BLOCK-HF：双室起搏对部分心衰患者有益

去年11月在美国心脏协会(AHA)年会上公布的BLOCK-HF研究结果已于4月24日在线发表在《新英格兰杂志》(New England Journal of Medicine)上。这项研究表明，对于存在房室传导阻滞合并左室收缩功能不全的轻中度心衰患者，双室起搏优于传统右室起搏。

美国纽约州立大学布法罗分校医学院院长Anne B. Curtis教授及其同事称，在这项由企业资助的前瞻性临床随机试验中，8年期间有来自美国和加拿大58家医疗中心的691例患者被随机分配至接受右室起搏或双室起搏，采用的是起搏器或者植入式心脏复律除颤器(ICD)。


Anne B. Curtis博士
 
平均随访37个月后，双室起搏组有53.3%的患者出现了主要结局(任何原因导致的死亡、因心衰紧急入院、或者左室收缩末期容积指数增加大于或等于15%的复合指标)，显著低于右室起搏组64.3%的发生率。无论是在使用起搏器还是ICD的患者中都观察到了这一优势；虽然接受起搏器或ICD的患者在平均射血分数上出现了明显差异，但总的来说这两种装置的“临床效应是非常相似的”。研究者指出，这说明双室起搏的优势很可能与射血分数没有多大的关系(N. Engl. J. Med. 2013 April 24 [doi:10.1056/NEJMoa1210356])。

在去年的AHA年会上，担任评论员的希腊雅典大学Gerasimos S. Filippatos博士表示，BLOCK-HF研究结果肯定会让欧洲心脏病学会以及美国心脏病学会/AHA/心律学会重新考虑其有关房室传导阻滞合并心衰患者的治疗指南。

作者指出，BLOCK-HF提供的证据进一步证明了双室起搏用于房室传导阻滞患者可以保护心脏的收缩功能。Curtis博士表示，她去年11月在公布BLOCK-HF研究结果时就曾说过，这项研究的重要意义之一在于“探讨让患者接受置入难度更高的双室起搏装置是否能产生明确的优势，现在看来答案是肯定的”。

这项研究由美敦力公司资助，该公司也参与了数据采集和分析工作。Curtis博士及其同事声明与多家企业存在利益关系。

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By: MARY ANN MOON, Cardiology News Digital Network

Biventricular pacing is superior to conventional right ventricular pacing in patients who have atrioventricular block and left ventricular systolic dysfunction with mild to moderate heart failure, according to a study that was presented at the American Heart Association meeting last November and has now been published online April 24 in the New England Journal of Medicine.

In the industry-sponsored prospective randomized clinical trial, 691 patients at 58 medical centers in the United States and Canada were randomly assigned to receive right ventricular or biventricular pacing using a pacemaker or implantable cardioverter defibrillator (ICD), during an 8-year period, said Dr. Anne B. Curtis, professor and chair of the department of medicine at the University of Buffalo (N.Y.), and her associates.
 
After a mean follow-up of 37 months, the primary outcome – a composite of death from any cause, an urgent care visit for HF, or an increase of 15% or more in LV end-systolic volume index – occurred in 53.3% of the biventricular group, which was significantly lower than the 64.3% rate in the right ventricular group. This benefit was seen both in patients given a pacemaker and in those given an ICD, with the two devices exerting "a remarkably similar clinical effect" even though there was a marked difference in mean ejection fraction between pacemaker recipients and ICD recipients. This suggests that the benefit of biventricular pacing is not likely to be strongly related to EF, the investigators said (N. Engl. J. Med. 2013 April 24 [doi:10.1056/NEJMoa1210356]).

At the AHA meeting, study discussant Dr. Gerasimos S. Filippatos of the University of Athens said that the BLOCK-HF results would certainly lead to a reconsideration of current European Society of Cardiology and joint American College of Cardiology/AHA/Heart Rhythm Society guidelines for heart failure patients with heart block.

The authors noted that BLOCK-HF adds to the body of evidence suggesting that biventricular pacing in patients with AV block preserves systolic function." Dr. Curtis said while presenting the results in November that one of the key points of BLOCK-HF "was to look at whether or not putting patients through the added difficulty of implanting a biventricular pacing device has clear benefits – and the answer is yes."

This study was funded by Medtronic, which also provided the data collection and analysis. Dr. Curtis and her associates reported numerous ties to industry sources.