title: Coupled pacing controls rapid heart rates better than paired pacing during atrial fibrillation.
abstract: OBJECTIVE
  Delivery of a ventricular extrastimulus shortly after the effective refractory period (ERP) of a sensed (coupled pacing; CP) or a paced (paired pacing; PP) ventricular event can instantly decrease the mechanical pulse rate (MPR) during rapidly conducting atrial fibrillation (AF). We compared the short-term rate-controlling effects of CP and PP during AF with rapid ventricular rates.
  
  
  RESULTS
  Sixteen patients with ongoing, spontaneous AF were examined. Mechanical pulse rate was registered via arterial pressure tracings. During CP a coupling interval (CI) of ERP+20 ms was used to reach an optimal haemodynamic effect. Paired pacing was started at a basic cycle length (CL) of 500 ms followed by an extrastimulus with an CI of ERP+20 ms. Drive train was changed at 50 ms increments until the lowest MPR was reached. Proarrhythmic effects were characterized by the number of premature ventricular complexes (PVCs). Mechanical pulse rate significantly decreased in all patients during CP (113 ± 9 vs. 58 ± 4/min). Using CP the controlled rhythm remained irregular (CL range: 896 ± 24-1452 ± 67 ms) while no PVCs were observed. With different drive trains PP resulted in different regular MPRs (range 62 ± 6-80 ± 4/min), but the lowest MPR achieved was significantly higher in the PP group than in the CP. Paired pacing caused premature beats in nine patients (56%) resulting in loss of continuous MPR control.
  
  
  CONCLUSIONS
  Both CP and PP can reduce the MPR during rapidly conducting AF. Coupled pacing is more applicable, but PP has the advantage to achieve different target heart rates. Paired pacing has more proarrhythmic effects as compared with CP.
authors.affiliation: Department of Pacing and Clinical Electrophysiology, National Institute of Cardiology, Haller u. 29, Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Kardos
authors.forename: Pal
authors.initials: P
authors.lastname: Abraham
authors.forename: Attila
authors.initials: A
authors.lastname: Mihalcz
authors.forename: Csaba
authors.initials: C
authors.lastname: Foldesi
authors.forename: Tamas
authors.initials: T
authors.lastname: Szili-Torok
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome