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Biomedical subjects

B G Baylen

Publications and source records attributed to B G Baylen.

47 records · Page 3Linked to original sources
PubMed1980

The occurrence of hyperaldosteronism in infants with congestive heart failure.

Serum aldosterone and plasma renin were measured in 20 normal infants and 15 infants with congestive cardiac failure. Serum aldosterone was significantly increased (151 +/- 38 ng/dl mean +/- standard error of the mean) in patients before treatment when compared with aldosterone in normal infants (29 +/- 7 ng/dl). Increasing serum aldosterone was related to increasing plasma renin. The response to furosemide appeared to be inversely related to serum aldosterone concentrations. In four infants, administration of an aldosterone antagonist (spironolactone) resulted in improved diuresis and decreased serum aldosterone. Hyperaldosteronism is an important factor contributing to fluid and sodium retention in infants with heart failure.

Aldosterone↗
PubMed1980

Main pulmonary artery distention: a potential mechanism for acute pulmonary hypertension in the human newborn infant.

Balloon-induced distention of the main pulmonary artery causes acute pulmonary hypertension and reflex pulmonary vasoconstriction in animals. Pulmonary artery pressure responses caused by MPA balloon inflation were measured in ten human newborn infants with cardiac failure (n = 5) or persistent fetal circulation (n = 5). During balloon inflation distal mean PAP increased significantly while cardiac rate remained unchanged. MPA distention caused greater increases of PAP in those infants with lower resting PAP. The greatest balloon-induced increases of PAP were observed in infants recovering from PFC. The existence of a pulmonary artery reflex and its possible role in the regulation of the human fetal and neonatal pulmonary circulation is discussed.

Cardiac Catheterization↗
PubMed1980

Pulmonary arterial hypertension induced by distention of the main pulmonary artery in conscious newborn, young, and adult sheep.

Distention of the main pulmonary artery by balloon inflation in sheep results in presumably reflex elevation of pulmonary arterial pressure and resistance distal to the balloon. This response to main pulmonary artery distention is significantly greater in newborn lambs than in older lambs or adult sheep. In several of the newborn lambs, pulmonary artery pressure was raised to suprasystemic levels. Further, in some of the newborn animals, these increases in pulmonary artery pressure and resistance were sustained after deflation of teh balloon for periods up to 2 hr. The functional significance of this pulmonary hypertension reflex was not elucidated. However, the data strongly suggest that this reflex may contribute to the maintenance of high pulmonary vascular resistance during fetal and early neonatal life.

Age Factors↗
PubMed1975

The critically ill premature infant with patent ductus arteriosus and pulmonary disease-an echocardiographic assessment.

The effect of left-right shunting upon left ventricular and atrial dimensions was assessed by means of 129 serial echocardiographic studies in 37 premature infants with patent ductus arterisus. The cardiac dimensions of asymptomatic premature infants and those with pulmonary disease were similar and served as control subjects. Left cardiac dimensions were enlarged in infants with significant PDA. Dimensions were greatest in surgically treated infants (post-operatively they returned rapidly to normal) in contrast with the persistent enlargement observed in some medically treated infants. Serial echocardiography was a valuable adjunct to clinical assessment of the course of PDA in premature infants with pulmonary disease.

Cardiomegaly↗
PubMedDate not supplied

Sequential longitudinal evaluation of cardiac growth and ventricular diastolic filling in fetuses of well controlled diabetic mothers.

Hypertrophic cardiomyopathy and abnormal ventricular diastolic filling in the infant of the diabetic mother is related to poor maternal glycemic control. Evaluation of fetuses of well controlled diabetic mothers has not been examined. Eleven fetuses of nondiabetic mothers (normals) and 9 fetuses of well controlled insulin-dependent diabetic mothers (FODMs) underwent serial evaluation of cardiac growth and ventricular diastolic filling using M-mode and Doppler echocardiography at 20-26 weeks' (period 1), 27-33 weeks' (period 2), 34-40 weeks' (period 3),m and 48-72 hours after birth (period 4). Indices of right and left ventricular diastolic filling included time velocity integral ratios (E/A and %E/E+A). Cardiac growth and birth weight in the two groups were similar consistent with "good" glycemic control. This conclusion was supported by similar maternal glycosylated hemoglobin (%A1C) prenatally and newborn %A1C and C-peptide values postnatally. Heart rate before and after birth and placental resistance prenatally were similar. Both normals and FODMs demonstrated an increase in left ventricular E/A and %E/E+A ratios from period 1 to 4 (p < 0.0001). This shift occurred earlier (by period 2) in normals (p < 0.01). Right ventricular filling ratios increased by period 4 in normals only (p < 0.01). No differences were noted between the groups during any period. Good glycemic control in FODMs results in normal cardiac growth and ventricular diastolic filling. Progression of diastolic filling is abnormally delayed, however, and is presumably more exaggerated in poorly controlled diabetics.

Birth Weight↗
PubMedDate not supplied

Transcatheter vascular occlusion of the small patent ductus arteriosus: an alternative method.

The current strategies concerning a small (</=2 mm) patent ductus arteriosus (PDA) include surgical ligation, transcatheter implantation of the Rashkind occluder device, or no intervention requiring indefinite endocarditis precautions. Five patients have undergone successful transcatheter closure of a small-caliber PDA utilizing a single 3 mm Gianturco occluder coil as an alternative to surgical ligation. The coil was delivered to traverse the narrowest dimension of the PDA, leaving loops of coil in both the pulmonary and aortic ends of the ductus. All PDAs were successfully occluded, and the duration of hospitalization for all patients was 1 day. At latest follow-up (11 +/- 2 months), echocardiography demonstrates complete ductus occlusion in all patients, with no obstruction to left pulmonary arterial or descending aortic flow. Transcatheter coil occlusion of the small ductus is an easily accomplished, safe, effective alternative to surgical ligation, thereby avoiding a lateral thoracotomy incision, shortening hospitalization, and reducing costs.

Aorta, Thoracic↗
PubMedDate not supplied

Magnetic resonance imaging demonstration of "remodeling" of the aorta following balloon angioplasty of discrete native coarctation.

Assessment of the hemodynamic and anatomic results following balloon angioplasty of discrete native coarctation of the aorta, with particular attention to "remodeling," has required repeat cardiac catheterization and angiography, which is invasive and has limited resolution. Eight patients with hypertension and discrete native coarctation with an otherwise normally developed aortic arch underwent angioplasty at 5.0 +/- 6.8 years of age. Angiographic cross-sectional areas of the aorta indexed to body surface area at the isthmus (I), coarctation site (C), and 1 cm distal to the coarctation site (Cd) pre- and postangioplasty were compared with MRI-indexed cross-sectional areas 18 +/- 10 months (MRI-1) and 35 +/- 11 months (MRI-2) postangioplasty. From preangioplasty to MRI-2, the isthmus was smaller (149 +/- 22 versus 127 +/- 27 mm2/m2; p < 0. 05). The coarctation site was larger postangioplasty (25 +/- 9 versus 116 +/- 40 mm2/m2; p < 0.001) with continued growth at latest follow-up (116 +/- 40 versus 164 +/- 36 mm2/m2; p < 0.01). The segment 1 cm distal to the coarctation site continued to decrease in area at latest follow-up (267 +/- 78 versus 163 +/- 38 mm2/m2; p < 0. 001). I versus C versus Cd at MRI-2 were similar, whereas postangioplasty and MRI-1 cross-sectional area measurements were significantly different. Following angioplasty of discrete native coarctation, the aorta becomes more uniform or undergoes "remodeling." Noninvasive MRI is an effective means of evaluating the anatomic result following balloon angioplasty, obviating the need for repeated invasive cardiac catheterizations.

Adolescent↗
PubMedDate not supplied

Estimation of right ventricular free-wall mass using two-dimensional echocardiography.

Echocardiographic methods based on geometric models have long been in use for estimating left ventricular mass, but there is currently no similar method for estimating right ventricular (RV) free-wall mass. We hypothesized that a one-quarter prolate ellipsoid model could be used with two-dimensional echocardiography to approximate RV mass. Over a 2-year period 39 patients who had both a complete cardiac magnetic resonance imaging (MRI) scan and an echocardiogram within 2 weeks of each other were retrospectively analyzed. MRI-derived RV mass was used as the standard for comparison. Echocardiographic RV mass was estimated using three equations based on the geometric model. Linear regression analysis was performed to determine the correction factors used in the final formulae. The formula with the lowest standard error of the estimate was then prospectively analyzed for accuracy using a separate group of 88 subjects. The most accurate echocardiographic equation derived was RV mass = 5.84 (apical four-chamber RV cavity planar area) (RV free-wall thickness) + 1. Compared to MRI-RV mass the correlation coefficient was 0.97 and the standard error of the estimate was 16.8%. The positive and negative predictive values for diagnosing RV hypertrophy were 95% and 88%, respectively. We conclude that RV free-wall mass can be estimated by two-dimensional echocardiography using a one-quarter prolate ellipsoid shell model.

Adolescent↗
PubMedDate not supplied

Application of intraoperative transesophageal echocardiography in infants and small children.

Intraoperative echocardiography is gaining increasing acceptance in the assessment of the surgical repair of congenital heart defects. Because of its ideal imaging location, intraoperative transesophageal echocardiography (TEE) has been especially helpful in evaluating pulmonary venous return and the integrity of the left atrioventricular valve following mitral valvuloplasty, complete atrioventricular valve repair and correction of complex congenital heart disease. It has not been routinely used in infants and small children because of a prohibitively large probe size. We report the successful use of a recently developed "pediatric" TEE probe capable of Doppler and color flow imaging in two patients less than 7 years of age. No complications were encountered. Recommendations regarding optimal probe imaging positions in infants are provided.

Abnormalities, Multiple↗