title: Ventricular pacemaker upgrade: experience, complications and recommendations.
abstract: OBJECTIVE
  To assess outcomes of pacemaker upgrade from single chamber ventricular to dual chamber.
  
  
  METHODS
  Retrospective analysis of patients undergoing the procedure.
  
  
  METHODS
  Specialist cardiothoracic unit.
  
  
  METHODS
  44 patients (15 female, 29 male), mean (SD) age at upgrade 68.2 (12.9) years.
  
  
  METHODS
  Upgrade of single chamber ventricular to dual chamber pacemaker.
  
  
  METHODS
  Procedure duration and complications.
  
  
  RESULTS
  Principal indications for upgrade were pacemaker syndrome (17), "opportunistic"--that is, at elective generator replacement (8), heart failure (7), non-specific breathlessness/fatigue (7), and neurally mediated syncope (3). Mean (SD) upgrade procedure duration (82.9 (32.6) minutes) significantly exceeded mean VVI implantation duration (42.9 (13.3) minutes) and mean DDD implantation duration (56.6 (22.7) minutes) (both p < 0.01). Complications included pneumothorax (1), ventricular arrhythmia requiring cardioversion (2), protracted procedure (10), atrial lead repositioning within six weeks (8), haematoma evacuation (1), superficial infection (1), and admission to hospital with chest pain (1); 20 patients (45%) suffered one or more complications including four of the eight who underwent opportunistic upgrade.
  
  
  CONCLUSIONS
  Pacemaker upgrade takes longer and has a higher complication rate than either single or dual chamber pacemaker implantation. This suggests that the procedure should be performed by an experienced operator, and should be undertaken only if a firm indication exists. Patients with atrial activity should not be offered single chamber ventricular systems in the belief that the unit can be upgraded later if necessary at minimal risk.
authors.affiliation: Department of Cardiology, Papworth Hospital, Cambridge, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hildick-Smith
authors.forename: M D
authors.initials: MD
authors.lastname: Lowe
authors.forename: S A
authors.initials: SA
authors.lastname: Newell
authors.forename: P M
authors.initials: PM
authors.lastname: Schofield
authors.forename: L M
authors.initials: LM
authors.lastname: Shapiro
authors.forename: D L
authors.initials: DL
authors.lastname: Stone
authors.forename: A A
authors.initials: AA
authors.lastname: Grace
authors.forename: M C
authors.initials: MC
authors.lastname: Petch
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D005260:Female; D006327:Heart Block / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011183:Postoperative Complications; D012086:Reoperation; D012189:Retrospective Studies; D012306:Risk; D013997:Time Factors