Centro de Investigación Biomédica en Red-Bioingeniería, Biomateriales y Nanomedicina, Universidad de Zaragoza, Zaragoza, Spain.
BSICoS Group, Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, Spain.
PLoS One. 2019 Feb 25;14(2):e0212971. doi: 10.1371/journal.pone.0212971. eCollection 2019.
Patients with left bundle branch block (LBBB) are known to have a good clinical response to cardiac resynchronization therapy. However, the high number of false positive diagnosis obtained with the conventional LBBB criteria limits the effectiveness of this therapy, which has yielded to the definition of new stricter criteria. They require prolonged QRS duration, a QS or rS pattern in the QRS complexes at leads V1 and V2 and the presence of mid-QRS notch/slurs in 2 leads within V1, V2, V5, V6, I and aVL. The aim of this work was to develop and assess a fully-automatic algorithm for strict LBBB diagnosis based on the wavelet transform. Twelve-lead, high-resolution, 10-second ECGs from 602 patients enrolled in the MADIT-CRT trial were available. Data were labelled for strict LBBB by 2 independent experts and divided into training (n = 300) and validation sets (n = 302) for assessing algorithm performance. After QRS detection, a wavelet-based delineator was used to detect individual QRS waves (Q, R, S), QRS onsets and ends, and to identify the morphological QRS pattern on each standard lead. Then, multilead QRS boundaries were defined in order to compute the global QRS duration. Finally, an automatic algorithm for notch/slur detection within the QRS complex was applied based on the same wavelet approach used for delineation. In the validation set, LBBB was diagnosed with a sensitivity and specificity of Se = 92.9% and Sp = 65.1% (Acc = 79.5%, PPV = 74% and NPV = 89.6%). The results confirmed that diagnosis of strict LBBB can be done based on a fully automatic extraction of temporal and morphological QRS features. However, it became evident that consensus in the definition of QRS duration as well as notch and slurs definitions is necessary in order to guarantee accurate and repeatable diagnosis of complete LBBB.
患有左束支传导阻滞（LBBB）的患者已知对心脏再同步治疗有良好的临床反应。然而，常规 LBBB 标准获得的大量假阳性诊断限制了这种治疗的有效性，因此定义了新的更严格的标准。这些标准需要延长 QRS 持续时间，在 V1 和 V2 导联的 QRS 综合波中出现 QS 或 rS 形态，并且在 V1、V2、V5、V6、I 和 aVL 导联中存在 2 个导联中的中 QRS 切迹/模糊。本工作旨在开发和评估基于小波变换的严格 LBBB 诊断的全自动算法。可从 MADIT-CRT 试验中纳入的 602 例患者的 12 导联、高分辨率、10 秒 ECG 中获得数据。数据由 2 位独立专家进行严格 LBBB 标记，并分为训练集（n = 300）和验证集（n = 302），以评估算法性能。在 QRS 检测后，使用基于小波的描绘符检测单个 QRS 波（Q、R、S）、QRS 起始和结束，并识别每个标准导联上的形态 QRS 模式。然后，定义多导联 QRS 边界，以计算全局 QRS 持续时间。最后，应用基于用于描绘的相同小波方法的自动算法来检测 QRS 综合波内的切迹/模糊。在验证集中，LBBB 的诊断灵敏度和特异性分别为 Se = 92.9%和 Sp = 65.1%（Acc = 79.5%、PPV = 74%和 NPV = 89.6%）。结果证实，可以基于 QRS 时间和形态特征的全自动提取来诊断严格的 LBBB。然而，很明显，需要在 QRS 持续时间以及切迹和模糊定义方面达成共识，以确保对完全性 LBBB 的准确和可重复诊断。
