Europace Advance Access originally published online on June 8, 2007
Europace 2007 9(10):869-874; doi:10.1093/europace/eum119
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CARDIAC RESYNCHRONISATION THERAPY
Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block
1 Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan; 2 Division of Cardiology, Nagoya Dai-ni Red Cross hospital, Nagoya, Japan; 3 Department of Cardiovascular Research, Research Institute of Environmental Medicine (RIEM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; 4 Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, AL, USA; 5 Department of Medicine and Research Center, Montreal Heart Institute, University of Montreal, Quebec, Canada; 6 Department of Pharmacology, McGill University, Montreal, Quebec, Canada
Aims 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).
Methods and 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).
Conclusion 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.
Key Words: Pacing, Heart failure, Resynchronization, Complete AV block
* Corresponding author. Tel: +81 52 789 5006; fax: +81 52 789 5003. E-mail address: y-tsuji{at}hh.iij4u.or.jp
Manuscript submitted 17 February 2007. Accepted after revision 3 May 2007.