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Conduction: Difference between revisions
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→The QT interval
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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: [[Image:Formule_QTc.png]] | 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: [[Image:Formule_QTc.png]] | ||
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 in the correct determination of the end of the T wave. Therefore, it is important to check the QT time manually. | On modern ECG machines, the QTc is given. However, the machines are not always capable in the correct determination of the end of the T wave. Therefore, it is important to check the QT time manually. | ||