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Biomedical subjects

J C Huhta

Publications and source records attributed to J C Huhta.

At least 19 recordsLinked to original sources
PubMed2001

Right ventricular function in the human fetus.

Fetal RV function is critical for survival and normal cardiovascular development. Doppler can be used to assess function. Combined with wise use of imaging techniques, the cause of abnormalities can be assessed. Both congenital heart defects and other cardiovascular defects can lead to hydrops and death. Serial semi-quantitation of fetal heart failure can be done with a Cardiovascular Profile score.

Female↗
PubMed2001

Fetal congestive heart failure: correlation of Tei-index and Cardiovascular-score.

INTRODUCTION: Congestive heart failure (CHF) may be present in fetuses with hydrops fetalis (HF) and the severity is difficult to quantitate. Differential ventricular dysfunction may be present in the fetus with CHF. A non-geometric measure of ventricular function that is not afterload dependent would be useful to measure the severity of myocardial dysfunction. METHODS: Tei-index (isovolumetric time/ejection time) was measured prenatally in 23 normals (24-34 weeks gestational age-GA) and in 7 with HF (24-34 weeks GA). Prenatal CHF severity was graded by a 10 point cardiovascular (CV) score (2 points each for absence of hydrops, normal venous Doppler, heart function, arterial Doppler, and heart size, and 10/10 = normal). A paired student t-test was used to compare RV and LV and non-paired t-test compared HF and normals. Tei-index and CV score were correlated. RESULTS: Tei-index normals were 0.38 +/- 0.04 in the right ventricle (RV) and 0.41 +/- 0.05 in the left ventricle (LV) and there were no significant RV-LV or gestational age (GA) differences. Among HF fetuses, RV and LV Tei-indices were both significantly increased (0.54 and 0.92) and not significantly different. CV score ranged from 2 to 8 (mean 5.43 out of 10) and correlated inversely with Tei-index (r = -0.52, r = -0.68). CONCLUSION: Hydrops fetalis is associated with biventricular dysfunction and congestive heart failure. Tei-index correlates with CV score obtained within two weeks of delivery or intrauterine death. Tei-index may be useful in the serial assessment of myocardial dysfunction in the fetus with hydrops.

Adult↗
PubMed2000

Superior vena caval syndrome: color flow Doppler detection of collateral venous channels.

Thrombosis of the superior vena cava (SVC) is an important clinical problem that requires prompt diagnosis. Confirmation of suspected SVC syndrome requires the use of an imaging study to document the obstruction and presence of collateral venous channels. Echocardiography is often used to evaluate suspected SVC obstruction; however, previous methods have allowed only indirect detection of collateral flow. We describe 3 patients with SVC obstruction in whom color flow Doppler allowed direct demonstration of collateral venous channels.

Adult↗
PubMed1999

The effects of maternal indomethacin therapy on human fetal branch pulmonary arterial vascular impedance.

OBJECTIVE: To examine whether maternal indomethacin therapy affects human fetal pulmonary arterial vascular impedance without constriction of the ductus arteriosus and to determine the changes in the pulmonary arterial vascular impedance in the presence of ductal constriction. STUDY DESIGN: In this cross-sectional study, 52 normal fetuses without maternal medication (control group), 33 fetuses without ductal constriction (Study group I) and 11 fetuses with ductal constriction (Study group II) during maternal indomethacin therapy between 24 and 34 weeks of gestation were examined by Doppler echo-cardiography. Blood velocity waveforms across the proximal right or left pulmonary artery were obtained and the pulsatility index (PI) of the proximal pulmonary arteries was calculated. RESULTS: In the control group, the proximal pulmonary artery PI was higher (p < 0.0001) at 24-25 weeks (n = 7) (3.73 +/- 0.33; mean +/- SD) than at 33-34 week of gestation (n = 11) (2.98 +/- 0.27). The PI was constantly greater (p < 0.005) in Study group I than in the control group. However, in this group the mean average weekly decrease in the PI of the proximal pulmonary arteries was similar to that in the control group. After 26 weeks of gestation, the PI values in Study group II were significantly higher than in the control group (27 weeks: 4.12 vs. 3.34 (p < 0.005); 30 weeks: 4.48 vs. 3.14 (p < 0.0001); 34 weeks: 4.96 vs. 3.00 (p < 0.0001), respectively). CONCLUSIONS: Human fetal pulmonary arterial vascular impedance is increased by maternal indomethacin therapy even without ductal constriction. In the presence of ductal constriction, the magnitude of the increase in the vascular impedance is related to the gestational age.

Blood Flow Velocity↗
PubMed1999

Fetal cardiac development and hemodynamics in the first trimester.

OBJECTIVE: To describe fetal cardiac and hemodynamic development in the first trimester of pregnancy. SUBJECTS AND METHODS: Forty-eight pregnancies were prospectively studied with transvaginal ultrasound and color Doppler. Fetal heart rate and size were documented together with the presence of inflow and outflow wave-forms and valve signals. RESULTS: Heart rate and size showed a positive correlation with gestational age. At 6 weeks of gestation, 20% of the cardiac cycle was occupied by the isovolumic contraction time (ICT); the isovolumic relaxation time (IRT) occupied 16% and remained unchanged, while the ICT progressively shortened and was not measurable after 12 weeks. The peak inflow velocities had changed from monophasic to biphasic by 10 weeks of gestation. At 7 weeks of gestation, semilunar valves were detected in 10% of examinations and the atrioventricular valves in 3%. The detection rate for both valves at 12 weeks was > or = 90%. In pregnancies that miscarried, the detection rate for both was < 25%. CONCLUSIONS: The Doppler signals that characterize the heart during the first trimester suggest effective heart compliance by 12 weeks. Normal valve development can be inferred from non-invasive Doppler recordings.

Female↗
PubMed1998

Reactivity of the human fetal pulmonary circulation to maternal hyperoxygenation increases during the second half of pregnancy: a randomized study.

BACKGROUND: The aims of the present study were to determine whether maternal hyperoxygenation affects human fetal pulmonary circulation and whether there is a gestational age-related response in the fetal pulmonary circulation to maternal hyperoxygenation during the second half of gestation. METHODS AND RESULTS: Twenty women between 20 and 26 weeks of gestation and 20 women between 31 and 36 weeks of gestation with normal singleton pregnancies were randomized to receive either 60% humidified oxygen or medical compressed air (room air) by a face mask. Fetal aortic and pulmonary valve; ductus arteriosus (DA); and right (RPA), left (LPA), and distal (DPA) pulmonary artery blood velocity waveforms were obtained by Doppler ultrasound before, during, and after maternal administration of either 60% oxygen or room air. Left and right ventricular cardiac outputs, DA volume blood flow, and RPA and LPA volume blood flows (Qp) were calculated. Foramen ovale volume blood flow (left ventricular cardiac output-Qp) was estimated. Pulsatility index (PI) values of DA, RPA, LPA, and DPA were calculated. Maternal hyperoxygenation did not change any of the measured fetal parameters between 20 and 26 weeks, whereas between 31 and 36 weeks, the PI values of RPA, LPA, and DPA decreased (P<.0001) and the PI of DA increased (P<.0001). In addition, Qp increased (P<.001), and DA volume blood flow (P<.01) and foramen ovale volume blood flow (P<.03) decreased. Left and right ventricular cardiac outputs were unchanged. All changes returned to baseline after maternal hyperoxygenation was discontinued. CONCLUSIONS: Reactivity of the human fetal pulmonary circulation to maternal hyperoxygenation increases with advancing gestation; this suggests that fetal pulmonary circulation is under acquired vasoconstriction at least after 31 to 36 weeks of gestation.

Blood Flow Velocity↗
PubMed1998

Cardiac malposition, redistribution of fetal cardiac output, and left heart hypoplasia reduce survival in neonates with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation.

OBJECTIVE: To evaluate cardiac position, left ventricular (LV) mass, and distribution of fetal cardiac output in infants with congenital diaphragmatic hernia (CDH) who required extracorporeal membrane oxygenation (ECMO), and in control subjects. STUDY DESIGN: Echocardiograms were performed on 23 neonates with CDH shortly after birth, and repeated within 5 days of repair on ECMO in 21 infants,aand on 12 infants receiving ECMO for other diagnoses, and on 10 healthy, term neonates. Cardiac angle between the midline saggital plane and the interventriculak septum was measured, and deviation from normal (45 degrees) was determined. The ratio of cross-sectional areas (proportional to flows) across the pulmonary (PV) and aortic (AV) valves was determined (PV2/AV2) in 19 infants with CDH and in the healthy control subjects. RESULTS: Thirteen (57%) infants with CDH survived and 10 (43%) died, with no difference in cardiac deviation before surgical repair (35 +/- 13 degrees vs Cardiac deviation persisted after repair in nonsurvivors (27 +/- 14 degrees vs 800.01 and LV mass was significantly less (1.68 +/- 0.39 vs 3.05 +/- 1.20 gm/kg, p00.0005). Neonates requiring ECMO for other diagnoses and well term babies did not have cardiac angle deviations; both these groups had a greater LV mass than did the infants with CDH. The PV2/AV2 flow ratios were higher in infants with CDH (median, 1.73; range, 1.25 to 16.50) compared with those of the healthy infants (0.96, 0.79 to 1.69, p < 0.0002). CONCLUSIONS: Cardiac malposition persisted despite CDH repair in nonsurvivors with low LV mass, and fetal cardiac output was redistributed away from the left ventricle. Lung hypoplasia with reduced pulmonary flow returning to the left atrium and altered left atrial hemodynamics may result in LV hypoplasia

Abnormalities, Multiple↗
PubMed1997

Human fetal right ventricular ejection force under abnormal loading conditions during the second half of pregnancy.

Our objective was to determine whether abnormal loading conditions can modify human fetal right ventricular ejection force during the second half of pregnancy. By Doppler echocardiography, we studied 73 normal fetuses between 19 and 41 weeks of gestation, 27 fetuses with hypoplastic left heart syndrome (chronic volume overload) between 18 and 38 weeks of gestation, 14 fetuses with mild to moderate constriction of the ductus arteriosus (pulsatility index (PI) between 1.0 and 1.9) and seven fetuses with severe constriction (PI < 1.0) or occlusion of the ductus arteriosus (relatively acute pressure overload) between 28 and 34 weeks of gestation. In the normal and ductal constriction/occlusion groups, blood velocity waveforms were recorded at the level of the aortic and pulmonary valves, and in the group with hypoplastic left heart syndrome at the level of the pulmonary valve. The ventricular ejection forces were calculated. In the normal group, right (RVEF; r = 0.91, p < 0.0001) and left (LVEF; r = 0.86, p < 0.0001) ventricular ejection forces increased and were equal during the second half of gestation. In the group with hypoplastic left heart syndrome the RVEF increased (r = 0.76, p < 0.0001) with advancing gestation. The RVEF (p < 0.0005) and its average weekly increase (p < 0.0001) were greater in the hypoplastic left heart syndrome group than in the normal group. In the group with mild to moderate ductal constriction, both ventricular ejection forces were similar to those of the normal group. The RVEF (p < 0.003) and its average weekly increase (p < 0.03) were lower in the group with severe ductal constriction or occlusion than in the normal group. The LVEF did not differ from that of the normal group We conclude that chronic volume overload increases and relatively acute pressure overload decreases human fetal RVEF. The right ventricular performance is modified by abnormal loading conditions.

Blood Flow Velocity↗
PubMed1996

Role of the pulmonary circulation in the distribution of human fetal cardiac output during the second half of pregnancy.

BACKGROUND: By using Doppler echocardiography, we determined the normal distribution of human fetal combined cardiac output (CCO) from the left and right ventricles. We also established weight-indexed pulmonary and systemic vascular resistances (Rpi and Rsi, respectively) and changes during the second half of pregnancy. METHODS AND RESULTS: Blood flows at the aortic and pulmonary valve annuli (LVCO and RVCO, respectively), right and left pulmonary arteries (QP), and ductus arteriosus (QDA) were calculated in 63 normal fetuses. Foramen ovale blood flow (QFO = LVCO-QP) was estimated. From 20 to 30 weeks of gestation, the proportion of QP of the CCO increased (from 13% to 25%, P < .001), while the proportion of QFO decreased (from 34% to 18%, P < .001). After 30 weeks, the proportions of QP and QFO were unchanged. At 38 weeks, the proportion of RVCO (60%) was higher (P < .05) than that of LVCO (40%). The proportion of QDA did not change significantly. The correlation between RVCO calculated from blood flow through the pulmonary valve and from QDA and QP was good (r = .97, P < .0001). RPi (P < .001) decreased from 20 to 30 weeks of gestation. From 30 to 38 weeks, RPi increased (P < .0001). Rsi increased (P < .001) from 20 to 38 weeks. The ratio of RPi to RSi decreased (P < .01) from 20 to 30 weeks and later remained unchanged. CONCLUSIONS: The human fetal pulmonary circulation has an important role in the distribution of cardiac output.

Blood Pressure↗
PubMed1996

Spontaneous closure of the human fetal ductus arteriosus--A cause of fetal congestive heart failure.

OBJECTIVE: Closure of the fetal ductus arteriosus, which is usually due to nonsteroidal antiinflammatory agents, may be detrimental. Therefore prenatal and postnatal clinical and echocardiographic findings in four human fetuses with spontaneous ductus arteriosus occlusion are reported. STUDY DESIGN: Echocardiographic and clinical data were retrospectively analyzed. RESULTS: Spontaneous closure of the ductus arterious was discovered in four fetuses (gestational age 34 to 38 weeks). No mother had received nonsteroidal antiinflammatory agents. Enlargement of the right heart and pulmonary arteries and tricuspid and pulmonary regurgitation were present in all cases. Two fetuses had right ventricular hypertension. Postnatally their right ventricular function recovered promptly. The others had severe right heart failure with abnormal umbilical venous pulsations. After immediate delivery none had signs of persistent pulmonary hypertension. However, they have echocardiographic evidence of right ventricular dysfunction 2 to 6 months after delivery. CONCLUSIONS: Occlusion of the fetal ductus arteriosus may also occur in the absence of treatment with nonsteroidal antiinflammatory agents. Immediate delivery resulted in good clinical outcome, although right ventricular dysfunction may persist.

Constriction, Pathologic↗
PubMed1996

Fetal branch pulmonary arterial vascular impedance during the second half of pregnancy.

OBJECTIVE: Our purpose was to establish normal physiologic parameters in the fetal proximal and distal branch pulmonary arterial vascular impedance during the second half of pregnancy and to analyze relationships between proximal and distal pulmonary arterial blood velocity waveforms. STUDY DESIGN: In this cross-sectional study 100 uncomplicated singleton pregnancies were studied by pulsed color Doppler techniques between 18 and 41 weeks of gestation (median 30 weeks). Both right and left proximal (immediately after the bifurcation of the main pulmonary artery) and distal (beyond the first bifurcation of the branch pulmonary artery) pulmonary artery blood velocity waveforms were recorded and pulsatility index values were calculated. Peak systolic velocities and time-to-peak-velocity intervals were measured. Time-to-peak-velocity intervals were also analyzed at the level of aortic and pulmonary valves and at the ductus arteriosus. Right and left pulmonary artery diameters and right lung length were measured. RESULTS: In both right and left proximal and distal pulmonary arteries pulsatility index values decreased (p < 0.0001) and the peak systolic velocities (p < 0.003) and time-to-peak-velocity intervals (p < 0.0001) increased during the second half of pregnancy. In the proximal pulmonary arteries the pulsatility index values decreased linearly until 34 to 35 weeks of gestation and in the distal pulmonary arteries until 31 weeks of gestation. Thereafter they remained unchanged. In pulmonary arteries time-to-peak-velocity intervals were shorter (p < 0.01) than at the pulmonary valve level. There were no significant differences between the right or left pulmonary arteries in the pulsatility index values, peak systolic velocities, time-to-peak-velocity intervals, or pulmonary artery diameters. In the proximal pulmonary arteries the pulsatility index values (p < 0.02) and peak systolic velocities (p < 0.0001) were higher and time-to-peak-velocity intervals (p < 0.0001) were longer than in the distal pulmonary arteries. There was a 2.5-fold increase in pulmonary artery diameters and right lung length. CONCLUSIONS: Fetal branch pulmonary arterial vascular impedance decreases significantly during the second half of pregnancy. The linear decrease in vascular impedance during the second trimester and in the beginning of the third trimester may be related to the growth of the lung and the increase in the number of resistance vessels. During the latter part of the third trimester pulmonary vascular impedance does not decrease further.

Adolescent↗
PubMed1996

Venous Doppler in the fetus with absent end-diastolic flow in the umbilical artery.

High perinatal mortality has been reported in association with the finding of absent end-diastolic flow velocities in the umbilical artery. The fetus is known to centralize its circulation during hypoxemia and abnormal venous blood flow velocities have been reported in cases of heart failure and imminent asphyxia. The aim of this study was to evaluate blood flow velocities recorded with Doppler ultrasound in the umbilical vein, inferior vena cava and middle cerebral artery as predictors of survival in 17 fetuses with absent or reversed end-diastolic flow in the umbilical artery. There were five perinatal deaths, all having abnormal umbilical cord venous pulsations. An increased proportion of diastolic blood flow velocity in the middle cerebral artery as a sign of hypoxia was found in 12 fetuses without a relationship to perinatal mortality. An increased proportion of retrograde blood flow in the inferior vena cava was recorded in only one fetus, which died on the same day of congestive heart failure, suggesting fetal heart sparing in the remaining complicated pregnancies. The results suggest that abnormal end-diastolic umbilical venous pulsation in the cord is a late and ominous sign of a severely compromised fetus, while abnormal blood flow velocimetry in the middle cerebral artery might be an earlier sign of fetal hypoxia, with a better prognosis.

Blood Flow Velocity↗