Data_Sheet_1_QT interval dynamics in patients with ST-elevation MI.docx

BackgroundAn association between excessively prolonged QT and ventricular arrhythmia in patients with ST-elevation myocardial infarction has been described; however, the QT dynamics, characterization, and long-term predictive value are not well known.
ObjectiveTo characterize QT interval dynamics in patients undergoing ST elevation myocardial infarction (STEMI) and determine its association with mortality.
MethodsA retrospective analysis of 4,936 consecutive patients, hospitalized for STEMI between 01/2013–12/2021. Patients with less than three electrocardiograms (ECGs) during index hospitalization were excluded. Baseline demographics, cardiovascular history, clinical risk factors, treatment measures, laboratory results, and mortality data were retrieved from the hospital’s electronic medical records.
ResultsWe included 1,054 patients and 5,021 ECGs in our cohort with a median follow-up of 6 years [interquartile range (IQR) 4.3–7.4 years]. The QT was longer in women in comparison to men (428.6 ms ± 33.4 versus 419.8 ms ± 32.52, P-value = 0.001). QT prolongation was greater in females, elderly patients, and patients with STEMI caused by occlusion of the left anterior descending (LAD) coronary artery. We determined QT cutoff to be 445 ms. This value of QT divided our cohort upon arrival into a long QT group (217 patients, 26% of the cohort) and a “normal” QT group (835 patients, 74% of the cohort). The long QT group experienced an increase in combined short and long terms all-cause mortality. The QT upon arrival, on day 2 of hospitalization, and before discharge from the hospital, correlated with long-term mortality.
ConclusionQT duration is often prolonged during STEMI; this prolongation is associated with increased mortality and adverse events. Gender is an important mediator of QT dynamics.

**研究背景** 已有研究报道ST段抬高型心肌梗死（ST-elevation myocardial infarction, STEMI）患者QT间期（QT interval）过度延长与室性心律失常（ventricular arrhythmia）存在关联，但目前对于QT间期的动态变化、特征及其长期预测价值仍未完全阐明。
**研究目的** 旨在明确ST段抬高型心肌梗死（ST-elevation myocardial infarction, STEMI）患者的QT间期动态变化特征，并探究其与患者死亡率的相关性。
**研究方法** 本研究为回顾性分析，纳入2013年1月至2021年12月期间因STEMI住院的连续4936例患者。排除首次住院期间心电图（electrocardiogram, ECG）检查次数少于3次的受试者。从医院电子病历系统中提取患者的基线人口学资料、心血管病史、临床危险因素、治疗方案、实验室检测结果及死亡率数据。
**研究结果** 最终本队列共纳入1054例患者及5021份心电图，中位随访时间为6年[四分位间距（interquartile range, IQR）4.3~7.4年]。女性患者的QT间期显著长于男性（428.6 ms ±33.4 vs 419.8 ms ±32.52，P=0.001）。女性、老年患者以及左前降支（left anterior descending, LAD）冠状动脉闭塞所致STEMI患者的QT间期延长程度更为显著。本研究确定QT间期的截断值为445 ms，以此将入院时的患者队列分为长QT间期组（217例，占队列的26%）与“正常”QT间期组（835例，占队列的74%）。长QT间期组患者的短期及长期全因死亡率均显著升高。入院时、住院第2天及出院前的QT间期均与患者的长期死亡率存在显著相关性。
**研究结论** STEMI患者的QT间期常出现延长，此种延长与患者死亡率升高及不良事件发生风险增加密切相关；性别是调控QT间期动态变化的重要中介因素。