Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France.
Service Cardiologie, GH Sud. Saint Pierre La Réunion, Saint-Pierre, France.
PLoS One. 2020 Mar 3;15(3):e0229078. doi: 10.1371/journal.pone.0229078. eCollection 2020.
Brugada syndrome (BS) is a genetic pathological condition associated with a high risk for sudden cardiac death (SCD). Ventricular depolarization disorders have been suggested as a potential electrophysiological mechanism associated with high SCD risk on patients with BS. This paper aims to characterize the dynamic changes of ventricular depolarization observed during physical exercise in symptomatic and asymptomatic BS patients. To this end, cardiac ventricular depolarization features were automatically extracted from 12-lead ECG recordings acquired during standardized exercise stress test in 110 BS patients, of whom 25 were symptomatic. Conventional parameters were evaluated, including QRS duration, R and S wave amplitudes ([Formula: see text], [Formula: see text]), as well as QRS morphological features, such as up-stroke and down-stroke slopes of the R and S waves ([Formula: see text], [Formula: see text] and [Formula: see text]). The effects of physical exercise and recovery on the dynamics of these markers were assessed in both BS populations. Features showing significantly different dynamics between the studied groups were used alone and in combination with the clinical characteristics of the patients in a logistic regression analysis. Results show larger changes in the second half of the QRS complex through [Formula: see text] and [Formula: see text] measured in the right precordial leads for asymptomatic patients, especially during recovery, when the vagal tone is more pronounced. Multivariate analysis involving both types of features resulted in a reduced model of three relevant features ([Formula: see text] in lead V2, Sex and heart rate recovery, HRR), which achieved a suitable discrimination performance between groups; sensitivity = 80% and specificity = 75% (AUC = 83%). However, after controlling the model for possible confounding factors, only one feature ([Formula: see text]) remained meaningful. This adjusted model significantly improved the overall discrimination performance by up to: sensitivity = 84% and specificity = 100% (AUC = 94%). The study highlights the importance of physical exercise test to unmask differentiated behaviors between symptomatic and asymptomatic BS patients through depolarization dynamic analysis. This analysis together with the obtained model may help to identify asymptomatic patients at low or high risk of future cardiac events, but it should be confirmed by further prospective studies.
布鲁加达综合征（BS）是一种与心脏性猝死（SCD）风险高度相关的遗传性病理状况。已提出心室去极化障碍是与 BS 患者高 SCD 风险相关的潜在电生理机制。本文旨在描述有症状和无症状 BS 患者在进行体力活动时观察到的心室去极化的动态变化。为此，从 110 名 BS 患者的标准化运动应激测试中获得的 12 导联心电图记录中自动提取了心脏心室去极化特征，其中 25 名患者有症状。评估了常规参数，包括 QRS 持续时间、R 和 S 波幅度([Formula: see text]、[Formula: see text])，以及 QRS 形态特征，如 R 和 S 波的上升和下降斜率([Formula: see text]、[Formula: see text]和[Formula: see text])。评估了体力活动和恢复对这两个 BS 人群中这些标记物动态的影响。在逻辑回归分析中，使用在研究组之间表现出明显不同动态的特征，单独使用和与患者的临床特征结合使用。结果表明，无症状患者右侧胸前导联的[Formula: see text]和[Formula: see text]测量的 QRS 复合体后半部分的变化更大，尤其是在恢复期间，那时迷走神经张力更为明显。涉及这两种特征的多变量分析导致了三个相关特征的简化模型([Formula: see text]在导联 V2、性别和心率恢复，HRR)，该模型在组间具有适当的区分性能；敏感性=80%，特异性=75%(AUC=83%)。然而，在控制模型中可能的混杂因素后，只有一个特征([Formula: see text])仍然有意义。调整后的模型显著提高了整体区分性能，最高可达：敏感性=84%，特异性=100%(AUC=94%)。该研究强调了运动测试的重要性，通过去极化动态分析揭示有症状和无症状 BS 患者之间的不同行为。这种分析与获得的模型一起，可以帮助识别未来心脏事件风险低或高的无症状患者，但需要进一步的前瞻性研究来证实。
