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Criteria for short QT interval based on a new QT-heart rate adjustment formula
1Department of Medicine (Cardiology), Division of Cardiology, University of British Columbia, Level 9 2775 Laurel St, Vancouver, B.C., Canada V5Z 1M9.
Background:
A short QT interval, within which an increased risk for atrial fibrillation and/or fatal cardiac arrhythmias occurs, has been difficult to define.
Methods:
The lower percentiles of a new QTc formula were determined, using a precise mathematical fitting of the QT-heart rate relationship from the ECGs of 13,600 individuals from the NHANES II and III surveys.
Results:
The QTc interval for persons in the lower fifth percentile, second (2.5th) percentile and first percentile, were calculated.
Conclusions:
Based on the new spline formula, a short QTc is defined at the first percentile, and is less than 380 ms in both men and women.
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