改善心脏骤停研究：基本原理和设计方案

Improve sudden cardiac arrest study： rationale and design

背景植入型心律转复除颤器（ICD）在心脏骤停（SCA）幸存者中的应用已得到公认，但在合并高危因素的无SCA患者中的应用仍需深入探讨。基本原理现有研究表明，以下4个风险因素[晕厥或先兆晕厥、左心室射血分数（LVEF）过低（LVEF〈25％）、非持续性室性心动过速（NSVT）、频发性室性早博（PVC）]均与SCA风险增加独立相关。本研究将符合上述危险因素的一级预防患者组成“1．5级预防”患者组，验证这组患者与二级预防患者出现SCA的风险相近，并可能会从ICD的植人中获益。设计方案“改善SCA”研究是一项前瞻性、非随机性、全球性、非盲、干预性多中心上市后研究。人选符合具有I类ICD植人适应证的患者。基线时，对人选者进行评估，以确定其归于一级预防组、1．5级预防组还是二级预防组。1．5级预防评估包括对晕厥或先兆晕厥、LVEF过低、NSVT和PVC的评估。对于植入器械患者，每隔6个月对受试者进行随访，直至受试者退出研究或研究结束。每次随访时，通过询问收集装置数据（或通过CareLink传输装置或通过诊室诊疗）。在12、24个月的随访时，对一级预防患者进行动态监测，以重新评估是否符合1．5级标准。对于未植入器械的一级预防受试者，需在12、24个月随访时，行心电监测检查，以评估NSVT和PVC情况。对于不接受植入的二级预防受试者将在拒绝植入后将结束研究。结论“改善SCA研究”试图证实符合1．5级预防标准的一级预防患者与二级预防患者发生危及生命的室性心律失常的风险类似，并且从ICD或心脏再同步治疗除颤器（CRT-D）的获益类似。

Background The use of implantable cardioverter defibrillator （ ICD ） in the patients who have survived an episode of sudden cardiac arrest （ SCA ） is well established.However, the use of ICD in the patients without a history of SCA but at high risk of such an episode is less established. Rationale Some factors have been independently associated with an increased risk of SCA, but no prospective data have been collected to determine if one or more of these factors in a primary prevention ICD population is associated with an increased likelihood of receiving an appropriate ICD therapy. The purpose of this study is to demonstrate that primary prevention patients with one or more additional risk factors [ 1.5 prevention criteria： syncope/ pre-syncope, low left ventricular ejection fraction （ LVEF ）, non-sustained ventricular tachycardia （ NSVT ）, and frequent premature ventricular contractions （ PVC ） ] are at a similar risk of lifethreatening ventricular arrhythmias （ LTVA ） when compared to secondary prevention patients, and will have similar benefit from an ICD. Design The improve SCA study is a prospective, non-randomized, non-blinded, global, interventional, multi-site post-market study. Patients who meeting indications of ACC/AHAPHRS or ESC Class I guidelines for an ICD implant are eligible for enrollment and will be considered enrolled upon informed consent completion. At baseline, subjects will be assessed to determine if they fall into the primary prevention, 1.5 prevention, or secondary prevention group.A 1.5 prevention assessment will include an assessment of syncope/pre-syncope, low LVEF, NSVT and frequent PVC. Patients who accept ICD implantation, will be followed every six months until exit or closure. Device data will be collected via interrogations at all follow-up visits （ either via CareLink or in-office visit ） ; information on device changes will be collected if applicable. At the 12-and 24-month visits, primary prevention （ 1.0 and 1.5 subjects ） will be provided with the option of another ambulatory test to reassess the 1.5 criteria. Primary prevention subjects who are not implanted with a device will be offered additional ambulatory monitoring at the 12-and 24-month visits.Secondary prevention subjects who do not receive an implant will be exited. Conclusion The improve SCA study will demonstrate that appropriate therapy rates for subjects meeting 1.5 prevention criteria implanted with a ICD are equivalent to rates in subjects meeting secondary prevention criteria.