Time-interval between maternal hepatic vein Doppler and ECG is shorter in pre-eclampsia than in normal third trimester pregnancy

Abstract

Objectives: Cardiac atrial contraction is initiated by the electrocardiographic P-wave (P) and provokes the central venous Doppler A-wave (A). This study aims to compare the Venous Wave Protraction Time (VWPT), defined as the PA time-interval corrected for changing heart rate (PA/RR), between normal third trimester pregnancy and pre-eclampsia at the level of hepatic veins.

Materials and Methods: Cross-sectional study in 2 groups of 10 women with normal or pre-eclamptic pregnancies at gestation of 28-33 weeks. Three consecutive venous Doppler waves were recorded at the craniocaudal midportion of the liver from each of the three main branches of hepatic veins, simultaneously with an electrocardiogram (ECG). The time-interval between the ECG P-wave and corresponding A-deflection of venous Doppler waves was measured, and corrected for changing heart rate (PA/RR). For both groups, means and standard deviations were calculated and compared statistically using conventional F-tests for linear mixed-effects models (SAS procedure MIXED).

Results: VWPT was significantly shorter in pre-eclampsia than in normal pregnancy [0.25±0.09 versus 0.42±0.14, p=0.0042]. This difference persisted under antihypertensive treatment [n=6; 0.23±0.10, p=0.0066].

Conclusions: VWPT is significantly shorter in pre-eclampsia than in normal pregnancy. This observation probably results from pre-eclampsia-related maternal cardiovascular maladaptation.