Goldberger Jeffrey J, Bonow Robert O, Cuffe Michael, Dyer Alan, Greenland Philip, Rosenberg Yves, O'Rourke Robert, Shah Prediman K, Smith Sidney
Bluhm Cardiovascular Center and the Division of Cardiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Am Heart J. 2008 Mar;155(3):455-64. doi: 10.1016/j.ahj.2007.10.041. Epub 2008 Jan 31.
Multiple clinical trials have demonstrated beta-blockers improving survival after myocardial infarction (MI). Patients with "bradycardia-related" contraindications to beta-blockers, such as those with asymptomatic bradycardia or AV conduction abnormalities, have been excluded from clinical trials of beta-blockers and continue to be excluded from post-MI beta-blocker therapy in routine clinical practice. These patients tend to be elderly and have a high 1-year mortality. If beta-blockers provide benefit to the post-MI patient independent of their heart rate-lowering effect, then these patients could benefit substantially from initiation of beta-blocker therapy. However, in this particular group of patients, beta-blockers can be safely initiated only if more severe or significant bradycardia can be prevented by pacemaker implantation. It is unclear whether adverse effects related to pacemaker implantation could also negate some or all of the hypothesized benefit of beta-blocker therapy. Although beta-blockers are particularly effective in the elderly, the benefit of beta-blocker therapy in patients with bradycardia-related contraindications to beta-blockers has not been established. The PACE-MI trial is a randomized controlled trial that will address whether beta-blocker therapy enabled by pacemaker implantation is superior to no beta-blocker and no pacemaker therapy after MI in patients with rhythm contraindications to beta-blockers or in those who have developed symptomatic bradycardia due to beta-blockers. The trial will randomize 1124 patients to standard therapy (not to include beta-blockers as patients must have a contraindication to be enrolled) or standard therapy plus pacemaker implantation and beta-blocker. The primary end point is the composite end point of total mortality plus nonfatal reinfarction.
多项临床试验已证明β受体阻滞剂可提高心肌梗死（MI）后的生存率。有β受体阻滞剂“心动过缓相关”禁忌证的患者，如无症状性心动过缓或房室传导异常患者，已被排除在β受体阻滞剂的临床试验之外，并且在常规临床实践中，心肌梗死后的β受体阻滞剂治疗也继续将其排除在外。这些患者往往年事已高，1年死亡率很高。如果β受体阻滞剂对心肌梗死后患者有益，且与其降低心率的作用无关，那么这些患者可能会从启动β受体阻滞剂治疗中大幅获益。然而，在这一特定患者群体中，只有在通过植入起搏器可预防更严重或显著的心动过缓时，才能安全地启动β受体阻滞剂治疗。目前尚不清楚与起搏器植入相关的不良反应是否也会抵消β受体阻滞剂治疗的部分或全部假定益处。尽管β受体阻滞剂在老年人中特别有效，但β受体阻滞剂治疗对有β受体阻滞剂心动过缓相关禁忌证患者的益处尚未得到证实。PACE-MI试验是一项随机对照试验，将探讨对于有β受体阻滞剂节律禁忌证或因β受体阻滞剂出现症状性心动过缓的心肌梗死后患者，起搏器植入启用的β受体阻滞剂治疗是否优于不使用β受体阻滞剂和不进行起搏器治疗。该试验将把1124名患者随机分为标准治疗组（不包括β受体阻滞剂，因为入选患者必须有禁忌证）或标准治疗加起搏器植入及β受体阻滞剂组。主要终点是总死亡率加非致命性再梗死的复合终点。
