早搏引起心动周期突然改变时QT间期和RR间距的关系

Relationship between QT and RR Interval in the Cardiac Cycle Abruptly Changed by Premature Beats

观察46例早搏患者早搏及其前后窦性心动周期的 QT 间期与 RR 间距之间的关系。当早搏引起RR 间距突然变化时,虽然 QT 间期也随之发生改变,但应用 Bazett 公式却出现了“过度校正”的现象,表现出二者变化的不同步。作者认为,QT 间期的变化需要逐渐适应和累积的理论可以对此作出解释。当心率突然变化时,Bazett 公式不再适用于 QT 间期的校正。

The authors observed the relationship between the QT and RR interval in three consecutive cardial cycles—before,during and after the premature beat in 46 patients with premature beats.The results showed that the QT interval did not undergo any sign of change following a premature-beat-caused abrupt change in the RR interval.The QT interval was overcorrected in heart rate by using Bazett's formula in this condition.We concluded that the QT interval will adapt gradually to a new RR inter- val and have a cumulative effect.Bazett's formula is not suitable for the correction of the QT interval when the heart rate changes abruptly.