time for generator exchange; however, patient declined. severely calcified, normal defibrillator pacing parameters (pace 796 Ω, pace threshold 0.8 V @ 0.4 msec). calcium shell removed (Figure 1A), dropped 146 remained 137 one year follow up. 2: 65-year-old female NICM, 20%, BiV QRS 1B). 65 138 (2019) 165 (2022). At exchange, heavily calcified. Defibrillator were 868 0.6 After decalcification, reduced 128 Ω. month up, stable 130 N/A High result increased circuit includes can. or will alter as well impedance. This managed by extraction. In contrast, calcification, only increases impedance, can be easily decalcification. both cases, patients benefited greatly keeping their functional device avoiding exchange. results abrupt increase Calcification tip slow rise. Unipolar bipolar also used localize area calcification. Normal should raise suspicion Our highlight importance recognizing context Calcium removal significantly reduces management strategy help avoid extraction, potentially high-risk operation.