Heart Rhythm:特发性室颤与右束支阻滞相关

特发性室颤（idiopathic ventricular fibrillation，IVF）定义为原因不明或发病机制不明的心室颤动，Brugada综合征是特发性室颤的一个常见病因，它的心电图表现主要是V1-V3导联的ST段抬高，另外下壁或侧壁导联J波出现或J点抬高也可能与IVF的发生相关，但是目前仍有许多IVF患者不表现为上述心电图特征，因此仍需寻找其他心电图指标以识别IVF患者。
右束支传导阻滞（Right bundle branch block,RBBB）常见于无器质性心脏病的患者，近来有研究表明RBBB可见于IVF患者，因此Chinushi等推测RBBB可能成为识别IVF患者的一种新指标，近来他在Heart Rhythm上发表了一篇临床研究，旨在探讨RBBB与IVF的关系。
该研究的对象为存在RBBB的IVF患者，除外器质性心脏病和原发性电生理异常，采用诱发试验除外Brugada综合征，将这些患者的临床特征与无RBBB的IVF患者及无IVF的RBBB患者进行比较。
结果显示：该研究共入选96例IVF患者，其中9例诊断为Brugada综合征而被排除，故共为87例患者，所有患者均排除器质性心脏病和冠状动脉痉挛。其中10例存在RBBB，比例为11.5%，这些患者的平均年龄为44岁，8例患者为男性，这些患者中3例室颤复发，2例表现为电风暴，肾上腺素&tace=dxy_heart" class="hot1" target="_blank" title="异丙肾上腺素">异丙肾上腺素治疗有效。比较存在RBBB的IVF患者和无RBBB的IVF患者的心电图特征，发现QRS波时限存在RBBB的患者长于无RBBB的患者，其余特征无明显差异。正常人群的RBBB发生率为1.37%，明显低于IVF人群，且存在RBBB的IVF患者的QRS波时限长于正常人群中的RBBB患者，两者的QRS波时限分别为150ms和139ms。
通过该项研究可得出以下结论：RBBB在IVF患者中的发生率明显高于正常人群，且其QRS波宽度大于正常人群，提示可能存在传导异常，因此RBBB可能成为IVF的一种新的预测因素。

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Ventricular fibrillation associated with complete right bundle branch block.
BACKGROUND
A substantial number of patients with idiopathic ventricular fibrillation (IVF) present with no specific electrocardiographic (ECG) findings.
OBJECTIVE
To evaluate complete right bundle branch block (RBBB) among IVF patients.
METHODS
IVF patients showing complete RBBB were included in the present study. Structural and primary electrical diseases were excluded, and provocation tests were performed to exclude the presence of spastic angina or Brugada syndrome (BrS). The prevalence of complete RBBB and the clinical and ECG parameters were compared either with IVF patients without RBBB or with the general population and age and sex comparable control with RBBB.
RESULTS
Out of 96 IVF patients, 9 patients were excluded for the presence of BrS. Out of 87 patients studied, 10 (11.5%) patients revealed complete RBBB. None had structural heart diseases, BrS or coronary spasms. Average age was 44±15 years, and 8 of the 10 were male. Among the ECG parameters, only the QRS duration was different from the other IVF patients without complete RBBB. VF recurred in three: two in the form of storms which were well suppressed by isoproterenol. Complete RBBB was found less often in control subjects　(1.37%, P<0.0001), and the QRS duration was more prolonged in the IVF patients:139±10 versus 150±14 ms (P=0.0061).
CONCLUSION
Complete RBBB exists more often among IVF patients than in controls. A prolonged QRS complex suggests a conduction abnormality. Our findings warrant further investigation of the role of RBBB in the development of arrhythmias among patients with IVF.