Recent researches suggested that the risk of drug-induced QTc prolongation is low in child and adolescent psychiatry setting. However, these cohorts enrolled mainly of Caucasian background. We aimed to assess the prevalence of QTc prolongation and its association with antipsychotic use in Japanese youth. The medical records of inpatients were reviewed. Two different definitions of QT prolongation, Bazett's corrected QT interval (QTcB) >450 msec and Fridericia's corrected QT interval (QTcF) >450 msec, were adopted. In 220 participants [age: 13.4 ± 2.3 years, antipsychotics according to the chlorpromazine equivalence: 50 (25th-75th percentiles; 0-150) mg/day], the prevalence of QTcB and QTcF prolongation was 13.6 and 2.3%, respectively. Patients with QTcB >450 msec had a significantly higher heart rate than those with QTcB ≤450 msec (91.2 ± 20.6 bpm vs. 76.1 ± 15.2 bpm; P < 0.001). The other variables, except potassium level (4.1 ± 0.4 mEq/L vs. 4.2 ± 0.3 mEq/L; P = 0.030), showed no significant difference. Clinically meaningful QTc prolongation was rare even in this Japanese cohort. This study also suggested that if QTcB is used, clinicians should be aware of possible overdiagnosis of QTc prolongation due to accelerated heart rate.

中文翻译：

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与 Friderica 相比，Bazett 高估了日本儿童和青少年住院患者的 QT 间期延长。

最近的研究表明，在儿童和青少年精神病学环境中，药物引起的 QTc 延长的风险较低。然而，这些队列主要是白种人背景。我们旨在评估 QTc 延长的患病率及其与日本青年使用抗精神病药的关联。对住院患者的病历进行了审查。采用了两种不同的 QT 间期延长定义，即 Bazett 校正 QT 间期 (QTcB) > 450 毫秒和 Fridericia 校正 QT 间期 (QTcF) > 450 毫秒。在 220 名参与者 [年龄：13.4 ± 2.3 岁，抗精神病药根据氯丙嗪等效剂量：50（第 25-75 个百分位数；0-150）mg/天]中，QTcB 和 QTcF 延长的发生率分别为 13.6% 和 2.3%。QTcB 患者 > 450 毫秒的心率明显高于 QTcB ≤ 450 毫秒的心率（91.2 ± 20.6 bpm 与 76.1 ± 15.2 bpm；P < 0.001）。除了钾水平（4.1 ± 0.4 mEq/L vs. 4.2 ± 0.3 mEq/L；P = 0.030）外，其他变量没有显着差异。即使在这个日本队列中，具有临床意义的 QTc 延长也很少见。该研究还表明，如果使用 QTcB，临床医生应该意识到由于心率加快可能导致 QTc 延长的过度诊断。