Time Course of Current of Injury Is Related to Acute Stability of Active-Fixation Pacing Leads in Rabbits

BackgroundMagnitude of current of injury (COI) consequent to pacemaker lead fixation is recognized as a predictor of acute lead stability. It is unclear whether dynamic monitoring of COI after lead fixation provides additional information beyond a single assessment performed at the time of fixation. ObjectivesThis study was aimed to test the hypothesis that the time course of COI is related to acute lead stability. Methods and ResultsActive fixation leads with fixed screw were anchored to either Langendorff-perfused rabbit hearts endocardially or in vivo hearts epicardially in manners of contact the helix with no rotation, half rotation and full rotation, respectively. Intracardiac electrogram (EGM) was monitored dynamically from onset to resolution of COI, and magnitudes of intrinsic R wave and COI, including ST-segment elevation, ST/R and intracardiac EGM duration (IED), were measured. A digital force gauge was applied to assess lead stability. In vitro, COI in contacted leads was significantly smaller than those in half rotated (pppvs. 5.6±2.0 min, pr = 0. 72, n = 48, p ConclusionsTime course of COI is related to acute lead stability in rabbits. One might be misled by a single assessment of COI magnitude right after lead placement, whereas persistence of COI is likely to be a useful indicator of adequate lead stability.