title: Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block.
abstract: OBJECTIVE
  We assessed the effects of cardiac re-synchronization therapy (CRT) in patients who developed otherwise unexplained heart failure (HF) during right ventricular apical (RVA)-pacing for acquired complete atrioventricular block (CAVB).
  
  
  RESULTS
  Eighteen consecutive CAVB patients with HF during RVA-pacing were assessed with haemodynamic studies immediately and 12 months after CRT-upgrade. Ten patients had idiopathic CAVB and 13 showed normal left ventricular (LV) function at RVA-pacemaker implantation. HF developed after 81 +/- 10 months. RVA-pacing duration correlated (r = 0.49, P < 0.05) with LV ejection fraction (LVEF) deterioration. Biventricular- (BiV) and LV-pacing acutely improved the systolic function comparably, but only BiV improved diastolic function. One-year post-CRT-initiation, New York Heart Association classification improved 35 +/- 3% (P < 0.05) and the number of hospitalizations decreased 85 +/- 3% (P < 0.0001). CRT decreased LV end-diastolic diameter (LVEDd) 7 +/- 2% (P < 0.01) and increased LVEF by 23 +/- 7% (P < 0.01). The CRT-induced reduction in LVEDd tended to be greater in patients with RVA-pacing for < 5 years vs. > 5 years (7.7 +/- 2.5 vs. 3.6 +/- 1.0 mm, P = 0.08).
  
  
  CONCLUSIONS
  CRT-upgrade improves the cardiac function and symptoms in CAVB patients with HF progression related to RVA-pacing. Because adverse LV-remodelling may be partly irreversible, consideration should be given to BiV- and LV-pacing upgrade as soon as possible after the indications appear, and prospective studies of the optimal timing of CRT-upgrade may be useful.
authors.affiliation: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shimano
authors.forename: Yukiomi
authors.initials: Y
authors.lastname: Tsuji
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Yasuya
authors.initials: Y
authors.lastname: Inden
authors.forename: Naoya
authors.initials: N
authors.lastname: Tsuboi
authors.forename: Teruo
authors.initials: T
authors.lastname: Itoh
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takashi
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Taro
authors.initials: T
authors.lastname: Okada
authors.forename: Shuji
authors.initials: S
authors.lastname: Harata
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.forename: Haruo
authors.initials: H
authors.lastname: Hirayama
authors.forename: Stanley
authors.initials: S
authors.lastname: Nattel
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Murohara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D006321:Heart / Q000502:physiology; D006329:Heart Conduction System; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D010138:Pacemaker, Artificial; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome