Biomedical subjects
Publications and source records attributed to O Scott.
Four infants with myocardial dysfunction associated with a persistent transitional circulation were given dopamine infusions in addition to standard treatment. The condition of each improved strikingly with rapid diminution in heart size as judged by chest x-ray. Dopamine has a place in the management of the sick infant with a persistent transitional circulation.
Three children are described in whom an unusual heart murmur was intermittently audible in the same room without a stethoscope. Subsequent investigations disclosed mitral valve prolapse in all three patients.
Ambulatory monitoring of the electrocardiogram was performed in 131 healthy boys aged between 10 and 13 years for two consecutive periods of 24 hours. When awake the maximal heart rates ranged from 100 to 200 and the minimal from 45 to 80 beats per minute. During sleep maximal rates were 60 to 110 beats and minimal rates 30 to 70 beats per minute. Sinus arrhythmia was seen in every boy and in 36 (27.5%) no other changes were found. Sinuatrial block, Mobitz type I, was not seen. Sinuatrial block, Mobitz type II, occurred twice only. Complete sinuatrial block occurred in 8.4 per cent, never lasted more than one cycle, and was always followed by a junctional beat. First degree atrioventricular block occurred in 8.4 per cent and Mobitz type I atrioventricular block in 10.7 per cent. Premature beats were always single, atrial in 13 per cent, ventricular in 26 per cent, and except in two boys were never more than four in 24 hours. There were no episodes of ventricular or supraventricular tachycardia. Changes in P wave morphology were common and slow junctional rhythm occurred in 13 per cent during sleep.
In a consecutive series of 100 cases of Fallot's tetralogy undergoing total correction, the mean birthweight was found to be just below the 50th centile. Blalock-Taussig or Waterston shunts were performed in 45 patients. Before their shunt operations a significant number of patients had become retarded in height and weight development but after the shunt operations many patients showed accelerated height and weight gain. Of the 73 patients followed up 2 years after correction, 23 had experienced accelerated development in both weight and height, but 11 patients remained on or below the 3rd centile for weight and height. In terms of the age at shunting, the oxygen saturation immediately before total correction, the age at total correction, the number of ventriculotomy patch repairs, and the post-correction ventricular pressure ratios, no significant difference could be detected between those 23 patients who had undergone accelerated development and those 11 who had remained retarded. More shunts, particularly of the Waterston type, were performed in the retarded group.
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Entry into the left atrium during cardiac catheterization may be essential for full assessment of the hemodynamic situation, particularly for the accurate calculation of pulmonary blood flow and pulmonary arteriolar resistance. The retrograde transaortic transmitral technique of left atrial catheterization has been described in adults but no detailed reports are available for the pediatric age group. Experience of this technique in 43 children with congenital heart disease is now presented, with a success rate of 67 per cent and a low incidence of complications. This method compares favorably with other methods of left atrial catheterization when the interatrial septum is intact.
The ages of 6 male patients with the sick sinus syndrome ranged from 10-15 years when their symptoms began. At rest all had a heart rate of 60/min or less. Two had syncopal attacks which threatened life; 1 had only attacks of dizziness; the other 3 had no syncopal attacks but had recurrent attacks of supraventricular tachycardia ('brady-tachycardia syndrome') which were more resistant to drug therapy than is usual in childhood. They were not controlled or suppressed by digoxin when it was given. Substernal pain occurred in 2 patients who had syncope. In all patients the heart rate remained inappropriately slow after exercise and atropine. Cardiac pacemakers were used in the 2 patients with life-threatening syncope. Any patient who has dizziness or syncopal attacks and an inappropriately slow heart rate should have electrocardiograms recorded at rest and after exercise to record the heart rate and to look for abnormal P-waves.
To correlate anatomy with hemodynamics, the angiocardiographic findings were reviewed in 42 patients with common ventricle (CV). Nine had normally related great arteries (NRGA), 12 d-malposition, 21 l-malposition and 5 a common atrioventricular valve. Selective outlet chamber (OLC) angiocardiograms were available in 14 out of 29 patients with OLCs. OLC position varied from anterior and to the right of the CV to posterior and to the left of it; two categories (anterior and lateral OLC) were delineated by a line 45 degrees to theleft of anterior in the horizontal plane. The OLC was anterior in all patients with NRGA, lateral in most l-malpositions, and almost equally divided between anterior and lateral in d-malposition (P less than 0.05). Complete hemodynamic data were obtained in 29 patients. Complete mixing of venous return occurred in four patients with atresia of one valve. In the remainder complete mixing occurred in 36%, unfavorable streaming in 12% and favorable streaming in 52%. Semilunar valve position and pulmonary stenosis did not affect the nature of mixing. Systemic arterial (SA) minus pulmonary arterial O2 saturation was positive and significantly higher in patients with malposition with lateral OLCs than anterior OLCs (P less than 0.001). However 79% of SA O2 saturation variation could be predicted from pulmonary and systemic blood flow alone.
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The angiocardiographic findings were reviewed in 21 patients with congenital mitral valve disease in whom the exact anotomic diagnosis was known independently. Patients with discordant (1)transposition and simple atrioventricular canal defects were excluded. No precise diagnosis was made in five patients (24%), all of whom had a cleft anterior leaflet or congenital short chordae. In the remainder, the specific diagnosis could have been made by injection of constrast medium downstream to the mitral valve alone in 15 (71%). Upstream injection was performed in 13 of these but would have made the precise diagnosis in only three (23%). In one patient both upstream and downstream injections were necessary. Anomalies giving characteristic angiocardiographic appearances were parachute valve, atresia, annular hypoplasia, dysplasia, anomalous arcade and anomalies associated with subaortic stenosis. Thus injection downstream to the valve is preferable to upstream injection, because it gives information about its patency, competence, tensor apparatus, and annular dimensions.
Eight patients were catheterized between 1.2 and 2.4 years after reconstruction of the right ventricular outflow tract with autologous fascia lata. Whereas the immediate post-bypass pressures had demonstrated a maximum gradient of 15 mm. Hg across the fascial valve at the time of recatheterization, this varied from 55 to 142 mm. Hg (mean 83 mm. Hg). Right ventricular systolic pressure varied between 80 and 160mm. Hg (mean 106 mm. Hg). All but one patient had clinical evidence of pulmonary incompetence. Selective angiography with injection into the right ventricle and pulmonary artery demonstrated shrunken, thickened, immobile valve cusps with an abrupt stenosis of the fascial tube or a diaphragm across it. Re-operation has been done in five patients. In each, the graft tube functioned satisfactorily, but at the site of the "valve," no leaflets were visible, and the orifice of the conduit narrowed abruptly to 6 to 10 mm. in diameter. It is concluded that autologous fascia lata is unsuitable for reconstruction of the right ventricular outflow tract.
A new performed, semi-rigid, polyethylene catheter, with built-in torque control, has been devised for entry to the pulmonary artery in complete transposition of the great arteries. It has been used 19 times in 17 patients: 18 times the pulmonary artery was entered from the right atrium (via the left atrium and ventricle) in a time between 40 s and 15 min (median 5 min); the patients' ages were 2 days to 6 years (median 8 months) and their weights were 3.1 to 13.3 kg (median 6.9 (kg: in the remaining 1 day-old patient, the procedures was terminated because of atrial flutter. The catheter was introduced into the axillary vein in 3 patients and thesaphenous or femoral vein in the remainder. It is suitable for angiocardiography, and the other heart chambers and vessels were easily entered. Thus the catheter has certain advantages over previously described methods for entry to the pulmonary artery, particularly when there is inferior vena caval thrombosis, or when angiocardiography is necessary. Its use does depend on the presence of an interatrial communication, so a method for entry to the pulmonary artery by retrograde catheterization from the axillary artery using a different catheter is also presented; this was successful in 2 patients with ventriculal sepatal defect.
When investigating complex congenital heart disease, determination of atrial situs is essential. Pathological studies have demonstrated that the best predictor of atrial situs is thoracic situs. To assess thoracic situs, bronchial tomography was performed in 92 patients with congenital heart disease. Sixty-four of these, without abnormalities of situs or cardiac position, formed 'normal' controls. The lengths of the left and right main bronchi were measured. When these were related to age, and the results analyzed statistically, linear discriminant equations resulted giving a chance of only 0.09% of misclassifying a bronchus of unknown morphology. The lowest ratio between bronchial lengths (BLR) in any individual was 1.71:1. These results were then used to assess thoracic situs in 17 patients with abnormal situs or CARDIAC POSITION. In 7 (2 with situs inversus), abdominal and thoracic situs agreed. Of 6 patients with bilateral left lung, 3 had an interrupted inferior vena cava. Of 4 patients with presumptive asplenia, 2 had bilateral right lung, but two had thoracic lateralization, one solitus and one inversus. The highest BLR in thoracic isomerism was 1.4:1. This emphasizes the complex interrelation of splenic status, thoracic, and abdominal situs, but demonstrates the value of bronchial measurement particularly in apparent situs indeterminatus.
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