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→Correcting the QT for the heart rate
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===Correcting the QT for the heart rate=== | ===Correcting the QT for the heart rate=== | ||
<flashow>http://nl.ecgpedia.org/images/1/12/QTc.swf|width=300px|height=200px</flashow> | <flashow>http://nl.ecgpedia.org/images/1/12/QTc.swf|width=300px|height=200px</flashow> | ||
The QT interval comprises the QRS-complex, the ST-segment, and the T-wave. One difficultly of QT interpretation is that the QT interval gets shorter if the heart rate increases. This can be solved by correcting the QT time for heart rate using the Bazett formula: | The QT interval comprises the QRS-complex, the ST-segment, and the T-wave. One difficultly of QT interpretation is that the QT interval gets shorter if the heart rate increases. This can be solved by correcting the QT time for heart rate using the Bazett formula: | ||
<div align="center" style="padding:10px"> | <div align="center" style="padding:10px"> | ||
[[Image:Formule_QTc.png]] | [[Image:Formule_QTc.png]] | ||
</div> | </div> | ||
Thus at a heart rate of 60 bpm, the RR interval is 1 second and the QTc equals QT/1. The QTc calculator can be used to easily calculate QTc from the QT and the heart rate or RR interval. | Thus at a heart rate of 60 bpm, the RR interval is 1 second and the QTc equals QT/1. The QTc calculator can be used to easily calculate QTc from the QT and the heart rate or RR interval. | ||
On modern ECG machines, the QTc is given. However, the machines are not always capable of recognizing the correct QT time. Therefore, it is important to check this manually. | On modern ECG machines, the QTc is given. However, the machines are not always capable of recognizing the correct QT time. Therefore, it is important to check this manually. | ||
===Correct measurement of the QT interval: how to measure the end of the T wave=== | ===Correct measurement of the QT interval: how to measure the end of the T wave=== | ||