OS095. Impedance cardiography: A straightforward and reliable tool to evaluate differences of cardiac reflex response between normal pregnancy and pre-eclampsia

K Tomsin; T Mesens; J Oben; G Molenberghs; L Peeters; W Gyselaers

doi:10.1016/j.preghy.2012.04.096

OS095. Impedance cardiography: A straightforward and reliable tool to evaluate differences of cardiac reflex response between normal pregnancy and pre-eclampsia

Pregnancy Hypertens. 2012 Jul;2(3):230. doi: 10.1016/j.preghy.2012.04.096. Epub 2012 Jun 13.

Authors

K Tomsin¹, T Mesens², J Oben¹, G Molenberghs³, L Peeters⁴, W Gyselaers¹

Affiliations

¹ Obstetrics and Gynaecology, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine, Diepenbeek, Belgium.
² Obstetrics and Gynaecology, Ziekenhuis Oost-Limburg, Genk, Belgium.
³ I-BioStat, Hasselt University, Diepenbeek, Belgium.
⁴ Obstetrics and Gynaecology (GROW), Maastricht University, Maastricht, Netherlands.

PMID: 26105309
DOI: 10.1016/j.preghy.2012.04.096

Abstract

Introduction: Reflex responses of cardiac cycle time intervals (CCTI) can be measured by echocardiography, and are reported to differ between uneventful pregnancy (UP) and pre-eclampsia (PE). It is unknown whether impedance cardiography (ICG) is a useful method to measure CCTI during pregnancy.

Objectives: ICG measurements of CCTI before and after orthostatic challenge are evaluated in UP and in the clinical phase of PE.

Methods: Examinations were performed twice in 16 UP (30-36 weeks), and once in 30 early PE (EPE, <34 weeks) and in 32 late PE (LPE, ⩾34 weeks). A 3rd generation ICG device using a 4 electrode arrangement (NICCOMO, Medis, Germany) was used to measure CCTI in supine position and after moving to upright position. The pre-ejection period (PEP) is the time-interval between ventricular depolarisation and start of aortic flow. The left ventricular ejection time (LVET) is the time-interval between opening and closing of the aortic valve. Diastolic time (DT) is heart period duration - (PEP+LVET). Orthostatic-induced changes from supine to upright position (cardiac reflex response or CRR) were evaluated using One-sample Wilcoxon Signed Rank Tests. All CRRs in EPE and LPE were compared to UP using Mann-Whitney U tests. Data are represented as medians (interquartile ranges).

Results: Maternal age was comparable between all groups [29 (26-32) years; p⩾0.47]. Gestational age was comparable between both early [31 (28-32) vs 31 (27-33) weeks] and late [37 (36-39) vs 38 (36-39) weeks] third trimester UP and PE [p⩾0.38]. Pre-gestational BMI was higher in EPE compared to UP [26 (24-32) vs 23 (21-24); p<0.01]. This was not true for LPE [25 (23-28); p=0.06]. Birth weight percentiles were lower in both EPE and LPE compared to UP [UP: 44 (38-78), EPE: 18 (5-28), LPE: 31 (18-59); p<0.05], and also lower in EPE compared to LPE [p=0.03]. CRRs within each group are shown in Table 1. The CRRs of PEP were significantly different between UP and both EPE and LPE [p⩽0.01], due to orthostatic-induced increase in PE but not in UP .

Conclusion: Our study confirms that orthostasis does not change PEP in UP but induces a significant increase of PEP in PE. The increased reflex-induced duration of isovolumetric contraction time can be explained by a decreased left ventricular performance in the clinical phase of PE as compared to UP. ICG turns out to be a straightforward and useful method to evaluate these hemodynamic features.