Department of Cardiology Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University Beijing China.
J Am Heart Assoc. 2024 Jul 16;13(14):e033619. doi: 10.1161/JAHA.123.033619. Epub 2024 Jul 9.
Few small-sample studies have quantified the T-wave alternans (TWA) value by 24-hour ambulatory recordings or exercise stress tests in patients with long QT syndrome (LQTS). The cutoff point of TWA ≥47 μV was based on patients with myocardial infarction. In our study, we aimed to (1) evaluate the association of TWA with life-threatening arrhythmic events (LAEs); (2) compare the predictive model of LAEs according to the TWA value measured by 24-hour ambulatory recordings and exercise stress tests; and (3) propose a cutoff point for the high risk of LAEs in patients with LQTS.
The study cohort included 110 patients with LQTS referred to our hospital, and the primary outcome was LAEs. Thirty-one patients with LQTS (31/110 [28.2%]) developed LAEs during the following 24 (12-47) months. Peak TWA value quantified from 12 leads by 24-hour ambulatory recordings in patients with LQTS with LAEs (LQTS-LAEs group) was significantly higher than LQTS without LAEs (LQTS-non-LAEs group) (64.0 [42.0-86.0] μV versus 43.0 [36.0-53.0] μV; <0.01). There was no statistical difference in TWA value measured by exercise stress tests between the 2 groups (69.0 [54.5-127.5] μV versus 68.5 [53.3-99.8] μV; =0.871). The new cutoff point of the peak TWA value measured by 24-hour ambulatory recordings was 55.5 μV, with a sensitivity of 75.0% and a specificity of 78.6%. A univariate Cox regression analysis revealed that TWA value ≥55.5 μV was a strong predictor of LAEs (hazard ratio [HR], 4.5 [2.1-9.6]; <0.001]. A multivariate Cox regression analysis indicated that TWA value ≥55.5 μV remained significant (HR, 2.7 [1.1-6.8]; =0.034).
Peak TWA measured by 24-hour ambulatory recordings was a more favorable risk stratification marker than exercise stress tests for patients with LQTS.
很少有小样本研究通过 24 小时动态记录或运动应激试验量化长 QT 综合征（LQTS）患者的 T 波交替（TWA）值。TWA≥47μV 的截断点基于心肌梗死患者。在我们的研究中，我们旨在：（1）评估 TWA 与威胁生命的心律失常事件（LAE）的关系；（2）比较 24 小时动态记录和运动应激试验测量的 TWA 值的 LAE 预测模型；（3）提出 LQTS 患者 LAE 高危的截断点。
研究队列包括 110 例转诊至我院的 LQTS 患者，主要结局为 LAE。31 例 LQTS 患者（31/110[28.2%]）在随后的 24（12-47）个月内发生 LAE。LQTS 伴 LAE（LQTS-LAE 组）患者的 24 小时动态记录 12 导联 TWA 峰值明显高于 LQTS 无 LAE（LQTS-non-LAE 组）（64.0[42.0-86.0]μV 比 43.0[36.0-53.0]μV；<0.01）。两组间运动应激试验测量的 TWA 值无统计学差异（69.0[54.5-127.5]μV 比 68.5[53.3-99.8]μV；=0.871）。24 小时动态记录 TWA 峰值的新截断点为 55.5μV，灵敏度为 75.0%，特异性为 78.6%。单变量 Cox 回归分析显示，TWA 值≥55.5μV 是 LAE 的强预测因子（危险比[HR]，4.5[2.1-9.6]；<0.001）。多变量 Cox 回归分析表明，TWA 值≥55.5μV 仍然显著（HR，2.7[1.1-6.8]；=0.034）。
与运动应激试验相比，24 小时动态记录的 TWA 峰值是 LQTS 患者更有利的风险分层标志物。
