title: Pulse amplitude adjustment provides immediate pacemaker longevity gain.
abstract: OBJECTIVE
  Adjusting pacemaker pulse amplitude influences the longevity of the pacemaker. Our aim was to establish the initial longevity gain.
  
  
  METHODS
  Forty randomly selected patients with implanted pacemakers were analyzed. Mean age was 65.58+/-13.7 years. All pacemakers were working on factory settings of pulse amplitude 3.5 V and pulse width of 0.4 ms for average of 3 years before the adjustment. Initial mean longevity was projected to 68.61+/-18.86 months, mean battery voltage 2.78 V, and mean battery current 14.21+/-2.61 microA.
  
  
  RESULTS
  Pulse amplitude threshold test was performed and average value of 0.632+/-0.22 V was obtained. Pulse amplitude was programmed to 2.5 V and pulse width was left unchanged. New readings of battery data were obtained. Battery voltage did not show immediate changes, and battery current decreased to 11.53+/-1.98 microA. New average longevity was projected to 81.03+/-19.82 months, which presents a 12.42 months of initial longevity gain with statistical significance at 95% confidence interval (p=0.003). Positive correlation was found between the new pulse amplitude and new values of battery current (p<0.01).
  
  
  CONCLUSIONS
  Pulse amplitude decrease of only 1 V provides significant initial longevity gain of more than a year. If found correlations would have any impact on further longevity gains over longer period of time is yet to be established.
authors.affiliation: Institute for Heart Diseases, University Clinical Center, Skopje, Republic of Macedonia. zlic2009@ukim.edu.mk
authors.forename: Nenad
authors.initials: N
authors.lastname: Zlatanovic
authors.forename: Sasko
authors.initials: S
authors.lastname: Kedev
authors.forename: Nikola
authors.initials: N
authors.lastname: Gjorgov
authors.forename: Branislav
authors.initials: B
authors.lastname: Miletic
authors.forename: Antonio
authors.initials: A
authors.lastname: Georgiev
authors.forename: Dejan
authors.initials: D
authors.lastname: Kovacevic
authors.forename: Ivan
authors.initials: I
authors.lastname: Trajkov
authors.forename: Mitko
authors.initials: M
authors.lastname: Kaev
authors.forename: Vladimir
authors.initials: V
authors.lastname: Borozanov
authors.forename: Vladimir
authors.initials: V
authors.lastname: Boskov
mesh_terms: D000368:Aged; D001919:Bradycardia / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D004567:Electrodes, Implanted; D004867:Equipment Design; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010138:Pacemaker, Artificial