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Biomedical subjects

S Stewart

Publications and source records attributed to S Stewart.

At least 343 records · Page 19Linked to original sources
PubMed1976

Double-outlet right ventricle. A collective review with a surgical viewpoint.

Double-outlet right ventricle (DORV) should be classified according to its various subsets. Van Praagh's symbolic terminology provides an appropriate mechanism for doing that. Each of these subsets is described in terms of its pathology, clinical characteristics, cardiac catheterization findings, and operative repair. The operative repair for each is different. The presence or absence of continuity between the semilunar and atrioventricular valves is unimportant from the standpoint of operation and should not be a criterion for classification.

Cardiac Catheterization↗
PubMed1976

Reconstruction of right ventricular-pulmonary artery continuity with a valved external conduit: unusual technical considerations.

The Hancock conduit containing a porcine xenograft valve has been used as part of the repair in 14 patients having complex congenital heart disease. The single death in this series resulted from the consequences of pulmonary vascular disease in a patient with truncus arteriosus. Several unusual technical considerations such as previous pulmonary artery banding, angulated Waterston anastomoses, and dextroversion required modifications in the standard approach to the correction of several of the anomalies encountered. This conduit has provided a satisfactory method to establish right ventricular-pulmonary artery continuity.

Adolescent↗
PubMed1976

The Waterston anastomosis with no deaths in the neonate.

The Waterston anastomosis has been performed with no deaths in 11 consecutive neonates during the past 24 months. Seven neonates had pulmonary atresia with either single ventricle or hypoplastic right ventricle, 3 had tetralogy of Fallot, and one had severe pulmonary stenosis with a normal right ventricle. Six neonates were one day old and only one was older than 7 days. All have obtained symptomatic and documented (increase Po2) benefit. This level of success is attributed to (1) minimal delay between the recognition of cyanosis and operation (mean time between hospital admission and catheterization was 3 hours and between catheterization and operation, 4 hours); (2) correction of any base deficit prior to, during, and after operation; (3) accurate construction of the anastomosis to avoid excessive size, and (4) careful postoperative management of the pulmonary subsystem by experienced personnel. We have demonstrated that the high mortality rate previously reported for the Waterston anastomosis in the neonate can be markedly improved by an appropriate patient management program.

Aorta, Thoracic↗
PubMed1975

Regional myocardial infarction at operation. An automated system of identification.

The difference between normal and infarcted myocardium at operation cannot always be defected by inspection or palpation. Infarcted myocardium may be identified by a decrease in the amplitude of the ventricular bipolar electrogram. Although this method is reliable and reproducible, it requires a second observer's visual analysis and interpretation of the electrogram signal. This method is therefore subject to the vagaries of human observation, analysis, and accounts of rapidly changing data. We have designed and built an automated instrument to simplify the recognition of transmural infarction.

Animals↗
PubMed1975

Action of prostaglandin F2alpha on pregnancy in hamsters: luteolytic and extra-ovarian effects.

Pregnancies in hamsters may be terminated by 10 mug PGF2alpha administered b.i.d. on days 4, k and 6 of gestation. Small (250 mug and above) daily injections of progesterone on the same days will reverse this PG effect; in contradistinction, 10 mg of progesterone per day failed to maintain normal pregnancies in hamsters spayed on day 5. Daily administration of 3 mg of progesterone and 1 mug of estrone essentially normalized the gestation; administration of PGF2alpha at 10 mg on days 5, 6 and 7 of pregnancy in steroid-maintained rats, resulted in pregnancy termination in all animals, while 1 mg was partly effective. These data demonstrate an extra-ovarian site of action of prostaglandin F2alpha on pregnancy in hamsters.

Animals↗
PubMed1975

Correction of truncus arteriosus after pulmonary artery banding.

Correction of truncus arteriosus can be performed in the older child with low mortality. However, many infants are severely symptomatic with increased pulmonary blood flow and require banding of the pulmonary artery at an age when correction has a high mortality. The pulmonary artery band can complicate the usual technique of the subsequent repair. An alternative approach following pulmonary artery banding is to interrupt the pulmonary artery--truncus continuity with a patch from within the truncus and then place the external valved conduit onto the pulmonary artery in an end-to-side manner.

Aorta↗
PubMed1975

Echocardiography of the intra-atrial baffle in dextro-transposition of the great vessels.

Twelve patients with dextro-transposition of the great vessels (age eight months to four years) were studied by echocardiography following Mustard's procedure. Nine of them had also been studied preoperatively. Postoperatively all patients demonstrated structural echoes in the atrial cavity behind the pulmonary root. In ten, the motion pattern generally resembled that of a stenotic atrioventricular valve iwth a sharp anterior movement followed by flattening in diastole and rapid posterior excursion in systole. The maximum amplitude of motion ranged from 4 to 9 mm (average 6.6 mm). In the remaining two cases, the anterior diastolic movement was attenuated. Similar moving, linear echoes with larger amplitudes of motion (10-14 mm) were observed behind the tricuspid valve in four patients while poorly moving, multiple or thick conglomerate echoes (2-11 mm wide) were detected in seven cases. Echocardiographic contrast studies performed by injecting indocyanine green via catheters placed on either side of the intra-atrial baffle identified it as the source of these echoes. Following operation, coarse diastolic undulations of the mitral valve (ten cases) and the tricuspid valve (nine cases) were noted. Also, fine flutter of both atrioventricular valves, not present before, appeared after operation in three patients. These findings may be related to the altered pathway of blood flow and turbulence resulting from the insertion of the baffle in the atria. Echocardiography appears useful in delineating the character and movement pattern of the intra-atrial baffle and this may have potential in evaluating its long-term functional status.

Child, Preschool↗
PubMed1975

Sutureless epicardial pacemaker lead: a satisfactory preliminary experience.

The first pacemaker systems used the epicardial electrode. The transvenous endocardial electrode rapidly supplanted the epicardial electrode since it could be positioned with less morbidity and mortality and was associated with a lower incidence of wire breakage. The long term complication rate of the transvenous electrode had not been inconsequential. The sutureless epicardial electrode combines the greater reliability of the epicardial lead system with the ease of insertion and low morbidity of the endocardial lead system. We have used this electrode in 33 patients. The electrode was positioned using the subxiphoid approach and local anesthesia in most patients. There have been few complications and none that resulted in long term morbidity. There have been no deaths related either to the operative approach or to the pacing system. There has been no instance of lead failure during the follow-up period.

Aged↗
PubMed1975

Simultaneous operative correction of aortic valve stenosis and idiopathic hypertrophic subaortic stenosis.

Idiopathic hypertrophic subaortic stenosis (IHSS) may coexist with aortic valve stenosis (AVS). This combination of lesions is uncommon and may not be identified by the usual preoperative clinical evaluation and laboratory studies including cardiac catheterization. Surgical relief of AVS without concomitant septal myectomy to relieve unrecognized underlying IHSS may be followed by a low cardiac output, evidence of residual outflow tract obstruction, and death. Echocardiography (ECHO) will accurately identify IHSS and should be performed in all patients suspected of having AVS. This report describes the first three patients in whom the preoperative diagnosis of both AVS and IHSS was made and who subsequently had both lesions corrected at the same operation. All patients survived operation. The outflow tract gradient was abolished in two patients and significantly reduced in the third. All patients with this combination of lesions should be offered operation for the same indication as isolated aortic valve stenosis. The operation should include a septal myectomy as well as relief of the aortic valve stenosis.

Aortic Valve Stenosis↗