Background More and more active-fixation leads were used in the implantation of pacemaker, but compared with the traditional passive-fixation leads, the differences of the pacing parameter were not clearly known.
Objective The aim of this study was to compare the pacing parameters of active-fixation leads and passive-fixation leads in right ventricular apical pacing.
Methods There were 54 patients implanted with single or dual chamber pacemaker involved in this study from January 2010 to May 2010 followed up for 3 months after operation. In these patients 21 with passive-fixation lead (Group I) and 33 with active-fixation lead (Group II). All the leads were implanted in right ventricle apex, the average age was 66.23 ± 13.90 years old, 21 patients with single chamber pacemaker and 33 with dual chamber pacemaker.
Results There were no obvious changes in the pacing parameters between the two groups not only during the operation (thresholds: 0.56 ± 0.20 vs 0.57 ± 0.21; pacing impedances : 818.25 ± 267.71 vs 823.59 ± 284.46; R Wave: 10.64 ± 3.08 vs 10.47 ± 3.10) but also at 1 month (thresholds: 0.55 ± 0.18 vs 0.55 ± 0.18; pacing impedances: 542.72 ± 190.30 vs 531.91 ± 189.48; R Wave: 10.53 ± 3.60 vs 10.22 ± 3.63) and 3 months after the operation (thresholds : 0.57 ± 0.17 vs 0.56 ± 0.17; pacing impedances: 499.80 ± 135.37 vs 494.29 ± 135.74; R Wave: 10.72 ± 3.48 vs 10.47 ± 3.53)(P > 0.05). But there were 1 of 33 patients in Group II (1/33.3%) with higher pacing threshold after operation. The threshold reached to 6.0 V at the second day after operation and the patient was dealt with dexamethasone for 1week, and there was no change of the higher pacing threshold, so we had to implant the new passive-fixation lead in the right ventricular apex and extract the old active-fixation lead simultaneously. The pacing thresholds were stable followed for 3 months. No patients with severely higher pacing thresholds in Group I.
Conclusions There were no obvious differences in the pacing parameters between the passive-fixation leads and active-fixation leads in right ventricular apical pacing. But it was possible that the stimulation thresholds were individually higher in patients with active-fixation leads than those with passive-fixation leads (3.3% vs 0). The long-term parameter changes still were observed.