In Reply We agree with Popkirov that left atrial volume is a better marker of incident atrial fibrillation than atrial diameter¹; however, we did not have these data available at all of the sites participating in the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS) trial.² Recently completed³ and ongoing⁴ studies will help determine if our observation has a clinical role and may provide additional data on left atrial size and function. Once all of these data are available, guidelines committees will likely make recommendations regarding the threshold values of left atrial size (if present) for which anticoagulation therapy appears beneficial for patients with embolic stroke of undetermined source. Such recommendations would have to consider how to extrapolate the clinical trial results, allowing for the many different methods for assessing left size. The clinical use of the proposed, nongated computed tomography protocol⁵ is interesting, but should await additional studies to define its sensitivity and specificity compared with echocardiography, particularly for detecting other potential cardioembolic causes of stroke, such as patent foramen ovale and left ventricular thrombus.⁶

在答复中，我们同意Popkirov的观点，即左心房容积比房径¹更能反映房颤的发生。但是，我们没有在全球性试验与ASA中采用新方法利伐沙班抑制因子Xa抑制ASA来预防不确定来源栓塞性卒中的栓塞（NAVIGATE-ESUS）试验的所有站点上都没有这些数据。²最近完成的³和正在进行的⁴研究将有助于确定我们的观察是否具有临床作用，并可能提供有关左心房大小和功能的其他数据。一旦获得所有这些数据，指导委员会将可能就左心房大小的阈值（如果存在）提出建议，对于这些左心房大小的阈值，抗凝治疗对未确定栓塞性卒中患者似乎有益。此类建议必须考虑如何推断临床试验结果，从而允许采用多种不同的方法来评估左手尺寸。拟议的非门控X线断层扫描方案的临床使用⁵有趣的是，但与超声心动图相比，应等待更多的研究来确定其敏感性和特异性，特别是对于检测其他可能的中风原因，如卵圆孔未闭和左心室血栓。⁶