International Centre for Centre for Circulatory Health, Imperial College, London, UK.
Eur J Heart Fail. 2013 Dec;15(12):1419-28. doi: 10.1093/eurjhf/hft139.
Prognostic benefit from CRT compared with controls is well established. Symptomatic response rates, however, are controversial and have never been systematically evaluated with standard subtraction of control rates to establish the incremental symptomatic response effect of CRT pacing.
First, we identified 150 consecutive CRT papers and assessed researchers' perceptions of the symptomatic response to CRT. The mean quoted response rate was 66%. Only 26 studies acknowledged the existence of response without the device. Secondly, we examined actual symptomatic response rates in the randomized trials (CARE-HF, COMPANION, CONTAK-CD, MIRACLE, MIRACLE-ICD, MIRACLE-ICD II, MUSTIC, and REVERSE) totalling 3904 patients. The NYHA status improved in 51% of those randomized to CRT vs. 35% of controls (incremental effect 16%). This incremental improvement was significantly greater in open studies (with no device for controls) than in blinded studies (control arm receiving a device but no CRT, such as a defibrillator or a CRT programmed off), 20% vs. 13%, P < 0.001.
Quoting CRT responder rates in isolation without recognizing spontaneous 'response' is common but unwise. The incremental symptomatic response rate from CRT pacing is ∼16%, much lower than widely reported. This value is similar to that for drugs in heart failure and should not be considered disappointing: they both exert powerful prognostic benefits. For scientific purposes, e.g. to explore potential improvements, symptomatic benefit from CRT should be quantified, like all other effects, by comparison with a control.
与对照组相比，心脏再同步治疗（CRT）具有明确的预后益处。然而，症状反应率存在争议，并且从未使用标准减去对照组的方法来系统评估 CRT 起搏的增量症状反应效果。
首先，我们确定了 150 项连续的 CRT 研究，并评估了研究人员对 CRT 症状反应的看法。引用的平均反应率为 66%。只有 26 项研究承认在没有设备的情况下存在反应。其次，我们在随机试验（CARE-HF、COMPANION、CONTAC-CD、MIRACLE、MIRACLE-ICD、MIRACLE-ICD II、MUSTIC 和 REVERSE）中检查了实际的症状反应率，共有 3904 名患者。与对照组相比，随机接受 CRT 的患者中 NYHA 状态改善了 51%（增量效应 16%）。与盲法研究（对照组接受设备但未接受 CRT，如除颤器或 CRT 程控关闭）相比，开放研究（对照组无设备）中这种增量改善更为显著，为 20%对 13%，P<0.001。
孤立地引用 CRT 反应率而不认识到自发的“反应”是常见的，但不明智的。从 CRT 起搏中获得的增量症状反应率约为 16%，远低于广泛报道的水平。这一数值与心力衰竭药物的反应率相似，不应被视为令人失望：它们都具有强大的预后益处。出于科学目的，例如探索潜在的改善，应通过与对照组比较来量化 CRT 的症状获益，就像评估所有其他效果一样。
