Investigating asymmetry in fetal and maternal heart rate accelerations and decelerations

Figures

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  Fig. 1. Simultaneously recorded tachograms of fetal (upper panel) and maternal (lower panel) heartbeat intervals recorded in the 20th week of gestation. Red arrows indicate the fetal heart rate variations that may have the biggest impact on the heart rate asymmetry in the recording.

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  Fig. 2. Distribution of gestational age in study group of 102 fetuses.

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  Fig. 3. Example of a Poincaré plot considering 200 consecutive heart rate intervals (approx. 2 min. 43 s.) from one recording. The perpendicular distance of a given point to the line of identity (used in Guzik Index–GI) and phase angle with respect to the line of identity (used to obtain Slope Index–SI) are pointed out.

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  Fig. 4. Examples of simultaneously recorded 5 min fetal (A) and maternal (B) Poincaré plots (left) in the 38th week of gestation and paths made by consecutive points on Poincaré plot (right). The arrows connecting consecutive points on the plot have blue color for two consecutive decelerations (above the line of identity), red color for subsequent accelerations and black ones are the transitions between the accelerations and decelerations.

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  Fig. 5. A fragment of fetal HR tachogram (GA = 23 weeks) with two types of HR transitions indicated: acceleration to deceleration and an opposite one. Note the difference between HR intervals (ΔRR) is greater in acceleration in both types of transition–therefore DIi < 0.5 in both of them.

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  Fig. 6. The procedure of Phase Rectified Signal Averaging for 10 deceleration surroundings obtained from a maternal (GA = 20 weeks) heart rate tachogram. The deceleration selection criterion T = 1 so the averaged value X(-1) will always be shorter than X(0). In this case the scale s = 2 and therefore the Deceleration Capacity is obtained by DC = [X(0) + X(1)–X(–1)–X(–2)]/4.

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  Fig. 7. The Deceleration Input (DI) boxplots in different Poincaré plot lags. Lags 1–4 are highlighted in red.

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  Fig. 8. Spearman’s Correlation between Deceleration Input calculated for deceleration to acceleration type of transitions only (DID2A) and gestation week (GA) in 102 pregnant women.

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  Fig. 9. The average PRSA measures dependence on s and T parameters in 102 healthy fetuses. Left panel presents mean values of Acceleration Capacity (AC), middle one–Deceleration Capacity (DC) and right one–Deceleration Reserve (DR). The 3D plots are located in the upper row and the 2D projection of each plot is presented respectively under a corresponding graph.

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  Fig. 10. Results of Spearman’s correlation between the fetal PRSA Acceleration Capacity (left) and Deceleration Capacity (right) and gestational age (GA) of 102 healthy fetuses. All p-values < 0.001

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  Fig. 11. The rank correlation between maternal PRSA and GA. The Spearman’s ρ not significantly different from 0 has been converted into 0 for better readability of the plot.

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  Fig. 12. The correlations (Spearman’s ρ–here marked as R) between chosen Poincaré plot–based measures (DI–left, GI–middle and PI–right panel) and PRSA-based asymmetry measure: Deceleration Reserve (DR). Poincaré plot lag and PRSA s and T parameters set to 1.