2022年12月26日 · QTc is prolonged if it is greater than 440 ms in men or greater than 460 ms in women. A QTc greater than 500 is associated with an increased risk of torsade de pointes. While several equations exist to help correct heart rate variation, the Bazett formula (QTC = QT / √ RR) is the most commonly used.

From a screening perspective, a QTc value ≥470 ms for a 2–4-week-old infant screening programme or a QTc ≥500 ms in adolescents/adults may represent far more optimal “penalty box” screening values with an estimated positive predictive value >50%.

2018年8月23日 · In this study, we present the results of a large cohort of LQTS patients and controls with a comprehensive evaluation of QTc cutoff values specified for QT interval measurement method, including corrections for heart rate, age, and sex.

2019年6月10日 · To this end, a prolonged QTc, defined as a QTc value >450 ms in males and >460 ms in females measured preferably in lead II or V 5 on a standard 12-lead ECG, predisposes to functional reentry, torsades de pointes, and sudden cardiac death (SCD), and represents a widely accepted, easily measured, and quantifiable risk factor for adverse outcomes ...

The Corrected QT Interval (QTc) adjusts the QT interval correctly for heart rate extremes.

This online evidence based resource will help guide you how to measure the QT interval and calculate the QTc value with an easy to use calculator which takes into account the patients underlying rhythm, gender and age.

This review discusses the components of accurate QTc measurement and diagnosis, re-examines what is known about factors affecting QT interval measurement, and clarifies current recommendations regarding diagnosis of so-called “borderline” QT interval prolongation.

2023年11月23日 · QT间期延长的原因可以是先天性和遗传的常染色体显性变异，也可以是短暂的和获得性的，通常是因为服用可延长QT间期轻的药物或电解质异常所致。 在临床上，该如何管理QT间期延长患者？ 本文根据加拿大心血管学会（CCS）最新发布的共识文件给出总结！ 1 QT间期是什么？ 心电图QT间期是从心室去极化开始到复极结束的总时程，反映了心室动作电位的持续时间（图1）。 心率、年龄、性别、循环儿茶酚胺和自主神经张力变化均会引起QT间期的轻度 …

2024年5月9日 · A maximum QTc threshold of 520 ms and median QTc threshold of 490 ms were determined to be strong predictors for BCEs. A landmark analysis controlling for age, sex, genotype, and symptomatic status demonstrated models utilizing both the median QTc and maximum QTc demonstrated the highest discriminatory value (c-statistic = 0.93–0.95).

At extremes of Heart Rate the Hodges correction may perform better than Bazett correction. Upper limit of normal is usually defined as 440 msec. A QTc >540 msec confers a 1.7x increased risk of...