Phan Derek Q, Silka Michael J, Lan Yueh-Tze, Chang Ruey-Kang R
Division of Pediatric Cardiology, Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles Medical Center, Torrance, CA.
Division of Cardiology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA.
J Pediatr. 2015 Apr;166(4):960-4.e1-2. doi: 10.1016/j.jpeds.2014.12.037. Epub 2015 Jan 31.
To compare 4 heart rate correction formulas for calculation of the rate corrected QT (QTc) interval among infants and young children.
R-R and QT intervals were measured from digital electrocardiograms. QTc were calculated with the Bazett, Fridericia, Hodges, and Framingham formulas. QTc vs R-R graphs were plotted, and slopes of the regression lines compared. Slopes of QTc-R-R regression lines close to zero indicate consistent QT corrections over the range of heart rates.
We reviewed electrocardiograms from 702 children, with 233 (33%) <1 year of age and 567 (81%) <2 years. The average heart rate was 122 ± 20 bpm (median 121 bpm). The slopes of the QTc-R-R regression lines for the 4 correction formulas were -0.019 (Bazett); 0.1028 (Fridericia); -0.1241 (Hodges); and 0.2748 (Framingham). With the Bazett formula, a QTc >460 ms was 2 SDs above the mean, compared with "prolonged" QTc values of 414, 443, and 353 ms for the Fridericia, Hodges, and Framingham formulas, respectively.
The Bazett formula calculated the most consistent QTc; 460 ms is the best threshold for prolonged QTc. The study supports continued use of the Bazett formula for infants and children and differs from the use of the Fridericia correction during clinical trials of new medications.
比较4种心率校正公式在婴幼儿中计算校正QT（QTc）间期的情况。
从数字心电图中测量R-R间期和QT间期。用Bazett、Fridericia、Hodges和Framingham公式计算QTc。绘制QTc与R-R的关系图，并比较回归线的斜率。QTc-R-R回归线斜率接近零表明在心率范围内QT校正一致。
我们回顾了702名儿童的心电图，其中233名（33%）年龄<1岁，567名（81%）年龄<2岁。平均心率为122±20次/分（中位数121次/分）。4种校正公式的QTc-R-R回归线斜率分别为：-0.019（Bazett）；0.1028（Fridericia）；-0.1241（Hodges）；0.2748（Framingham）。使用Bazett公式时，QTc>460 ms比平均值高2个标准差，而Fridericia、Hodges和Framingham公式的“QTc延长”值分别为414、443和353 ms。
Bazett公式计算的QTc最一致；460 ms是QTc延长的最佳阈值。该研究支持在婴幼儿中继续使用Bazett公式，这与新药临床试验中使用Fridericia校正不同。
