Factors Influencing the Twisting and Untwisting Properties of the Left Ventricle during Normal Pregnancy (original) (raw)
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Changes in Fetal Left and Right Ventricular Strain Mechanics during Normal Pregnancy
Journal of the American Society of Echocardiography, 2013
Background: The aim of this study was to detect normal changes in fetal two-dimensional speckle-tracking echocardiography-derived values for global and regional longitudinal left and right ventricular strain, strain rate, and time to peak (T2P) global strain during pregnancy. Methods: Forty-four healthy fetuses were examined prospectively during the second-trimester and thirdtrimester ultrasound examinations (20-24 and 30-34 weeks, respectively). Clips with high frame rates (mean, 120 frames/sec) of two-dimensional (B-mode) grayscale images of apical or basal four-chamber views of both ventricles were used for offline analyses of global and regional walls and segments (basal, mid, and apical) of myocardial strain and strain rate as well as T2P global strain in the longitudinal direction. Results: There were statistically significant decreases in global and regional strain of the right ventricle between the second and third trimesters. No statistically significant changes were observed in global and regional strain of the left ventricle. Global and regional strain rates of both ventricles decreased in a similar way during pregnancy. The mean T2P longitudinal left ventricular global strain (adjusted for heart rate) increased mildly during fetal life. Whereas T2P longitudinal strain of the left ventricle at 20 to 24 weeks was statistically significantly shorter than that of the right ventricle, no difference in T2P longitudinal strain was found at 30 to 34 weeks of gestation between both ventricles. Conclusions: The establishment of these changes between the second-trimester and third-trimester twodimensional speckle-tracking echocardiography-derived reference values is a mandatory prerequisite for its use in evaluating (pathologic) changes in both ventricular functions during pregnancy.
Left Ventricular Torsional Mechanics in Uncomplicated Pregnancy
Clinical Cardiology, 2011
Background: Alterations in left ventricular (LV) twist (torsion) and untwist have been described for a variety of physiologic and pathologic conditions. Little information is available regarding changes in these parameters during normal pregnancy. Hypothesis: Pregnancy is associated with significant changes in LV torsional mechanics. Methods: Left ventricular twist and untwist was measured in 32 pregnant females (mean gestation 199 ± 48 d) and 23 nonpregnant controls using speckle-tracking echocardiography. Results: Left ventricular ejection fraction (68 ± 5% vs 66 ± 5%) was similar between the groups (P not significant). There was a significant increase in peak LV twist from nonpregnant controls (9.4 ± 3.7 degrees) to second-trimester (12.0 ± 4.2 degrees) and third-trimester subjects (12.6 ± 5.9 degrees, all P < 0.05). Peak LV twist velocity was also increased in second-and third-trimester groups compared with controls (94 ± 24 degrees/sec and 93 ± 30 vs 64 ± 21 degrees/sec, respectively, both P < 0.05). Both peak untwist velocity and time to peak untwist velocity were not significantly different between groups (P not significant). Multiple regression analysis indicate that only systolic blood pressure (r = 0.394, P = 0.005) was an independent predictor for increased LV torsion. Conclusions: There are significant changes in LV torsional indices during the course of pregnancy, whereas untwist parameters remain unchanged. Blood pressure is independently associated with increased torsion during pregnancy.
Altered maternal left ventricular contractility and function during normal pregnancy
Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology, 2013
To evaluate maternal left ventricular (LV) systolic and diastolic function during normal pregnancy by non-invasive measures of LV contractility incorporating loading conditions. Sixty-five women were examined using echocardiography, including tissue Doppler and two-dimensional speckle tracking, and subclavian artery pulse trace recordings at gestational weeks 14-16, 22-24 and 36, and at 6 months postpartum. The mean ± SD age of the women was 32.0 ± 4.6 years. Cardiac output and LV end-diastolic volume were on average 20% and 23% higher, respectively, during pregnancy, compared to that at 6 months postpartum (both, P < 0.01). LV ejection fraction, global peak systolic strain and rate-corrected LV velocity of circumferential fiber shortening (Vcfc) were 11%, 6% and 6% lower, respectively, at 36 weeks' gestation compared to at 6 months postpartum (all, P < 0.01). Afterload, measured as LV end-systolic wall stress (ESWS) increased by 10% between 14-16 and 36 weeks' gestati...
Obstetrics & Gynecology, 1997
Objective: To investigate the hemodynamic changes occurring in normal pregnancy and to see if these changes were associated with an increase in myocardial contractility. Methods: In a longitudinal study, primigravidas were studied with echocardiography in early (15 + 1.8 weeks), mid (26 rt 1.2 weeks), and late (36 f 1.0 weeks) gestation, as well as at 6 weeks postpartum. Cardiac dimensions were measured with two-dimensional and M-mode echocardiography and hemodynamic indices were calculated. All measurements were made with subjects in the left lateral decubitus position. Statistical analysis was performed with repeated measures analysis of variance. Results: Seventy-six women with normal pregnancy outcomes completed all four studies. From the baseline study to late gestation, an increase in cardiac output of 27% (from [mean f standard error] 4.2 f 0.1 to 5.8 f 0.2 L/min, P = .OOl), and a decrease in total peripheral resistance of 33% (from 1356-C 69 to 941 f 37 dynes/second cmm5, P = .OOl) occurred. Over this same time period, left ventricular function, while demonstrating a small and non-significant increase in velocity of circumferential fiber shortening (from 1.25 f 0.02 to 1.27-C 0.02 cm/second), revealed a 12% decrease in wall stress (from 36.3 + 1.0 to 31.9 + 1.0 g/cm', P = .OOl) and a 13% decrease in the load-independent wall stress to velocity of circumferential fiber shortening ratio (from 30.0 f 1.2 to 26.1 f 1.0, P = .Ol), implying enhanced intrinsic myocardial contractility. Conclusion: Normal pregnancy is characterized by enhanced myocardial performance.
Effect of Pregnancy on Left Ventricular Motion (Twist) in Women With Aortic Stenosis
The American Journal of Cardiology, 2008
The combination of fixed outflow obstruction from aortic stenosis (AS) and the hemodynamic changes of pregnancy increased the risk of maternal or fetal deterioration. Left ventricular (LV) response in patients with AS to the hemodynamic changes of pregnancy has not been examined. We studied and compared myocardial mechanics with echocardiography in 3 groups of 10 women each, including (1) pregnant with bicuspid aortic valve (BAV; peak aortic gradient 59 ؎7 mm Hg, aortic valve area 0.9 ؎ 0.04 cm 2 ), (2) pregnant without BAV, and (3) nonpregnant, healthy volunteer. Measurements in the pregnant BAV group were made on 3 occasions, within a year before pregnancy (baseline), in the antepartum period, and at least 6 weeks postpartum. Tissue tracking ultrasound was used to assess longitudinal strain and LV twist. During pregnancy, peak AS gradient rose from 59 ؎ 7 to 70 ؎ 9 mm Hg (p ؍ 0.004) whereas valve area remained unchanged 0.9 ؎ 0.04 to 0.8 ؎ 0.04 cm 2 (p ؍ 0.48) as compared with baseline (before pregnancy). Overall, in all patients, there was no significant change in the longitudinal strain (؊22 ؎ 1, ؊21 ؎ 0.6, ؊20 ؎ 0.6 percent, p ؍ 0.21)] at baseline, during pregnancy, or after pregnancy, respectively. Patients with AS had a higher baseline LV twist compared with both control groups (5.4 ؎ 0.3, pregnant, with AS; 4.1 ؎ 0.8, pregnant, without AS; 3.6 ؎ 0.3, nonpregnant volunteer; expressed in degrees; p ؍ 0.023). Additionally, all but 2 patients had a significant increase in LV twist during pregnancy compared with baseline. These 2 women had symptomatic deterioration requiring urgent aortic balloon valvuloplasty. Postpartum, in all AS patients, LV twist returned to antepartum values. In conclusion, we found that LV twist was significantly increased in women with congenital AS. During pregnancy, LV twist further increased in the antepartum period, except in those women who experienced functional deterioration.
Maternal left ventricular transverse and long-axis systolic function during pregnancy
Ultrasound in Obstetrics and Gynecology, 2001
Objectives Circumferential fiber shortening has been the dominant basis for conventional analysis by echocardiography of left ventricular systolic function during pregnancy. Results in the literature have been conflicting due mainly to the fact that geometric assumptions for the calculation of these indices are made that may not be valid due to changes in left ventricular shape during pregnancy. Left ventricular long-axis displacement is expected to be a useful index of systolic function, independent of the changes in left ventricular geometry. The aim of this study was to compare circumferential to long-axis shortening during left ventricular contraction in pregnant women. Methods This was a cross-sectional study of 125 pregnant women at 9 -42 weeks of gestation and 19 non-pregnant female controls. Two-dimensional and M-mode echocardiography of the left ventricle was performed including measurement of left ventricular long-axis displacement and activation time on the lateral, septal, anterior and inferior sides of the mitral annulus. Activation time was assessed as the time from the start of the Q-wave of the electrocardiogram to the onset of left ventricular long-axis shortening. Results Mean arterial pressure and activation time decreased during pregnancy, reaching a nadir at about 19 weeks' gestational age of 4% and 13%, respectively, below non-pregnant values; they subsequently increased towards term. Left ventricular long-axis displacement mirrored the changes in mean arterial pressure and activation time and increased with gestational age at all four sites of the atrioventricular plane reaching a peak at about 23 weeks (+ 12% compared to nonpregnant levels). The ejection fraction and fractional shortening remained stable until 30 and 32 weeks, respectively, and then decreased towards term. Conclusion Changes in left ventricular long-axis performance during pregnancy occur earlier than do measures of transverse function. Left ventricular long-axis function during pregnancy Kametas et al.
Morphological and Functional Adaptation of the Maternal Heart During Pregnancy
Circulation: Cardiovascular Imaging, 2012
Background-Pregnancy provides a unique model to study the adaptation of the heart in a physiological situation of transient load changes. The aim of this study was to assess the performance of the left ventricle (LV) in normal, uncomplicated pregnancies while considering the actual LV load and shape. Methods and Results-Serial echocardiographic examinations were performed in 51 women in each pregnancy trimester and 3 to 6 months after delivery. Data from 10 nulliparous, age-matched women were used as the control. Conventional parameters of LV function (ejection fraction) as well as myocardial deformation (strain) were interpreted, taking into consideration maternal hemodynamics and LV shape. Cardiac output increased during pregnancy because of a higher stroke volume in early pregnancy and a late increase in heart rate, whereas total vascular resistance decreased. Progressive development of eccentric hypertrophy was observed, which subsequently recovered postpartum. Sphericity index decreased from the first to the third trimester (1.92Ϯ0.17 versus 1.71Ϯ0.17) and returned postpartum to values comparable to the control. Although higher LV stroke work was noted toward the third trimester (5.9Ϯ1.1 versus 5.3Ϯ1.0 Newton meter, PϽ0.001), ejection fraction showed no significant changes. LV strain decreased significantly in late pregnancy (Ϫ19.5Ϯ2% to Ϫ17.6Ϯ1.6%, PϽ0.001) and returned to baseline values after delivery (Ϫ19.5Ϯ2%). Conclusions-Pregnancy is a physiological process associated with increased cardiac performance and progressive LV remodeling. These changes are not directly reflected by parameters traditionally considered to describe systolic function, such as ejection fraction and longitudinal deformation. While ejection fraction was insensitive to the functional changes, the transient decrease in longitudinal deformation becomes only plausible when considering the changes in LV geometry.
Ultrasound in Obstetrics & Gynecology, 2012
Objectives Most studies during pregnancy have assessed maternal left ventricular (LV) function by load-dependent indices, assessing only chamber function. The aim of this study was to assess afterload-adjusted LV myocardial and chamber systolic function at 24 weeks' gestation and 6 months postpartum in high-risk normotensive pregnant women. Methods A group of 118 high-risk women with bilateral notching of the uterine arteries underwent an echocardiographic examination to evaluate midwall mechanics (midwall shortening (mFS%) and stress-corrected midwall shortening (SCmFS%)) of the LV at 24 weeks' gestation and 6 months postpartum. Patients were followed until delivery and pregnancies were classified retrospectively as uneventful (uncomplicated outcome) or complicated. A control group of 54 low-risk women with uneventful pregnancies without bilateral notching was also enrolled. Results The pregnancy was uneventful in 74 (62.7%) women, whereas 44 (37.3%) developed complications. At 24 weeks' gestation, mFS% and SCmFS% were greater in the uncomplicated-outcome compared with the complicated-outcome group (25.9 ± 4.8 vs 18.8 ± 5.0%, P < 0.001 and 107.9 ± 18.4 vs 77.9 ± 20.7%, P < 0.001, respectively). At 6 months postpartum, SCmFS% remained greater in the uncomplicated-outcome compared with the complicated-outcome group (100.4 ± 21.6 vs 87.8 ± 19.1, P < 0.05). In the uncomplicatedoutcome group, SCmFS% was higher during pregnancy than it was postpartum, whereas in the complicatedoutcome group, it was lower during pregnancy than it was postpartum (P < 0.05). Conclusions Maternal cardiac midwall mechanics appear to be enhanced (SCmFS% increased compared with controls) during pregnancy compared with postpartum in high-risk patients with uncomplicated pregnancy, whereas midwall mechanics are depressed both during pregnancy and postpartum in patients with pregnancy complications.
Effects of gestational hypertension on left ventricular geometry
Kardiologia polska
During pregnancy heart rate, stroke volume, cardiac output and left ventricular (LV) mass increase while peripheral vascular resistance decreases. Gestational hypertension (GHT) which is noted in some pregnancies during the third trimester, is considered a temporary condition. Its effects on LV geometry are not known. To assess the effects of acute pressure overload in GHT on the LV geometry. Forty three pregnant women (mean age 28.7+/-8.9 years) with GHT were included in the study (Group A). Blood pressure levels >140/90 mmHg were considered diagnostic for GHT. Fifty six pregnant women (mean age 25.7+/-5.7 years) with normal blood pressure formed the control group (Group B). Transthoracic echocardiography was performed in all subjects before delivery. LV end-systolic (ESD) and end-diastolic (EDD) diameters, LV septal and posterior wall thickness were measured, and LV mass index (MI) as well as relative wall thickness (RWT) were calculated using Devereux and Ganau formulas. LV ge...
Cardiac structure and function in normal pregnancy
Current Opinion in Obstetrics & Gynecology, 2012
Purpose of review To review the published data on maternal cardiac adaptation to pregnancy. Recent findings Normal pregnancy is characterized by significant changes in the cardiovascular system. Studies on systemic arterial system and heart remodelling in pregnancy provide somewhat uniform results. In normal pregnancy, left ventricle mass, cardiac output and arterial compliance increase, whereas total vascular resistance decreases. In contrast, findings on left ventricular systolic and diastolic chamber and myocardial function are conflicting.