Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, Amsterdam, The Netherlands.
Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands.
Europace. 2021 Dec 7;23(12):2020-2028. doi: 10.1093/europace/euab128.
In patients with Brugada syndrome (BrS) but without spontaneous Type-1 electrocardiogram, several electrocardiographic characteristics have been studied, including the β-angle. Previous studies suggested that the β-angle might be useful in distinguishing BrS-patients from patients with only suggestive repolarization patterns without performing sodium channel blocker provocation testing. In this study, we aimed to determine the diagnostic value of the β-angle in patients suspected of BrS.
A large cohort (n = 1430) of consecutive patients who underwent provocation testing was evaluated. β-angles were measured in leads V1, V2, and their corresponding positions over the second and third intercostal space. Receiver-operating characteristic curves were constructed and the diagnostic accuracy of previously reported β-angle cut-offs were calculated and evaluated. The importance of the β-angle for predicting the provocation test outcome was determined using a prediction model constructed with logistic regression. The optimum β-angle cut-off in our cohort for ruling out a positive provocation test was 15°; sensitivities were 80-98% and negative predictive values were 79-96% among the right precordial leads. Previously reported β-angle cut-offs performed less well, indicated by lower Youden indices. In the optimism-corrected prediction model [C-statistic: 0.78 (95% CI: 0.75-0.81)], the β-angle had large value (Z-score: 2.1-10.3) and aided construction of a nomogram to predict test outcome.
To predict the outcome of provocation testing for BrS, the β-angle alone does not demonstrate strong diagnostic characteristics. However, the β-angle is an important variable to predict provocation test outcome and thus has added value.
在 Brugada 综合征（BrS）患者中，存在自发 1 型心电图，但也存在几种心电图特征，包括β角。先前的研究表明，β角可能有助于在不进行钠通道阻滞剂激发试验的情况下，将 BrS 患者与仅存在提示性复极模式的患者区分开来。在本研究中，我们旨在确定β角在疑似 BrS 患者中的诊断价值。
评估了接受激发试验的连续患者的大队列（n=1430）。在 V1、V2 导联及其相应的第二和第三肋间位置测量β角。构建了接受者操作特征曲线，并计算和评估了先前报道的β角截断值的诊断准确性。使用逻辑回归构建的预测模型确定了β角对预测激发试验结果的重要性。在我们的队列中，排除阳性激发试验的最佳β角截断值为 15°；右胸导联的敏感度为 80-98%，阴性预测值为 79-96%。先前报道的β角截断值表现较差，提示约登指数较低。在优化校正的预测模型[C 统计量：0.78（95%置信区间：0.75-0.81）]中，β角具有较大的值（Z 分数：2.1-10.3），并有助于构建预测试验结果的列线图。
单独使用β角预测 BrS 激发试验的结果并不能显示出较强的诊断特征。然而，β角是预测激发试验结果的重要变量，因此具有附加价值。
