Extramiana Fabrice, Maury Philippe, Maison-Blanche Pierre, Duparc Alexandre, Delay Marc, Leenhardt Antoine
Lariboisière University Hospital, Paris 7 University, APHP, Paris, France.
Am J Cardiol. 2008 Mar 15;101(6):855-60. doi: 10.1016/j.amjcard.2007.10.049. Epub 2008 Feb 21.
The definition of the short QT syndrome (SQTS) is based on QT duration, but thorough QT- and T-wave evaluation has not been performed to date. To evaluate the influence of QT rate-correction formulas in SQTS diagnosis, 12-lead electrocardiograms (ECGs) were recorded in 27 subjects from a single family with SQTS. Based on QT duration corrected by Bazett formula (QTc), 4 men were considered to have SQTS (QTc <or=340 ms), and 16 were classified to have "suspected" SQTS (QT <or=320 ms and/or QTc <or=380 ms). Holter ECGs were recorded in the 4 patients with SQTS, 8 with suspected SQTS, and 62 healthy volunteers. We evaluated QT duration at each RR interval and calculated individual alpha coefficient of the QT/RR relation. The QT interval duration at the mean Holter heart rate was corrected using an individual approach and 5 "universal" correction formulas (Bazett, Fridericia, Sagie-Framingham, Hodges, Rautaharju). Patients with SQTS and controls had lower alpha coefficients of the QT/RR relation when compared with Bazett and Fridericia formulas. The QT rate-dependence was lower in patients with SQTS (alpha 0.146 +/- 0.070) when compared with control subjects (alpha 0.203 +/- 0.039, p <0.05). The universal correction-formulas consistently provided higher values of corrected QT interval duration at the mean Holter heart rate than a subject-specific correction formula (p <0.05), which induced false negative diagnoses. In conclusion, the Bazett correction formula is not appropriate for making a diagnosis of SQTS. The subject-specific correction formula may provide a better cut-off value definition for the diagnosis of SQTS.
短QT综合征（SQTS）的定义基于QT间期，但迄今为止尚未对QT间期和T波进行全面评估。为了评估QT心率校正公式对SQTS诊断的影响，我们记录了来自一个患有SQTS的单一家族的27名受试者的12导联心电图（ECG）。根据Bazett公式校正的QT间期（QTc），4名男性被认为患有SQTS（QTc≤340毫秒），16名被归类为“疑似”SQTS（QT≤320毫秒和/或QTc≤380毫秒）。对4例确诊的SQTS患者、8例疑似SQTS患者和62名健康志愿者进行了动态心电图记录。我们评估了每个RR间期的QT间期，并计算了QT/RR关系的个体α系数。使用个体方法和5种“通用”校正公式（Bazett、Fridericia、Sagie-Framingham、Hodges、Rautaharju）对动态心电图平均心率时的QT间期持续时间进行校正。与Bazett和Fridericia公式相比，SQTS患者和对照组的QT/RR关系α系数较低。与对照组（α0.203±0.039，p<0.05）相比，SQTS患者的QT心率依赖性较低（α0.146±0.070）。通用校正公式在动态心电图平均心率时始终提供比个体校正公式更高的校正QT间期持续时间值（p<0.05），后者会导致假阴性诊断。总之，Bazett校正公式不适用于SQTS的诊断。个体校正公式可能为SQTS的诊断提供更好的临界值定义。
