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Biomedical subjects

J C Huhta

Publications and source records attributed to J C Huhta.

At least 55 records · Page 3Linked to original sources

Venous Doppler ultrasonography in the fetus with nonimmune hydrops.

Eighteen pregnancies with nonimmune hydrops fetalis were referred for fetal echocardiography to rule out congenital heart disease. In 14 of these cases, pulsating blood velocities were recorded in the umbilical vein, which in a normal population had a nonpulsatile blood velocity pattern. The four cases without pulsations in the umbilical vein were found to have intrauterine viral infections. In the last 10 cases examined, the umbilical venous pulsations were found to reflect abnormal central venous pulsations during atrial systole suggesting increased fetal central venous pressure. Right ventricular shortening fraction was significantly decreased in the group with umbilical venous pulsations compared with those without (0.18 versus 0.32, p less than 0.05). All the fetuses without venous pulsations survived, but only four of the 14 with pulsations survived (p less than 0.05). The results suggest that blood velocity recordings in the umbilical and central veins of the fetus can give valuable clinical information with regard to the presence of fetal congestive heart failure and differentiate between this physiologic state and other causes of nonimmune hydrops fetalis. This may have implications for fetal diagnostic work-up and prognosis.

Blood Flow Velocity↗

Doppler echocardiography of fetal ductus arteriosus constriction versus increased right ventricular output.

A prospective longitudinal study from 121 examinations of 41 normal pregnant women showed that fetal ductal flow velocities increased with gestational age. These normal data were compared with data in three groups of fetuses with altered ductal flow velocities: 22 fetuses (mean gestational age 31.3 weeks) had ductal constriction due to maternal indomethacin treatment; 10 fetuses (mean gestational age 27.9 weeks) had been exposed to terbutaline, a positive inotropic agent and 14 fetuses (mean gestational age 33.3 weeks) had hypoplastic left heart syndrome. In normal fetuses maximal systolic, mean and end-diastolic ductal flow velocities increased linearly (p less than 0.0001). The pulsatility index did not change (mean +/- 2 SD: 2.46 +/- 0.52). Fetuses with ductal constriction had higher maximal, mean and end-diastolic flow velocities and a significantly lower pulsatility index than did normal fetuses (1.25 +/- 0.76; p less than 0.0005). Six of 10 fetuses of the terbutaline group and 8 of 14 fetuses with hypoplastic left heart syndrome had increased maximal flow velocity, but normal or only mildly elevated mean flow velocity. The pulsatility index in fetuses during terbutaline therapy and with hypoplastic left heart syndrome was significantly higher than in normal fetuses (3.11 +/- 0.46 and 3.09 +/- 0.7, respectively, vs. 2.46 +/- 0.52; p less than 0.0005). Fetal ductal waveform analysis was necessary to distinguish fetal ductal constriction from increased right ventricular output. These measurements may be helpful in the diagnosis of left-sided outflow obstruction and assessment of fetal hemodynamic data.

Blood Flow Velocity↗

Cardiac ultrasound: its role in the recognition and management of fetal heart disease.

This article briefly reviews the role of ultrasound scanning in the diagnosis and management of fetal cardiac disease. Currently, the potential exists for the accurate identification of a wide range of cardiac defects and for the diagnosis and successful management of many cardiac rhythm disturbances. Considerable benefit is derived for families with previously affected children when a normal fetal cardiac ultrasound report can be provided.

Arrhythmias, Cardiac↗

Fetal supraventricular tachycardia and hydrops fetalis: combined intensive, direct, and transplacental therapy.

A 25-week fetus with severe hydrops fetalis secondary to supraventricular tachycardia was treated with fetal intramuscular injections of digoxin in conjunction with maternal intravenous digoxin, followed by oral digoxin and subsequently by oral procainamide therapy. Fetal umbilical blood sampling revealed poor placental transfer of digoxin, even after 2 weeks of therapeutic maternal levels. This case suggests that direct fetal therapy is of value in the treatment of some fetuses with supraventricular tachycardia, and lends further evidence that the role of transplacental digoxin therapy is limited in the compromised fetus. It also demonstrates that resolution of hydrops may require a prolonged period.

Adult↗

Diagnosis, transport, and outcome in fetuses with left ventricular outflow tract obstruction.

Between March 1986 and April 1990, 22 consecutive fetuses (at gestational ages of 21 to 38 weeks) with a suspected diagnosis of critical (ductus-dependent) left ventricular outflow tract obstruction on fetal echocardiogram were referred to our center for delivery and surgical treatment. Diagnoses were hypoplastic left heart syndrome (n = 16), valvular aortic stenosis (n = 2), common atrioventricular canal with subaortic stenosis (n = 3), and single ventricle with subaortic stenosis (n = 1). Postnatal echocardiography revealed that fetal echocardiography was correct in predicting left ventricular outflow tract obstruction to be critical in all but one patient, for a positive predictive value of 96%. Of the 21 patients with true, critical left ventricular outflow tract obstruction, 17 patients underwent cardiac surgery as neonates (birth to 6 days of age, median 2 days); 13 (or 77%) survived and were discharged from the hospital. In addition, one patient underwent successful balloon aortic valvotomy for critical valvular aortic stenosis but later died of sepsis. Lethal chromosomal and congenital abnormalities should be sought and are contraindications for this approach. In utero transport of fetuses with suspected critical left ventricular outflow tract obstruction to a neonatal cardiac surgical center can result in improved neonatal condition and may improve overall survival.

Echocardiography, Doppler↗

Changes in fetal hemodynamics with terbutaline treatment and premature labor.

The aim of this study was to examine the fetal hemodynamic effects of terbutaline treatment and premature labor. Image-directed pulsed and continuous wave Doppler ultrasound studies, using 3.3-MHz and 5-MHz transducers (GE PASII and ATL echocardiographic machines), were used to assess fetal cardiac blood velocities in three groups of pregnancies matched for menstrual age (MA). Group 1: 13 normal pregnancies, mean MA 31 weeks. Group 2: 7 women in premature labor prior to tocolytic therapy, mean MA 32 weeks. Group 3: 8 women treated with terbutaline, average dose 18.8 mg daily, for previous premature labor, mean MA 31 weeks. Heart rate averaged 150 bpm, 135 bpm, and 127 bpm in the terbutaline, premature labor, and normal groups, respectively, and each were significantly different from each other. Products of time velocity interval and heart rate at the aortic valves were 1603 cm +/- 140 cm, 1413 cm +/- 190 cm and 1238 cm +/- 200 cm, and at the mitral valves 1102 cm +/- 170 cm, 812 cm +/- 110 cm, and 878 cm +/- 150 cm in the terbutaline, premature labor, and the normal groups, respectively. Aortic and mitral blood velocity products of time velocity integrals and heart rates were significantly higher (p = 0.01) in the terbutaline group relative to the normal group. In addition, the terbutaline group was significantly higher than the labor group at the mitral valve (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

The effect of indomethacin on the pulsatility index of the umbilical artery in human fetuses.

Pulsed and continuous-wave Doppler ultrasonography was used to assess blood velocities in the ductus arteriosus and the pulsatility index of the umbilical artery in 20 fetuses (1 pair of twins and 18 singletons) at 23 to 33 weeks' gestation during maternal indomethacin therapy for preterm labor or polyhydramnios. There was no statistically significant difference in the pulsatility index of the umbilical artery during maternal indomethacin treatment (mean +/- SD, 1.11 +/- 0.20) when compared with baseline values (1.12 +/- 0.19) in all 20 fetuses studied. An increase in the peak systolic and diastolic blood velocities in the ductus arteriosus consistent with ductal constriction was noted in 9 fetuses. Analysis of the umbilical artery pulsatility index values before and during indomethacin in this subgroup of fetuses failed to reveal a statistically significant change (1.12 +/- 0.19 vs. 1.11 +/- 0.20). Indomethacin therapy does not influence the pulsatility index of the umbilical artery at the gestational ages studied.

Blood Flow Velocity↗

Acute fetal hemodynamic alterations after intrauterine transfusion for treatment of severe red blood cell alloimmunization.

One of the compensatory hemodynamic mechanisms seen in the anemic human fetus is an increased cardiac output. With Doppler techniques, cardiac output was measured in 21 fetuses before and immediately after 38 intrauterine transfusions for severe red cell alloimmunization. Umbilical venous pressures were measured before and after transfusion; amniotic fluid pressure was also quantitated. After subtraction of amniotic pressure, umbilical venous pressure increased by 1.7 +/- 2.8 mm Hg (p less than 0.01). Left and right ventricular output declined by 19% and 22%, respectively (p less than 0.001). Four factors are known to affect cardiac output: heart rate, cardiac contractility, preload, and afterload. Fetal heart rate and mean acceleration, a measure of myocardial contractility, were unchanged after transfusion. A calculated mean increase in the fetoplacental volume of 18% in conjunction with an increase in umbilical venous pressure would indicate that cardiac preload was increased. We propose that intravascular intrauterine transfusion leads to an increased cardiac afterload, possibly by increasing blood viscosity. The fetal heart responds to the increased afterload by a decrease in stroke volume, leading to a fall in cardiac output.

Blood Transfusion, Intrauterine↗

Nuclear magnetic resonance imaging of the pulmonary arteries, subpulmonary region, and aorticopulmonary shunts: a comparative study with two-dimensional echocardiography and angiography.

Twelve patients more than 8 years of age with complex congenital heart disease were evaluated prospectively with nuclear magnetic resonance (NMR) imaging and with echocardiographic and angiographic imaging techniques. The subpulmonary region, main pulmonary artery, right and left pulmonary arteries, and aorticopulmonary shunts were clearly visualized by means of NMR imaging in all patients. Angiography defined the subpulmonary region and main pulmonary artery in all patients, the right and left pulmonary arteries along their length in 11 of 12 patients, and aorticopulmonary shunts in seven of eight patients. Except for the right pulmonary artery, echocardiography defined the remaining structures in less than or equal to 50% of patients. Measurement of the pulmonary artery diameters on NMR images correlated well with the angiographic measurements of both the left (r = 0.96) and right (r = 0.94) pulmonary arteries. These results suggest that NMR imaging may be the preferable noninvasive imaging technique for defining the anatomy of the subpulmonary region, main and left pulmonary arteries, and aorticopulmonary shunts in older patients with congenital cardiovascular disease and that it compares well with the angiographic standard.

Adolescent↗

Echocardiographic evaluation of fetal arrhythmias.

When during routine prenatal care, the auscultation++ of the fetal heart beat reveals an abnormal rate or rhythm, two things are needed: 1) the accurate diagnosis of the arrhythmia, and 2) the hemodynamic impact of the rhythm disturbance on the fetus. In Poland, external cardiotocography is the most widely Supported in part by the American Heart Association, Delaware Affiliate, Grant = 41161 available diagnostic system used by obstetricians, but it records only the mean heart rate or the instantaneous heart rate. Cardiotocography is therefore useful only in identifying tachycardia or bradycardia. The most frequent tape of fetal arrhythmia is an irregular rhythm, especially premature contractions (1, 15, 18). We believe that any disturbance in fetal cardiac condition should be evaluated more fully by fetal echocardiography.

Arrhythmias, Cardiac↗

Two-dimensional echocardiographic determination of ventricular septal defect size: correlation with autopsy.

The presence of a large ventricular septal defect (VSD) may affect the surgical treatment of congenital heart defects. VSD size and shape by two-dimensional echocardiography (2DE) and at autopsy were compared in 18 patients, average age 6 months, who had 2DE studies shortly prior to death. Six had isolated VSD and the other 12 had additional cardiac anomalies. The maximal diameter of the VSD was measured in long- and short-axis views and the VSD area was calculated assuming an elliptical shape. A large VSD was present in 11 of 18 (61%) and was correctly detected by 2DE in 10 of 11 (91%, no false positives). 2DE-predicted area of VSDs correlated with autopsy measurements (r = 0.94). The shape and orientation of the VSD were correctly predicted by 2DE (16 of 18); it was elliptical in 13 and circular in five, with the major axis of the elliptical VSDs aligned with the short axis of the heart in eight and with the long axis in five. The diameters of the VSD ranged from 3 to 25 mm (r = 0.93). Diameters measured from the long-axis and short-axis views correlated with autopsy (r = 0.98 and 0.89, respectively). Thus: (1) 2DE was useful in distinguishing large VSDs from smaller defects, and in measuring their diameters and areas. (2) The shape and orientation of the VSD were well predicted by 2DE.

Adolescent↗

Critical pulmonary valve stenosis in patients less than 1 year of age: treatment with percutaneous gradational balloon pulmonary valvuloplasty.

A new technique of percutaneous gradational balloon pulmonary valvuloplasty was used successfully in 17 infants less than 1 year of age, including four neonates, with critical congenital pulmonary valve stenosis, who would otherwise have required surgical intervention. This technique uses a sequential series of balloon catheters of gradually increasing size as a means of eventually crossing the very small valve orifice with a balloon catheter of adequate size to achieve successful pulmonary valvuloplasty. The initial dilatations were achieved with balloon catheters 2, 3, or 4 mm in diameter. Immediately after successful balloon valvuloplasty, the mean pulmonary systolic pressure gradient was reduced from 105 +/- 11 to 20 +/- 5 mm Hg. Percutaneous balloon pulmonary valvuloplasty can be performed safely with good results despite critical congenital pulmonary valve obstruction in severely ill infants.

Catheterization↗

Doppler assessment of the pulsatility index of the middle cerebral artery during constriction of the fetal ductus arteriosus after indomethacin therapy.

To investigate the effects of constriction of the ductus arteriosus on the pulsatility index of the middle cerebral artery, maximum velocity waveforms were obtained in 13 fetuses (one set of twins) whose mothers were treated with indomethacin for preterm labor (n = 9) or polyhydramnios (n = 3). Eleven of the fetuses manifested ductal constriction within 48 hours of therapy, whereas two fetuses had constriction after 1 week of therapy. Six of the 13 fetuses also manifested tricuspid insufficiency in association with constriction of the ductus arteriosus. All abnormal cardiac changes resolved in utero after discontinuation of indomethacin. No difference in the pulsatility index values of the middle cerebral artery was observed in the fetuses with ductal constriction but without tricuspid regurgitation (n = 7) when the values were compared with those obtained in absence of ductal constriction (1.87 +/- 0.37 vs. 1.88 +/- 0.33). In the fetuses that manifested both ductal constriction and tricuspid insufficiency (n = 6), the pulsatility index values in the middle cerebral artery were significantly lower in the presence of ductal constriction when compared with the values obtained in the absence of ductal constriction (2.22 +/- 0.26 vs. 1.57 +/- 0.34). These results indicate that a response to indomethacin sufficient to cause both ductal constriction and tricuspid insufficiency decreases the pulsatility index of the middle cerebral artery.

Blood Circulation↗

Doppler assessment of the pulsatility index in the cerebral circulation of the human fetus.

To determine whether the pulsatility index was similar in all cerebral vessels, 30 fetuses at 23 to 37 weeks' gestation were studied. There were 12 normal fetuses, 14 growth-retarded fetuses, and 4 fetuses that were transfused in utero because of Rh isoimmunization. The middle cerebral artery and the internal carotid artery were studied in all fetuses. The proximal anterior cerebral artery was also studied in addition to the other two vessels in 12 fetuses from the three groups. The pulsatility index was significantly higher in the middle cerebral artery than in the internal carotid artery in all three groups. The pulsatility index of the proximal anterior cerebral artery was between the values shown for the middle cerebral artery and the internal carotid artery. The pulsatility index of the proximal anterior cerebral artery was significantly different from the index for the middle cerebral artery and not significantly different from the index for the internal carotid artery. These data indicate the importance of knowing exactly which cerebral vessel is being insonated, so that the Doppler waveform can be interpreted correctly.

Carotid Artery, Internal↗

Future directions in noninvasive Doppler evaluation of the fetal circulation.

Doppler gives important new information in the evaluation of the fetal circulation. Doppler can be used for uteroplacental assessment, measurement of blood velocities inside the heart, and diagnosis of the hemodynamic correlates of congenital cardiac defects in utero. Examples of how pulsed, continuous wave, and color Doppler can be used are illustrated. Integration of the cardiac and noncardiac Doppler examinations promises to provide a wealth of information concerning the normal and abnormal developing fetal physiology.

Blood Flow Velocity↗