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Biomedical subjects

W J Duncan

Publications and source records attributed to W J Duncan.

At least 37 records · Page 2Linked to original sources
PubMed1992

Congenital cardiac disease and contemporary dental care of the pediatric patient: a cardiologist's point of view.

Good dental health makes common sense--even more so in patients with underlying cardiac abnormalities. Today, the practising dentist may be confronted by an ever-increasing cohort of patients who have survived complicated repairs of congenital cardiac abnormalities. A basic knowledge of such conditions is useful, primarily to gain an understanding of the physiological abnormalities that may be adversely influenced by dental manipulation. This article reviews some of the important points that practising dentists should know about patients with congenital cardiac disease.

Child↗
PubMed1991

Neurological complications of balloon angioplasty in children.

We report on the occurrence of cerebrovascular accidents as a possible complication of balloon angioplasty in children. The first patient underwent balloon angioplasty for aortic stenosis and subsequently developed a right temporoparietal infarct in the vascular territory of the right middle cerebral artery. The second patient developed a right temporoparietal infarct also in the vascular territory of the right middle cerebral artery following balloon angioplasty of native coarctation of the aorta. This experience suggests that, in addition to the previously reported complications of balloon angioplasty, the occurrence of a potential cerebrovascular accident must be considered in the risk-benefit analysis of this procedure.

Angioplasty, Balloon↗
PubMed1991

Analyzing the health care environment: "You can't hit what you can't see".

The health care environment of the 1990s promises to be every bit as dynamic and complex as the environment of the 1980s. Health care managers must identify emerging issues and incorporate these issues into the strategic management process. This article discusses a five-step process for analyzing the changing environment facing health care organizations.

Delivery of Health Care↗
PubMed1991

Disopyramide as a negative inotrope in obstructive cardiomyopathy in children.

Two children with left ventricular outflow tract obstruction due to myocardial hypertrophy received oral disopyramide as a negative inotrope. Both showed rapid improvement in clinical signs and by echo Doppler examination. Nearly complete abolition of severe left ventricular outflow tract obstruction was documented in each case. This experience may prompt further application of disopyramide as a therapeutic agent to relieve dynamic muscular subaortic obstruction in children.

Cardiomyopathy, Hypertrophic↗
PubMed1989

Changes in intraventricular septal thickness, left ventrical wall thickness and left ventricular volume in obese adolescents on a high protein weight reducing diet.

Ten obese adolescents (153 percent ideal body weight) underwent significant weight reduction over a two to three month period using a low calorie, low carbohydrate, protein diet. The subjects lost a mean of 13.9 +/- 4.3 kg, representing a decrease of 15.5 +/- 5.0 percent of initial body weight. Serial measures of intraventricular septal thickness (ST), left ventricular wall thickness (LVWT) and left ventricular volume (LVV) were determined by standard m-mode echocardiographic methods over 14 weeks to determine the effect of weight reduction on these indicators of cardiac size. The ST changed over the study period from 8.2 +/- 1.9 mm to 7.3 +/- 2.0 mm; the LVWT from 7.6 +/- 1.8 mm to 6.3 +/- 1.1 mm; and the LVV from 47.1 +/- 4.0 mm to 42.0 +/- 2.8 mm. These numerical decreases were not significantly different. Over this study period, the diet allowed weight loss with no apparent effect on the cardiac size (ST, LVWT, LVV) as measured by echocardiography in these obese adolescents.

Adolescent↗
PubMed1988

Intraoperative Doppler flow studies: emphasis on colour mapping.

Colour Doppler flow imaging (CD) is a well-established method of assessing valvular and congenital disease of the heart. The technique has proven useful intraoperatively in patients undergoing valve repair or replacement or intracardiac reconstruction. In 21 patients with various cardiac anomalies, colour Doppler flow imaging was used intraoperatively, before cardiac cannulation and again after cardiopulmonary bypass. Previously undisclosed features were demonstrated preoperatively in two patients and important residual defects after cardiopulmonary bypass in three others. Adequacy of valve replacement was confirmed in four patients and small leaks in ventricular septal defect patches were shown in another three. The procedure facilitated repair of complex cardiac fistulas in two patients. There were no apparent complications from CD. As intracardiac repairs become more complex, the role of intraoperative CD will expand.

Adult↗
PubMed1988

Traumatic wound of the heart: value of intraoperative colour Doppler flow imaging.

A patient who sustained a traumatic ventricular septal defect from a stab wound is presented. Intraoperative echo-Doppler imaging provided an additional diagnosis of avulsion of anterior papillary muscle of the tricuspid valve prior to cardiotomy. It was concluded that intraoperative echo-Doppler imaging proves a useful guide for cardiac surgery following penetrating trauma.

Adult↗
PubMed1988

Treatment of pulmonary hypertension with diltiazem in a child with bronchopulmonary dysplasia.

A two-year-old child dying of pulmonary hypertension and cor pulmonale secondary to bronchopulmonary dysplasia, was demonstrated to have reactive pulmonary hypertension in response to 100% oxygen and isoproterenol infusion. In an attempt to find an oral medication to maintain pulmonary vasodilatation, experimental trials were done using hydralazine, salbutamol, nifedipine and diltiazem. Cardiac index, pulmonary and systemic vascular resistances and intrapulmonary shunts were monitored during the trials. Hydralazine, salbutamol and nifedipine were ineffective. Diltiazem 2.0 mg given every 6 h resulted in a profound and sustained decrease in pulmonary pressures and resistance, and a reversal of the cor pulmonale.

Albuterol↗
PubMed1987

Anomalous left coronary artery from the pulmonary artery: effect of coronary anatomy on clinical course.

Nine children and 1 adolescent with anomalous left coronary artery from the pulmonary trunk (ALCA) were studied between 1970 and 1982. Serial angiographic and hemodynamic data are compared with the clinical course. Four patients had separate conus coronary arteries with a major contribution to collateral flow. Eight patients survived various surgical procedures with 1 late death, 1 awaits operation, and 1 died in infancy. The authors' data show a significant potential for improvement in left ventricular function as shown by an increase in LV ejection fraction on medical therapy alone (5/6 patients), including all 4 with separate conus coronary arteries. The authors conclude that medical treatment alone may be indicated for a time in selected patients with ALCA, and a subgroup with a separate conus coronary artery may have a more favorable natural history.

Cardiac Catheterization↗
PubMed1985

Congenital tracheal occlusion in neonates--a minireview.

Congenital tracheal occlusion, though seemingly rare, is generally fatal if not attended to immediately. A high index of suspicion should help to make the diagnosis in a neonate when there are respiratory distress at birth and no audible cry and an endotracheal tube cannot be advanced beyond the vocal cords. We present our experience with cases of congenital tracheal obstruction due to various causes during a period of four years.

Female↗
PubMed1984

Mitral valve replacement in the neonate: a report of two cases.

Mitral valve replacement was performed in two critically ill neonates with severe mitral stenosis and regurgitation. Both patients had coexisting severe aortic stenosis previously treated by transventricular aortic valve dilatation. Preoperative echocardiography showed a mitral annulus measuring between 11 and 12 mm in diameter--too small for any of the commercially available free-standing valve prostheses. Accordingly, the porcine valve from a commercially available 12-mm external-valved conduit was removed and sutured into position. The function of the valve was satisfactory in both cases and cardiopulmonary bypass was discontinued easily with a good cardiac output established in both. Both patients died--one at 20 h and one 36 h after surgery. In each case, the immediate cause of death was acute bleeding secondary to preexisting hepatic failure and depletion of coagulation factors. At autopsy, both prostheses had been correctly placed and were competent. Left ventricular outflow tract obstruction secondary to strut imposition was not evident. Both patients were very ill preoperatively. Although neither patient survived mitral valve replacement, we were encouraged by the relative hemodynamic improvement in the immediate postoperative period. We believe that prosthetic valve replacement could become a viable therapy for the neonate with severe mitral valve abnormalities.

Aortic Valve↗
PubMed1984

Saccular aortic aneurysm in an asymptomatic child.

An asymptomatic boy was found to have coarctation of the thoracic aorta. Despite no history of endocarditis or trauma, a large saccular aneurysm involving the coarctation site was identified angiographically, confirmed, resected surgically, and examined histologically.

Aortic Aneurysm↗
PubMed1984

Right ventricular size and ventricular septal motion after repair of atrial septal defect in children.

An enlarged right ventricle and abnormal ventricular septal motion are characteristic echocardiographic features of atrial septal defect and often persist after the defect has been completely closed, even when the operation clinically is judged to be successful. These features were examined retrospectively 15 to 21 months after operation in a group of children whose atrial septal defect had been closed between January 1976 and July 1979. Despite satisfactory postoperative results in all, about two thirds had an enlarged right ventricular dimension and about the same number had abnormal septal motion when examined echocardiographically an average of 18 months after operation. The best operative strategy seems to be to operate while the right ventricular end-diastolic dimension is still relatively small in echocardiographic terms.

Adolescent↗
PubMed1983

Noninvasive diagnosis of neonatal coarctation and associated anomalies using two-dimensional echocardiography.

Two-dimensional echocardiography (2DE) was used to study 51 neonates in whom coarctation of the aorta had been diagnosed clinically. In 40 patients, studies showed coarctation or arch interruption that was later confirmed at angiography, surgery, or autopsy. Of the remaining 11 studies, one gave a false positive result, one was technically poor, three had echocardiographic evidence of only mild arch narrowing and are being followed clinically, and six were negative. There were two false negative studies. Four studies were apparently true negatives. Many additional lesions were correctly identified by echocardiography although some, such as patent ductus arteriosus and small ventricular septal defect, were frequently missed. Twelve patients underwent surgery without preoperative catheterization. 2DE has proven extremely useful in confirming the diagnosis of neonatal coarctation of the aorta and sometimes obviates the need for invasive catheterization.

Aorta, Thoracic↗
PubMed1982

The atrioventricular junction in the univentricular heart: a two-dimensional echocardiographic analysis.

The atrioventricular junction of 40 patients with univentricular heart was evaluated by two-dimensional echocardiography. The apical 4 chamber view optimally imaged the atrioventricular junction, and allowed determination of the type of atrioventricular connection: double inlet, common atrioventricular orifice, and absent right or left atrioventricular connection. When double inlet to 1 ventricle was demonstrated, the 4 chamber view allowed immediate comparison of the form and function of the right and left atrioventricular valves. Because anomalies of the atrioventricular valves frequently complicate the univentricular heart, two-dimensional echocardiographic assessment is a most important adjunct to the preoperative investigation of these patients.

Adolescent↗
PubMed1982

Space-occupying lesions of the myocardium: role of two-dimensional echocardiography in detection of cardiac tumors in children.

Four patients with space-occupying myocardial lesions were studied using electronically focused high-resolution two-dimensional echocardiography. In two patients with clusters of high-intensity echoes at various depths on the epicardial surface, histology confirmed the diagnosis of lymphosarcoma, showing patchy, malignant infiltrates of different thickness. The remaining two patients had very different features: the lesions appeared to be intrinsic to the posterior left ventricular wall. One patient who had arrhythmias and a small encapsulated noncontractile mass had a histologically proved rhabdomyoma. In the second patient fibroma was histologically confirmed. In these two patients the position of the lesions was confirmed by angiocardiography. Two-dimensional echocardiography greatly improved delineation of space-occupying cardiac masses and is an accurate method for confirming the presence of such lesions.

Adolescent↗