Ariga Rina, Tayebjee Muzahir H, Benfield Anne, Todd Michelle, Lefroy David C
Department of Cardiology, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, United Kingdom.
Pacing Clin Electrophysiol. 2010 Dec;33(12):1490-6. doi: 10.1111/j.1540-8159.2010.02895.x. Epub 2010 Oct 8.
Effective cardiac resynchronization therapy (CRT) is more likely with widely separated left ventricular (LV) and right ventricular (RV) pacing leads tips. We hypothesized that lead separation is an important factor in determining the clinical response to CRT.
A retrospective study of 86 consecutive patients age 71 ± 10 years, male (74%), coronary disease (71%), atrial fibrillation (23%), LV ejection fraction (22 ± 9%), QRS duration (160 ± 27 ms), New York Heart Association (NYHA) class III (81%), NYHA class IV (19%) undergoing CRT from January 2006 to September 2008. The median follow-up was 12 months and clinical response to CRT was defined as reduction of NYHA class by one or more. The three-dimensional separation between RV and LV pacing lead tips was calculated using measurements obtained from orthogonal posteroanterior and lateral chest radiographs performed the day after implantation.
Fifty-nine patients (69%) responded to CRT. There was a statistically significant association between increased three-dimensional lead separation and clinical response to CRT (P= 0.005). Stronger association was obtained when lead separation was corrected for cardiac size (P= 0.001). A significantly higher response rate of 88% was achieved in patients with QRS duration of 160 ms or more, and lead separation of 100 mm or more compared with 60% when lead separation was less than 100 mm and QRS duration remained the same (P = 0.027).
Greater three-dimensional separation of LV-to-RV leads is associated with improved response to CRT. A prospective multicenter trial is needed to assess lead separation as a predictor for response.
左心室（LV）和右心室（RV）起搏导线尖端距离越远，心脏再同步治疗（CRT）的效果可能越好。我们假设导线间距是决定CRT临床反应的重要因素。
对2006年1月至2008年9月期间连续86例年龄为71±10岁、男性（74%）、患有冠心病（71%）、心房颤动（23%）、左心室射血分数为22±9%、QRS波时限为160±27毫秒、纽约心脏协会（NYHA）心功能分级为III级（81%）、IV级（19%）的患者进行回顾性研究。中位随访时间为12个月，CRT的临床反应定义为NYHA心功能分级降低一级或更多。使用植入后第二天拍摄的胸部正位和侧位正交X线片测量值计算右心室和左心室起搏导线尖端之间的三维距离。
59例患者（69%）对CRT有反应。三维导线间距增加与CRT临床反应之间存在统计学显著关联（P=0.005）。校正心脏大小后导线间距与临床反应的关联更强（P=0.001）。QRS波时限为160毫秒或更长且导线间距为100毫米或更长的患者的反应率显著更高，为88%，而导线间距小于100毫米且QRS波时限不变时反应率为60%（P=0.027）。
左心室至右心室导线的三维间距越大，CRT反应越好。需要进行一项前瞻性多中心试验来评估导线间距作为反应预测指标的价值。
