title: Heart failure and echocardiographic changes during long-term follow-up of patients with sick sinus syndrome randomized to single-chamber atrial or ventricular pacing.
abstract: BACKGROUND
  In patients with sick sinus syndrome, choice of pacing mode has been implicated in the development of congestive heart failure.
  
  
  RESULTS
  A total of 225 consecutive patients with sick sinus syndrome and intact atrioventricular conduction were randomized to either single-chamber atrial pacing (n = 110) or single-chamber ventricular pacing (n = 115). Clinical assessment included New York Heart Association classification, medication, and M-mode echocardiography before pacemaker implantation, after 3 months, and subsequently once every year. At long-term follow-up (mean, 5.5+/-2.4 years), NYHA class was higher in the ventricular group than in the atrial group (NYHA class I/II/III/IV: 65/44/4/0 versus 84/22/2/1 patients, P=.010). Increase in NYHA class during follow-up was observed in 35 of 113 patients in the ventricular group versus 10 of 109 in the atrial group (P<.0005). Increase in dose of diuretics from randomization to last follow-up was significantly higher in the ventricular group than in the atrial group (21+/-49 versus 8+/-42 mg furosemide/d, P=.033). The left ventricular fractional shortening decreased significantly in the ventricular group (from 0.36+/-0.12 to 0.31+/-0.08, P<.0005) but not in the atrial group (from 0.35+/-0.13 to 0.33+/-0.09, P=.087). The left atrial diameter increased significantly in both treatment groups (ventricular group: from 34+/-7 to 41+/-7 mm, P<.0005; atrial group: from 34+/-6 to 37+/-7 mm, P=.002), but the increase was significantly higher in the ventricular group than in the atrial group (P<.0005).
  
  
  CONCLUSIONS
  During long-term follow-up, ventricular pacing is associated with a higher incidence of congestive heart failure and consumption of diuretics than atrial pacing. This is accompanied by a decrease in left ventricular fractional shortening and an increased dilatation of the left atrium in the ventricular paced patients.
authors.affiliation: Department of Cardiology, Skejby Sygehus, Aarhus University Hospital, Denmark.
authors.forename: J C
authors.initials: JC
authors.lastname: Nielsen
authors.forename: H R
authors.initials: HR
authors.lastname: Andersen
authors.forename: P E
authors.initials: PE
authors.lastname: Thomsen
authors.forename: L
authors.initials: L
authors.lastname: Thuesen
authors.forename: P T
authors.initials: PT
authors.lastname: Mortensen
authors.forename: T
authors.initials: T
authors.lastname: Vesterlund
authors.forename: A K
authors.initials: AK
authors.lastname: Pedersen
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D012804:Sick Sinus Syndrome / Q000150:complications / Q000503:physiopathology* / Q000628:therapy