Left ventricular torsional mechanics in uncomplicated pregnancy

Transthoracic Echocardiographic Assessment of the Heart in Pregnancy-a position statement on behalf of the British Society of Echocardiography and the United Kingdom Maternal Cardiology Society

Pregnancy is a dynamic process associated with profound hormonally mediated haemodynamic changes which result in structural and functional adaptations in the cardiovascular system. An understanding of the myocardial adaptations is important for echocardiographers and clinicians undertaking or interpreting echocardiograms on pregnant and post-partum women. This guideline, on behalf of the British Society of Echocardiography and United Kingdom Maternal Cardiology Society, reviews the expected echocardiographic findings in normal pregnancy and in different cardiac disease states, as well as echocardiographic signs of decompensation. It aims to lay out a structure for echocardiographic scanning and surveillance during and after pregnancy as well as suggesting practical advice on scanning pregnant women.

Adaptation of left ventricular diastolic function to pregnancy: a systematic review and meta-analysis

Objective:

To meta-analytically determine the adaptation of left ventricular diastolic function (LVDF)-indices to singleton normotensive pregnancies.

Methods:

Literature was retrieved from PubMed and Embase. We included studies that reported a nonpregnant reference measurement and LVDF indices (mitral inflow signals, left atrial volume and tissue Doppler measurements). Mean differences between pregnant and reference measurements and weighted means of absolute values were calculated using a random-effects model.

Results:

We included 34 eligible studies. Normotensive pregnancies were characterized by an initially larger increase in the passive left ventricular filling (E-wave peak velocity, 13%) compared to active left ventricular filling during diastole (A-wave peak velocity, 6%) resulting in a 16% increase of the E/A ratio in the first trimester. The E/A ratio progressively decreased during advancing gestation to −18% at term, resulting from stabilizing E-wave peak velocity and increased A-wave peak velocity. The E/e′ ratio was increased between 22 and 35 weeks (a maximal increase of 13%) in normotensive pregnancy. Left atrial volume (LAV) progressively increased from 15 weeks onwards with a maximal increase of 30% between 36 and 41 weeks.

Conclusion:

LVDF in normotensive pregnancy was improved in the first trimester after which LVDF progressively worsened. Large-scale studies in normotensive and hypertensive complicated pregnancies are needed for a more precise insight into LVDF changes during pregnancy.

Left ventricular mechanics in late second trimester of healthy pregnancy

OBJECTIVE

To evaluate left ventricular (LV) mechanics in the second trimester of healthy pregnancy and to determine the influence of underpinning hemodynamics (heart rate (HR), preload and afterload) on LV mechanics during gestation.

METHODS

This was a cross-sectional study of 18 non-pregnant, 14 nulliparous pregnant (22-26 weeks' gestation) and 13 primiparous postpartum (12-16 weeks after delivery) women. All pregnant and postpartum women had uncomplicated, singleton gestations. Cardiac structure and function were assessed using echocardiography. LV mechanics, specifically longitudinal strain, circumferential strain and twist/untwist, were measured using speckle-tracking echocardiography. Differences between groups were identified using ANCOVA, with age, HR, end-diastolic volume (EDV) and systolic blood pressure (SBP) as covariates. Relationships between LV mechanics and hemodynamics were examined using Pearson's correlation.

RESULTS

There were no significant differences in LV structure and traditional measurements of systolic and diastolic function between the three groups. Pregnant women, compared with non-pregnant ones, had significantly higher resting longitudinal strain (-22 ± 2% vs -17 ± 3%; P = 0.002) and basal circumferential strain (-23 ± 4% vs -16 ± 2%; P = 0.001). Apical circumferential strain and LV twist and untwist mechanics were similar between the three groups. No statistically significant relationships were observed between LV mechanics and HR, EDV or SBP within the groups.

CONCLUSIONS

Compared to the non-pregnant state, pregnant women in the second trimester of a healthy pregnancy have significantly greater resting systolic function, as assessed by LV longitudinal and circumferential strain. Contrary to previous work, these data show that healthy pregnant women should not exhibit reductions in resting systolic function between 22 and 26 weeks' gestation. The enhanced myocardial contractile function during gestation does not appear to be related to hemodynamic load and could be the result of other physiological adaptations to pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac remodeling in normotensive pregnancy and in pregnancy complicated by hypertension: systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to describe comprehensively the pattern of cardiac remodeling during normotensive human singleton pregnancy and to compare it with that of pregnancy complicated by hypertension.

METHODS

We performed a meta-analysis of the current literature on cardiac remodeling during normotensive and complicated pregnancies. Literature was retrieved from PubMed (NCBI) and EMBASE (Ovid) databases. Included studies needed to report a reference measurement (matched non-pregnant control group, prepregnancy or postpartum) and measurements made during predetermined gestational-age intervals. Mean differences between reference and pregnancy data were calculated using the random-effects model described by DerSimonian and Laird.

RESULTS

Forty-eight studies were included in the meta-analysis, with publication dates ranging from 1977 to 2016. During normotensive pregnancy, most geometric indices started to increase in the second trimester. Left ventricular mass (LVM) increased by 28.36 (95% CI, 19.73-37.00) g (24%), and relative wall thickness (RWT) increased by 0.03 (95% CI, 0.02-0.05) (10%) compared with those in the reference group. During hypertensive pregnancy, LVM and RWT increased more than during normotensive pregnancy (92 (95% CI, 75.46-108.54) g (95%) and 0.14 (95% CI, 0.09-0.19) (56%), respectively).

CONCLUSIONS

During normotensive pregnancy, most cardiac geometric indices change from the second trimester onwards. Both LVM and RWT increase, by 20% and 10%, respectively, consistent with concentric rather than eccentric remodeling. Cardiac adaptation in hypertensive pregnancy deviates from that in healthy pregnancy by a greater change in LVM (95% increase from reference) and RWT (56% increase from reference). Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Shortness of Breath During Pregnancy: Could a Cardiac Factor Be Involved?

BACKGROUND

Shortness of breath (SOB) is common among healthy women with normal pregnancies. However, when no overt cardiac or extra cardiac etiology is found, a subtle cardiac source must be excluded.

HYPOTHESIS

Pregnancy may induce or unmask myocardial dysfunction that may cause SOB.

METHODS

Healthy pregnant women with significant SOB were recruited for this study. We performed a comprehensive echocardiographic assessment including tissue Doppler imaging (TDI) and 2- dimensional strain imaging (2DS). The echocardiographic data obtained were compared with that of a control group of pregnant women without SOB.

RESULTS

Thirty pregnant women with SOB were enrolled in the study (age, 31.8 ± 4.9 years, and gestation, 38.2 ± 2.8 weeks) for whom no overt etiology for SOB was detected. Patients with SOB compared with controls had thicker hearts (septum: 10.1 ± 1.1 vs 8.9 ± 0.9 mm; P < 0.001; posterior wall: 9.4 ± 1.1 vs 8.9 ± 0.9 mm; P < 0.01), shorter E-wave deceleration time (158.0 ± 50.1 vs 187.1 ± 37.6 msec; P = 0.01), and higher pulmonary artery pressure (26.8 ± 6.2 vs 19.0 ± 6.5 mm Hg, P < 0.01). Women with SOB tended to have a lower S' velocity TDI (P = 0.05) and a trend toward increased torsion on 2DS (P = 0.09).

CONCLUSIONS

Significant SOB during otherwise normal pregnancy is associated with significant echocardiographic findings that may suggest a subtle cardiac involvement. Further investigation is necessary to verify such an association, which may have therapeutic implications for treating SOB of pregnancy.

MATERNAL CARDIAC TWIST PRE-PREGNANCY: POTENTIAL AS A NOVEL MARKER OF PRE-ECLAMPSIA

Healthy pregnancy is characterised by progressive physiological adaptation of the maternal cardiovascular (CV) system that facilitates optimal fetal development. The adaptations that constitute a healthy or normal progression are not always evident, and, in particular, CV adaptation to pregnancy is highly individualised. Some women develop pregnancy-related CV dysfunction such as pre-eclampsia (PE). Typically, PE is diagnosed by the development of hypertension and proteinuria after 20 weeks of pregnancy and is the leading cause of maternal and perinatal mortality and morbidity. Despite continued efforts to improve the understanding of the aetiology, pathophysiology and subsequently treatment for the disease, CV changes in PE are not well understood. PE before 34 weeks (early onset PE) is believed to differ in pathogenesis from late onset PE (>34 weeks) and can be characterised by a haemodynamic profile of increased systemic vascular resistance (SVR) and lower cardiac output (CO). Early onset PE is more often associated with uteroplacental insufficiency and significant adverse maternal and perinatal outcomes. In contrast, late onset PE (>34 weeks) involves an increased CO and lower SVR and is less likely to be associated with uteroplacental insufficiency and adverse perinatal outcomes. It is not known if PE develops secondary to the CV maladaptation in pregnancy or if a preexisting CV dysfunction predisposes some women to develop PE. Screening, diagnosis and disease management would be vastly improved if more were known about the onset of the maladaptive process associated with PE. To date, a combination of maternal factors including medical history, body mass index, age, parity and blood pressure (BP) have been used to predict the development of PE. In the first trimester, arterial stiffness is significantly increased in women who develop PE. Current hypotheses speculate that CV dysfunction is evident very early in pregnancy in PE and precedes the clinical manifestation at a later stage but whether CV dysfunction is present before pregnancy remains to be elucidated.