title: [The research of related factors affecting the longevity of double chamber cardiac pacemaker].
abstract: OBJECTIVE
  To research the related factors affecting the dual chamber cardiac pacemaker (PM) longevity, and provide the clinical basis for the PM reasonable application and design.
  
  
  METHODS
  From 1991, 71 patients with AVB or SSS who used 9 kinds of dual-chamber PM were followed up. Every installed PM's related parameters, such as sensing electric current, resistance and pacing electric voltage, which may affect the PM longevity voltage had been recorded regularly. At the end point of survey, according to the related parameters of patients and PMs, the 71 patients were grouped into several groups. Then the related parameters were analyzed by statistical methods.
  
  
  RESULTS
  The average of PM service life is 111 months +/- 19 months. Patient's basal heart rate, battery capacity, pacing electric voltage, pacing frequency, resistance, threshold value, pulse width and sensing electric current had all affected the PM's longevity (all P < 0.05) counted by Wilcoxon (Gehan) test. Sensing electric current (P = 0.000, RR = 3.072, 95% CI = 2.130 - 4.429), pacing electric voltage (P = 0.040, RR = 2.121, 95% CI = 1.126 - 3.998) and resistance (P = 0.049, RR = 1.786, 95% CI = 1.007 - 3.169) were the important predicting indictors of the PM longevity by Cox'proportional hazard risk regression analysis.
  
  
  CONCLUSIONS
  Sensing electric current, pacing electric voltage and resistance are the important affecting factors of the PM longevity. Patient's basal heart rate, battery capacity, pacing frequency, threshold value and pulse width have influence of different degree on dual-chamber PM longevity.
authors.affiliation: Department of Cardiology, Shandong University Qilu Hospital, Jinan 250012, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Su-jia
authors.initials: SJ
authors.lastname: Wang
authors.forename: Xiu-rong
authors.initials: XR
authors.lastname: Pan
authors.forename: Ke-fu
authors.initials: KF
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000328:Adult; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D016016:Proportional Hazards Models; D012804:Sick Sinus Syndrome / Q000628:therapy*; D012848:Sinoatrial Block / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome