* Fetal medicine unit, Cairo University, Egypt;
** El Galaa Teaching Hospital;
***Radiology department, Kasr Alainy hospitals, Cairo University, Egypt;
Irregularity in fetal heart rate is attributed in the vast majority of cases to premature contractions 1. Premature contractions can arise either in the atria or ventricles with the former being more common with reported minimal risk of developing supra-ventricular tachycardia in the former and ventricular tachycardia in the latter, thus a follow up is required in both and should be more close in the ventricular type 2. The degree of maturity of premature atrial contraction is the determinant of their conduction to the ventricle or blockage into the atrio-ventricular node 1. The risk of developing tachycardia is higher in cases of multiple atrial ectopic beats that are blocked resulting in decrease in ventricular rate than in cases with normal rate 3.
Umbilical vein varix is diagnosed if there is increase in the diameter of the umbilical vein more than 9 mm or more than 50% of the intrahepatic portion of the vein according to some authors4. However it should be mentioned that there are no clear criteria either for the diagnosis neither for the follow-up 4. The vascular nature of this anomaly renders its diagnosis into a simple process by Doppler techniques 4,5. There is controversy about the significance of this anomaly; several reports have linked it to high risk of adverse outcome while other reports link it to good outcome4,5.Â
Case report
24 year old G2P1 woman referred to Cairo University Fetal Medicine Unit at 39 weeks of gestation due to a concern about an irregularity in fetal heart rhythm noted during auscultation of the fetal heart by CTG. Our ultrasound examination revealed the following:
- Irregular heart rhythm.
- During periods of irregularity of the heart rhythm; the atrial contractions were perfectly regular with premature ventricular contractions noticed on M-mode tracing associated with compensatory pauses during this type of irregularity.
- During other periods of irregularity; there were premature atrial contractions that made the atrial contractions irregular; the vast majority of them were conducted to the ventricles.
- Dilatation of the umbilical vein starting nearly at the level of origin of the inferior branch of the left portal vein (LPVi) and extending to the level of origin of the superior branch of left portal vein (LPVs).
- Color Doppler examination demonstrated filling of the varix with color signal denoting absence of any thrombotic events.
Postnatal follow up of the case confirmed our findings. A 24-hour ambulatory ECG confirmed the presence of premature contractions denoting that the vast majority of them were originating from the ventricles with some originating form the atria. M-mode tracing of the heart of the neonate strikingly demonstrated the premature atrial contractions at the time of examination.
Neonatal abdominal ultrasound confirmed the presence of the varix extending from the level of the origin of LPVi to the origin of LPVs exactly as prenatally documented with physiological near total obliteration of the umbilical vein.
One month after delivery (time of reporting this case), there was no adverse outcome and the neonate was doing well with infrequent premature contractions (7% as reported by the 24 hour ambulatory ECG).
To the best of our knowledge, we are unaware of any prenatal report describing the simultaneous occurrence of premature both atrial and ventricular contractions. This finding may suggest that the immaturity of the fetal cardiac conductive system may make it susceptible to an atrial and a ventricular pacemakers simultaneously. Â
In all images white arrows point to the atrial contractions with the yellow arrows pointing to the premature atrial contractions. Also the ventricular contractions are demarcated by red arrows with the blue arrows pointing to the premature ventricular contractions.Â
Video 1: Four-chamber and LVOT views demonstrating the irregularity in the fetal heart rhythm.