***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Preeclampsia is associated with asymptomatic global left ventricular abnormal function and geometry during the acute phase of the disorder . These sub clinical abnormalities in cardiac findings are known to be important in cardiovascular risk stratification for nonpregnant patients . Furthermore , epidemiological studies have also demonstrated a relationship between preeclampsia and cardiac morbidity and mortality later in life . The aim of this study was to evaluate the postpartum natural history and clinical significance of asymptomatic left ventricular impairment known to occur with acute preeclampsia . This was a prospect i ve longitudinal case-control study of 64 subjects with preeclampsia and 78 matched controls . There were 3 time point assessment s , pregnancy and 1 and 2 years postpartum . The assessment s included a  medical and family history , blood pressure profile , echocardiography , and 12-lead ECG .  At 1 year postpartum , asymptomatic left ventricular moderate-severe dysfunction/hypertrophy was significantly higher in preterm preeclampsia ( 56 % ) compared with term preeclampsia ( 14 % ) or matched controls ( 8 % ; P values < 0.001 ) . The risk of developing essential hypertension within 2 years was significantly higher in both preterm preeclamptic women and those with persistent left ventricular moderate-severe abnormal function/geometry . The cardiovascular implication s of preeclampsia do not end with the birth of the infant and placenta . The majority of preterm preeclamptic women have stage B asymptomatic heart failure postpartum , and 40 % develop essential hypertension within 1 to 2 years after pregnancy . Women with a history of preterm preeclampsia may benefit from formal cardiovascular risk assessment in the 1 to 2 years after delivery to identify those who would benefit from targeted therapeutic intervention OBJECTIVE : The factors affecting cardiac output in normal pregnancy remain controversial . This study prospect ively evaluates maternal central hemodynamics and cardiac structure and function by echocardiography , together with maternal stature correction and correlation of these variables in healthy pregnant women in the latter half of pregnancy . METHODS : One hundred sixty  echocardiographic studies were performed in 35 healthy pregnant women for longitudinal evaluation from early second trimester until term and 6–12 weeks postpartum . RESULTS : Cardiac output increased significantly at the early to mid third trimester and was maintained until term . It increased predominantly in the latter half of pregnancy , and peak cardiac output of 46–51 % occurred from a 15 % increase in heart rate and 24 % increase in stroke volume . Maternal cardiac output measured in the early third trimester showed a good correlation with maternal body surface area ( r = 0.72 ; P < .001 ) and fetal birth weight ( r = 0.52 ; P = .008 ) . Left ventricular systolic function was preserved until term . CONCLUSION : Maternal cardiac output peaks in the early to mid third trimester and is maintained until term . Significant correlations were observed among maternal cardiac output , maternal body surface area , and fetal birth weight . LEVEL OF EVIDENCE : Left ventricular ( LV ) adaptation to the hemodynamic load of pregnancy has been studied with load-sensitive ejection-phase indexes , but the results of these studies are conflicting . The aim of this study was to examine the effects of the hemodynamic load of pregnancy on the contractile state of the left ventricle by using load-adjusted indexes of contractility . Thirty-four healthy women were prospect ively studied by serial echo and Doppler examinations at six periods during pregnancy and after delivery . LV volume increased 10.5 % , paralleling the change in stroke volume . End-systolic stress , an index of myocardial afterload , decreased 28.8 % because of a decrease in end-systolic pressure and an increase in LV thickness/diameter ratio . Despite the increase in preload and the decrease in afterload , ejection phase indexes did not change during or after pregnancy . Although remaining within the normal range , the afterload-adjusted velocity of circumferential fiber shortening , an index of contractility that is relatively insensitive to preload , transiently decreased by 1.75 SDs during gestation , returning to non-pregnant values 2 to 4 weeks postpartum . Thus the increase in hemodynamic load that characterizes normal pregnancy is associated with preservation of global pump function . The transient decrease in contractile state may represent an adaptation phase of the contractile elements of the myocardium to the rapid changes in loading conditions observed during the first trimester of pregnancy Background Cardiovascular disease in pregnancy is the leading cause of maternal mortality in North America . Although transthoracic echocardiography ( TTE ) is the most widely used imaging modality for the assessment of cardiovascular function during pregnancy , little is known on the role of cardiovascular magnetic resonance ( CMR ) . The objective of the Cardiac Hemodynamic Imaging and Remodeling in Pregnancy ( CHIRP ) study was to compare TTE and CMR in the non-invasive assessment of maternal cardiac remodeling during the peripartum period . Methods Between 2010–2012 , healthy pregnant women aged 18 to 35 years were prospect ively enrolled . All women underwent TTE and CMR during the third trimester and at least 3 months postpartum ( surrogate for non-pregnant state ) . Results The study population included a total of 34 women ( mean age 29 ± 3 years ) . During the third trimester , TTE and CMR demonstrated an increase in left ventricular end-diastolic volume from 95 ± 11 mL to 115 ± 14 mL and 98 ± 6 mL to 125 ± 5 mL , respectively ( p < 0.05 ) . By TTE and CMR , there was also an increase in left ventricular ( LV ) mass during pregnancy from 111 ± 10 g to 163 ± 11 g and 121 ± 5 g to 179 ± 5 g , respectively ( p < 0.05 ) . Although there was good correlation between both imaging modalities for LV mass , stroke volume , and cardiac output , the values were consistently underestimated by TTE . Conclusion This CMR study provides reference values for cardiac indices during normal pregnancy and the postpartum state BACKGROUND Pregnancy and arterial hypertension ( AH ) have a prohypertrophic effect on the heart . It is suspected that the 2 conditions combined cause disproportionate myocardial hypertrophy . We sought to evaluate myocardial hypertrophy ( LVH ) and left ventricular function in normotensive and hypertensive women in the presence or absence of pregnancy . METHODS This prospect i ve cross-sectional study included 193 women divided into 4 groups : hypertensive pregnant ( HTP ; n = 57 ) , normotensive pregnant ( NTP ; n = 47 ) , hypertensive nonpregnant ( HTNP ; n = 41 ) , and normotensive nonpregnant ( NTNP ; n = 48 ) . After clinical and echocardiographic evaluation , the variables were analyzed using 2-way analysis of variance with pregnancy and hypertension as factors . Left ventricular mass ( LVM ) was compared using nonparametric analysis of variance and Dunn 's test . Predictors of LVH and diastolic dysfunction were analyzed using logistic regression ( significance level , P < 0.05 ) . RESULTS Myocardial hypertrophy was independently associated with hypertension ( odds ratio ( OR ) = 11.1 , 95 % confidence interval ( CI ) = 3.2 - 38.5 ; P < 0.001 ) and pregnancy ( OR = 6.1 , 95 % CI = 2.6 - 14.3 ; P < 0.001 ) in a model adjusted for age and body mass index . Nonpregnant women were at greater risk of LVH in the presence of AH ( OR = 25.3 , 95 % CI = 3.15 - 203.5 ; P = 0.002 ) . The risk was additionally increased in hypertensive women during pregnancy ( OR = 4.3 , 95 % CI = 1.7 - 10.9 ; P = 0.002 ) in the model adjusted for stroke volume and antihypertensive medication . Although none of the NTNP women presented with diastolic dysfunction , it was observed in 2 % of the NTP women , 29 % of the HTNP women , and 42 % of the HTP women ( P < 0.05 ) . CONCLUSIONS Hypertension and pregnancy have a synergistic effect on ventricular remodeling , which elevates a woman 's risk of myocardial hypertrophy We evaluated the predictive value of elevated total vascular resistance on the outcome of pregnancy in normotensive high-risk primigravidas with bilateral notching of the uterine artery Doppler . A total of 526 high-risk primigravidas referred to the obstetrics outpatient clinic of Tor Vergata University with bilateral notching of the uterine artery at 20 to 22 weeks ’ gestation were su bmi tted to a maternal echocardiographic examination and uterine artery Doppler evaluation at 24 weeks ’ gestation .  Blood pressure was recorded at the time of the examination , total vascular resistance was calculated , and the geometric pattern of the left ventricle was assessed . Patients were followed until the end of pregnancy to detect fetal/maternal adverse outcomes ( gestational hypertension , preeclampsia , abruptio placentae , fetal growth restriction , perinatal death , etc ) . A total of 111 of the 526 pregnancies showed a bilateral notch at 24 weeks ’ gestation , and 97 had an adverse outcome ( 18.44 % ) . The best independent predictor for maternal and fetal complications was total vascular resistance ( odds ratio : 91.25 ; 95 % CI : 39.64 to 210.05 ; P<0.001 ) . The cutoff value was 1400 dynes · s · cm−5 , with a sensitivity and a specificity of 89 % and 94 % , respectively . A high relative wall thickness of the left ventricle ( > 0.37 ; odds ratio : 2.47 ; 95 % CI : 1.12 to 5.44 ) and a hypertrophized ventricle ( left ventricular mass > 130 g ; odds ratio : 2.52 ; 95 % CI : 1.12 to 5.64 ) were also independent predictors ( P<0.05 ) . Echocardiography might identify at 24 weeks ’ gestation patients who subsequently develop maternal and fetal complications through the assessment of maternal hemodynamics and left ventricular geometry The aim of this study was to investigate cardiac functional status in pregnancy using a comprehensive approach taking into account the simultaneous changes in loading and geometry , as well as maternal age and anthropometric indices . This was a prospect i ve cross-sectional study of 559 nulliparous pregnant women assessed at 4 time points during pregnancy and at 1 year postpartum . All women underwent conventional echocardiography and tissue Doppler velocities and strain rate analysis at multiple cardiac sites . Mean arterial pressure and total vascular resistance index significantly decreased ( both P<0.001 ) during the first 2 trimesters of pregnancy and increased thereafter . Stroke volume index and cardiac index showed the opposite trend compared with mean arterial pressure and total vascular resistance index ( both P<0.05 ) . Myocardial and ventricular function were significantly enhanced in the first 2 trimesters but progressively declined thereafter . By the end of pregnancy , significant chamber diastolic dysfunction and impaired myocardial relaxation was evident in 17.9 % and 28.4 % of women , respectively , whereas myocardial contractility was preserved . There was full recovery of cardiac function at 1 year postpartum . Cardiovascular changes during pregnancy are thought to represent a physiological adaptation to volume overload . The findings of a drop in stroke volume index , impaired myocardial relaxation with diastolic dysfunction , and a tendency toward eccentric remodeling in a significant proportion of cases at term are suggestive of cardiovascular maladaptation to the volume-overloaded state in some apparently normal pregnancies . These unexpected cardiovascular findings have important implication s for the management of both normal and pathological pregnancy states OBJECTIVE Tissue Doppler imaging ( TDI ) is an echocardiographic technique for assessing the diastolic function that is relatively independent of preload . Since loading conditions change significantly during pregnancy , a load-independent technique will give a more accurate assessment of diastolic function in pregnant women . The aim of this study was to evaluate maternal diastolic function using tissue Doppler imaging . METHODS This was a prospect i ve observational study on 35 healthy pregnant women .  M-mode , transmitral inflow ( peak transmitral flow velocities during early diastole ( E wave ) and atrial contraction ( A wave ) ) and TDI studies ( peak myocardial velocities during early diastole ( Em wave ) , during atrial contraction ( Am wave ) and peak systole in ejection phase ( Sm ) ) were performed in each trimester and postpartum . The differences in variables between trimesters were analyzed . RESULTS The peak transmitral inflow velocity during early diastole ( E wave ) was significantly decreased during the third trimester and postpartum . The peak flow velocity during atrial contraction ( A wave ) was increased in the second trim 
    Output:
    
During normotensive pregnancy , most cardiac geometric indices change from the second trimester onwards .