Cardiology Division of the Department of Medicine, University of Rochester Medical Center, Rochester, New York, USA.
J Am Coll Cardiol. 2010 Feb 23;55(8):783-8. doi: 10.1016/j.jacc.2009.11.042.
The aim of this study was to identify risk factors for fatal arrhythmias in long QT syndrome (LQTS) patients presenting with syncope.
Syncope is highly predictive for future fatal arrhythmias in the LQTS. However, there are no data regarding risk stratification and management strategies in the high-risk subset of LQTS patients presenting with syncope.
A total of 1,059 LQTS patients with a corrected QT interval > or =450 ms presenting with syncope as a first symptom were drawn from the International LQTS Registry. Cox proportional hazards regression was used to identify risk factors for a severe arrhythmic events comprising aborted cardiac arrest, appropriate implantable cardioverter-defibrillator therapy, and sudden cardiac death.
The lowest risk was found in patients with only 1 syncopal episode occurring before the start of beta-blocker therapy. In contrast, patients experiencing syncope after starting beta-blocker therapy had a 3.6-fold increase in the risk of severe arrhythmic events (p < 0.001) relative to this low-risk group and displayed a risk of severe arrhythmic events similar to that of patients not treated with beta-blockers. Multiple syncopal episodes occurring before initiation of beta-blocker therapy were associated with an intermediate risk (hazard ratio: 1.8, p < 0.001). The risk of syncope during beta-blocker therapy is high during childhood in both sexes but is higher in women than in men (hazard ratio: 2.3, p < 0.001).
Patients with syncope during beta-blocker therapy are at high risk of life-threatening events, and implantable cardioverter-defibrillator therapy should be considered in these patients. The risk of beta-blocker failure is highest in young children and in women.
本研究旨在确定长 QT 综合征（LQTS）患者晕厥首发时发生致命性心律失常的危险因素。
晕厥对 LQTS 患者未来发生致命性心律失常具有高度预测性。然而，对于晕厥首发的 LQTS 高危亚组患者，尚无关于风险分层和管理策略的数据。
从国际 LQTS 注册中心共抽取 1059 例 QTc 间期>或=450 ms 的 LQTS 患者，这些患者晕厥为首发症状。采用 Cox 比例风险回归分析确定由心搏骤停、恰当的植入式心脏复律除颤器治疗和心源性猝死组成的严重心律失常事件的危险因素。
仅在开始使用β受体阻滞剂治疗前发生 1 次晕厥的患者风险最低。相比之下，在开始β受体阻滞剂治疗后发生晕厥的患者严重心律失常事件的风险增加了 3.6 倍（p < 0.001），与低危组相比，发生严重心律失常事件的风险与未接受β受体阻滞剂治疗的患者相似。在开始β受体阻滞剂治疗前发生多次晕厥与中间风险相关（危险比：1.8，p < 0.001）。β受体阻滞剂治疗期间儿童期晕厥的风险在两性中均较高，但女性高于男性（危险比：2.3，p < 0.001）。
β受体阻滞剂治疗期间发生晕厥的患者发生危及生命的事件的风险很高，应考虑在这些患者中植入式心脏复律除颤器治疗。β受体阻滞剂治疗失败的风险在幼儿和女性中最高。
