Difficult QT: Difference between revisions

Difficult QT (view source)

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 * The QT interval ends where the tangent and the baseline cross.
 * The QT interval is the time in milliseconds between the start and end of the QT interval.
-* If the QRS interval exceeds 120 millisseconds, than some specialists advice to deduct the amount of milliseconds that exceeds 120 ms from the QT interval (i.e. if QRS is 140 ms and QT is 480, then 140-120ms=20ms should be deducted from the QT interval, yielding 460ms).
+* If the QRS interval exceeds 120 milliseconds, than some specialists advice to deduct the amount of milliseconds that exceed 120 ms from the QT interval (i.e. if QRS is 140 ms and QT is 480, then 20ms (i.e. 140 - 120ms) should be deducted from the QT interval, yielding 460ms).
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 ===QTc is the heart rate corrected QT interval===
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 * The QT interval should be corrected for the heart rate, as the QT interval shortens with increasing heartrate.
 * Bazetts formula: [[Image:Formule QTc.png]], can be used to calculate the QTc: the heart rate corrected QT. When entering the formula the RR interval should be entered in seconds. The preceding RR interval should be used. You can also use this [[QTc calculator]]
-* Preferably one uses the average of three QTc
+* Preferably one uses the average of several QTc measurements
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