CAE：房颤/房速或为CRT治疗效果欠佳的原因

心脏再同步化治疗（CRT）的疗效与术后患者CRT起搏的数量密切相关。目前对CRT术后未能CRT起搏的原因、各种原因的所占比例未做过很好的研究。

来自霍普金斯大学的Cheng A等研究者收集了2006年至2011年间，通过起搏器程控获得起搏器数据的CRT患者作为研究对象。使用自动算法对相关数据进行分析，将未能CRT起搏的原因分为十类。对完成分类队列中的部分数据进行人工矫正。共检索了80768名患者的数据，CRT植入至数据分析平均时长594天（四分位间距，294-1003天）。在此队列中，有40.7%的患者CRT起搏比例<98%，11.5%的患者CRT起搏比例<90%。

在CRT起搏比例<98%患者中，数据分析发现了其中55.8%的患者未起搏原因为：房性心动过速或房颤占30.6%；室性早搏占16.6%；心室感知异常占8.6%。所谓心室感知异常定义为至少10个以上CRT起搏脱落的事件。在心室感知异常的患者中，有34.5%未能CRT起搏的原因为不恰当的房室间期感知或起搏（SAV/PAV）。在那些CRT起搏比例＜90%的患者中，随着房颤和/或房性心动过速以及SAV/PAV的增加，CRT未起搏的现象也增加。在这部分患者中，房性心动过速/房颤造成的CRT失起搏所占比例超过50%，室性期前收缩所占比例小于10%。

根据此研究，研究者认为在研究对象中有40.7%的患者CRT起搏比例小于98%。在这些起搏未达最优化的患者中，房型心动过速/房颤是CRT失起搏的最常见原因。不恰当的SAV/PAV是最常见的持续性CRT失起搏时间的原因。这一研究结果或可帮助临床医生改善患者对CRT治疗的反应。

Reasons for loss of cardiac resynchronization therapy pacing: insights from 32 844 patients.
BACKGROUND
The efficacy of cardiac resynchronization therapy (CRT) is associated with the amount of CRT pacing delivered. The specific causes of CRT pacing loss and their relative frequencies remain poorly defined.
METHODS AND RESULTS
CRT patients who transmitted device data from 2006 to 2011 were screened for inclusion. Device diagnostics were analyzed using an automated algorithm to categorize CRT loss into 10 different causes. The algorithm was validated against manual adjudications using a portion of the entire cohort. There were 80 768 patients analyzed with a median time of 594 (interquartile range, 294-1003) days from implant to time of analysis. In this cohort, 40.7% of patients had <98% pacing, and 11.5% of patients had <90% pacing. For patients with <98% pacing, device diagnostics explained 55.8% of pacing loss: 30.6% atrial tachycardia/atrial fibrillation; 16.6% premature ventricular contractions; and 8.6% captured as episodes with at least 10 consecutive beats of CRT loss (ventricular sensing episodes). Inappropriately programmed sensed and paced atrioventricular (AV) intervals (SAV/PAV) accounted for 34.5% of all ventricular sensing episodes. As the severity of CRT loss increased, the contribution of atrial tachycardia/atrial fibrillation and SAV/PAV to the loss increased. Atrial tachycardia/atrial fibrillation accounted for >50% and premature ventricular contractions accounted for <10% of CRT loss in those with <90% CRT pacing.
CONCLUSIONS
CRT pacing <98% was observed in 40.7% of patients. Among those with suboptimal pacing, atrial tachycardia/atrial fibrillation was the most common reason for CRT pacing loss. Inappropriately programmed SAV/PAV intervals was the most common reason for episodes of sustained loss of CRT pacing. This information can help in defining more effective treatments to improve CRT delivery.