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.

2024年10月8日 · Normal QTc values. QTc is prolonged if > 440ms in men or > 460ms in women; QTc > 500 is associated with an increased risk of torsades de pointes; QTc is abnormally short if < 350ms; A useful rule of thumb is that a normal QT is less than half the preceding RR interval

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%.

Before puberty, a QTc <450 ms is considered normal, between 450 and 459 borderline, and ≥460 prolonged. After puberty in males, a QTc between 460 and 469 is borderline and ≥470 is considered prolonged. In post-pubertal females, 460 to 479 is borderline and ≥480 ms is considered prolonged.

2019年6月10日 · Until recently, the heart rate–corrected QT interval (QTc), which represents a dynamic measurement of the time required to reset the heart’s electric system, fell squarely into this latter category.

Note that a QTc interval >480 is always considered pathological. For patients with bundle branch blocks, the corresponding figure is >500 ms. It is recommended that the automatic (machine) calculation of the corrected QT interval be used.

Reference intervals for QTc duration according to Bazett’s formula. Note that a QTc interval >480 is always considered pathological. For patients with bundle branch blocks, the corresponding figure is >500 ms.

2024年7月19日 · Long QT syndrome can cause sudden fainting and seizures. Young people with LQTS syndrome have a higher risk of sudden cardiac death. Treatment for long QT syndrome includes lifestyle changes and medicines to prevent dangerous heartbeats. Sometimes a medical device or surgery is needed.

2013年4月25日 · Regardless of the cause, a prolonged QTc (greater than 500 milliseconds) has been recognized as a non-invasive risk marker for congenital or acquired LQTS-triggered sudden death, stroke and all-cause cardiovascular mortality.

2023年3月20日 · Long QT syndrome is a problem with the electrical system in your heart taking too long to recharge. This issue can lead to a life-threatening type of abnormal heart rhythm. People can inherit or acquire long QT syndrome. Most people take medication for long QT. Others may need a device or surgery to lower their risk of abnormal heart rhythms.