2024年10月8日 · Corrected QT interval (QTc) The corrected QT interval (QTc) estimates the QT interval at a standard heart rate of 60 bpm; This allows comparison of QT values over time at different heart rates and improves detection of patients at increased risk of arrhythmias; There are multiple formulas used to estimate QTc.

These reference values are the best available for the neonatal period. The intervals are 98% confidence intervals (the mean is presented in the parenthesis). Values without confidence interval are simply the 98 th percentile (i.e the upper reference limit). Table 2. Reference values for the most important parameters (Rijnbeek et al)

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 ...

2018年10月16日 · Normal range for the QTc is generally accepted as < 0.44 sec or 440 msec. QTc from 0.44-0.46 sec is considered borderline and only significant if symptomatic. Anything greater than 0.46 sec is prolonged QT.

QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, the interpretation of QTc is difficult in neonates due to hemodynamic maturational …

Manual QT-intervals and QTc were determined by the tangent and threshold methods and compared to automatically generated, vendor-provided values. We assessed agreement globally by intra-class correlation coefficients and pairwise by Bland–Altman analyses and 95% limits of agreement (LoA).

Accurate determination of the QTc interval in children is important especially when using drugs which can prolong cardiac repolarization. Previous work suggests the most appropriate correction formula to be QTc = QT/RR 0.38. We set out to compute the best population‐derived age and gender‐related QT correction formula factor in normal children.

2020年9月17日 · Evaluation of the neonatal QT interval is important to diagnose arrhythmia syndromes and evaluate side effects of drugs. We aimed at describing the natural history of the QT interval duration during the first 4 weeks of life and to provide reference values from a large general population sample.

延迟心脏复极化是一些非抗心律失常药物的一个不良特性，可以通过体表心电图 (ECG) 上 QT 间期的延长来衡量。 这种QT间期的延长可致心率失常，最明显的是尖端扭转型室性心动过速 (TdP)。 TdP 可退化为心室颤动，严重的可导致猝死。 从图1可以看出QT 间期是从QRS波群到T波结束的间隔，代表心室去极化和随后的复极化的持续时间。 大多数引起 TdP 的药物都会明显增加绝对 QT，因此对新药上市前在安全性方面包括其对 QT 间期的影响进行充分地研究是非常必要的 …

2023年7月26日 · 2005 年国际人用药品注册技术协调会（ICH）发布了《E14 ：非抗心律失常药物QT/QTc 间期延长及致心律失常潜力的临床评价》详细描述了如何开展一项独立的临床研究进行全面QT/QTc（thorough-QT/QTc study, TQT）的考察，用来充分评估药物对QT间期的影响。