Abstract: AIM To investigate characteristics of current injury (COI) of different permanent leads in right ventricular apical pacing. METHODSOne hundred and forty-four patients were divided into passive fixed lead group and active fixed lead group. Subjects were implanted with permanent pacing lead in right ventricular apical. We determined COI and conventional pacing parameters at 0, 5 and 10 min after lead fixed and the characteristics of COI were analyzed. RESULTSIn the 146 patients, COI could not be measured accurately in two cases due to the large amplitude of intracardiac electrogram (ICEG). COI gradually reduced after lead fixed in the remaining 144 cases. COI at 0, 5 and 10 min after passive fixed lead was significantly lower than after active fixed lead (P<0.01). The decline of COI of passive fixed lead was significantly greater than active fixed lead (P<0.01) and COI of three cases with postoperative dislocated lead was <5.0 mV. CONCLUSIONCOI of passive fixed lead is significantly smaller and decreases faster than active fixed lead in right ventricular apical pacing. COI produced by both passive fixed lead and active fixed lead will decrease gradually after lead fixed.