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A 7-year old female child was admitted for recurrent bronchopulmonary since one week of life. She was diagnosed to have ventricular septal defect and was treated conservatively. At seven years of life, repeat echocardiogram revealed a large perimembranous ventricular septal defect, absent pulmonary valve with overriding of aorta, narrow pulmonary artery annulus, and dilated main pulmonary artery and its branches. She was treated conservatively, discharged and follow-up at the National Heart Institute Kuala Lumpur, for corrective surgery.

Nine children, aged 2.5 months to 16 years, presenting with tachyarrhythmias were treated with intravenous (i.v.) flecainide, a type 1C antiarrhythmic drug. There were four boys and five girls; seven were supraventricular and two ventricular tachycardias and three had structural cardiac abnormalities. The i.v. dose required to terminate the arrhythmias ranged from 1.0 to 2.4 mg/kg (mean 1.55 mg/kg) although a mean of 1.94 mg/kg per dose was required to maintain sustained sinus rhythm after a single i.v. dose. Eight of the patients--six supraventricular and two ventricular tachyarrhythmias, required maintenance oral flecainide. Oral dosages of 6.7-9.5 mg/kg per day (mean of 7.97 mg/kg per day in three divided doses) were required to effectively prevent the tachyarrhythmias. Intravenous and oral flecainide are safe and effective in terminating supraventricular and ventricular tachyarrhythmias. No evidence of proarrhythmia was found in the patients during follow up of between 5 and 9 months. The present limitation of performing radiofrequency ablation on infants and small children justifies the important place of medical therapy for re-entrant supraventricular tachyarrhythmias.

Computerised data of 110,236 Singaporean males aged 15 to 25 (mean 17.75) years who underwent compulsory medical examination from April 1987 to January 1992 were used to estimate the prevalence and severity of myopia among young Chinese, Malay, Indian and Eurasian Singaporean males with different educational levels. The prevalence and severity of myopia amongst the groups with different educational levels were compared. These groups were fairly well-matched for important known confounding factors such as age, sex, race and degree of urbanisation of place of residence. Our data showed a positive association between educational attainment and both the prevalence and severity of myopia. Both the prevalence of myopia and the proportion of myopes with severe myopia were in general higher among those with more years of formal education.

Computerised data of 110,236 Singaporean males aged 15 to 25 (mean 17.75) years who underwent compulsory medical examination from April 1987 to January 1992 was used to estimate the prevalence of myopia among young Chinese, Malay, Indian and Eurasian Singaporean males. The prevalence of myopia amongst the different racial groups was compared after they had been matched for important known confounding factors such as age, sex, educational attainment and degree of urbanization of place of residence. The estimated myopia prevalence was 48.5% in Chinese, 34.7% in Eurasians, 30.4% in Indians and 24.5% in Malays. The overall myopia prevalence rate for all races combined was 44.2%. Within each educational group, the Chinese generally had the highest myopia prevalence whilst the Malays generally had the lowest. Myopia prevalence among the Indians tended to be between that of the Chinese and the Malays. Having matched the various racial groups for age, sex, educational attainment and degree of residential urbanization, it would appear that racial and cultural differences are major influences responsible for the difference in myopia prevalence observed amongst the different races.

Data of 421,116 Singaporean males aged 15 to 25 (mean 17.75) years who underwent compulsory medical examination in 1974-84 and 1987-91 were used to estimate the prevalence of myopia and to study the correlation between the prevalence and severity of myopia and educational attainment. The estimated myopia prevalence rate was 26.3% in 1974-84 and 43.3% in 1987-91. This rise in the rate was accompanied by an increase in the proportion of males who achieved higher levels of education over the same period. The overall myopia prevalence rate was 30.4%. Both the prevalence and severity of myopia were higher as the level of education attained increased. The myopia prevalence rate was 15.4% in males with no formal education and increased steadily through groups with intermediate education to 65.2% among those with GCE 'A' level education, 57.5% among diploma holders and 65.1% among university graduates in 1987-91. Seventy out of 173 (40%) myopes with no formal education compared to 1035 out of 1612 (64%) myopes with university degrees had unaided visual acuity worse than 6/60 in 1987-91. Our findings confirm indications from other sources that the association between the prevalence and severity of myopia and education attainment is real. A combination of genetic and environmental factors may be the cause of this association.

Colour Doppler flow mapping was used to determine the time of closure of the arterial duct in 51 healthy newborn infants. Initial time of closure corresponded with previous reports: 20% on the first day, 82% by the second day, 96% by the third day, and 100% by the fourth day. Twenty infants were delivered by caesarean section and followed up for seven days even if the duct had apparently closed; in six intermittent patency was demonstrated with flow in the third, fourth or fifth day, although earlier functional closure had been observed. All were found to be closed on the sixth and seventh days. It is necessary to be aware of the phenomenon of intermittent closure in any study determining or assessing the effect of any intervention on ductal patency.

Xq28 is the genetic locus of two closely associated conditions of red-green colour blindness and G6PD deficiency. Epidemiologically, both rank among the more frequent sex-linked clinical problems that affect military servicemen in Singapore. This retrospective study is based on the findings of 35714 subjects screened at the Medical Classification Centre--Central Manpower Base (MCC--CMPB) over an eighteen-month period using pseudoisochromatic and fluorescent techniques as well as anomaloscopic and spectrometric methods. The overall prevalence rates of red-green colour blindness, G6PD deficiency and association were determined to be 4.8%, 2.2% and 0.1% respectively. Malays showed the highest prevalence rates among the major races. Statistically significant difference was found with regards to the prevalence rates of G6PD deficiency and its association with red-green colour blindness. Review of literature yielded comparable results with a few local studies of good sample size done over the past twenty years. Sex-linkage analysis was hindered by the lack of pedigree studies.

A clinically undetectable, small ductus arteriosus was identified by Doppler ultrasonography in 21 individuals. Infants were excluded from the study and no patient had pulmonary hypertension. Persistence of the ductus arteriosus is likely to be more common than shown by less sensitive diagnostic methods. Some patients considered to have infective endocarditis with a normal heart may have a silent ductus arteriosus. Evidence of such an association would justify ligation or antibiotic cover as prophylactic measures.

A prominent resonance frequency, due to swollen soft tissue, was observed below the first mode resonance frequency of the bone in the mechanical impedance measurement of the limb. Distinction should be made between these two frequencies in the diagnosis of fracture healing. A two-port network analogy is used to explain the existence of the resonance frequency.

Doppler ultrasound was used to assess the pressure drop between the ventricles in 109 infants and children (61 less than two years old) with a ventricular septal defect who underwent cardiac catheterisation. The pressure in both ventricles was measured at catheterisation in 103 patients either simultaneously through two catheters (41) or with a single catheter withdrawn across the septum or removed from one ventricle to the other (62). When pressure was measured simultaneously with two catheters (41 patients) the peak to peak and instantaneous gradients showed a maximum difference of 20 mm Hg with levels within 10 mm Hg of each other in 36. Comparison of the difference in the gradients with the average of the measurements demonstrated a tendency for Doppler to underestimate the difference when it was high (greater than 50 mm Hg) and overestimate it when it was low. A Doppler estimate of a low pressure difference between the ventricles indicates pulmonary arterial hypertension and a high one low pulmonary artery pressure, but in the intermediate group Doppler is as yet not sufficiently sensitive to allow selection of those patients who require further investigation and possible operation. Doppler ultrasound was found to be a sensitive method of detecting a very small ventricular septal defect. Thus although Doppler is a very useful means of assessing and following patients with a ventricular septal defect, further studies are required to determine its exact place in clinical practice.

The Doppler spectral pattern of flow through the ductus arteriosus was studied in 117 patients. In 37 who underwent catheterisation, Doppler records and aortic and pulmonary artery pressure were available (21 simultaneously with two catheters) for review while the others had surgical ligation of the duct on the basis of the results of non-invasive tests. Four flow patterns were obtained: (a) continuous flow, maximum velocity in late systole with gradual fall throughout diastole; (b) continuous flow, high systolic flow with rapid fall to a very low early diastolic velocity maintained throughout diastole; (c) continuous low velocity, maximum in late diastole; and (d) bidirectional flow. Flow pattern (a) was associated with normal or slightly raised pulmonary artery pressure; (b) with raised pulmonary artery pressure; and (c) and (d) with pulmonary artery pressure at systemic values. Comparison of the Doppler and measured pressure differences between the great arteries was reasonably good for peak values but poor for the trough readings. Doppler ultrasound clearly showed ductal flow; the flow pattern gave an indication of the pulmonary artery pressure, but pressure measurement by application of the Bernoulli equation to the flow velocities cannot yet be regarded as reliable.

The variability of the valve gradient measured by Doppler in pulmonary stenosis was compared with the variability of the gradient measured at catheterisation in 42 infants and children undergoing catheterisation with a view to balloon dilatation of the pulmonary valve. The maximum value measured by Doppler when the patient was unsedated was significantly higher than that measured when the patient was sedated for catheterisation, and the maximum gradient was significantly higher shortly after than several days later. In a patient with pronounced infundibular obstruction after dilatation the Doppler signal clearly showed that the obstruction was dynamic, with a superimposed lower fixed signal that correctly predicted the final low gradient. The Doppler gradient in an alert and unsedated patient may be a better measure of the true physiological value. The highest Doppler value so obtained is a more appropriate indicator of the need for balloon dilatation than a single catheter measurement. The result of dilatation is best assessed by Doppler measurement at least a day after the procedure.

In a group of six dogs with Heidenhain pouches, the infusion of a solution of L-amino acids caused identical increases in gastric secretion when given into the jejunum as when administered directly into the portal venous system. Elevations in plasma amino nitrogen were also similar in the two circumstances. In four dogs with Heidenhain pouches and portacaval transposition, a similar infusion caused an identical increase in gastric secretion when given into the jejunum as when given into the peripheral venous system; plasma amino nitrogen levels were almost as high with the jejunal administration as with venous infusion. It is concluded that all, or almost all, of the gastric secretion evoked by amino acids in the canine intestine can be accounted for by the direct effect of absorbed amino acids on parietal cell secretion, with little or no contribution from release of an intestinal hormone.

Patients with traumatic rupture of the pericardium rarely survive to reach a hospital. Ten cases from the Maryland Institute for Emergency Medical Services Systems and 132 previously published cases are reviewed. Patients were usually men who were victims of violent thoracic trauma. The median age was 40 years. Half of the patients had left pleuropericardial tears; tears of the diaphragmatic pericardium, right pleuropericardium, and superior mediastinal pericardium were less frequent. Associated injuries of the heart or left hemidiaphragm were common. Pericardial rupture was usually discovered during surgical exploration for other indications, but physical or radiographic signs were occasionally present. Repair is indicated for most pericardial tears to prevent herniation of the heart or abdominal viscera.

After giving oral frusemide (Lasix) to 14 normal volunteers significant hypercalciuria occurred in all of them. This could not be accounted for by any change in glomerular filtration rate, but was possibly due to decreased tubular reabsorption.