[Reasons and complications of pacemaker replacement operation: clinical analysis of 69 case-times].

Objective: To analyze the reasons of cardiac permanent pacemaker replacement and the strategies to prevent relevant complications.

Methods: The clinical data of 57 patients, 38 males and 19 females, aged 74 +/- 8 (56-94), 31 with sick sinus syndrome, 26 with II or III degree atrioventricular block, who underwent 63 times of cardiac permanent pacemaker replacement, including 13 times of lead replacement, were analyzed.

Results: The reason of replacement included battery normal exhaustion for 57 case-times, battery exhaustion before the defined schedule for 2 case-times, lead electrodes incompletely fractured for 2 case-times, and infection of pacemaker pocket for 2 case-times. There were 9 cases of placement-related complications: pacemaker pocket hematoma (n=4), lead dislocation (n=3), and abandoned leads falling into the right ventricle (n=2). The average lifetime of old pacemakers was 9. 25 years (2 -15 years). The pacing threshold of ventricular leads after pacemaker replacement was (0.77 +/- 0. 40)V, significantly higher than the initial pacing threshold [(0.60 +/- 0.21)V, P < 0.01]. There were no significant differences in the lead impedance and R wave amplitude between the pacemaker replacement and initial implantation [(854 +/- 136)omega vs. (828 +/- 176)omega, and (12 +/- 4)mV vs. (12 +/- 4)mV, both P > 0.05].

Conclusion: The main reason of pacemaker replacement is battery exhaustion. Most implanted ventricular leads still can be used. A rare serious complication of cardiac pacemaker replacement operation is abandoned lead falling into the right ventricle, and correct disposing of initial leads help avoid this complication .