title: Clinical performance of a ventricular automatic capture verification algorithm.
abstract: BACKGROUND
  This study was conducted to evaluate the clinical performance of the ventricular automatic capture feature as implemented in the Insignia I Ultra pacemaker system (Guidant) utilizing a variety of ventricular leads. Currently, the optimal programming of the pacemaker output considers both pacemaker efficiency (prolonging battery longevity) and patient safety (adequate safety margin). The ability of a pacemaker to automatically adjust the ventricular output above the pacing threshold while maintaining the appropriate safety margin has been explored since the early 1970s and is only available today in conjunction with a specific low polarization lead system.
  
  
  METHODS
  One hundred and five patients were enrolled from 17 European centers utilizing 31 different types of ventricular leads were followed through their 3-month follow-up visit. There were no restrictions on the type of ventricular leads used.
  
  
  RESULTS
  The average mean difference between the commanded autothreshold test (0.652 + 0.335 V) and the manual threshold test (0.651 + 0.335 V) was 0.001 + 0.49 (P < 0.0001). The average mean difference between the ambulatory autothreshold test (0.696 + 0.322 V) and the commanded autothreshold test (0.682 + 0.315 V) was 0.002 + 0.74 (P < 0.0001). Holter recordings confirmed that there were no loss of capture incidences without a backup pulse being delivered. In addition, the mean number of backup pulses delivered in a 24-hour period was less than 0.1% of the total number of paced beats.
  
  
  CONCLUSIONS
  This study provided that the automatic capture feature while using a variety of leads accurately determines the ventricular stimulation threshold and safely delivers a backup pulse when required.
authors.affiliation: Kerckhoff Klinik, Benekestrasse 2-8, D-61231 Bad Nauheim, Germany. J.Sperzel@Kerckhoff-Klinik.de
authors.forename: Johannes
authors.initials: J
authors.lastname: Sperzel
authors.forename: Charles
authors.initials: C
authors.lastname: Kennergren
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffi
authors.forename: Mitchell
authors.initials: M
authors.lastname: Smith
authors.forename: Marie
authors.initials: M
authors.lastname: Knops
authors.forename: Jaswinder
authors.initials: J
authors.lastname: Gill
authors.forename: Jean
authors.initials: J
authors.lastname: Boland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015716:Electrocardiography, Ambulatory; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D013686:Telemetry