Background: The prolongation or shortening of heart rate-corrected QT (QTc) predisposes patients to fatal ventricular arrhythmias and sudden cardiac death (SCD), but the association of dynamic change of QTc interval with mortality in the general population remains unclear.

Methods: A total of 11,798 middle-aged subjects from the prospective, population-based cohort were included in this analysis. The QTc interval corrected for heart rate was measured on two occasions around 3 years apart in the Atherosclerosis Risk in Communities (ARIC) study. The ΔQTc interval was calculated by evaluating a change in QTc interval from visit 1 to visit 2.

Results: After a median follow-up of 19.5 years, the association between the dynamic change of QTc interval and endpoints of death was U-shaped. The multivariate-adjusted hazard ratios (HRs) comparing subjects above the 95th percentile of Framingham–corrected ΔQTc (ΔQTcF) (≥32 ms) with subjects in the middle quintile (0–8 ms) were 2.69 (95% CI, 1.68–4.30) for SCD, 2.51 (1.68–3.74) for coronary heart disease death, 2.10 (1.50–2.94) for cardiovascular death, and 1.30 (1.11–1.55) for death from any cause. The corresponding HRs comparing subjects with a ΔQTcF below the fifth percentile (<-23 ms) with those in the middle quintile were 1.82 (1.09–3.05) for SCD, 1.83 (1.19–2.81) for coronary heart disease death, 2.14 (1.51–2.96) for cardiovascular death, and 1.31 (1.11–1.56) for death from any cause. Less extreme deviations of ΔQTcF were also associated with an increased risk of death. Similar, albeit weaker associations also were observed with ΔQTc corrected with Bazett's formula.

Conclusions: A dynamic change of QTc interval is associated with increased mortality risk in the general population, indicating that repeated measurements of the QTc interval may be available to provide additional prognostic information.

背景： 心率校正 QT (QTc) 的延长或缩短使患者容易发生致命的室性心律失常和心源性猝死 (SCD)，但 QTc 间期的动态变化与一般人群死亡率的关系尚不清楚。

方法：本次分析共包括来自前瞻性、基于人群的队列的 11,798 名中年受试者。在社区动脉粥样硬化风险 (ARIC) 研究中，间隔大约 3 年两次测量了校正心率的 QTc 间期。ΔQTc 间期是通过评估 QTc 间期从访问 1 到访问 2 的变化来计算的。

结果：在中位随访 19.5 年之后，QTc 间期的动态变化与死亡终点之间的关联呈 U 型。将高于 Framingham 校正的 ΔQTc (ΔQTcF) (≥32 ms) 的第 95 个百分位的受试者与处于中间五分位 (0-8 ms) 的受试者进行比较的多变量调整风险比 (HR) 为 2.69（95% CI，1.68-4.30） ) 对于 SCD，冠心病死亡为 2.51 (1.68–3.74)，心血管死亡为 2.10 (1.50–2.94)，任何原因死亡为 1.30 (1.11–1.55)。将 ΔQTcF 低于第五个百分位数 (<-23 ms) 的受试者与中间五分之一的受试者进行比较的相应 HR 为 SCD 的 1.82 (1.09-3.05)，冠心病死亡的 1.83 (1.19-2.81)，2.14 (1.51- 2.96) 为心血管死亡，1.31 (1.11-1.56) 为任何原因死亡。ΔQTcF 的不太极端的偏差也与死亡风险增加有关。类似地，尽管用 Bazett 公式校正的 ΔQTc 也观察到较弱的关联。

结论： QTc 间期的动态变化与一般人群死亡风险的增加有关，这表明 QTc 间期的重复测量可用于提供额外的预后信息。