Cardiology Division, Veterans Affairs Palo Alto Health Care System/Stanford University, Palo Alto, California; Division of Cardiology, Department of Medicine, University of California, San Francisco, California.
Cardiology Division, Veterans Affairs Palo Alto Health Care System/Stanford University, Palo Alto, California.
Heart Rhythm. 2017 Aug;14(8):1210-1216. doi: 10.1016/j.hrthm.2017.05.002. Epub 2017 May 8.
The results from studies of the association of QT prolongation with cardiovascular death (CVD) have been inconsistent.
The purpose of this study was to compare the major correction formulas to percentile values of QT for heart rate ranges as to their ability to remove the relationship of QT to heart rate and to predict CVD.
Participants were 16,531 veterans who had an initial ECG at the Veterans Affairs Medical Center, Palo Alto, between March 31, 1987, and December 20, 1999, and were followed for CVD. The 4 major correction formulas (Bazett, Fridericia, Framingham, and Hodges) were used to correct QT interval. In addition, the percentiles for heart rate ranges as proposed by Schwartz were calculated.
During median follow-up of 17.8 years, 455 CVD events occurred. When compared to the other equations, QTc Bazett had the greatest dependence on heart rate (R = 0.18). The hazard ratio (95% confidence interval) for CVD was 2.08 (1.28-3.9) for the 98th percentile of QT interval by heart rate ranges, 2.05 (1.27-3.33) for QTc Bazett, 1.39 (0.44-4.34) for QTc Fridericia, 1.05 (0.26-4.24) for QTc Hodges, and 1.12 (0.28-4.52) for QTc Framingham. The hazard ratio of QTc Bazett was significantly higher than the other formulas except for the 98th percentile method.
The Framingham, Hodges, and Fridericia equations remove the effect of heart rate on QT interval significantly better than the Bazett equation. Using QT-interval percentiles based on heart rate provides a consistent approach both for identifying those whose QT intervals prolong due to drugs or other stressors and for assessing CVD risk.
QT 延长与心血管死亡（CVD）相关的研究结果一直不一致。
本研究旨在比较主要的校正公式与 QT 对心率范围的百分位值，以评估它们消除 QT 与心率之间关系的能力，并预测 CVD。
参与者为 1987 年 3 月 31 日至 1999 年 12 月 20 日期间在帕洛阿尔托退伍军人事务医疗中心进行首次心电图检查的 16531 名退伍军人，并对 CVD 进行随访。使用了 4 种主要的校正公式（Bazett、Fridericia、Framingham 和 Hodges）来校正 QT 间期。此外，还计算了 Schwartz 提出的心率范围的百分位值。
在中位数为 17.8 年的随访期间，发生了 455 例 CVD 事件。与其他方程相比，QTc Bazett 对心率的依赖性最大（R=0.18）。心率范围第 98 百分位 QT 间期的 CVD 风险比（95%置信区间）为 2.08（1.28-3.9），QTc Bazett 为 2.05（1.27-3.33），QTc Fridericia 为 1.39（0.44-4.34），QTc Hodges 为 1.05（0.26-4.24），QTc Framingham 为 1.12（0.28-4.52）。除第 98 百分位方法外，QTc Bazett 的风险比明显高于其他公式。
与 Bazett 方程相比，Framingham、Hodges 和 Fridericia 方程显著更好地消除了心率对 QT 间期的影响。使用基于心率的 QT 间期百分位值为识别因药物或其他应激源导致 QT 间期延长的人群以及评估 CVD 风险提供了一种一致的方法。
