Prolongation of Electrocardiographic T Wave Parameters Recorded during the Head-Up Tilt Table Test as Independent Markers of Syncope Severity in Children

Figures

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  Figure 1. Method of measuring QT and TpTe intervals in ECG. QT—the total repolarization period, TpTe (Tpeak–Tend)—the late repolarization period. Authors’ source.

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  Figure 2. Inter-time comparison of RR intervals in electrocardiograms (ECGs) on admission to the hospital (Phase 0), during the resting supine phase (Phase 1), the upright phase (Phase 2), and the returning to supine phase (Phase 3) in the groups: C—control, S—syncopal Sa—syncopal with abnormal T, Sn—syncopal with normal T. Values [ms] are shown as a median and interquartile range. A significant difference (p < 0.05) was calculated using the ANOVA Friedman test with the Iman-Davenport statistic and post hoc test (Conover-Iman).

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  Figure 3. Values of QTc intervals in electrocardiograms (ECGs) on admission to the hospital (Phase 0) and during the resting supine (Phase 1), the upright phase (Phase 2), and the returning to supine phase (Phase 3) in the group: S—syncopal, C—control, Sa—syncopal with abnormal T, Sn—syncopal with normal T. Values [ms] are shown as a median and interquartile range. A significant difference (p < 0.05) while comparing the syncopal group to the control group was calculated using the ANOVA Friedman test with the Iman-Davenport statistic and post hoc test (Conover-Iman).

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  Figure 4. Values of TpTe intervals in ECG on admission to hospital (Phase 0), the resting supine phase (Phase 1), the upright phase (Phase 2), and the returning to supine phase (Phase 3) in the groups: S—syncopal, C—control, Sa—syncopal with abnormal T, Sn—syncopal with normal T. Values [ms] are shown as a median and interquartile range. A significant difference (p < 0.001) while comparing the syncopal group to the control group was calculated using the ANOVA Friedman test with the Iman-Davenport statistic and post hoc test (Conover-Iman).

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  Figure 5. The ROC curve (AUC) analysis for TpTe intervals [ms] in a syncopal group and control group in the upright phase during the HUTT—Phase 2 (TpTe2).

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  Figure 6. The ROC curve (AUC) analysis for QTc intervals [ms] in the syncopal group and control group in the upright phase during the HUTT—Phase 2 (TpTe2).

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  Figure 7. The pairwise comparison of ROC curves TpTe2~QTc2 [ms] in the syncopal group and control group in the upright phase during the HUTT—Phase 2 (TpTe2~QTc2).