It has been recognized that heart rate variability (HRV), defined as the fluctuation of ventricular response intervals in atrial fibrillation (AFib) patients, is not completely random, and its nonlinear characteristics, such as multiscale entropy (MSE), contain clinically significant information. We investigated the relationship between ischemic stroke risk and HRV with a large number of stroke-naïve AFib patients (628 patients), focusing on those who had never developed an ischemic/hemorrhagic stroke before the heart rate measurement. The ${\mathrm{CHA}}_2{\mathrm{DS}}_2-\mathrm{VASc}$ score was calculated from the baseline clinical characteristics, while the HRV analysis was made from the recording of morning, afternoon, and evening. Subsequently, we performed Kaplan–Meier method and cumulative incidence function with mortality as a competing risk to estimate the survival time function. We found that patients with sample entropy ($S_E^{\left(s\right)}$) $\ge$ 0.68 at 210 s had a significantly higher risk of an ischemic stroke occurrence in the morning recording. Meanwhile, the afternoon recording showed that those with $S_E^{\left(s\right)}$ $\ge$ 0.76 at 240 s and $S_E^{\left(s\right)}$ $\ge$ 0.78 at 270 s had a significantly lower risk of ischemic stroke occurrence. Therefore, $S_E^{\left(s\right)}$ at 210 s (morning) and 240 s ≤ s ≤ 270 s (afternoon) demonstrated a statistically significant predictive value for ischemic stroke in stroke-naïve AFib patients.

中文翻译：

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通过多尺度熵分析对持续性心房颤动患者心率变异性进行缺血性卒中风险评估

人们已经认识到，心率变异性（HRV），定义为房颤（AFib）患者心室反应间隔的波动，并不是完全随机的，其非线性特征，如多尺度熵（MSE），包含有临床意义的信息. 我们通过大量未发生过卒中的 AFib 患者（628 名患者）研究了缺血性卒中风险与 HRV 之间的关系，重点关注那些在测量心率之前从未发生过缺血性/出血性卒中的患者。这${\mathrm{查房}}_2{\mathrm{DS}}_2-\mathrm{VASc}$评分是根据基线临床特征计算的，而HRV分析是根据早上、下午和晚上的记录进行的。随后，我们使用 Kaplan-Meier 方法和累积发生率函数，以死亡率作为竞争风险来估计生存时间函数。我们发现样本熵（${秒}_{乙}^{\left(秒\right)}$) $\ge$0.68 在 210 s 有一个显着较高的缺血性中风发生的风险在早上记录。与此同时，下午的录音显示，那些有${秒}_{乙}^{\left(秒\right)}$ $\ge$ 0.76 在 240 秒和 ${秒}_{乙}^{\left(秒\right)}$ $\ge$270 秒时 0.78 发生缺血性中风的风险显着降低。所以，${秒}_{乙}^{\left(秒\right)}$ 在 210 秒（早上）和 240 秒 ≤ 秒 ≤ 270 秒（下午）显示出对未发生卒中的 AFib 患者的缺血性卒中具有统计学意义的预测价值。