Prenatal diagnosis and prognosis of accelerated idioventricular rhythm.

OBJECTIVES: As postnatal identification of accelerated idioventricular rhythm (AIVR) relies on specific electrocardiographic patterns, prenatal diagnosis of this condition is challenging and its true incidence is unknown. The objectives of this study were to evaluate the performance of prenatal ultrasonography in identifying intrauterine cardiocirculatory events linked to specific electrocardiographic signs of postnatal AIVR, including left or right ventricular origin, and to assess the prenatal prognosis of this arrhythmia. METHODS: We reviewed Doppler tracings from the superior vena cava/ascending aorta (SVC/Ao), ductus venosus (DV), ductus arteriosus (DA) and aortic isthmus (AoI), as well as simultaneous M-mode recordings of septal and left ventricular wall motions of fetuses diagnosed with AIVR from January 2004 to December 2014. RESULTS: Three cases of AIVR were identified among 27 912 fetuses. SVC/Ao Doppler flow recordings revealed atrioventricular dissociation (ventricular rates within 20% of atrial rates) in all three fetuses and episodes of isorhythmic atrioventricular dissociation in one, while M-mode confirmed normal left ventricular shortening fraction in all cases. Fusion beats were observed on AoI tracing in one fetus, while simultaneous recordings of AoI and DA revealed signs of right bundle branch block in one case and left bundle branch block in the other two. On DV Doppler recordings, retrograde a-waves in the presence of simultaneous atrial and ventricular contractions were observed in all three fetuses, leading to an increase in central venous pressure in all and hydrops fetalis in two cases without evidence of ventricular dysfunction. CONCLUSIONS: Echocardiographic criteria required for postnatal diagnosis of AIVR can be documented in utero using specific ultrasonographic approaches. During fetal life, AIVR may not be a benign entity. Hydrops fetalis is frequently associated with AIVR because of increase in central venous pressure related to simultaneous atrioventricular contractions; thus, the ultrasonographic investigation protocol of fetuses with unexplained hydrops fetalis should aim at ruling out AIVR and include Doppler flow recordings in SVC/Ao, DV, AoI, DA and umbilical vein. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Prediction of neonatal outcome of TTTS by fetal heart and Doppler ultrasound parameters before and after laser treatment.

OBJECTIVES: To determine the prognostic value of fetal Doppler and echocardiographic parameters for neonatal survival up to 30 days after laser coagulation in monochorionic pregnancies complicated by twin-twin transfusion syndrome (TTTS). METHODS: Fetal echocardiography and outcome data of consecutive cases of TTTS treated by laser were retrospectively reviewed. Hemodynamic and cardiac function parameters were collected before and after laser. RESULTS: Between February 2006 and January 2015, 106 fetoscopic laser were performed. The final analysis was limited to cases with ultrasound within 2 days before laser (n = 77) and 4 weeks after laser (n = 86). Overall neonatal survival rate was 64.9% (135/208) and 77.9% of pregnancies (81/104) had at least one baby alive. For the recipient twin, the preoperative predictors of neonatal survival were umbilical artery (UA) pulsatility index (PI), cerebro-placental PI ratio, UA end diastolic flow (EDF), ductus venosus a-wave, right ventricular myocardial performance index (RV-MPI) and CHOP score. The postoperative predictors of donor survival were donor RV-MPI and recipient UA EDF, umbilical vein pulsations, tricuspid regurgitation, cardiac hypertrophy and CHOP score. CONCLUSION: The hemodynamic predictors of postnatal survival after laser were preoperative signs of recipient cardiomyopathy and postoperative signs of cardiac overload in both twins. © 2016 John Wiley & Sons, Ltd.

Profiling left and right ventricular proportional output during fetal life with a novel systolic index in the aortic isthmus.

OBJECTIVE: Left ventricular ejection causes forward flow in the fetal aortic isthmus while the right ventricle has a retrograde influence. The aim of this study was to create reference values for an isthmic systolic index (ISI) reflecting the changing influence of right and left ventricular performance on Doppler flow velocity waveforms of the aortic isthmus throughout normal pregnancy. METHODS: Doppler recordings of 260 normal fetuses with a gestational age of 18-37 weeks were reviewed. Peak systolic velocity (PSV) and end-systolic velocity (or systolic nadir; Ns) were measured on all aortic isthmus waveforms. An ISI was derived from the ratio Ns/PSV. Left and right ventricular outputs were also calculated. RESULTS: Up to 22-23 weeks' gestation, the mean ISI is stable at around 0.2. At about 28 weeks, a brief end-systolic deceleration wave is observed on the aortic isthmus waveforms, progressing steadily with gestation and causing a fall of ISI towards a mean value of zero between 30 and 31 weeks. This trend continues thereafter and a mean value of -0.4 was observed at the end of pregnancy. An inverse correlation was found between right ventricular output and Ns (r = -0.334, P = 0.001). Simultaneous recordings of the isthmus and the ductus arteriosus Doppler waveforms demonstrated that the primary cause of the end-systolic deceleration and ultimate reversal of flow at the isthmus is the increasingly dominant flow from the right ventricle. CONCLUSION: The transitional changes of the respective right and left ventricular outputs throughout pregnancy are well profiled by the ISI. This index highlights the physiological increase in fetal right ventricle flow preponderance as pregnancy progresses. Alteration of the ISI profile could be expected in clinical conditions associated with unbalanced alteration of the fetal ventricular outputs.

Blood pressures in newborns with twin-twin transfusion syndrome.

OBJECTIVE: In addition to unbalanced flow through placental anastomoses, evidence suggests that transfer of circulating vasoactive elements from the donor to the recipient contribute to the pathological process of twin-twin transfusion syndrome (TTTS). The objective of this study was to test the hypothesis that TTTS recipients have higher blood pressure (BP) at birth than donors. STUDY DESIGN: Chart review of all TTTS infants born from 1996 to 2007 with both twins alive 24 h (51 pairs; average gestational age 30±3 weeks). RESULTS: Both systolic and diastolic neonatal BPs were significantly higher in recipients. When expressed relative to predicted BP for birth weight (BW), BP were lower than expected in donors and higher in recipients. CONCLUSIONS: Data indicate that TTTS recipients have BP significantly higher than donors and than BP expected for BW. The long-term impact of these early hemodynamic perturbations remains to be determined.

Neonatal oxygen exposure leads to increased aortic wall stiffness in adult rats: a Doppler ultrasound study.

We have previously shown that neonatal high oxygen (O2) exposure in rats leads to hypertension and vascular dysfunction in adulthood. Pulse-wave velocity (PWV), an indirect measure of vascular biophysical properties (arterial stiffness or distensibility), is a sensitive marker of cardiovascular health. Its measurement in rats is mostly based on invasive hemodynamics measurements, prohibiting longitudinal studies particularly relevant in models of developmental programming of cardiovascular dysfunctions. With this study, we sought (1) to verify the feasibility and validity of measuring of aortic PWV in Sprague-Dawley rats by ultrasound; (2) to use the technique to compare aortic PWV in adult rats exposed to O2 as newborns (80% day 3-10 of life) v. controls; and (3) to develop an algorithm to calculate PWV in a non-invasive manner. We calculated aortic PWV using standard echocardiography and electrocardiogram, and validated the measures with PWV obtained by intraaortic catheters. Aortic full length was measured at sacrifice. PWV was significantly increased in O2 exposed (505 ± 18 cm/s) v. control animals (421 ± 17 cm/s, P < 0.01). With regard to weight, femur length and distance from the manubrium to the anal margin (MA length), the latter showed the best correlation (R = 0.84, P < 0.0001) with full aorta length derived from (L) = 0.339 × (MA length) + 4.281. The current data using echo-Doppler method demonstrated increased aortic stiffness in adult rats exposed to hyperoxia as newborns and suggests that non-invasive longitudinal studies of aortic PWV can be performed using the proposed algorithm for estimation of the full aorta length.

Profiling fetal cardiac function in twin-twin transfusion syndrome.

OBJECTIVES: Cardiomyopathy in the recipient twin is a marker of severity in twin-twin transfusion syndrome (TTTS), making it a potentially valuable tool for staging the disease. This study aimed to provide a quantitative description of cardiac function in the recipient twin. METHODS: Consecutive monochorionic pregnancies complicated with TTTS and treated by percutaneous laser coagulation underwent fetal echocardiography before surgery. An unsupervised classification analysis was conducted to identify groups of twins with similar cardiac profiles. The predictive value of the recipient twin's preoperative cardiac function based on these profiles was assessed, using perinatal death of at least one twin as the main outcome. The cardiac function profiles that we identified were compared with the current Quintero staging. RESULTS: A total of 107 pregnancies were included, with six of these lost to follow-up; 63/107 complete cases were available for multivariate description of the recipient's cardiac function. Three different preoperative cardiac profiles were identified with increasing right and left myocardial performance index, decreasing right and left shortening fraction, and increasing ductus venosus pulsatility index. Although the three groups represented progressive stages of the syndrome-related cardiomyopathy, no correlation was found with pregnancy outcome. Of Quintero Stage 1 cases, 55% showed significant alterations of cardiac function in the recipient twin. CONCLUSIONS: Progressive cardiomyopathy can be assessed quantitatively in the recipient twin and does not influence pregnancy outcome when fetoscopic laser coagulation is the first-line treatment. Compared with the current staging, cardiac profiling allows discrimination of cases with significant myocardial dysfunction.

Feasibility and reliability of Doppler flow recordings in the fetal aortic isthmus: a multicenter evaluation.

OBJECTIVES: To evaluate the performance of three different centers with respect to their ability to identify the fetal aortic isthmus (AoI) adequately and place a Doppler sample volume in the AoI correctly, and to address the reproducibility of the isthmic flow index (IFI) calculated from Doppler waveforms recorded in the three centers. METHODS: The three collaborating centers sent several ultrasonographic recordings taken at random over a 6-week period to the Saint-Justine Fetal Cardiology Unit (StJ-FCU). A performance quotient ((number of total readings - number of unsatisfactory results)/number of total readings) was calculated for each center by each of three judges, who were experienced fetal cardiologists, to assess the ability of each center to identify the isthmus and to place the Doppler sample volume (DSV) adequately. Intraclass correlation coefficients (ICC) were computed to quantify the variability of IFI measurements ((systolic + diastolic)/systolic flow velocity integrals). RESULTS: Fifty-five recordings were available for this study. Concerning isthmus identification, there was 100% agreement between the three judges from StJ-FCU and the performance quotients of Centers A, B and C were: 0.90, 0.95 and 1.00, respectively. For DSV positioning, agreement between the judges varied; for Judge 1 vs. Judge 2, kappa = 0.836 (95% CI, 0.651-1.000); for Judge 1 vs. Judge 3, kappa = 0.773 (95% CI, 0.557-1.000); for Judge 2 vs. Judge 3, kappa = 0.941 (95% CI, 0.805-1.000). The performance quotients of the three centers for DSV positioning were consistently lower than were those for identification of the isthmus, being 0.85, 0.76 and 0.92, respectively. The ICC between the first and second measurements of the IFI by Rater 1 was 0.96 (95% CI, 0.93-0.98, P < 0.001) and that between Raters 1 and 2 was 0.97 (95% CI, 0.95-0.99, P < 0.001). CONCLUSION: Adequate imaging of the fetal AoI can be achieved easily by a trained sonographer, while DSV positioning is challenging. The intra- and interrater variability of the IFI are low.

Relevance of measuring diastolic time intervals in the ductus venosus during the early stages of twin-twin transfusion syndrome.

OBJECTIVE: To determine if the discrete myocardial diastolic dysfunction documented previously in the recipient twin during the early stages of twin-twin transfusion syndrome (TTTS) has any repercussion on flow velocities through the ductus venosus (DV) and to investigate if this could allow early differentiation between TTTS and selective intrauterine growth restriction (IUGR). METHODS: Two groups of monochorionic twin pregnancies with growth discordance between twins were reviewed retrospectively. Group I was composed of fetuses in Stages I and II of TTTS; laser or amnioreduction was not performed in any instance. Group II twin pairs each included one fetus with IUGR due to placental circulatory insufficiency. Intertwin differences (smaller minus larger fetus) were analyzed for myocardial performance index of the right ventricle (MPI-RV) and for time variables in the DV. RESULTS: There were 38 pairs of monochorionic twins (24 TTTS and 14 IUGR) in this study. In the TTTS group, the donors had a significantly lower MPI-RV (0.419 +/- 0.18 vs. 0.596 +/- 0.17, F(1,19df) = 24.017, P < 0.001), a significantly longer total ventricular filling time (150.9 +/- 25.6 ms vs. 124.0 +/- 22.6 ms; F(1,21df) = 19.631, P < 0.001) and a significantly longer early filling time (118.9 +/- 22.9 ms vs. 92.6 +/- 18.9 ms, F(1,21df) = 28.419, P < 0.001) than had the recipient. None of these three differences was present in the IUGR group. Probability studies revealed that cut-off values of 12.75 for intertwin differences in total filling time and 8.5 for intertwin differences in early filling time had sensitivities of 71% and 92%, respectively. The false-positive rates were 23% and 15%, respectively, for the early diagnosis of TTTS. CONCLUSION: In monochorionic twin pregnancies, shortening of the ventricular filling time in the recipient twin indicates diastolic myocardial dysfunction occurring early in the pathophysiology of TTTS. This early interwin difference in myocardial function is not found in pregnancies with IUGR in one twin due to placental circulatory insufficiency, allowing early differentiation between TTTS and selective IUGR.

[Fetal haemodynamic and left heart dysfunction]. / Hémodynamique foetale et dysfonction du coeur gauche.

Foetal cardiology is a well established field of paediatric cardiology. It is no longer a simple exercise of prenatal diagnosis of cardiac malformations. It also covers the investigation and treatment of arrhythmias and functional and dynamic cardiocirculatory evaluation of the foetus which does not always have primary organic cardiac disease. It is this aspect which will be described in this article. The interactions of the left heart / foetal haemodynamics are classified in two main groups according to whether the left myocardial dysfunction is primary or secondary to changes of pre- or afterload. The haemodynamics singularities of the normal foetal circulation are and essential basis for the understanding of the phenomena observed.

Structural, functional and metabolic remodeling of rat left ventricular myocytes in normal and in sodium-supplemented pregnancy.

OBJECTIVES: Pregnancy is an important physiological condition associated with hemodynamic and endocrine changes that affect the heart. Nevertheless, very little is known about cardiomyocyte remodeling in this condition. Here, we studied the morphological, functional and metabolic remodeling of rat left ventricular myocytes that occurs in late stages of normal pregnancy (P) and in experimental preeclampsia induced by elevated (0.9%) sodium intake (P0.9). METHODS: We applied confocal microscopy to examine the morphology and the contractility of single cells, while the patch clamp technique was used to assay ionic currents. RESULTS: Our results revealed a significant increase in the volume of single left ventricular cardiac myocytes in P, mainly resulting from cell elongation. In P0.9, further increase in the cell length led to a significant rise in the length/width ratio. Cell contractility was significantly decreased in glucose-based solutions in response to stimulation at 0.5 Hz and 6 Hz in P as well as in P0.9. The density of L-type calcium current (I(Ca)L) was not significantly altered in P or in P0.9. Metabolic substrates lactate and pyruvate, increased in the blood of P and P0.9 rats, enhanced contractility in P, without affecting I(Ca)L. The same effect, present but blunted in P0.9, was associated with a significant increase in I(Ca)L. CONCLUSION: Our results demonstrate that processes of adaptive remodeling take place in normal pregnancy, while maladaptive components are identified in experimental preeclampsia; they also reveal an adaptation in the use of energy substrates in pregnancy and its impairment by sodium supplementation.

Prenatal diagnosis of complete atrioventricular block associated with structural heart disease: combined experience of two tertiary care centers and review of the literature.

OBJECTIVE: To review the pattern of presentation, management and outcome of fetal complete atrioventricular block (CAVB) associated with major structural congenital heart disease (CHD), when compared to isolated CAVB. METHODS: Retrospective analysis of the medical records and echocardiograms of all CAVB cases, diagnosed prenatally at two tertiary care centers between the years 1990 and 2002. RESULTS: Of a total of 59 consecutive fetal cases of CAVB, 24 (41%) had underlying major CHD, mainly left isomerism (n = 18) and congenitally corrected transposition of the great arteries (cc-TGA) (n = 3). When compared to isolated CAVB (n = 35), cases with CHD were detected earlier (21 +/- 6 vs. 26 +/- 6 weeks; P < 0.02) and-despite comparable heart rates-more often had fetal hydrops (38% vs. 9%; P < 0.02), while pregnancy continuation (66% vs. 94%; P < 0.02) or prenatal treatment (19% vs. 64%; P < 0.001) was less likely. Of 16 CHD cases with pregnancy continuation, beta-inotropic treatment of fetal bradycardia was attempted in three cases: all had left isomerism and died early postnatally. Livebirth and 1-year survival rates of CAVB with CHD were 56% and 19%, respectively, when compared to isolated CAVB with 88% and 75%, respectively (P < 0.0001). The four neonatal survivors (one left isomerism, three cc-TGA) had heart rates persistently > 60 bpm throughout gestation and 3/4 underwent a biventricular repair. CONCLUSIONS: Fetal CAVB with CHD continues to be associated with a poor outcome, in particular in the presence of left isomerism and fetal heart rates < 60 bpm.

Early intertwin differences in myocardial performance during the twin-to-twin transfusion syndrome.

BACKGROUND: In the twin-to-twin transfusion syndrome (TTTS), pressure rather than volume overload is increasingly considered as a key factor in the pathogenesis of the cardiomyopathy of the recipient twin. If this is the case, cardiac dysfunction should be among the first signs observed with TTTS. The objective of this study was to determine whether intertwin differences in myocardial function are modified early in the course of TTTS and whether they can help to differentiate this condition from intrauterine growth restriction (IUGR). METHODS AND RESULTS: Eight variables were analyzed on the first fetal echocardiography on 21 pairs of twins with TTTS and 11 with IUGR. No difference was found between the 2 groups for the cardiothoracic ratio, pulsatility indices in the umbilical and middle cerebral arteries, and peak velocity of the middle cerebral artery. Significant difference was found for ventricular septal thickness, but with no association with the conditions under study. With TTTS, left ventricular shortening fraction was consistently greater in the donor twins, and myocardial performance indices (MPIs) were elevated in the recipient twins. This increase in MPI was caused by a lengthening of the isovolumic periods compared with those of the donor twin: left ventricular and right ventricular isovolumic periods 0.105+/-0.047 and 0.097+/-0.026 seconds, respectively, for the recipient twins versus 0.0561+/-0.46 and 0.065+/-0.03 seconds, respectively, for the donor twins (P<0.001). These changes in the isovolumic periods were mainly due to significant prolongation of isovolumic relaxation times. A change in left ventricular MPI > or =0.09 combined with a change in right ventricular MPI > or =0.05 would identify a TTTS with a sensitivity of 75% and a false-positive rate of 9%. CONCLUSIONS: The observed diastolic function impairment goes along with the pressure-overload pathogenic concept proposed in TTTS. Assessment of intertwin difference in MPI is a valuable tool for early differential diagnosis between TTTS and isolated IUGR.

Immediate and short-term effects of pulmonary artery banding on left ventricular performance in foetal sheep.

AIM: To evaluate foetal left ventricular performance when its preload was increased by banding the pulmonary artery, a study design where a simultaneous change in left ventricular afterload is unlikely. METHODS: Nine ovine foetuses were studied with real-time images and Doppler echocardiography before, 3-4 and 6-8 d after surgery. Seven of these foetuses were also studied during the surgical intervention, immediately before and within 2 min after banding. RESULTS: The immediate effects of a 90-95% reduction of the pulmonary artery cross-sectional area were: a 53 +/- 20% (mean +/- SD) decrease and a 38 +/- 10% increase of right (RvQ) and left ventricular output (LvQ), respectively. Comparing measurements before and 3-4 d after operation, there was a 64 +/- 16% decrease of RvQ and a 64 +/- 25% increase of LvQ. The increase in LvQ was due to an increase in both heart rate (19 +/- 10%) and stroke volume (38 +/- 18%). After an additional 3-4 postoperative days, heart rate remained increased to the same extent, but there was a more pronounced increase of LvQ (93 +/- 19%) and stroke volume (59 +/- 22%). CONCLUSION: The parallel foetal circulation has a capacity to handle a severely increased afterload for the right ventricle by immediately improving and maintaining an increased left ventricular performance. This improvement was in part accomplished by an increase in stroke volume.

Management of fetal tachyarrhythmia based on superior vena cava/aorta Doppler flow recordings.

OBJECTIVE: To evaluate a management protocol of fetal supraventricular tachycardia (SVT) based on prior identification of the underlying mechanism. DESIGN AND SETTING: Prospective study in a mother-child tertiary university centre. PATIENTS: During a consecutive 36 month period, 18 fetuses with sustained SVT underwent a superior vena cava/ascending aorta (SVC/AA) Doppler investigation in an attempt to determine the atrioventricular (AV) relation and to treat the arrhythmia according to a pre-established management protocol. MAIN OUTCOME MEASURE: Rate of conversion to sinus rhythm. RESULTS: Seven fetuses had short ventriculoatrial tachycardia, five of these with a 1:1 AV conduction suggesting re-entrant tachycardia. The first choice drug was digoxin and all were converted. One fetus had AV dissociation leading to the diagnosis of junctional ectopic tachycardia, which was resistant to digoxin and sotalol; amiodarone achieved postnatal conversion. One fetus had SVT and first or second AV block; the diagnosis was atrial ectopic tachycardia (AET), which responded to sotalol given as a drug of first choice. Seven fetuses had long ventriculoatrial tachycardia: one with sinus tachycardia (no treatment), one with permanent junctional reciprocating tachycardia (PJRT), and three with AET. The first choice drug was sotalol and all were converted. One AET was classified postnatally as PJRT. Six fetuses had intra-atrial re-entrant tachycardia: five with 2:1 AV conduction and one with variable block. The first choice drug was digoxin. Conversion was achieved in all but one, who died after birth from advanced cardiomyopathy. CONCLUSION: The electrophysiological mechanisms of fetal SVT can be clarified with SVC/AA Doppler. The proposed management protocol has so far yielded a good rate of conversion to sinus rhythm.

Reference values for an index of fetal aortic isthmus blood flow during the second half of pregnancy.

OBJECTIVE: During fetal life, the parallel position of the two cardiac ventricles confers a special status to the aortic isthmus. Flow through the isthmus reflects the balance between the performances of the two ventricles and their respective peripheral impedances. This study proposes a fetal aortic isthmus flow velocity index and its reference values defined on the basis of gestational age (GA). METHODS: Video recordings of 111 normal fetuses from 18 to 39 weeks of gestation were retrospectively reviewed. An isthmus flow velocity index (IFI) was calculated as follows: IFI = (systolic + diastolic)/systolic velocity integrals. GA-specific reference ranges of IFI were constructed. RESULTS: An IFI of 1.33 +/- 0.03 was found at 18 weeks. This value decreased slightly but steadily with GA to reach 1.23 +/- 0.16 at 39 weeks. This change is mainly related to a decrease in diastolic velocity integrals. CONCLUSION: The proposed IFI provides information on the direction and, indirectly, on the volume of blood flow through the fetal aortic isthmus.

Changes in flow velocity patterns of the superior and inferior venae cavae during placental circulatory insufficiency.

OBJECTIVES: Placental circulatory insufficiency, expressed by the disappearance of the diastolic component of the umbilical artery Doppler velocity waveforms, causes blood flow redistribution that could disturb, to different extents, the systemic venous returns to the heart. The purpose of this study was to investigate the effect of an absence of diastolic blood flow in the umbilical artery on the relationship between the Doppler flow velocities of the venae cavae. METHODS: Fifteen normal fetuses (normal group) were matched for gestational age with 11 fetuses with absent diastolic flow in the umbilical artery (abnormal group). In the venae cavae, the following Doppler variables were measured and compared between groups: (a) during ventricular systole: maximum (S(max)) and minimum velocities (S(min)) and velocity integrals (SI); (b) during ventricular diastole: peak velocity of the E-wave and its integral (EI), the A-wave and its integral (AI). A venous velocity index (VVI) was defined as (S(max) + S(min))/S(max). RESULTS: In the normal group, S(min) and VVI were significantly higher in the inferior vena cava (IVC) than in the superior vena cava (SVC). The ratio SVC-VVI/IVC-VVI was therefore always less than one. In the abnormal group, S(min), SI, E, EI and VVI were higher in the SVC compared to those of the IVC. The ratio SVC-VVI/IVC-VVI was always greater than one. CONCLUSION: In the absence of umbilical artery diastolic flow, a reciprocal shift is observed between the IVC and SVC velocity waveforms characterized by a flow profile in the IVC which resembles that of a normal SVC profile and vice versa. These changes are another manifestation of blood flow redistribution towards the brain in the presence of placental circulatory insufficiency. They should be taken into account on Doppler assessment of ventricular diastolic function based on venous flow patterns during placental circulatory impairment.