Premium
Subthreshold Test Pulses Versus Low Energy Shock Delivery to Estimate High Energy Lead Impedance in Implanted Cardioverter Defibrillator Patients
Author(s) -
VOLLMANN DIRK,
LUETHJE LARS,
ZENKER DIETER,
DOMHOF SEBASTIAN,
UNTERBERG CHRISTINA
Publication year - 2003
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1046/j.1460-9592.2003.00071.x
Subject(s) - subthreshold conduction , medicine , shock (circulatory) , energy (signal processing) , electrical impedance , high impedance , pulse (music) , cardiology , electrical engineering , physics , voltage , transistor , quantum mechanics , engineering
VOLLMANN, D., et al .: Subthreshold Test Pulses Versus Low Energy Shock Delivery to Estimate High Energy Lead Impedance in Implanted Cardioverter Defibrillator Patients.The high energy lead impedance is valuable for detecting lead failure in ICDs, but until recently shock delivery was necessary for high energy impedance measurement. This study compared the use of subthreshold test pulses and low energy test shocks to estimate the high energy impedance. Immediately after implantation of Ventak Prizm ICDs in 29 patients, the lead impedance was measured with five subthreshold (0.4 μJ) test pulses, 5 low energy (1.1 J) shocks, and two to three high energy(16 ± 4.5 J)shocks. The mean impedances measured using high energy shocks, low energy shocks, and subthreshold pulses were42.0 ± 7.3 Ω, 46.5 ± 8.1 Ω, and42.4 ± 7.1 Ω, respectively. The impedances measured using high and low energy shocks differed significantly(P <0.0001), while those obtained by high energy shocks and low energy pulses did not(P = 0.63). According to the Pearson correlation coefficient, the impedance measurements with subthreshold pulses and low energy shocks were both closely correlated (P < 0.0001) with impedance values determined with high energy shocks. However, while the impedance values tended to be higher when measured with low energy shocks, the concordance correlation coefficient (c) was higher for subthreshold test pulse versus high energy shock (c = 0.92) than for low versus high energy shock (c = 0.73) . Furthermore, the intraindividual variability of impedance measurements was lower with subthreshold pulse measurements than with low energy shocks. Compared with low energy shocks, impedance measurement with subthreshold pulses has higher reproducibility and a higher correlation with the impedance obtained by high energy shock delivery. Safe and painless high energy impedance estimation with subthreshold pulses might, therefore, help to detect ICD lead failure during routine follow‐up. (PACE 2003; 26:[Pt. II]:457–460)