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Biomedical subjects

N S Talner

Publications and source records attributed to N S Talner.

At least 19 recordsLinked to original sources
PubMed2000

Clinical auscultation skills in pediatric residents.

OBJECTIVE: The aim of this study is to determine the level of clinical auscultation skills in pediatric residents at Duke University Medical Center. METHODS: Forty-seven residents from pediatrics and joint medicine/pediatrics training programs at Duke University Medical Center were enrolled in this study. They were asked to examine the cardiovascular patient simulator, Harvey, and report their findings. Five common conditions seen in the pediatric population were presented: ventricular septal defect, atrial septal defect, pulmonary valve stenosis, combined aortic valve stenosis and insufficiency, and innocent systolic ejection murmur. The responses were scored by the number of features and diagnoses accurately reported. Five pediatric cardiologists and cardiologists in training were also asked to participate in a manner similar to the trainees. RESULTS: The mean score of features identified for the resident group was 11.4 +/- 2.6 of a possible 19. The diagnostic accuracy was 33%. There was no significant difference between residents by year of training or by type of residency program, although there was a trend toward improved performance with more training. The difference in performance between the pediatric cardiology group and the residents group was striking. The condition that was most frequently misdiagnosed was the innocent systolic ejection murmur. CONCLUSIONS: The clinical auscultation skills of pediatric residents in this study were suboptimal. There was a trend toward improvement as training progressed, although not statistically significant. These skills are likely to improve further with increased exposure to patients with cardiovascular disease especially in the ambulatory care setting.

Adult↗
PubMed1992

Anomalous left coronary artery from the main pulmonary trunk: physiologic and clinical importance of its association with persistent ductus arteriosus.

Anomalous left coronary artery (ALCA) from the pulmonary trunk presents in early infancy with a clinical picture of failure to thrive, congestive heart failure (CHF), angina-like episodes, and mitral insufficiency. These manifestations which are due to myocardial ischemia may change in the presence of an associated lesion. We present a case and review two previous reports of a patent ductus arteriosus (PDA) associated with this anomaly. Although signs and symptoms are not as clear due to the less impaired coronary perfusion and the presence of a PDA, the presence of mitral insufficiency should raise the possibility of an anomalous coronary artery and, therefore, a cardiac catheterization and angiocardiography are recommended in anticipation of reparative surgery.

Aortography↗
PubMed1990

Thirty-year follow-up of superior vena cava-pulmonary artery (Glenn) shunts.

The first superior vena cava-pulmonary artery shunt (Glenn shunt) in our series was performed in February 1958. From then through September 1988, 91 patients have undergone this procedure for a wide variety of congenital defects. We here report follow-up data available on all patients. Ages ranged from 2 days to 46 years (mean 6.8). Diagnoses were as follows: tricuspid atresia, 27; single ventricle, 22; tetralogy of Fallot, 14; D-transposition of the great arteries, ventricular septal defect, and pulmonary stenosis, 9; D-transposition, 5; Ebstein's anomaly, 4; pulmonary atresia + intact septum, 4; and others, 6. The hospital mortality rate was 7.7% (one death in the last 53 patients, 1.9%). Five deaths occurred in patients less than 6 months old. There were 20 late deaths (22%) with actuarial survival rates of 84% and 66% at 10 and 20 years, respectively. Pulmonary arteriovenous fistula formation was seen in 18 patients (19.7%), six of whom have undergone therapeutic embolization with improvement in saturation. The prevalence of pulmonary arteriovenous fistula increases with time after shunt. No long-term shunt thrombosis or stricture formation was seen. Fifty percent of shunts were still functioning at 20 years. Palliation was limited because of decrease in blood flow to the contralateral pulmonary artery, collaterals between the inferior and superior venae cavae, and pulmonary arteriovenous fistula formation. Improvement in saturation was obtained in eight otherwise inoperable patients by creation of a right axillary arteriovenous fistula up to 19 years after the Glenn shunt. Three patients had conversion of a Blalock-Taussig shunt to a Glenn shunt with improvement in congestive heart failure. Twenty-six patients have undergone a Fontan procedure with two deaths. Compared with the group having a Fontan procedure without a prior Glenn operation, there was no difference in early or late mortality. Thirty years after a Glenn shunt, the first patient in this series is working full time after having undergone a modified Fontan procedure in 1981. We conclude that the Glenn connection, usually with supplemental procedures to enhance oxygenation, has provided excellent physiologic palliation with low mortality up to 30 years with no late thrombosis or stricture formation. The incidence of pulmonary arteriovenous fistula increases with time and can be effectively treated with embolization. Physiologic repair after the Glenn shunt carries a low mortality. Although currently used infrequently, superior vena cava-pulmonary artery shunting remains a useful method of palliation in selected patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Perioperative care of the infant with congenital heart disease.

The current approach to the perioperative management of the infant and child with congenital heart disease has been discussed. The major focus has been on potential problems of oxygen transport as they relate to vital organ system function. Management strategies for specific defects or perioperative problems have also been considered as well as the newer on-line monitoring techniques, while stressing the importance of careful clinical evaluation. The ultimate surgical outcome is dependent not only on the adequacy of repair or palliation but on the treatment of potential life-threatening situations that may take place during the critical postoperative period.

Heart Defects, Congenital↗
PubMed1987

Persistent left superior vena cava causing subdivided left atrium: diagnosis, embryological implications, and surgical management.

A 3-month-old infant is described in whom a persistent left superior vena cava impinged on the posterior wall of the left atrium, producing a subdivided left atrium with left-to-right shunting and congestive heart failure. To our knowledge, this anomaly has not previously been reported. The preoperative diagnosis, surgical management, and embryological implications are discussed.

Echocardiography↗
PubMed1986

Accessory mitral valve tissue causing left ventricular outflow obstruction (two-dimensional echocardiographic diagnosis and surgical approach).

Accessory mitral valve tissue, a rare cause of left ventricular outflow tract obstruction, can be difficult to diagnose preoperatively and confusing even at surgery. The reported case illustrates how preoperative evaluation can be made using two-dimensional echocardiography combined with Doppler flow analysis. The intraoperative technique for removing the accessory tissue without causing damage to the native mitral valve is discussed.

Aortic Stenosis, Subvalvular↗
PubMed1984

Effects of alterations of oxygen transport on the neonate.

In the foregoing discussion we have attempted to provide an overview of much of the information available on the effects of changes in systemic oxygen transport on the neonatal and young subject. Using data synthesized from both human and animal studies, we have described the normal developmental changes and the findings of studies in which oxygen transport has been acutely altered by experimental means. This was intended to highlight the potentially delicate balance that can occur between oxygen supply and utilization during the critical period of rapid growth after birth. Finally, using the left-to-right shunt as an example, we have tried to show how a common pathologic condition can impair oxygen transport at multiple sites, and how normal development can make matters worse. It is anticipated that from an understanding of both normal and abnormal physiology, we will be able to develop rational approaches to the management of infants in whom the oxygen transport system has been stressed beyond its reserve.

2,3-Diphosphoglycerate↗
PubMed1983

Fetal echocardiography. A tool for evaluation of in utero cardiac arrhythmias and monitoring of in utero therapy: analysis of 71 patients.

Fetal echocardiographic studies were performed in 71 patients referred for evaluation of cardiac rhythm disturbances at 24 to 40 weeks' gestation. After 2-dimensional echocardiographic study of cardiac structure was performed, M-mode echocardiograms were analyzed for measurement of cardiac rate, atrioventricular contraction sequence, atrioventricular valve motion, and duration of postectopic pauses. Arrhythmias were diagnosed in 59 patients. In 34 patients with isolated ectopic beats, the arrhythmia resolved during later pregnancy in 26 or within the first 5 days of life in 8. Six patients had mild sinus bradycardia and 8 had frequent sinus pauses; all 14 had resolution of the arrhythmia during pregnancy. Sustained arrhythmias occurred in 11 patients. Deaths occurred when there was associated fetal congestive heart failure (hydrops fetalis), structural heart disease, or both. M-mode echocardiography diagnosed supraventricular tachycardia in 3 fetuses. The echocardiogram was used thereafter for monitoring transplacental digoxin therapy.

Anti-Arrhythmia Agents↗
PubMed1983

Evaluation of the preterm infant for patent ductus arteriosus.

As a first step in a multicenter, collaborative project to study the role of indomethacin in the management of patent ductus arteriosus in premature infants, a diagnostic scheme was developed, on an a priori basis, by a consensus of the participating neonatologists and pediatric cardiologists. The scheme, which utilizes clinical and noninvasive findings, was designed to detect infants with a "hemodynamically significant" patent ductus arteriosus (PDA). Among 1,689 infants with birth weight less than 1,750 g who were monitored during the first year of the study, 342 (20.2%) met the criteria for PDA. Rates were higher for smaller infants (42% with birth weight less than 1,000 g) than for larger infants (7% with birth weight 1,500 to 1,750 g). Although study protocol did not require a direct procedure to confirm the diagnosis of PDA, a marked decrease in the presence of most criteria was noted following surgical ligation of the ductus. Although the echocardiographic criterion (ratio of left atrium to aorta [LA/Ao] greater than or equal to 1.15) proved to have a low specificity for PDA, the data suggest that the overall scheme led to a very low rate of false-positive diagnosis. Following the application of the scheme for 1 year at 13 clinical centers, it has been shown to be a highly acceptable means of detecting infants with PDA.

Clinical Trials as Topic↗
PubMed1982

Fetal echocardiography for evaluation of in utero congestive heart failure.

Thirteen fetuses with nonimmune hydrops (22 to 39 weeks of gestation) were evaluated with two-dimensional and M-mode echocardiography. Ten fetuses had cardiovascular abnormalities resulting in heart failure, and three had noncardiac causes of hydrops. In three cases, hydrops was caused by supraventricular tachycardia. One of these fetuses responded to cardioversion at birth, another responded to transplacental digoxin therapy, and the third died with atrial flutter and high-grade atrioventricular block before delivery. There were no cases of "idiopathic" hydrops. Our results show that fetal echocardiography is useful in determining cardiac causes of in utero heart failure resulting in hydrops fetalis. The fetal echocardiogram may also be used in monitoring transplacental therapy of heart failure.

Adolescent↗
PubMed1982

Physiologic effects of increasing hemoglobin concentration in left-to-right shunting in infants with ventricular septal defects.

We studied the acute effects of increasing hemoglobin concentration and hematocrit on the pulmonary and systemic circulations of nine infants with large left-to-right shunts. After isovolemic exchange transfusion, which was designed to raise hemoglobin but keep blood volume constant, a consistent rise in systemic and pulmonary vascular resistances occurred. This rise was comparable to those previously found in isolated circulations showing a linear relation between hematocrit and loge of the vascular resistance. These changes in resistance were accompanied by decreases in systemic and pulmonary blood flow and a marked decline in left-to-right shunt. Despite the decrease in systemic blood flow, there was no decline in systemic oxygen transport, and there may have been a marginal decrease in left ventricular stroke work. These observations help explain why the newborn with a large ventricular septal defect and a high hemoglobin concentration does not have clinical signs of a large left-to-right shunt, and also suggest that the postnatal decline in hematocrit has a substantial role in the normal fall in pulmonary vascular resistance after birth.

Blood Circulation↗
PubMed1982

Myocardial damage following transthoracic direct current countershock in newborn piglets.

The effect of transthoracic direct current countershock on the myocardium of 21 newborn piglets was studied. Myocardial damage was quantified by measuring the myocardial uptake of technetium-99m pyrophosphate injected 24 hours after countershock. Substantial myocardial damage occurred in animals given greater than 150 joules/kg but not at lower energy doses. Damage occurred in both ventricular free walls, but more frequently in the right ventricle. The epicardial half of the myocardium was more severely affected than the endocardial half. The relationship between myocardial damage and total countershock energy dose was well modeled by an exponential function. Transthoracic direct current countershock appears unlikely to cause myocardial damage in newborn piglets unless greatly elevated energy doses are employed.

Animals↗
PubMed1982

Reversible changes in norepinephrine extraction by the lungs in children with pulmonary hypertension.

Extraction of circulating vasoactive hormones by the lung may influence systemic vasomotor tone. Since this process occurs in the pulmonary microcirculation, we evaluated the effects of pulmonary artery hypertension (PAH) secondary to congenital heart disease (CHD) on this metabolic function of lung. Eleven patients with varying congenital cardiac lesions were studied preoperatively and postoperatively. Five had normal pulmonary artery pressure (PAP) (group I), and six had PAH with peak systolic PAP greater than 40 mm Hg (group II). PA and postpulmonary arterial blood samples were collected before and after surgery at the time of pressure measurements. Norepinephrine (NE) and epinephrine (EPI) levels were determined by radioenzymatic assay. Preoperatively, circulating NE levels were higher (P less than 0.05) and NE extraction measured was lower (P less than 0.01) in group II patients as compared with group I. Extraction increased in group II postoperatively after PA pressures were reduced, becoming equivalent to group I postoperative values. EPI extraction was negligible in either group at any time. These data demonstrate that lungs of children are capable of selective catecholamine uptake and that elevated PAP occuring with CHD is associated with a decrease in this capability and an increase in circulating NE levels. Additionally, the decrease in NE extraction observed with PAH is reversible once PAP is reduced by surgical repair of the cardiac defect.

Adolescent↗
PubMed1981

The pathophysiology of disorders of oxygen transport in the infant.

The major attempt in this monograph has been to provide a systematic approach to OT in the infant under normal and abnormal conditions based on an appreciation of pathophysiologic mechanisms. This has included a consideration of oxygen uptake, gas transfer from the lungs to the circulation, oxygen delivery to the tissues, and various adaptive responses. We have discussed disorders involving the control of respiration, the upper and lower airways, lung parenchyma, pulmonary circulation, heart, and the oxygen carrier, hemoglobin, that may impair OT to tissues, and how compensation for these conditions can be achieved. The clinical presentation in each of these pathologic processes represents the net effect of the lesion on the multiple steps involved in the transport of oxygen to the tissues and the adaptation provided by the lungs, heart, circulation, and hematologic system. These must be taken into account in developing a plan for medical and/or surgical treatment that is focused on improving the supply of oxygen to the various organ systems of the body.

Heart Diseases↗
PubMed1981

Patch reconstruction of the right ventricular outflow tract with pulmonary valve insertion.

Although pulmonary regurgitation is generally well tolerated, reconstruction of the right ventricular outflow tract and insertion of a pulmonary valve are indicated in some patients. This procedure was performed in 12 patients, ages 1 1/2-17 years (mean 10 years). Seven had tetralogy of Fallot; of these, one underwent primary repair with Glenn shunt takedown and six underwent repeat operations after previous repairs. Of these six, the major indication for reoperation was right ventricular outflow tract obstruction in four, tricuspid and pulmonary regurgitation in one, and a residual ventricular septal defect and patent shunt in one. Three had absent pulmonary valve syndrome and two had pulmonary atresia. There were no early complications or deaths in this series during a mean follow-up of 28 months. Repeat cardiac catheterization was performed in eight patients and revealed that the preoperative right ventricular-pulmonary artery gradient was reduced from 58 +/- 25 mm Hg to 11.6 +/- 7 mm Hg at rest postoperatively and was located at the level of the valve. This gradient increased with exercise or isoproterenol infusion to 31 +/- 9 mm Hg. Our experience suggests that right ventricular outflow tract reconstruction with porcine valve insertion can be safely performed with good hemodynamic results. This technique allows insertion of a larger porcine valve and avoids kinking and compression of a conduit behind the sternum.

Adolescent↗