Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block.
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.
Shimano
Masayuki
M
Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Tsuji
Yukiomi
Y
Yoshida
Yukihiko
Y
Inden
Yasuya
Y
Tsuboi
Naoya
N
Itoh
Teruo
T
Suzuki
Hirohiko
H
Muramatsu
Takashi
T
Okada
Taro
T
Harata
Shuji
S
Yamada
Takumi
T
Hirayama
Haruo
H
Nattel
Stanley
S
Murohara
Toyoaki
T
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