Estimating the birth prevalence and pregnancy outcomes of congenital malformations worldwide.

Congenital anomaly registries have two main surveillance aims: firstly to define baseline epidemiology of important congenital anomalies to facilitate programme, policy and resource planning, and secondly to identify clusters of cases and any other epidemiological changes that could give early warning of environmental or infectious hazards. However, setting up a sustainable registry and surveillance system is resource-intensive requiring national infrastructure for recording all cases and diagnostic facilities to identify those malformations that that are not externally visible. Consequently, not all countries have yet established robust surveillance systems. For these countries, methods are needed to generate estimates of prevalence of these disorders which can act as a starting point for assessing disease burden and service implications. Here, we describe how registry data from high-income settings can be used for generating reference rates that can be used as provisional estimates for countries with little or no observational data on non-syndromic congenital malformations.

Fate of the stented arterial duct.

BACKGROUND: The technical aspects of ductal stenting have been reported, but little is known of the fate of the duct after stent implantation. METHODS AND RESULTS: Nineteen patients underwent stent implantation to maintain ductal patency. Eight had hypoplastic left heart (HLH) syndrome, 10 had pulmonary atresia, and 1 had tricuspid atresia. Median survival with HLH was 57 (12 to 907) days. Stent implantation was successful in all cases of HLH, but there were no long-term survivors. Two well-palliated infants died at transplantation. Median survival with duct-dependent pulmonary flow was 183 (0 to 1687) days, with 3 patients well at latest follow-up (56, 55, and 9 months, respectively). There were 2 operative deaths due to ductal spasm and 4 late deaths, 1 due to duct thrombosis, 1 due to chronic lung disease, and 2 of unknown cause. Stent implantation failed in 4 of the 11 cases. Assessment of endothelialization was possible in 13 cases; the stent was partially covered in 3 and fully endothelialized in all 10 cases assessed >8 weeks after implantation. In patients stented for inadequate pulmonary flow, ductal intimal hyperplasia occurred by 9 months in all 3 survivors but responded to repeated dilation. CONCLUSIONS: Ductal stenting cannot be recommended. In patients with HLH, it provides only short-term palliation even when combined with pulmonary artery banding. With duct-dependent pulmonary blood flow, the procedure carries high risk, and duration of palliation is poor. In patients with bilateral ducts and absent central pulmonary arteries, good palliation may be achieved, but repeated angioplasty is necessary to counteract intimal hyperplasia.

Natural history of supravalvular aortic stenosis and pulmonary artery stenosis.

Data from 35 patients with supravalvular aortic stenosis or pulmonary artery stenosis, or both, undergoing cardiac catheterization between 1973 and 1989 were analyzed retrospectively. Twenty-seven patients had supravalvular aortic stenosis: 11 required surgery after the first investigation and 8 (80%) of 10 others undergoing serial investigation showed an increase in the left ventricle to aorta pressure gradient. Angiographic measurements showed that the increase in the aortic pressure gradient was related to failure of normal growth of the ascending aorta lumen. Nineteen patients had pulmonary artery stenosis, with a right ventricular pressure greater than 33 mm Hg. At restudy, right ventricular pressure had decreased in 9 (82%) of 11 patients. This decrease in right ventricular pressure was associated with an increase in the systolic distensibility of the proximal pulmonary arteries, although there was no increase in the diastolic diameters. One patient had a rapid early increase in right ventricular pressure and no pulmonary artery growth. In two patients, multiple peripheral pulmonary artery stenoses became evident with time and produced persistent right ventricular hypertension. Supravalvular aortic stenosis is usually a progressive lesion, with an increase in left ventricular outflow tract pressure gradient related to poor growth of the ascending aorta. Pulmonary artery stenosis usually improves and only rarely limits prognosis.

Treatment of recoarctation: balloon dilation angioplasty.

Balloon dilation of recoarctation of the aorta was performed 47 times in 44 patients 49 +/- 54 months after surgical repair. The initial operation was performed in the neonatal period in 29 patients (66%). The age at balloon dilation was 4.9 +/- 5.3 years (range 2 months to 20 years) and weight was 18 +/- 15 kg (range 2 to 72). Systolic pressure difference across the recoarctation site decreased from 37 +/- 16 to 14 +/- 11 mm Hg and coarctation/aortic diameter ratio increased from 0.45 +/- 0.14 to 0.85 +/- 0.16 immediately after balloon dilation regardless of the nature of the previous operation (subclavian flap [n = 12], resection with end to end anastomosis [n = 21], patch angioplasty [n = 4] or multiple operations [n = 5]). In the ascending aorta, systolic pressure decreased from 120 +/- 25 to 113 +/- 20 mm Hg. In the descending aorta, systolic pressure increased from 85 +/- 15 to 100 +/- 19 mm Hg and pulse pressure increased from 22 +/- 7 to 36 +/- 8 mm Hg. At repeat cardiac catheterization in 21 patients (48%) 12 +/- 8 months after balloon dilation, there was further reduction in systolic pressure difference from 17 +/- 11 to 12 +/- 9 mm Hg with no further change in coarctation/aortic diameter ratio. Aneurysm formation was evident in one patient (2%) immediately after balloon dilation; the aneurysm was unchanged at repeat study 15 months later. A "new" aneurysm was apparent in 2 (10%) of the other 20 patients restudied to date. The occurrence of aneurysm in these three patients was unrelated to balloon size. There were no procedure-related deaths. Three patients (7%) had femoral artery occlusion. Balloon dilation affords good relief of obstruction without adverse sequelae from aortic wall disruption at medium-term follow-up.

Digoxin or flecainide for prophylaxis of supraventricular tachycardia in infants?

OBJECTIVES: This study compared the safety and efficacy of digoxin and flecainide in the prophylaxis of supraventricular tachycardia in infants. BACKGROUND: Recurrence of supraventricular tachycardia in infants is common. Digoxin is the conventional drug of first choice for prophylaxis, but its efficacy has not been tested in a controlled clinical trial, and there is no consensus on the drug of choice when digoxin is ineffective. METHODS: We reviewed retrospectively the records of all infants with supraventricular tachycardia due to atrioventricular (AV) reentry admitted to our hospital between January 1986 and December 1993. RESULTS: Thirty-nine infants presented with sustained AV reentrant tachycardia at age 1 to 330 days (median 12). Intravenous flecainide was required to maintain immediate control in six patients who were then treated with oral flecainide. The other 33 patients were treated with oral digoxin. There was no recurrence of tachycardia in 14 (42%) of the 33 patients (95% confidence interval [CI] 25% to 61%). In the other 19 patients (58%) (95% CI 39% to 75%), digoxin was replaced by oral flecainide because of multiple recurrence of tachycardia. Full control was achieved in all 19 of these patients (100%) (95% CI 82% to 100%) and in 5 of the 6 patients treated with both intravenous and oral flecainide. Thus, overall, flecainide was effective in 24 (96%) of 25 patients (95% CI 80% to 100%). CONCLUSIONS: Comparison with previous natural history studies suggests that digoxin is ineffective in the prophylaxis of supraventricular tachycardia. Oral flecainide was effective in a small number of infants, with no adverse effects (95% CI 0% to 12%), and may now be preferred as the primary prophylactic agent.

Cardiac rhythm in atrial isomerism.

Standard electrocardiograms from 126 consecutive patients with atrial isomerism were reviewed. Of 67 patients with left isomerism, 49 had sinus rhythm, 8 nodal rhythm and 10 atrioventricular (AV) block. Fifty-eight of 59 patients with right isomerism had sinus rhythm. Complete AV block was significantly more frequent in association with AV septal defect in left isomerism (5 of 45 patients) than in right isomerism (0 of 47 patients, p = 0.049). The P-wave axis was superior in 49% of patients with left isomerism but did not correlate with abnormalities of systemic or pulmonary venous connection. A significant shift of P-wave axis (more than 90 degrees) was seen on a subsequent electrocardiogram in 14 of 44 patients (32%) with left isomerism and 2 of 16 (13%) with right isomerism. Ambulatory electrocardiographic monitoring in 17 patients (14 with left isomerism) showed that only 4 had sinus rhythm throughout 24 hours. Only 1 patient with complete AV block received a permanent pacemaker. Despite the high incidence of electrocardiographic abnormalities, significant arrhythmias appear to be rare. The arrhythmias apparently do not influence the natural history of this condition or affect the outcome of palliative or corrective surgery. The prognosis is determined mainly or solely by the associated anatomic abnormalities.

Comparison of nasopharyngeal washings and swab specimens for diagnosis of respiratory syncytial virus by EIA, FAT, and cell culture.

Respiratory secretions for viral diagnosis are often collected with nasopharyngeal (NP) swabs, although many laboratories recommend NP aspirates or washings. We compared results using NP washings and NP swabs in three diagnostic RSV tests, a rapid RSV EIA antigen test (Abbott Laboratories), an indirect fluorescent antibody test (FAT) with rabbit antiserum, and virus culture (HEp-2 cells). Paired samples were collected from 121 children with suspected RSV bronchiolitis or pneumonia. A minitip swap was passed into the nasopharynx for 10 sec, rotated and withdrawn. The opposite nares was irrigated with approximately 1 ml of saline and aspirated using a syringe and plastic feeding tube. Fifty-one children (42%) grew RSV in culture, 49 from NP washings versus 27 from NP swabs (p less than 0.001). Fifty-three (44%) were positive by FAT, 52 from NP washings versus 12 from NP swabs (p less than 0.001). Fifty-eight children (48%) had positive RSV EIA tests, 57 from NP washings versus 35 from NP swabs (p less than 0.001). Detection by EIA was more sensitive than culture regardless of the method of specimen collection. We conclude that NP washings are superior to NP swabs for RSV culture and rapid diagnosis by EIA or FAT.

The rapid diagnosis of infectious mononucleosis using an ELISA that detects IgM antibody to a peptide component of Epstein-Barr virus nuclear antigen.

An enzyme-linked immunosorbent assay (ELISA) that detects IgM antibody to a peptide component of the Epstein-Barr virus (EBV) nuclear antigen (EBNA-1) was compared with a conventional rapid heterophil antibody method for the rapid diagnosis of infectious mononucleosis. Discrepancies between the two methods were further analyzed using an indirect immunofluorescence assay to detect antibodies to EBV antigens. We evaluated 298 cases of suspected infectious mononucleosis. The ELISA was very sensitive (98.7%) and able to detect some cases (seven (9%) of 75 confirmed positives) that were negative by the rapid heterophil antibody test, but confirmed by immunofluorescence. However, approximately 17% of all positive tests could not be confirmed by EBV-specific immunofluorescence; thus, the overall positive predictive value was 83%; negative predictive value was 99.5%; and specificity was 93%. The high rate of false-positive tests makes this rapid ELISA unsuitable for the diagnosis of infectious mononucleosis.

Truncus arteriosus with interrupted aortic arch: successful correction in a neonate.

Truncus arteriosus (type II) with interrupted aortic arch (type B) was successfully repaired at 11 days of age using anterior translocation of the pulmonary arteries, resection of the ductus arteriosus, and direct anastomosis between the descending aorta and truncus. This technique permitted wide reconstruction of the aortic arch and minimized the number of suture lines. It also positioned the right ventricle-pulmonary artery conduit anteriorly, which may simplify its subsequent replacement.

Aortic coarctation endarteritis and aneurysm: diagnosis by transoesophageal echocardiography.

A 17-year-old girl developed infective endarteritis, caused by Staphylococcus aureus, at the site of a previously undiagnosed aortic coarctation. Transoesophageal echocardiography revealed a clinically unsuspected false aneurysm. Foreknowledge of the presence of the aneurysm proved to be life saving when an acute deterioration required emergency surgery.

Presentation of congenital heart disease in infancy: implications for routine examination.

AIM: To investigate the performance of routine neonatal and 6 week examinations for detecting congenital heart disease. METHODS: A retrospective review of findings on clinical examination was conducted of a cohort of live born infants with congenital heart disease in one health region in 1987-94. RESULTS: Of 1590 babies with congenital heart disease, 523 (33%) presented before neonatal examination because of symptoms or non-cardiac abnormalities. 1061 underwent routine neonatal examination which was abnormal in 476 (45%), but only 170 were referred directly for diagnosis. Of 876 discharged with no diagnosis, 306 presented or died undiagnosed before 6 weeks. At 6 weeks 252 of 569 babies underwent a second routine examination which was abnormal in 164 (65%). CONCLUSIONS: Routine neonatal examination fails to detect more than half of babies with heart disease; examination at 6 weeks misses one third. A normal examination does not exclude heart disease. Babies with murmurs at neonatal or 6 week examinations should be referred for early paediatric cardiological evaluation which will result either in a definitive diagnosis of congenital heart disease or in authoritative reassurance of normal cardiac anatomy and function.

Prevalence and clinical significance of cardiac murmurs in neonates.

AIM: To determine the prevalence and clinical significance of murmurs detected during routine neonatal examination. METHODS: In a two year prospective study, 7204 newborn babies underwent routine examination by senior house officers. All those with murmurs underwent echocardiographic examination. All babies presenting later in infancy were also identified, to ascertain the total prevalence of congenital heart disease in infancy. RESULTS: Murmurs were detected in 46 babies (0.6%) of whom 25 had a cardiac malformation. The most common diagnosis was a ventricular septal defect, although four babies had asymptomatic left heart outflow obstruction. A further 32 infants from the same birth cohort had a normal neonatal examination but were found to have a cardiac malformation before 12 months of age. CONCLUSIONS: The neonatal examination detects only 44% of cardiac malformations which present in infancy. If a murmur is heard there is a 54% chance of there being an underlying cardiac malformation. Parents and professionals should be aware that a normal neonatal examination does not preclude a clinically significant cardiac malformation. The detection of a murmur should prompt early referral to a paediatric cardiologist for diagnosis or appropriate reassurance.

Examination for cardiac malformations at six weeks of age.

AIM: To attempt to define the prevalence and significance of murmurs detected on routine clinical examination at six to eight weeks. METHODS: A retrospective review of the results of routine clinical examination of a cohort of 6 to 8 week old babies resident in Newcastle upon Tyne, was carried out in two 12 month periods. All cardiac defects diagnosed in infancy in the same cohort were ascertained. RESULTS: 7132 babies were eligible for routine examination; 83% of these were examined. Murmurs were heard in 47 of 5395 babies and in 11 of 25 referred for evaluation congenital heart disease was found. The six to eight week examination led to diagnosis of 11 of 35 cases (31%) of congenital heart disease in the study population. CONCLUSIONS: Nearly one baby in 100 had a murmur on routine examination at six to eight weeks. Nearly half of those with murmurs who were referred had a structural cardiovascular malformation.

Presentation of obstructive left heart malformations in infancy.

This study documents the presentation of acutely life threatening congenital heart disease in infancy in order to assess the performance of screening examinations soon after birth and at 6 weeks of age. All cases of obstructive left heart malformations presenting in infancy in one health region from 1987-91 were analysed retrospectively. Altogether, 120 infants presented with either hypoplastic left heart syndrome, interruption of the aortic arch, coarctation of the aorta, or aortic valve stenosis. Twelve became symptomatic or died within 24 hours. Thirty four had an abnormal neonatal examination, eight of whom were referred. Six more became symptomatic before discharge. Ninety four babies went home, 51 developed heart failure before 6 weeks, and another seven died without diagnosis. Twenty five of 36 (69%) reaching 6 weeks without diagnosis had a second examination which was abnormal in 17. Two babies died undiagnosed after 6 weeks and the other 18 presented at up to 11 months of age. The neonatal and 6 week examinations perform poorly as screening tests for congenital heart disease. A normal neonatal examination does not exclude life threatening congenital heart disease.

The influence of congenital heart disease on survival of infants with oesophageal atresia.

OBJECTIVE: To examine the prevalence of congenital heart disease in babies with oesophageal atresia and its influence on outcome. DESIGN: Retrospective analysis. SETTING: The resident population of one health region. RESULTS: A total of 153 babies with oesophageal atresia were identified from 509 975 live births (0.30 per 1000); 26 (17%) had cardiac defects. Survival of babies with normal hearts was 97%, 97%, and 95% at one week, one month, and one year. Survival of babies with congenital heart disease was 85%, 85%, and 67% at one week, one month, and one year, but only one of ten deaths was the result of the congenital heart disease. The remaining deaths were due to other congenital malformations, respiratory disease, or chromosome abnormalities. CONCLUSIONS: There is a high prevalence of congenital heart disease in babies with oesophageal atresia. Congenital heart disease is associated with a higher mortality in oesophageal atresia but it is not the cause of it.

Strategies for antenatal detection of Down's syndrome.

AIM: To predict the effect of maternal serum screening and fetal echocardiography on the birth prevalence of Down's syndrome. METHODS: The outcome of all Down's syndrome pregnancies in the Northern Health Region between 1985 and 1991 was retrospectively ascertained. The number and outcome of all Down's syndrome pregnancies were used to define a theoretical population which would exist in the absence of screening. Published reports were used to predict the effects of screening strategies. RESULTS: Down's syndrome was identified in 412 pregnancies of which 315 (76%) resulted in live birth. A theoretical population with no antenatal screening would be expected to produce 31 stillbirths and 381 (92%) live births affected by Down's syndrome. In the same population a programme of maternal serum screening and fetal echocardiography would lead to 155 and 14 terminations, respectively, and when combined, would reduce affected live births to 229 (56%). CONCLUSIONS: Even if maternal serum screening and fetal echocardiography achieve their predicted potential, around half of all pregnancies affected by Down's syndrome will result in live born babies.

Variability of four limb blood pressure in normal neonates.

AIMS: To assess the variation in blood pressure (BP) between limbs in normal neonates. To assess whether comparison of arm and leg BP in neonates is reproducible enough to allow the difference to raise suspicion of coarctation of the aorta. METHODS: Infants recruited from the postnatal wards and the postnatal murmur clinic underwent echocardiography and BP measurement in each limb using a Dinamap Compact T 482210. The method of BP measurement was guided by a telephone survey of 40 UK neonatal units. RESULTS: Forty healthy neonates underwent echocardiography and all had a normal aortic arch. BP was measured in 39. In three, BP in the arms was 20 mm Hg higher than in the legs. This gave a specificity of comparison of the upper and lower limb BPs of 92 (36/39) or a false positive rate of 8% (3/39). The standard deviation in BPs was 15.7 mm Hg between arms, 14.5 mm Hg between legs, and 11 mm Hg when the nearest arm and leg were compared. CONCLUSIONS: With current measurement techniques, normal neonates may have a wide variation in BP between limbs. A difference of 20 mm Hg in isolation is more likely to be due to random variability in measurement than to coarctation of the aorta. If coarctation of the aorta is suspected, it can only be excluded or confirmed by echocardiography.

Extensive patch tracheoplasty with a silicon "T" tube stent in a 7-month-old infant.

Congenital tracheal stenosis is difficult to manage. We describe the combination of an extensive patch tracheoplasty and silicon "T" tube stenting performed in a 7-month-old infant following classical repair of a coexisting pulmonary artery sling.

Distribution of metals in tissues of beaver, raccoon and otter from Ontario, Canada.

Mercury and selenium concentrations were positively correlated in liver tissue of beaver, raccoon and otter from an undisturbed watershed in south central Ontario. Selenium accumulation in piscivorous mammals may represent a protective mechanism against methylmercury toxicity to animals exposed to high mercury levels in their diet. This paper also reports the levels of several other metals in tissues of three wild fur-bearing mammal species.

The effect of acidification on the accumulation and toxicity of metals to freshwater invertebrates.

This paper reviews the literature to determine if lowered water pH (a) affects metal bioaccumulation in freshwater invertebrates, (b) enhances the toxicity of a given metal, and (c) increases waterborne metal concentrations to levels toxic to invertebrates. The elements considered are mercury, lead, cadmium and aluminum. The available evidence suggests that of these elements only mercury is biomagnified in aquatic foodchains. The bioaccumulation of all these elements is influenced by water pH, but data concerning invertebrates is meagre for mercury and lead. The effect of pH on mercury and lead toxicity to invertebrates is unclear and may be largely species specific. Cadmium toxicity is reduced by lower pH, while aluminum toxicity to invertebrates is markedly higher due to changes in aluminum speciation at low pH.