title: VDD vs DDD pacemakers: a meta-analysis.
abstract: BACKGROUND
  Dual-chamber (DDD) and VDD pacing are recognized alternatives for patients with advanced atrioventricular (AV) conduction abnormalities and spared sinus node function. The comparative data between these 2 modes are limited.
  
  
  METHODS
  A literature search was performed using multiple major databases. Outcomes of interest were (1) adverse events including incidence of atrial fibrillation (AF) and (2) procedural parameters. Odds ratio (OR) was reported for dichotomous variables and standardized mean difference (SMD) for continuous variables.
  
  
  RESULTS
  Eight controlled studies (7 cohorts and 1 randomized controlled trial: total 1942 patients) were included. VDD mode was used in 922 patients. Mean follow-up period for the VDD group was 51 ± 24 months. There was a trend toward lower overall adverse events in the VDD group (9.6% vs 11.6%; OR, 0.74 [95% confidence interval (CI), 0.51-1.05; P = 0.09]). Shorter implantation and fluoroscopy times were noted with VDD pacing (46.2 ± 12 vs 65.9 ± 20 minutes; SMD, -0.96 [95% CI, -1.26 to -0.66; P < 0.0001] and 4.6 ± 1 vs 9.3 ± 0.4 minutes; SMD, -0.83 [95% CI, -1.38 to -0.29; P = 0.003], respectively). Mean P-wave amplitude was significantly lower in VDD (1.5 ± 0.8 mV vs 3.1 ± 0.9 mV; P = 0.02). The incidence of AF was lower in the VDD group but it did not reach statistical significance (7.5% vs 13.0%; OR, 0.7; 95% CI, 0.39-1.27; P = 0.24).
  
  
  CONCLUSIONS
  This meta-analysis suggests that VDD is a reasonable alternative to DDD pacemakers with lower pneumothorax risk and shorter implantation and fluoroscopy times. More high-quality data are required to definitively compare the 2 strategies.
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Shurrab
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Yair
authors.initials: Y
authors.lastname: Elitzur
authors.affiliation: Arrhythmia Services, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Healey
authors.affiliation: Arrhythmia Services, London Health Science Center, London, Ontario, Canada.
authors.forename: Lorne
authors.initials: L
authors.lastname: Gula
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Kaoutskaia
authors.affiliation: Ev. Krankenhaus Bethel, Bielefeld, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Israel
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ching
authors.initials: C
authors.lastname: Lau
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada. Electronic address: eugene.crystal@sunnybrook.ca.
authors.forename: Eugene
authors.initials: E
authors.lastname: Crystal
mesh_terms: D001145:Arrhythmias, Cardiac / Q000628:therapy*; D004867:Equipment Design; D006801:Humans; D010138:Pacemaker, Artificial; D016896:Treatment Outcome