高危心肌病患者植入式除颤器中的晕厥：频率、危险因素、机制及与死亡率的关系：多中心自动除颤器植入试验-减少不适当治疗（MADIT-RIT）研究结果。
Syncope in high-risk cardiomyopathy patients with implantable defibrillators: frequency, risk factors, mechanisms, and association with mortality: results from the multicenter automatic defibrillator implantation trial-reduce inappropriate therapy (MADIT-RIT) study.
机构信息
Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, NY (M.H.R., V.K., A.-C.H.R., S.M., W.Z., A.J.M.); Department of Cardiology, Gentofte Hospital, Hellerup, Denmark (M.H.R., A.-C.H.R.); Department of Cardiology, Hirosaki University Hospital, Hirosaki, Japan (K.O.); Department of Cardiology, Kyoto University Hospital, Kyoto, Japan (T.K.); Department of Cardiology, Tsukuba University Hospital, Tsukuba, Japan (K.A.); and Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan (M.S.).
出版信息
Circulation. 2014 Feb 4;129(5):545-52. doi: 10.1161/CIRCULATIONAHA.113.004196. Epub 2013 Nov 7.
BACKGROUND
There is a relative paucity of studies investigating the mechanisms of syncope among heart failure patients with implantable cardioverter-defibrillators, and it is controversial whether nonarrhythmogenic syncope is associated with increased mortality.
METHODS AND RESULTS
The Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT) randomized 1500 patients to 3 different implantable cardioverter-defibrillator programming arms: (1) Conventional programming with therapy for ventricular tachycardia ≥170 bpm; (2) high-rate cutoff with therapy for ventricular tachycardia ≥200 bpm and a monitoring zone at 170 to 199 bpm, and (3) prolonged 60-second delay with a monitoring zone before therapy. Syncope was a prespecified safety end point that was adjudicated independently. Multivariable Cox models were used to identify risk factors associated with syncope and to analyze subsequent risk of mortality. During follow-up, 64 of 1500 patients (4.3%) had syncope. The incidence of syncope was similar across the 3 treatment arms. Prognostic factors for all-cause syncope included the presence of ischemic cardiomyopathy (hazard ratio [HR], 2.48; 95% confidence interval [CI], 1.42-4.34; P=0.002), previous ventricular arrhythmias (HR, 2.99; 95% CI, 1.18-7.59; P=0.021), left ventricular ejection fraction ≤25% (HR, 1.65; 95% CI, 0.98-2.77; P=0.059), and younger age (by 10 years; HR, 1.25; 95% CI, 1.00-1.52; P=0.046). Syncope was associated with increased risk of death regardless of its cause (arrhythmogenic syncope: HR, 4.51; 95% CI, 1.39-14.64, P=0.012; nonarrhythmogenic syncope: HR, 2.97; 95% CI, 1.07-8.28, P=0.038).
CONCLUSIONS
Innovative programming of implantable cardioverter-defibrillators with therapy for ventricular tachycardia ≥200 bpm or a long delay is not associated with increased risk of arrhythmogenic or all-cause syncope, and syncope caused by slow ventricular tachycardias (<200 bpm) is a rare event. The clinical risk factors associated with syncope are related to increased cardiovascular risk profile, and syncope is associated with increased mortality irrespective of the cause.
CLINICAL TRIAL REGISTRATION URL
http://www.clinicaltrials.gov. Unique identifier: NCT00947310.
背景
目前研究心力衰竭合并植入式心脏复律除颤器患者晕厥机制的研究相对较少，非心律失常性晕厥是否与死亡率增加有关仍存在争议。
方法和结果
多中心自动除颤器植入试验-减少不适当治疗（MADIT-RIT）将 1500 例患者随机分为 3 种不同的植入式心脏复律除颤器编程臂：（1）常规编程，室性心动过速≥170 bpm 时进行治疗；（2）高速率截止，室性心动过速≥200 bpm 时进行治疗，监测区为 170-199 bpm，（3）延长 60 秒延迟，治疗前监测区。晕厥是预先规定的安全性终点，由独立的裁决者进行裁决。多变量 Cox 模型用于确定与晕厥相关的危险因素，并分析随后的死亡率风险。在随访期间，1500 例患者中有 64 例（4.3%）发生晕厥。3 种治疗组的晕厥发生率相似。所有原因晕厥的预测因素包括缺血性心肌病（危险比[HR]，2.48；95%置信区间[CI]，1.42-4.34；P=0.002）、先前的室性心律失常（HR，2.99；95%CI，1.18-7.59；P=0.021）、左心室射血分数≤25%（HR，1.65；95%CI，0.98-2.77；P=0.059）和年龄较小（每 10 岁；HR，1.25；95%CI，1.00-1.52；P=0.046）。无论晕厥的原因如何，晕厥都与死亡风险增加相关（心律失常性晕厥：HR，4.51；95%CI，1.39-14.64，P=0.012；非心律失常性晕厥：HR，2.97；95%CI，1.07-8.28，P=0.038）。
结论
治疗室性心动过速≥200 bpm 或延长延迟的植入式心脏复律除颤器的创新性编程与心律失常性或所有原因晕厥的风险增加无关，而慢室性心动过速（<200 bpm）引起的晕厥是罕见事件。与晕厥相关的临床危险因素与心血管风险状况增加有关，无论病因如何，晕厥均与死亡率增加有关。
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