Echocardiographic measurements in infants of diabetic mothers and macrosomic infants of nondiabetic mothers

AIM: To compare echocardiographic findings of infants of diabetic mothers (IDMs), macrosomic infants of nondiabetic mothers and healthy full term appropriate-for-gestational-age (AGA) infants. METHODS: Included in this study were 83 infants, admitted to our Neonatology Unit. Thirty-three IDMs, including both macrosomic and nonmacrosomic, comprised Group A, 25 macrosomic infants of nondiabetic mothers comprised group B, and 25 healthy full term AGA infants comprised group C. Echocardiographic measurements were performed in the first three days after birth and compared by using one-way ANOVA, Post Hoc Tukey HSD and Student's t tests. RESULTS: The left ventricular end-systolic/left ventricular end-diastolic diameter ratio of group A was significantly smaller than that of group C (P<0.05). The interventricular septum/posterior wall thickness ratios of groups A and B were greater than those of group C (P<0.05). The left ventricular mass index of group A was greater than those of groups B and C (P<0.05). The shortening fraction and ejection fraction of group A were increased in comparison to group C (P<0.05). When comparing the values of echocardiographic measurements of macrosomic IDMs (n=9) with nonmacrosomic ones (n=24), and infants of pregestational diabetic mothers (n=11) with those of gestational diabetes mothers (n=22), no statistical difference was found. CONCLUSION: The present study suggests that underlying mechanisms common to both macrosomic infants of nondiabetic mothers and IDMs lead to less cardiac alterations in the macrosomic infants of nondiabetic mothers than in IDMs.     

Echocardiography during pregnancy--longitudinal studies in primigravidae

As a result of hormonal changes processes of adaptation of the cardio-vascular system occur during pregnancy. These regulative changes are the basis for the present echo-cardiographic study which was made under standardized conditions with healthy primigravidae (n = 20) compared to nulligravidae (n = 24). Besides blood pressure and heart frequency dimension and volume sizes of the left ventricle (LV) as well as the LV-weight of muscle and the peripheral vascular resistance were analysed. As result significant increases from the 15th to the 35th week of pregnancy (SSW) could be found for the following parameters: heart frequency, arterial blood pressure, endosystolic volume of the left ventricle, cardiac output, left ventricular weight of muscle (p less than 0.01) endosystolic diameter of the left ventricle, enddiastolic volume of the left ventricle and heart index (p less than 0.05). The peripheral resistance was continuously decreased in the course of pregnancy (p less than 0.01). Compared to non-pregnant women the following parameters showed significantly higher values: heart frequency, cardiac output and heart index (p less than 0.01). The peripheral resistance was significantly lower in pregnant women compared to non-pregnant women (p less than 0.01). From the results the conclusion can be drawn that with statistic certainty echocardiography records adaptive processes of the circulation regulation relative to pregnancy and enables a separation in the groups of pregnant and non-pregnant women.     

Acute effects of maternal ethanol infusion on fetal cardiac performance

In adult animals and man, both acute and chronic ethanol intake is associated with depression of myocardial performance. Accordingly, the cardiac effects of maternal ethanol infusions, in a manner comparable to common obstetric practice for inhibition of premature labor, were evaluated in six chronically instrumented fetal sheep. Fetal and ewe arterial Po₂, Pco₂, and pH values remained within normal limits with infusion rates of 15 c.c. per kilogram of 10 per cent ethanol over two hours (blood ethanol = 110 mg. per cent) and 15 c.c. per kilogram over one hour (blood ethanol = 210 mg. per cent). Fetal instrument evaluation (for 14 to 30 days after operation) provided data concerning pressures and cardiac dimensions which allowed analysis of left ventricular performance. Ethanol produced a significant depression of the extent (p < 0.01) and velocity (p < 0.001) of left ventricular myocardial fiber shortening as well as in the mean rate of left ventricular circumferential fiber shortening (p < 0.01). These indices of cardiac contractility were depressed in the absence of changes in end diastolic diameter, left atrial pressure, and systemic arterial pressure. Thus, the practice of inhibition of premature labor with ethanol might contribute to depressed myocardial performance in the neonatal period.     

Acute effects of maternal smoking on human fetal heart function

M-mode echocardiography was used to evaluate fetal heart function following maternal smoking in 21 healthy smoking pregnant women between 24 and 39 weeks of uneventful gestation. Prior to smoking one cigarette (nicotine content 1.7 mg), a fetal M-mode echocardiographic examination was performed and repeated 5 and 10 min after maternal smoking. Maternal heart rate and systolic blood pressure increased 8.7% and 15.0%, respectively, immediately after smoking, while diastolic blood pressure remained unchanged. Fetal heart rate increased 4.3% and left ventricular diastolic and systolic diameters decreased 4.5% and 15.0%, respectively. No changes in right ventricular dimensions, ventricular ejection times, ventricular wall thickness or septal thickness were observed. Fractional shortening, mean velocity of fractional shortening, stroke volume and cardiac output of the left ventricle also remained unchanged subsequent to smoking. Thus, maternal smoking of one cigarette seems to elicit only a transitory acceleration in fetal heart rate without concomitant significant changes in fetal heart function.     

重度子痫前期孕妇及胎儿左室重构与ET浓度的研究

目的:研究重度子痫前期孕妇及胎儿左室重构与内皮素(endothelin,ET)的相关性。方法:53例重度子痫前期孕妇分娩前测定外周血ET水平,用二维多普勒彩超检测孕妇和胎儿左心室舒张末期室间隔厚度(IVST)、左室后壁厚度(PWT)、室壁相对厚度(RWT)及孕妇左心室质量指数(LVMI)等指标;选取与病例组孕妇同期的健康孕妇53例为对照组,测量其心脏结构指标及ET水平,比较两组间孕产妇及胎儿左室重构与内皮素间有无相关性,同时比较实验组与对照组间有无差别。结果:(1)病例组孕妇及胎儿的IVST、PWT及孕妇的LVMI和RWT均高于对照组;(2)病例组孕妇及胎儿的ET水平高于对照组。结论:(1)重度子痫前期孕妇及胎儿有左室重构;(2)血浆ET升高是表明重度子痫前期严重程度的指标之一。     

Effect of exercise on placental blood flow in pregnancies complicated by hypertension, diabetes or intrahepatic cholestasis

The effects of a standardized exercise test on intervillous placental blood flow were studied in 13 hypertensive, 10 diabetic and 8 cholestatic pregnant women in late pregnancy, and the results were compared with those of a normal control group. Analysis of variance for repeated measures revealed that in all the pathologic groups, placental blood flow was lower than in the controls. In all groups placental blood flow rose slightly 1 min after the cessation of exercise. The diabetics showed a decreased placental blood flow 30 min after the cessation of the exercise test (p less than 0.02). In diabetics, a fall was found in stroke volume, from 63 +/- 12 ml (mean +/- SD) before the exercise to 53 +/- 11 ml 30 min after the cessation of exercise (p less than 0.05), and a rise in peripheral vascular resistance, from 1540 +/- 200 (mean +/- SD) dynes/cm5 before exercise to 1750 +/- 390 dynes/cm5 30 min after the cessation of exercise (p less than 0.05). Pre-eclamptic patients had a higher peripheral vascular resistance than had normal controls. Pre-eclamptic, diabetic and cholestatic patients had lower cardiac index values than the normal subjects. The difference was significant in the pre-eclamptic and diabetic patients at 30 min after the cessation of exercise. Maternal heart rate, and systolic, diastolic and mean arterial blood pressures rose significantly from values at rest to values at the end of exercise in all groups. One of the pre-eclamptic patients showed a 74% decline in placental blood flow 1 min after the cessation of exercise coincident with fetal bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heart Function in Normotensive and Hypertensive Pregnancy — A Preliminary Communication

Summary: Heart function in 19 normotensive and 27 hypertensive pregnant women was studied by a new technique for measuring systolic time intervals and by standard methods for measuring haemodynamic variables. In the hypertensive pregnant women, although heart rate and blood volume were not altered significantly, cardiac output, stroke volume, left ventricular work and total peripheral resistance were all increased and were accompanied by slightly less efficient cardiac contractility compared with findings in normotensive pregnant women.     

Haemodynamics of mild hypertension in pregnancy.

One hundred and sixty-three haemodynamic studies were done serially in 23 normotensive and 25 mildly hypertensive women during pregnancy. With all subjects resting in the left lateral position, heart rate, cardiac output, stroke volume, left ventricular work index, total peripheral vascular resistance and haematocrit were all significantly higher while plasma volume per unit body weight was significantly lower in the hypertensive than in the normotensive pregnant women. It is postulated that this hyperkinetic circulatory state is due to hyperactivity of the sympathetic adrenergic component of the autonomic nervous system in hypertensive pregnancy.     

Fetal myocardial thickening measured by ultrasonic-based technique called 'phased-tracking method'

OBJECTIVE: To evaluate fetal myocardial movement by using newly developed ultrasonic technique. METHODS: We analyzed 50 normal fetuses between 25 and 41 weeks' gestation for changes in thickness of fetal myocardium using the phased-tracking method, a technique with high vertical distance resolution and the potential to evaluate fine ventricular wall movements. We analyzed differences in the rate of change in ventricular wall thickness and in changes in the inner and outer wall layers with advancing gestation. We also analyzed myocardial thickening period and evaluated the ratio of increasing thickness period to stroke interval. RESULTS: Mean thickness changing rate was significantly higher in the right (1.18 +/- 0.34 m/s/m) than in the left ventricular wall (0.86 +/-0.31 m/s/m) (p < 0.001). Mean ratio of increasing thickness period to stroke interval was significantly higher in the right (0.57 +/- 0.064) than in the left ventricle (0.46 +/- 0.075) (p < 0.001), indicating that myocardial contraction in the fetal right ventricle predominates. The thickness-changing rate of the bilateral ventricular walls was positively and linearly correlated with gestational age. The myocardial-wall thickness-changing rate was higher in the outer layer than in the inner layer in late gestation. CONCLUSIONS: We conclude that measurement of the thickness-changing rate of fetal ventricular walls using the phased-tracking method might be useful for evaluation of fetal cardiac function.     

Echocardiographic evaluation in patients with hypogonadotropic hypogonadism

OBJECTIVE: To assess cardiac function in patients with hypogonadotropic hypogonadism. STUDY DESIGN: We studied heart structure and left ventricular systolic and diastolic function by echocardiography in 38 patients with hypogonadotropic hypogonadism (34 men and 4 women, mean age 24 +/- 4 years) and in 30 healthy subjects (25 men and 5 women, mean age 22 +/- 3 years). Left ventricular end-diastolic diameter, end-systolic diameter, left ventricular septal wall thickness, posterior wall thickness and ejection fractions were measured by M-mode echocardiography. Parameters of mitral flow were measured by pulsed wave Doppler echocardiography. RESULTS: Between patients with and without hypogonadotropic hypogonadism, there were no significant differences in echocardiographic measurements. CONCLUSION: Cardiac function is normal in patients with hypogonadotropic hypogonadism.     

Effect of estrogen replacement therapy on cardiac function in postmenopausal women with and without flushes.

Left ventricular heart function and its response to long-term estrogen replacement therapy was assessed in 30 postmenopausal women, 20 of whom had modest to severe hot flushes and 10 of whom had never had them. Continuous transdermal estradiol was given to women who had surgically induced menopause, and a combination of transdermal estradiol and sequential medroxyprogesterone acetate was given to those who had spontaneous menopause. Left ventricular systolic and diastolic function was evaluated by complete two-dimensional M-mode and pulsed Doppler echocardiography before and after 6 and 12 months of therapy. The parameters assessed were: systolic and diastolic blood pressure, heart rate, cardiac septal and posterior wall dimensions, left ventricular end-systolic and end-diastolic dimensions and volumes, ejection fraction (EF), ejection time, peak left ventricular outflow velocity (PFV), flow velocity integral (FVI), acceleration time (AT), mean acceleration of systolic flow (MA), duration of early and late filling phase, peak velocity of the early (E) and late (A) mitral flow, and A/E velocity ratio. Although no difference in chamber and wall dimensions between flushers and non-flushers was found, women with hot flushes had lower (not significantly) EF, PFV, FVI, MA, blood pressure and heart rate before therapy. Twelve-month estrogen replacement therapy significantly reduced cardiac wall dimensions and improved systolic function in both flushers and non-flushers. However, stroke volume, EF and MA were increased whereas systolic blood pressure and heart rate were decreased more in flushers. Also, the increase in E mitral flow and decrease in A/E were more pronounced in flushers. Thus, although estrogen replacement therapy significantly improves heart function in healthy postmenopausal women, there appears to be some minor differences in response between flushers and non-flushers.     

Factors influencing aortocaval compression in late pregnancy

The circulatory effects of postural change in late pregnancy were investigated in 20 healthy pregnant women. Maximum stroke volume (93.2 +/- 11.9 ml) was recorded with the subject in the left lateral position and was significantly (p less than 0.001) reduced in the supine, right lateral, and lithotomy positions, but was largely unchanged in the standing motionless position (89.9 +/- 12.6 ml). Diastolic, systolic, and mean arterial blood pressures and total peripheral vascular resistance were significantly (p less than 0.001) increased in the supine, right lateral, lithotomy, and upright motionless positions when compared to the same variables in the left lateral position. The following factors were found to be significantly correlated to the hemodynamic response to the supine recumbent position: maternal age (p less than 0.05), the position of the fetus in the uterus (p less than 0.05), and systolic (p less than 0.001) and diastolic (p less than 0.001) blood pressures measured with the subject in the left lateral position. The implications of the present findings for modern obstetric delivery care and the etiology of the supine hypotensive syndrome are discussed.     

Modulation of echocardiographic parameters by fetal behaviour

In order to verify if fetal behavioural states could affect cardiac parameters, thirty-one healthy fetuses were studied near term. We evaluated systolic time intervals (pre-ejection period and ventricular ejection time), M-mode parameters (fractional shortening and mean circumferential shortening) and Doppler flow velocities (mean peak velocity of aortic and pulmonary arteries) of left and right ventricles. Both fetal breathing movements and fetal heart rate patterns seem to modify these parameters with an increase of cardiac contractility during active phases of fetal behaviour.     

Myometrial thickness according to uterine site, gestational age and prior cesarean delivery.

OBJECTIVE: To evaluate the myometrial thickness (MT) of multiple uterine sites during all three trimesters of pregnancy in an attempt to identify anticipated myometrial thickness in each trimester for these sites. METHODS: In this prospective cross sectional study, MT was evaluated by ultrasound in women with viable singleton pregnancies. Women with suspected abruption, accreta, previa, fibroids, uterine and fetal anomalies, abnormal fluid volume, labor were excluded. MT was measured at the fundus, anterior wall (AW), posterior wall (PW), right and left side walls, lower uterine segment (LUS) and under the placenta. The cohort was divided to determine differences in MT at each site in each trimester (TRI). Differences in MT between sites were assessed. RESULTS: One hundred and seventy five women underwent ultrasound by a single observer. There were 25 1st, 100 2nd and 50 3rd TRI scans at mean (SD) gestations of 11.0 (1.9), 21.5 (3.6) and 34.1 (3.0) weeks, respectively. Women were 37% African American, 72% government insured, 39.4% nulliparous. A total of 13% of women had a prior cesarean. MT of the fundus was less than AW, PW, right and left side walls (p < 0.05 each). For all sites, MT was less in 2nd compared with 1st TRI (p < 0.0001 each). This was most evident with fundal and LUS MT (35% less each). There was no difference in MT between 2nd and 3rd TRI. Fundal, AW, left side wall, subplacental and LUS MT were greater in parous women (p < 0.05 each). With anterior placentation, AW MT was less than when the placenta was implanted elsewhere (6.6 vs 7.4 mm, p = 0.008). This was not found with fundal or posterior placentas. The LUS MT was not less with prior cesarean (6.1 vs 6.0 mm, p = 0.84). CONCLUSION: Myometrial thickness of all uterine sites is less in 2nd and 3rd trimesters compared with the 1st trimester. Fundal MT is less than other upper segment MT in the 2nd and 3rd trimesters. LUS MT is not less with prior cesarean.     

Effects of terbutaline sulfate on fetal cardiac function

An isolated heart preparation was used to study the effects of terbutaline sulfate (Brethine) on fetal cardiac function. Pregnant guinea pigs received daily subcutaneous injections of terbutaline for 10 day, whereas a control group received placebo injections. Fetal guinea pig hearts were evaluated for cariodynamic and pathologic differences. Fetuses exposed to terbutaline demonstrated a higher mean heart rate (p less than 0.01), a higher mean heart weight (p less than 0.05), a higher mean heart weight/body weight ratio (p less than 0.01), and a trend toward higher left ventricular systolic pressure levels (p less than 0.1). These hemodynamic responses in fetuses exposed to terbutaline may result in increased functional demands that may predispose myocardial tissue to damage.     

Growth and function of human fetal heart in normal, hypertensive and diabetic pregnancy

Fetal cardiac left and right ventricular dimensions and contractility were measured by echocardiography in late pregnancy in 51 normal, 26 hypertensive and 18 diabetic pregnancies. In relationship with the fetal size, both of the ventricular dimensions, the contractility and left ventricular output were decreased in diabetic cases. In hypertensive pregnancy the relative size of the right ventricle was increased and its contractility decreased, but the function of the left ventricle was no different from normal. These findings may reflect biochemical changes in diabetic myocardium and increased peripheral fetal and placental resistance in hypertensive pregnancy.     

Evaluation of the human fetal cardiac size and function

Two-dimensional-directed M-mode echocardiography was done on 80 normal fetuses between the 17th to 42nd weeks of gestation. The M-mode beam transected the ventricles at the level of the chordae tendineae at the tip of atrioventricular valves. Right and left ventricular dimensions and free wall thicknesses correlated well with gestational age. Calculated measurements showed a good correlation of the stroke volume and cardiac output with gestational age. The right ventricular dimension, however, was significantly greater than the left ventricular one. Fractional shortening of the right and left ventricle did not change significantly with advancing gestational age. This study indicates that the human fetal right ventricle dimension, stroke volume, and cardiac output are slightly larger than that of the left ventricle. This study also suggests that the human fetus increases its cardiac output to match its growth and it does so by increasing ventricular size rather than fractional shortening or heart rate.     

Peripheral and intracardiac concentrations of atrial natriuretic peptide in patients with heart disease.

To study the relationship between the plasma concentration of the atrial natriuretic peptide (ANP) and heart function and to discern the secretion pathway of ANP, we determined the peripheral plasma concentration of ANP in 18 heart patients and the intracardiac concentration of ANP in six heart patients during cardiac catheterization. All plasma was extracted through a Sep-Pak C18 cartridge by acid alcohol. The concentration of ANP was determined by a sensitive and specific radioimmunoassay method. We found that the plasma ANP concentration (pg/mL) in heart patients (ranging from 12 to 139, mean = 36.1 +/- 28.9) was statistically higher than that in normal adults (ranging from 8 to 20, mean = 12.4 +/- 3.3, n = 16; p less than 0.05). The ANP level in heart patients was inversely correlated with the left ventricular ejection fraction (r = -0.53, p less than 0.05) evaluated by radionuclide angiocardiography. The intracardiac level of ANP was 88 +/- 58 at the superior vena cava, 77 +/- 55 at the inferior vena cava, 124 +/- 68 at the right atrium, 98 +/- 64 at the right ventricle, 107 +/- 58 at the pulmonary artery, 98 +/- 52 at the left ventricle, 109 +/- 73 at the aorta and greater than 351 at the coronary sinus. In conclusion, ANP is mainly secreted via the coronary sinus into the atrial cavity. The peripheral plasma ANP concentration is higher in heart patients. It increases as the left ventricular ejection fraction decreases. Therefore, plasma ANP concentration may be a useful indicator for the assessment of cardiac function.     

Evaluation of the regional ventricular systolic function by two-dimensional strain echocardiography in gestational diabetes mellitus (GDM) fetuses with good glycemic control

Objective: The aim is to quantitatively assess regional ventricular systolic function by two-dimensional strain (2DS) echocardiography in gestational diabetes mellitus (GDM) fetuses with good glycemic control.

Methods: We studied 60 consecutive normal fetuses and 35 fetuses of GDM mothers with good glycemic control by echocardiography. M-mode and two-dimensional echocardiography were used to measure ejection fraction and wall dimensions of left ventricle and right ventricle. Both left and right ventricle peak systolic myocardial strain values were obtained by 2DS echocardiography.

Results: Compared with normal fetuses, the thickness of the interventricular septum (IVS) and the thickness of right ventricular wall were significantly increased in GDM fetuses (p?<?0.05). Compared with those of normal fetuses, the peak systolic myocardial strain decreased significantly in the apical segments of the IVS and the apical segments of the left ventricular lateral wall in GDM fetuses (p?<?0.05), as well as the apical and middle segments of right ventricular wall in GDM fetuses (p?<?0.05). Peak negative 2DS values in 60 normal fetuses increased with the gestational age, showing a significant linear correlation(r?=?–0.625, p?<?0.001). The average ventricular strain was not correlated to ventricular wall thickness (r?=?0.127, p?=?0.394).

Conclusions: 2DS is a feasible approach to assess regional ventricular systolic function in the fetal hearts and it can be used to examine cardiac systolic function in GDM fetuses with good glycemic control.     

The relationship between experimentally determined litter size and maternal blood pressure in spontaneously hypertensive rats

Pregnancy lowers blood pressure in hypertensive rats. To evaluate the role of the conceptus in maternal blood pressure regulation, we measured the changes in systolic blood pressure b (by tail-cuff plethysmography) throughout gestation and mean arterial pressure, cardiac output, and organ blood flows (with radioactive microspheres) on postmating day 21 for calculation of total peripheral and organ vascular resistances in spontaneously hypertensive rats with litter size surgically adjusted to 0 to 10 conceptuses on postmating day 7. Blood pressure remained elevated in those rats with zero fetuses but decreased during the last week of pregnancy in those rats with three or more fetuses. The magnitude of the decrease was directly related to litter size. At term, cardiac output was positively correlated (r = 0.61; p less than 0.001), whereas mean arterial pressure and total peripheral resistance were negatively correlated (r = -0.74; p less than 0.001 and r = -0.79; p less than 0.001, respectively) with litter size. Resistances of all the vascular beds in the body, except the kidneys, spleen, and hepatic artery were also negatively correlated with fetal number. Thus pregnancy is characterized by a generalized maternal vasodilation, and the fetal/placental unit may play a significant role in modulating maternal vascular tone.