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Biomedical subjects

J C Fouron

Publications and source records attributed to J C Fouron.

At least 73 records · Page 4Linked to original sources
PubMed1991

In utero sonographic diagnosis of diaphragmatic hernia with hepatic protrusion into the pericardium mimicking an intrapericardial tumour.

A case of right-sided congenital diaphragmatic hernia was detected at 33 weeks of gestation. Fetal echocardiography revealed the presence of an intrapericardial mass (3.5 x 3 cm) localized at the right of the heart and surrounded by a massive pericardial effusion. This mass had the same echogenicity as the liver, with which it shared vascular channels. The diagnosis of right diaphragmatic hernia with protrusion of hepatic tissue into the pericardial sac and secondary pericardial effusion was made and confirmed after birth. In utero diagnosis of this anomaly enabled correct assessment of perinatal risk, and optimal fetal and infant management.

Adult↗
PubMed1991

Diastolic circulatory dynamics in the presence of elevated placental resistance and retrograde diastolic flow in the umbilical artery: a Doppler echographic study in lambs.

To evaluate the effects of elevated placental resistance on the diastolic blood flow in the main arteries of the fetus, placental resistance was mechanically increased in six exteriorized lambs. A string was inserted into the exposed section of the umbilical cord and placed around the veins isolating them from the arteries. Doppler flow velocities waveforms were measured by placing a lightweight acoustic bag on the umbilical cord. Placental resistance was increased by tightening the string until retrograde diastolic flow was observed in the umbilical artery. All measurements were obtained within 10 minutes. Heart rate, PO2, PCO2, and pH before umbilical vein compression were 177 +/- 24 beats/min, 16.4 +/- 1.8 mm Hg, 42.5 +/- 4 mm Hg, and 7.3 +/- 0.05, respectively, and 112 +/- 38 beats/min, 5.9 +/- 1.5 mm Hg, 56.6 +/- 7.0 mm Hg, and 7.2 +/- 0.05, respectively, after umbilical vein compression. The patterns of diastolic flow observed after compression were descending aorta, retrograde; aortic arch, retrograde; ascending aorta, bidirectional; cephalic aorta, forward, which were quite different from their respective baseline patterns. It is concluded that the appearance of reverse diastolic flow in the umbilical artery indicates that (1) the lowest vascular resistance in the fetal circulatory network is no longer at the placental but at the cerebral level, and (2) preplacental blood with low oxygen content from the descending aorta and pulmonary artery is being shifted toward the brain.

Animals↗
PubMed1991

Closure of the ductus arteriosus: determinant factor in the appearance of transient peripheral pulmonary stenosis of the neonate.

We speculated that a relationship may exist between transient peripheral pulmonary stenosis and the closure of the ductus arteriosus. Fifty preterm infants had pulmonary artery and ductal color Doppler flow velocity assessments performed before and after closure of the ductus arteriosus. No flow turbulence or increase in velocity was observed immediately after birth, although a significant discrepancy in size was observed between the main pulmonary artery and its two branches. After closure of the ductus, 15 infants had signs of transient peripheral pulmonary stenosis of the left pulmonary artery in association with a significant decrease of diameter at the origin of the same artery. In all 50 infants, no significant gradient was observed in the right pulmonary artery. We conclude that, at least in the preterm infant, transient peripheral pulmonary stenosis is not present at birth but is an acquired phenomenon closely related to closure of the ductus arteriosus.

Blood Flow Velocity↗
PubMed1991

Usefulness of non-invasive indices in the monitoring of heart-transplanted pediatric patients.

Seven patients underwent cardiac transplantation at Ste-Justine Hospital between June 1984 and October 1988 (age 3-16 years). Indices derived from M-mode echocardiography--left ventricular mass (LVM), isovolumetric relaxation time (IRT), shortening fraction (SF), velocity of circumferential fiber shortening (VCF), ejection fraction (EF), LV pre-ejection period/ejection time (PEP/ET), isometric contraction time (ICT)--and electrocardiography--summation of potentials (Sum Pot)--were used as non-invasive markers of rejection (367 studies), while rejection status was monitored by serial endomyocardial biopsy (55 biopsies). Spontaneous variation of such indices, as defined by the 90% distribution interval of their variation when biopsy was unchanged, was found to be important: -20% to +28% for IRT, -30% to +28% for LVM, -30% to 32% for Sum Pot, -32% to 42% for PEP/ET, etc. Using limits of spontaneous variation such as thresholds, none of the studied indices could consistently predict the 2 biopsy-documented episodes of rejection or the 7 episodes of improvement. Among all the studied indices, IRT was the most promising, correctly predicting 1 of the episodes of rejection and almost predicting the 2nd. Remeasurement of all M-mode tracings by an unique observer, following strict rules to maximize reproducibility, did not decrease the spontaneous variation of these indices, nor did it improve their performance as predictors of changes in the rejection status. These results warrant the continuing search for other non-invasive methods for accurate monitoring of the rejection status.

Adolescent↗
PubMed1991

[Treatment of congenital pulmonary valve stenosis by percutaneous valvuloplasty].

The purpose of this study was to evaluate the efficacy technique and follow-up results of balloon valvuloplasty for congenital valvular pulmonary stenosis. Percutaneous dilatation was performed in 48 patients aged 0.5 to 21 years (m = 7.5 yrs) from two pediatric cardiology centers (Lyon and Montreal). The right ventricular peak systolic pressure ranged from 42 to 180 mmHg (m = 93) before dilatation and fell from 24 to 105 mmHg (m = 48) immediately after dilatation. The pulmonary valvular peak systolic pressure gradient ranged from 22 to 156 mmHg (m = 73) and fell to 4 to 70 mmHg (m = 27) after the procedure (P less than 0.001). Follow-up continuous doppler data was available from 33 patients at 1 to 37 months (m = 9.2 months) after dilatation. The maximal instantaneous gradient from right ventricle pulmonary artery ranged from 0 to 74 mmHg (m = 27).

Adolescent↗
PubMed1991

[Evaluation and prognosis of fetal arrhythmia].

From January 1986 to August 1990, a fetal arrhythmia was diagnosed in 97 pregnant women referred to our unit. Atrial or ventricular extrasystoles were the most frequent rhythm disturbance encountered (71%). They were always well tolerated and all disappeared during the perinatal period. Tachycardia was found in 16 fetuses; 6 had a supraventricular reentrant tachycardia, 6 an atrial chaotic tachycardia, 1 an ectopic atrial tachycardia and the remaining 3 an atrial flutter. A congenital heart malformation was present in 4 fetuses. The arrhythmia induced hydrops fetalis in 25% of cases. One hydropic fetus died in utero and another needed premature delivery. Bradycardia was diagnosed in 12 cases, 3 had benign atrial blocked extrasystoles, 3 others sinus bradycardia due to fetal distress and 6 atrio-ventricular block. Atrio-ventricular block was associated with congenital malformation in 4 cases (66%). All these fetuses were hydropic and died. The 2 fetuses without cardiac malformation tolerated well their bradycardia during fetal life. Fetal arrhythmia is not rare, but in most cases is benign. Sustained tachycardia requires prompt treatment, because when hydrops fetalis appears the prognosis is worse. The major prognostic factor for atrio-ventricular block is the association with a cardiac malformation.

Arrhythmias, Cardiac↗
PubMed1990

Frequency and prognosis of arrhythmias after operative "correction" of tetralogy of Fallot.

Two hundred twenty-four consecutive patients operated on for tetralogy of Fallot were followed from 1 to 28 years (mean 11). Mean age at surgery was 5.3 years (range 1 to 14). Postoperative right ventricular systolic pressure was 60 mm Hg in 19 of 213 patients (9%). Fourteen patients (6%) had ventricular premature complexes on surface electrocardiograms. Seventy-nine patients underwent treadmill exercise tests, and ventricular premature complexes were induced in 17 (22%). Twenty-four-hour ambulatory monitoring in 92 patients demonstrated significant ventricular arrhythmias (greater than or equal to grade 2 of the Lown classification) in 41 (45%). The frequency of ventricular arrhythmias correlated with length of follow-up and duration of cardiopulmonary bypass. No correlation was found with age at surgery, postoperative right ventricular systolic pressure and importance of conduction defects on electrocardiogram. There were no sudden or unexpected deaths during follow-up.

Adolescent↗
PubMed1990

Effects of hypoxemia with and without acidemia on the isometric contraction time and the electromechanical delay of the fetal myocardium: an experimental study on the ovine fetus.

This study assessed the response of the preejection period during hypoxemia with and without acidemia. In five pregnant ewes, hypoxemia was created during 1 hour followed by fetal infusion of lactic acid during 2 hours. A micromanometer catheter positioned above the fetal aortic valve, an endocavitary phonocardiogram, and a fetal electrocardiogram allowed measurements of the two components of the preejection period--the isometric contraction time and the electromechanical delay. At the onset of hypoxemia, because of changes in isometric contraction time, the preejection period began to shorten. When acidemia was induced, the preejection period modified slowly in the opposite direction and lengthened, initially because of a prolongation of electromechanical delay and later because of an increase in the already shortened isometric contraction time. This process developed slowly and at the end of 2 hours of acidemia, preejection period were back to preexperimental values. It can be concluded that systolic time intervals can be normal and misleading when acidosis complicates hypoxemia.

Acids↗
PubMed1990

Effect of intermittent positive pressure ventilation on diastolic ventricular filling patterns in premature infants.

Eleven preterm newborn infants had a Doppler echocardiographic examination of their ventricular filling patterns during intermittent positive pressure ventilation. Peak velocity during early ventricular filling (VE) and during atrial systole (VA) and diastolic velocity-time integral of early (IE) and late (IA) ventricular filling caused by atrial contraction were measured. The ratios of VE/VA and IE/IA were also calculated. Diastolic peak velocities, as well as the diastolic velocity-time integral of early and late ventricular filling measured through the mitral valve were significantly higher during inspiration. The peak of the wave representing the velocity during atrial systole (A) was always higher than the peak of the wave representing the velocity of early ventricular filling (E). As a result, the ratio of these two variables (E/A) was always less than 1, showing no significant variation from inspiration to expiration. The flow patterns into the right ventricle were the opposite of those observed through the mitral valve. During inspiration, a significant decrease (p less than 0.001) in peak and time integral velocities of both the early ventricular filling and atrial systole waves was observed. Heart rate did not vary with respiration. It is concluded that during positive pressure ventilation, inspiration decreases right ventricular filling and enhances left ventricular filling. Opposite changes are recorded during expiration. Early and late phases of diastolic filling are equally affected. These changes are different from those observed during spontaneous breathing and should be taken into account in the assessment of diastolic ventricular function in preterm infants requiring assisted ventilation.

Blood Flow Velocity↗
PubMed1990

Dilated and contracted forms of primary endocardial fibroelastosis: a single fetal disease with two stages of development.

Left ventricular endocardial fibroelastosis was diagnosed by echocardiographic scanning in a fetus at 20 weeks' gestation. Repeated prenatal examination over the next 20 weeks' gestation showed the development of the left ventricle from a chamber with a dilated cavity to a small cavity with a very thick wall. These findings were confirmed at necropsy and by the absence of other morphological anomalies. The contracted form of primary fibroelastosis in the fetus must have followed an insult that prevented any further increase in the size of the left ventricular cavity.

Adult↗
PubMed1990

[Characteristics of paroxysmal atrial tachycardia in infants according to the age of onset].

Seventy consecutive patients hospitalized before 1 year of age for reentrant paroxysmal atrial tachycardia (PAT) were studied according to the age of onset of arrhythmia making 3 distinctive groups: group I: 10 patients in whom onset of the arrhythmia occurred during foetal life; group II: 39 infants whose arrhythmia appeared during the first month of life and group III consisting of 21 patients in whom tachycardia began between 1 and 12 months of age. The characteristics and the consequences of the arrhythmia as well as the patients' course and the different treatments used were analysed. Foetal tachycardias were characterized by a slower heart rate. Episodes were most often short and repetitive as opposed to post-natal tachycardias which were often prolonged but somewhat unfrequent. Before the age of 3 months the occurrence of heart failure was more frequent. Independently of the age of onset, 43% of patients presented Wolff-Parkinson-White syndrome (WPW), which disappeared spontaneously in 1 out of 3 cases. The existence of WPW syndrome was correlated with late relapses.

Age Factors↗
PubMed1989

Echocardiographic and angiographic findings in superior-inferior cardiac ventricles.

The anatomy of superior-inferior ventricles was studied in 17 patients, aged 1 day to 22 years, using echocardiography and angiography. In all patients, the right ventricle was located superiorly and the left ventricle inferiorly. The right ventricular sinus was underdeveloped in 14 of the 17 patients. Conversely, the right ventricular outflow tract was normally developed in all 17 patients. The visceroatrial situs was solitus in all patients, and it was associated with a concordant D-loop in 9 patients and with a discordant L-loop in 8. There was a high incidence of associated transposition of the great arteries (9 patients) or double-outlet right ventricle (5). Segmental combination was unpredictable, D-loop being associated with L-position of the great arteries in 4 of 8 patients and L-loop being associated with D-position of the great arteries in 4 of 9. There were only 3 concordant ventriculoarterial connections. Frequently associated anomalies included ventricular septal defect (17 patients), atrioventricular valve malformations (17) subaortic conus (14) and pulmonary outflow tract stenosis or atresia (11). Criss-cross hearts were present in only 7 patients.

Adult↗
PubMed1989

Atrial septal defect, ventricular septal defect, and coarctation of the aorta in sibs: an autosomal recessive disorder?

We report on two sisters with secundum atrial septal defect, perimembranous ventricular septal defect, and coarctation of the aorta. Identical anatomical malformations were verified by echocardiography and at operation. No other affected relatives were identified. We suggest that this is a specific, possibly recessively inherited type of complex cardiac malformation.

Aortic Coarctation↗
PubMed1988

The increase in fetal hemoglobin synthesis in the fetal lamb during hyperglycemic hypoxemia.

To determine whether fetal hypoxemia induced by hyperglycemia has any effect on the proportions of fetal and adult hemoglobin synthesized during fetal development, hemoglobin synthesis was determined after a period of hyperglycemic hypoxemia in the fetal lamb. These experiments were carried out at a time in gestation during the switch from fetal to adult hemoglobin. Twelve catheterized fetal sheep were included in this study. Seven were made hyperglycemic by glucose infusions during 5 days (group I) and five were control animals (group II) that received saline solution infusions (0.45 gm/dl). In group I, glycemia increased from 14.7 +/- 5.0 to 54.6 +/- 16.4 mg/dl (p less than 0.001), whereas oxygen content decreased from 8.5 +/- 1.7 to 6.4 +/- 2.2 ml/dl (p less than 0.01). Red blood cells obtained before and after 5 days of glucose or saline solution infusions were incubated in an amino acid mixture containing 14C-leucine. The hemoglobins were then subjected to polypeptide chain elution with carboxymethyl cellulose chromatography. The amount of fetal hemoglobin synthesized was determined by the ratio of radioactive gamma-chain to total of radioactive non-alpha-chains. The data demonstrated that the hyperglycemic fetus synthesizes more fetal hemoglobin than expected for the period of fetal development (78.0% +/- 10.9% versus 59.8% +/- 11.3%, p less than 0.02).

Animals↗
PubMed1988

Left ventricular diastolic function during the first month of life.

UNLABELLED: In order to assess possible changes in myocardial relaxation occurring during the neonatal period, M-mode echocardiograms were recorded serially in 9 normal term infants and in another group of 10 one-month-old infants. The tracings were studied with an M-mode calculator. Although individual variations were greater in the data collected during the first 24 h, no significant difference was found in the indices of diastolic function of the left ventricle during the first 4 days of age. The following changes were observed between data recorded at 4 days and 1 month, respectively: normalized peak rate of left ventricle filling, 4.03 vs. 4.71 cm/s; diastolic peak velocity of early posterior motion of aortic root, 1.89 vs. 5.15 cm/s; peak velocity of left ventricle posterior wall motion in diastole, 3.31 vs. 3.50 cm/s; mitral valve EF slope, 59.05 vs. 84.92 mm/s; left ventricle isometric relaxation time, 43.88 vs. 28.50 ms. IN CONCLUSION: (1) greater individual variations are observed in indices of left ventricle diastolic function during the first day of life, and (2) significant increase in left ventricle compliance occurs during the first month of life. These changes should play a critical role in the clinical course of newborn with cardiopulmonary disease.

Diastole↗