Model-based estimation of QT intervals of mouse fetal electrocardiogram

Figures

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  Fig. 1. Bland–Altman and correlation analyses were performed to compare the Q-Ac interval values that were estimated by the two measurers a, and to compare model-based QT interval values with Q-Ac interval values of the two measurers b–c. QT and Q-Ac intervals were estimated beat by beat and the total number of heart beats was 309 from five fetal mice. a 95% of the values are within the limits of agreement (r = 0.93, P < 0.05). b 93% of the values are within the limits of agreement (r = 0.89, P < 0.05). c 92% of the values are within the limits of agreement (r = 0.91, P < 0.05)

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  Fig. 2. A fECG and pulsed Doppler images were obtained from the fetal mouse by using different systems. In order to match Doppler images with fECG records, a signal generator was connected to both systems to input pulsed signals. B The pulse signal that was recorded with fECG is aligned with the same signal that was recorded simultaneously with DUS. Q-Ac intervals were calculated by drawing vertical lines from the Ac timings of DUS to fECG. The red asterisks in fECG indicate the estimated end of T waves. End of T waves were calculated from R(t), Eq. 3. Ac timings were determined by drawing tangent lines where blood flow crosses the base line