Mean and Cut-Off Values of the Corrected QT Interval From Childhood to Adolescence

Figures

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  Central Figure.

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  Figure 1.. Change in mean values of RR and QT intervals with growth in males and females. Blue and orange denote males and females, respectively. Circles, squares, and triangles indicate 1st, 4th, and 7th grades, respectively. Fine and coarse dashed lines represent QTcB and QTcF values, respectively. QTcB, QT interval corrected using Bazett’s formula; QTcF, QT interval corrected using Fridericia’s formula.

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  Figure 2.. Histograms of the corrected QT interval in 4th-grade males. QTcB in the total cohort (A) and in participants with QTcB ≥400 ms (B), and QTcF in the total cohort (C) and in participants with QTcF ≥400 ms (D). Arrows indicate the 99th, 99.5th, and 99.8th percentiles (1/100, 1/200, and 1/500, respectively). Red arrows and numbers indicate the cut-off values. QTcB, QT interval corrected using Bazett’s formula; QTcF, QT interval corrected using Fridericia’s formula.

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  Figure 3.. Histograms of the corrected QT interval in 4th-grade females. QTcB in the total cohort (A) and in participants with QTcB ≥400 ms (B), and QTcF in the total cohort (C) and in participants with QTcF ≥400 ms (D). Arrows indicate the 99th, 99.5th, and 99.8th percentiles (1/100, 1/200, and 1/500, respectively). Red arrows and numbers indicate the cut-off values. QTcB, QT interval corrected using Bazett’s formula; QTcF, QT interval corrected using Fridericia’s formula.

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  Figure 4.. Histograms of the corrected QT interval in 1st graders. (A) Males; (B) Females. QTcB in the total cohort (a) and in participants with QTcB ≥400 ms (b), and QTcF in the total cohort (c) and in participants with QTcF ≥400 ms (d). Arrows indicate the 99th, 99.5th, and 99.8th percentiles (1/100, 1/200, and 1/500, respectively), as well as the identified hiatus. Red arrows and numbers indicate the cut-off values. QTcB, QT interval corrected using Bazett’s formula; QTcF, QT interval corrected using Fridericia’s formula.

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  Figure 5.. Histograms of the corrected QT interval in 7th graders. (A) Males; (B) Females. QTcB in the total cohort (a) and in participants with QTcB ≥400 ms (b), and QTcF in the total cohort (c) and in subjects with QTcF ≥400 ms (d). Arrows indicate the 99th, 99.5th, and 99.8th percentiles (1/100, 1/200, and 1/500, respectively), as well as the identified hiatus. Red arrows and numbers indicate the cut-off values. QTcB, QT interval corrected using Bazett’s formula; QTcF, QT interval corrected using Fridericia’s formula.