Fetal Conduction Disease and Arrhythmia in Ebstein's Anomaly and Tricuspid Valve Dysplasia Assessed by Fetal Magnetocardiography

Figures

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  Figure 1. Complete bundle branch block and ST‐T changes in fetus #13. PR indicates PR intervals; QTc, heart rate–corrected QT interval; and RR, RR intervals.

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  Figure 2. Fetal cardiac time intervals and P/QRS amplitude ratio in EA/TVD subjects. Normal fetus data are shown as gray open circles and their linear regression line is shown as a solid line. The correlations with gestational age were significant for P (R 2=0.17, P <0.001), PR (R 2=0.07, P=0.0025), QRS (R 2=0.10, P <0.001), and RR (R 2=0.13, P <0.001), but not for QTc or P/QRS amplitude ratio. The 95% prediction interval (Z=±1.96) is shown by the dashed lines. The red dots correspond to subjects #3, #4, #6, #14, and #16 that died. The red open dot corresponds to subject #5 that died and had incessant atrial flutter. Serial data from 3 subjects are connected by lines. EA indicates Ebstein's anomaly; QTc, heart rate–corrected QT interval; PR, PR intervals; RR, RR intervals; and TVD indicates tricuspid valve dysplasia.

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  Figure 3. Fetal heart rate variability measured as the SD of the RR intervals. Normal fetus data are shown as gray open circles, and their linear regression line is shown as a solid line. The correlation with gestational age was statistically significant (R 2=0.32, P <0.01). The 95% prediction interval is shown by the dashed lines. The red dots correspond to subjects that died. The red open dot corresponds to subject #5 that died and had incessant tachycardia. Serial data from 3 subjects are connected by lines. HRV indicates heart rate variability.

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  Figure 4. fMCG rhythm strips from subjects that died and were studied after 28 weeks' gestation. A, Subject #3 showed intermittent second‐degree atrioventricular block. (B), Subject #4 showed giant P‐waves and extreme PR and QRS prolongation, (C) Subject #5 showed incessant atrial flutter with wide QRS complexes indicative of bundle branch block. The nonconducted P wave is obscured by the QRS. The PR interval of the conducted beats is 140 milliseconds. (D), Subject #6 showed several episodes of second‐degree atrioventricular block. Notice that PP is shorter for PP intervals that embrace QRS complexes than for those that do not, indicative of ventriculophasic sinus arrhythmia. (E) Subject #14 showed frequent ectopy and U‐waves. fMCG indicates fetal magnetocardiography.

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  Figure 5. Fetal heart rate (black) and movement (blue) tracings from 5 subjects that died and were studied after 28 weeks' gestation. A, Subject #3 showed flat heart rate tracings with brief episodes of type II second‐degree atrioventricular block. These episodes were associated with fetal movement but, in contrast to normal heart rate reactivity, the heart rate decelerated before atrioventricular block. (B), Subject #4 showed periods of flat, nonreactive fetal heart rate tracings in sinus rhythm. (C), Subject #5 showed flat nonreactive fetal heart rate tracings in tachycardia, (D) Subject #6 showed an extended period of second‐degree atrioventricular block, preceded by sinus slowing, and periods of flat nonreactive fetal heart rate tracings. (E), Subject #14 showed an irregular heart rate and rhythm due to frequent ectopy.