title: System upgrade and its complications in patients with a single lead atrial pacemaker: data from the DANPACE trial.
abstract: OBJECTIVE
  To investigate the indications for system upgrade with single lead atrial pacing (AAIR), complications associated with these re-interventions, and possible predictors for system upgrade among patients included in the Danish Multicenter Randomized Trial on AAIR vs. dual-chamber pacing (DDDR) in sick sinus syndrome (DANPACE).
  
  
  RESULTS
  A total of 707 of 1415 patients were randomized to AAIR pacing. Mean follow-up was 5.5 ± 2.6 years. Information on indications for system upgrade and complications were collected by reviewing patient charts. Multiple logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals (CI) for the association between predictors and system upgrade. Sixty-six patients (9.3%) in the AAIR group underwent system upgrade. Fifty-nine of these patients (89.3%) had a documented class I indication for system upgrade. Age (aOR 0.98 for each 1-year increase in age; 95% CI 0.6-1.0), and left atrial enlargement (aOR 1.9; 95% CI 1.0-3.8) were predictors for system upgrade. No single clinically applicable predictor for upgrade was identified. A total of 11 patients (16.7%) experienced at least one major complication after system upgrade.
  
  
  CONCLUSIONS
  The majority of patients with AAIR pacing who underwent system upgrade had a class I indication. The incidence of major complications after system upgrade was high. The present data support the use of DDDR pacing rather than AAIR pacing in sick sinus syndrome.
authors: Department of Cardiology, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark. reki@svf.au.dk
authors: Rikke Esberg
authors: RE
authors: Kirkfeldt
authors: Henning Rud
authors: HR
authors: Andersen
authors: Jens Cosedis
authors: JC
authors: Nielsen
mesh_terms: D000368:Aged; D054537:Atrioventricular Block / Q000453:epidemiology* / Q000517:prevention & control*; D058406:Cardiac Resynchronization Therapy / Q000706:statistics & numerical data*; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D020878:Device Removal / Q000706:statistics & numerical data; D004567:Electrodes, Implanted / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012804:Sick Sinus Syndrome / Q000453:epidemiology* / Q000517:prevention & control*; D016896:Treatment Outcome
keywords: Atrioventricular block; Complications; DANPACE; Pacing; Sick sinus syndrome; Upgrade