title: Non-physiological increase of AV conduction time in sinus disease patients programmed in AAIR-based pacing mode.
abstract: OBJECTIVE
  The EVOCAV(DS) trial aimed to quantify the paradoxal atrioventricular (AV) conduction time lengthening in sinus node (SD) patients (pts) paced in AAIR-based pacing mode.
  
  
  METHODS
  SD pts, implanted with dual-chamber pacemaker programmed in AAIR-based pacing mode, were randomized in two arms for a 1-month period: the low atrial pacing (LAP; basic rate at 60 bpm, dual sensor with minimal slope) and the high atrial pacing (HAP; basic rate at 70 bpm, dual sensor with optimized slope, overdrive pacing) arm. At 1 month, crossover was performed for an additional 1-month period. AV conduction time, AV block occurrence and AV conduction time adaptation during exercise were ascertained from device memories at each follow-up.
  
  
  RESULTS
  Seventy-nine pts participated to the analysis (75 ± 8 years; 32 male; PR = 184 ± 38 ms; bundle branch block n = 12; AF history n = 36; antiarrhythmic treatment n = 53; beta-blockers n = 27; class III/Ic n = 18; both n = 8). The mean AV conduction time was significantly greater during the HAP (275 ± 51 ms) vs. LAP (263 ± 49 ms) period (p < 0.0001). Class III/Ic drugs were the only predictors of this abnormal behaviour. Degree II/III AV blocks occurred in 49 % of pts in the HAP vs. 19 % in the LAP period (p < 0.0001). Fifty-two patients (66 %) presented a lengthening of AV conduction time during exercise.
  
  
  CONCLUSIONS
  AAIR-based pacing in SD pts may induce a significant lengthening of pts' AV conduction time, including frequent abnormal adaptation of AV conduction time during exercise.
authors: CHU Rennes, Rennes, France. philippe.mabo@chu-rennes.fr
authors: Philippe
authors: P
authors: Mabo
authors: Jean-Pierre
authors: JP
authors: Cebron
authors: Aude
authors: A
authors: Solnon
authors: Aude
authors: A
authors: Tassin
authors: Laurence
authors: L
authors: Graindorge
authors: Daniel
authors: D
authors: Gras
mesh_terms: D000368:Aged; D000465:Algorithms; D000704:Analysis of Variance; D001283:Atrioventricular Node / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012804:Sick Sinus Syndrome / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome