title: How can the rate-adaptive atrioventricular delay be programmed in atrioventricular block pacing?
abstract: OBJECTIVE
  To optimize recommendations for programming of the rate-adaptive atrioventricular (AV) delay.
  
  
  RESULTS
  Optimal AV delay (AVD(opt)) is the net effect of the pacemaker-related interatrial conduction time (IACT), duration of the left-atrial electromechanical action (LA-EAC(long)) and duration of left-ventricular latency (S(V)-EAC(short)). It can be calculated by AVD(opt) = IACT + LA-EAC(long)-S(V)-EAC(short). We measured these three components in 20 DDD pacemaker patients (EF >45%) with the third degree AV block (AVB) at rest and submaximal ergometric exercise load of 71 +/- 9 W which resulted in a 31.5 +/- 9.9 bpm rate increase. Between exercise and rest, the components of and the final AVD(opt) showed no significant differences. Interatrial conduction time in VDD and DDD pacing varied by 2.3 +/- 8.4 ms and 1.4 +/- 8.8 ms, respectively, S(V)-EAC(short) changed by -2.6 +/- 21.8 ms and AVD(opt) by -3.5 +/- 33.3 ms and -4.3 +/- 37.8 ms in VDD and DDD operation, respectively. The greatest variation was of LA-EAC(long) by -8.4 +/- 32.7 ms. Linear regressions of the rate-dependent variations (Deltaf) in VDD operation yielded DeltaIACT(f) = 0.04Deltaf + 0.95 ms, DeltaLA-EAC(long) = -0.59Deltaf + 10.1 ms, and DeltaS(V) - EAC(short) = 0.14Deltaf -7.2 ms which resulted in DeltaAVD(opt) = -0.69Deltaf + 18.2 ms.
  
  
  CONCLUSIONS
  A recommendation for programming of rate-adaptive AV delay in AV block patients cannot be given.
authors.affiliation: Charité Campus Mitte, Medizinische Klinik mit Schwerpunkt, Kardiologie, Angiologie, Pneumologie, Berlin, Germany. christoph.melzer@charite.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Melzer
authors.forename: Thomas
authors.initials: T
authors.lastname: Körber
authors.forename: Heinz
authors.initials: H
authors.lastname: Theres
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Nienaber
authors.forename: Gert
authors.initials: G
authors.lastname: Baumann
authors.forename: Bruno
authors.initials: B
authors.lastname: Ismer
mesh_terms: D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006327:Heart Block / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012146:Rest / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology