Contemporary epidemiology of infective endocarditis in patients with congenital heart disease: A UK prospective study

OBJECTIVES

Infective endocarditis is a life-threatening complication of congenital heart disease (CHD), but there are few studies concerning the contemporary risk profile, preceding invasive procedures and outcomes in this patient population. The aim of this study was to investigate the epidemiology of infective endocarditis (IE) in patients with CHD.

METHODS

Cases of IE in children and adults with CHD were prospectively recorded as part of the UK National Institute for Cardiovascular Outcomes Research (NICOR) National Congenital Heart Disease Audit. Patients were entered into the database between April 2008 and March 2016.

RESULTS

Eight hundred episodes of IE were recorded in 736 patients with CHD. Sixty-five patients (9%) were infants (aged <1 year), 235 (32%) were children (aged 1-15 years), and 436 (59%) were adults (aged >15 years). The most common diagnoses were Tetralogy of Fallot (n = 150, 22.8%), ventricular septal defect (n = 129, 19.6%) and bicuspid aortic valve (n = 70, 10.7%). Dental procedures preceded 67 of 635 episodes (11%) of IE, and non-dental invasive procedures preceded 177 of 644 episodes (27.4%). The most common causative organisms were streptococci, accounting for 40% of cases. Overall in-hospital mortality was 6.7%. On multivariable analysis, adverse factors associated with in-hospital mortality were staphylococcal infection and presence of an underlying atrioventricular septal defect.

CONCLUSIONS

Infective endocarditis in patients with CHD is an ongoing clinical challenge. In contemporary practice in tertiary congenital centers, 1 of 15 patients do not survive to hospital discharge. Streptococci remain the most common causative organism, and antecedent dental or medical procedures were undertaken in a significant minority in the 3 months before diagnosis. The presence of an atrioventricular septal defect or staphylococcal infection is associated with significantly increased risk of early mortality.

Pregnancy Alters Renal and Blood Burden of Mercury in Females

Methylmercury (CH₃Hg⁺), a common environmental toxicant, has serious detrimental effects in numerous organ systems. We hypothesize that a significant physiological change, like pregnancy, can alter the disposition and accumulation of mercury. To test this hypothesis, pregnant and non-pregnant female Wistar rats were exposed orally to CH₃Hg⁺. The amount of mercury in blood and total renal mass was significantly lower in pregnant rats than in non-pregnant rats. This finding may be due to expansion of plasma volume in pregnant rats and dilution of mercury, leading to lower levels of mercury in maternal blood and kidneys.

Why quad bike safety is a wicked problem: an exploratory study of attitudes, perceptions, and occupational use of quad bikes in northern Queensland, Australia

Quad bike safety represents the quintessential wicked problem. To address this wicked problem, this research explores the use of quad bikes in the northwestern region of outback Queensland, Australia, concentrating efforts on the pastoral industry. Focus groups and interviews were conducted with pastoralists, farmers, retailers, repairers, healthcare professionals, and regulators. The discussions revealed the diverse activities currently undertaken in the region's pastoral enterprises while riding a quad bike, and that attitudes toward the purchase and use of quad bikes vary and may be influenced by retailers. Perceptions of risk and safety in the use of quad bikes in occupational settings also varied. The findings from this study provide insight into the decisions of local pastoralists and agriculturalists to use quad bikes in their workplaces, and attitudes toward safety and injury prevention relating to quad bike use in these industries in northwestern outback Queensland. This study is the first step toward understanding quad bike use in this region, with the goal of reducing injury and death, and will be used in policy and legislation development regarding the use and safety of quad bikes in Australia.

Hearing screening program impact on noise reduction strategies

The objective of this study was to determine the impact of the New South Wales Rural Hearing Conservation Program on the implementation of personal hearing protection (PHP) and noise management strategies among farmers who had participated in this program in New South Wales, Australia. A follow-up survey of a random sample of people screened through the New South Wales Rural Hearing Conservation Program was linked to their baseline data. The use of PHP at baseline was compared to use at follow-up in four specific scenarios: use with non-cabbed tractors, with chainsaws, with firearms, and in workshops. For non-cabbed tractors, the net gain in PHP use was 13.3%; the net gain was 20.8% for chainsaws, 6.7% for firearms, and 21.3% for workshops. Older farmers and those with a family history of hearing loss were less likely to maintain or improve PHP use. Those with severe hearing loss, males, and participants reporting hearing problems in situations where background noise was present were more likely to maintain or improve PHP use. Forty-one percent of farmers had initiated other strategies to reduce noise exposure beyond the use of PHP, which included engineering, maintenance, and noise avoidance solutions. The early (hopefully) identification of hearing deficit in farmers and farm workers can help promote behavior change and help reinforce a farm culture that supports hearing conservation. The continuation and expansion of hearing screening programs such as these should be encouraged as basic public health strategy in farming communities.

Factors Affecting Farm Noise During Common Agricultural Activities

Hearing injury due to exposure to excessive noise during common farming activities is a significant problem for farmers. The aim of this study was to investigate factors that affect the level of risk to hearing caused by common farming activities. Noise levels on farms were measured across a range of activities and producer groups, and situational factors that effect noise levels were also investigated. Older tractors were found to be 6 dB louder than newer tractors. Cabs reduced noise to the operator by 16 dB, which was halved to 8 dB if a door was open. Radios added between 3 and 5 dB to the noise in the cab. These variables significantly affect the noise level at the ear of operators and others in the workplace, and affect the subsequent exposure limits that are considered safe. Situational factors need to be considered in assessing the level of risk to farmers' hearing and in choosing noise management strategies on the farm. This information has been incorporated into material about hearing and discussions with farmers who participated in field day hearing screening programs in Australia.

Farm Noise Emissions During Common Agricultural Activities

Noise injury in agriculture is a significant yet often unrecognized problem. Many farmers, farm workers, and family members are exposed to noise levels above recommended levels and have greater hearing loss than their non-farming contemporaries. The aim of this study was to gather up-to-date information on farm noise levels and to enhance the quality of information available to assist farmers in reducing noise exposure and meeting Occupational Health and Safety (OHS) regulations regarding noise management. Farm visits were conducted on 48 agricultural establishments that produce a range of commodities. Noise levels were measured at the ears of operators and bystanders involved in typical activities on farms. The average and peak noise levels were measured for 56 types of machinery or sites of farming activity, totaling 298 separate items and activities. Common noise hazards identified included firearms, tractors without cabs, workshop tools, small motors (e.g., chainsaws, augers, pumps), manual handling of pigs, shearing sheds, older cabbed tractors, and heavy machinery such as harvesters, bulldozers, and cotton module presses. We found that use of firearms without hearing protection presents a pressing hearing health priority. However, farming activities involving machinery used for prolonged periods also present significant risks to farmers' hearing health. Noise management strategies on the farm are essential in order to prevent noise injury among farmers.

Agricultural work-related fatalities in Australia, 1989-1992

Farm-related fatalities in Australia were studied as part of a larger study of all work-related traumatic fatalities from 1989-1992. Information concerning 373 unintentional work-related fatalities was obtained from inspection of coronial files and described. The fatality rate per 100,000 workers was four times higher for agricultural industry workers (20.6) compared to the all-industry rate during the same time frame (5.5). Males comprised 95% of all agricultural work-related deaths. Agents such as farm vehicles, mobile farm machinery (mainly tractors), and farm structures (mainly dams) were among the most common involved in the fatal incident. Being hit by moving objects, vehicle accidents, and rollovers of mobile machinery (mainly tractors) were among the most common mechanisms of fatal injury on farms. Transport for work purposes, working with animals, working with crops, and maintenance were the most common activities being undertaken. The information obtained from this study is being used to develop health and safety risk profiles for agricultural industries, and these profiles are being used in turn to develop guidance material for farmers, on-farm checklists, and other tools to help farmers manage their occupational health and safety risk.

Non-work-related farm fatalities in Australia, 1989-1992

This study aims to examine farm fatalities, between 1989-1992 in Australia, of individuals not working at the time of the incident. Non-work-related farm fatalities in Australia were studied as part of a larger study of all work-related traumatic fatalities from 1989-1992. Information on 214 unintentional non-work-related farm fatalities was obtained from inspection of coronial files. The information was examined according to type of bystander (bystander to work or bystander to farm equipment) and other farm deaths. Agents such as dams, tractors, utilities, and cars were among the most common causes of death for bystanders involved in fatal incidents. Fire and smoke, creeks or rivers, and cars were the most common agents for other farm deaths. Drowning, vehicle accidents, and being hit by moving objects were among the most common mechanisms of fatal injury for non-work-related farm deaths. The information gained from this study has been used to develop the Child Safety on Farms Strategy for Farmsafe Australia and Farmsafe Australia's Farm Machinery Safety Strategy.

Octreotide to treat postoperative chylothorax after cardiac operations in children

Chylothorax after pediatric cardiac operations is associated with significant morbidity and increased hospitalization. An octreotide (a synthetic somatostatin analogue) infusion (1 to 4 microg/kg per hour) with medium-chain triglyceride diet or parenteral nutrition was used in 4 pediatric cardiac surgical patients after chylothorax was diagnosed. Resolution followed within 5 days in all without recurrence, while on a normal diet.

Farm-related fatalities involving children in Australia, 1989-92

OBJECTIVE

To describe the types of and circumstances surrounding unintentional farm-related fatal injuries involving children aged less than 15 years in Australia.

METHODS

Information concerning 115 deaths were obtained from inspection of coronial files for the period 1989-92.

RESULTS

Children less than 15 years made up 20% of all unintentional farm-related fatalities in Australia, with children less than 5 years representing 63% of all child fatalities. The majority of children were fatally injured while bystanders to farm work and equipment used on the farm (including dams), with drowning the most common mechanism of the fatal incident for children aged both 5 years or less and 5-9 years. Vehicle accidents were common for children aged 10-14 years.

CONCLUSIONS

Children are exposed to various hazards in the farming environment and as such are at risk of being injured.

IMPLICATIONS

This study has highlighted a number of particular hazards for children on farms, with drowning, transport and tractor-related injuries of particular concern. A national strategy for child safety on farms has been developed by Farmsafe Australia aimed at providing a nationally co-ordinated plan for improving child safety on farms.

Severe airflow limitation after the unifocalization procedure: clinical and morphological correlates

BACKGROUND

While unifocalization techniques have improved the treatment options in patients with pulmonary atresia, ventricular septal defect (PA-VSD), and major aortopulmonary collaterals (MAPCAs), severe airflow limitation contributes to significant early postoperative morbidity and mortality. Although this has been attributed to bronchospasm, characteristically it is refractory to bronchodilators, suggesting that other mechanisms may play a role.

METHODS AND RESULTS

The clinical course and preoperative angiograms of patients who underwent unifocalization were reviewed. Patients who developed airflow limitation early after surgery underwent fiberoptic bronchoscopy. In addition, the anatomy of the MAPCAs was examined in 14 heart-lung blocks from patients with PA-VSD. Twenty-two procedures were performed in 16 children. Three developed marked airflow limitation early after surgery, necessitating prolonged high-pressure ventilation. Bronchoscopy demonstrated tracheobronchial epithelial necrosis in 2 and signs of tracheobronchial ischemia in the third. Two were successfully extubated after 15 and 16 days, but the third died after 57 days of ventilatory support. Review of the preoperative angiograms demonstrated an extensive peribronchial arterial supply arising from a MAPCA in 1 of the patients who developed severe airway necrosis after unifocalization. This was also obvious in a second patient, but the MAPCA was not included in the unifocalization. In 7 autopsy specimens, MAPCAs contributed to a peribronchial or peritracheal vascular network. Dissection of the distribution of these branches in 2 specimens revealed extensive intrapulmonary peribronchial anastomoses.

CONCLUSIONS

Airflow limitation early after unifocalization is related to airway ischemia resulting from interruption of the tracheobronchial blood supply during mobilization of MAPCAs.

Heterotopic cardiac transplantation and Batista operation

We report the case of an infant who was first seen with dilated cardiomyopathy at the age of 3 1/2 months and 2 months later, successfully underwent heterotopic cardiac transplantation in combination with partial left ventriculectomy. The benefits of combining both procedures in such a young infant particularly with regard to containment of early graft dysfunction, reduction of respiratory problems, and weight mismatch are discussed.

The European Paediatric Cardiac Code Long List: structure and function

The Long List is a comprehensive hierarchical system of coding and classification for the diagnosis and treatment of heart disease. Although originally aimed at the clinician or surgeon treating heart disease first appearing in infancy or childhood, it has now been enlarged to encompass abnormalities first diagnosed in fetal life, as well as heart disease first acquired during adult life. There are a total of 3,876 individual terms. For the most part, these are mutually exclusive and unambivalent, given the constraints of clinical ambiguities and differing cultures of practice. In addition, there are 564 qualifier terms. These provide additional detail to individual or multiple items, such as fine anatomical detail, the severity of a lesion, the size of an interposition shunt or conduit, or the material used to close a septal defect. Finally, there are a further 341 duplicate diagnostic or procedural terms included in the List to aid its use, as some terms may have relevance in multiple areas. For example, Hypoplastic left heart syndrome is found under congenital anomalies of the left ventricle as well as in the section dealing with the aortic valve. Thus, altogether the listing consists of 4,781 items. The System is hierarchically arranged, with a major division between diagnostic and therapeutic subhierarchies. The developmental history of the Long List has been published previously, and is detailed earlier in this supplement.

The real fate of pulmonary arteries after bidirectional superior cavopulmonary anastomosis: is there a need for concern?

Controversy remains about the growth of the pulmonary arteries following a bidirectional superior cavopulmonary anastomosis in children with complex cyanotic congenital cardiac malformations. This is partially due to the morphological heterogeneity of the patients, and partially due to methodological differences in series published so far. It is further complicated by the variable use, in different centres, of additional sources of pulmonary blood flow. We believe that the fate of these arteries preoperatively is significantly influenced by the amount of pulmonary blood flow and the initial size of the arteries. Separate assessment of the pulmonary arterial development postoperatively is recommended for those who, initially, had relatively small as opposed to larger than normal pulmonary arteries. Measurement of the diameters of both pulmonary arteries just prior to their first point of branching, together with the use of Z-score evaluation rather than the Nakata index, is discussed. It remains to be established whether, over time, the bidirectional cavopulmonary anastomosis is effective in developing adequately the pulmonary arteries in preparation for an ultimate total cavopulmonary connection, or even as isolated long-term palliation. A prospective, multi-institutional study involving sequential non-invasive assessment of pulmonary arterial development (using, for example, magnetic resonance imaging) is required to solve the outstanding problems.

An empirical comparison of expert-derived and data-derived classification trees

Classification trees provide an attractively transparent discrimination technique, and may be derived from both expert opinion and from data analysis. We consider a real and complex problem concerning the diagnosis of babies with suspected critical congenital heart disease into one of 27 classes. A full loss matrix for all possible misclassifications was obtained from clinical assessments. A tree derived from expert opinion was compared with those derived from analysis of 571 past cases, both for the full problem and for a subset of 6 diseases. Automatic methods for tree creation and pruning were found to have problems for rare diseases, and hand-pruning was carried out. Inclusion of costs led to much improved clinical performance, even for trees that had originally been constructed to minimize classification errors. The expert tree showed a specific building strategy that could not be reproduced automatically. The expert tree generally outperformed those derived from data, particularly in the ability to identify important composite features.

Effect of phonophoresis with dexamethasone on adrenal function

One of the side effects of corticosteroid ingestion and inhalants is suppression of the adrenal glands. Phonophoresis of topically applied corticosteroids is commonly used to treat musculoskeletal inflammatory conditions. The purpose of this study was to determine whether phonophoresis with dexamethasone sodium phosphate affected adrenal function. The subjects included 28 male volunteers (mean = 25.3 years, SD = 6.4) who received phonophoresis to the left shoulder every other day for 2 weeks. Subjects were randomly assigned to one of four groups, including a control group (N = 8), an ultrasound group (N = 8), a .33% dexamethasone group (N = 7), and a ultrasound with .33% dexamethasone group (N = 5). Adrenal function was assessed by 24-hour urinary-free cortisol (microgram cortisol/g creatinine) collected two days prior to and following the phonophoresis treatments. A nonparametric analysis of variance using a split plot factorial design was calculated for ranked urinary-free cortisol scores and found no significant (p > 0.05) differences in urinary-free cortisol levels between the four groups and between the four collection days, and there were no significant (p > 0.05) interactions exhibited between group and collection day. This study suggests that phonophoresis with dexamethasone sodium phosphate, using common clinical parameters, does not cause dexamethasone sodium phosphate to become systemic in large enough quantities to impair adrenal function.

Prognostic significance of ventricular arrhythmia after repair of tetralogy of Fallot: a 12-year prospective study

OBJECTIVE

The aim of this study was to examine the prognostic significance of ventricular arrhythmia on the ambulatory electrocardiogram (ECG) after repair of tetralogy of Fallot.

BACKGROUND

Ventricular arrhythmia is common after repair of tetralogy of Fallot and has been proposed as the basis for late sudden death. The prognostic significance of ventricular arrhythmia on ambulatory ECG and the indications for therapy are uncertain.

METHODS

We performed a 48-h ambulatory ECG in 86 patients (3 to 45 years old [mean age 14 years]) after repair of tetralogy of Fallot. These patients were then followed up prospectively for 12 years.

RESULTS

At initial assessment in 1980, 47 patients (55%) had infrequent uniform ventricular extrasystoles (16 patients) or normal cardiac rhythm (31 patients) Group 1), and 39 patients (45%) had frequent uniform ventricular extrasystoles (> 30/h, 2 patients), complex extrasystole (30 patients) or nonsustained ventricular tachycardia (7 patients) (Group 2). There were no significant clinical or hemodynamic differences between the groups. In addition, nine patients had supraventricular tachyarrhythmia. Antiarrhythmic therapy was prescribed only for the 10 patients who had symptoms attributable to arrhythmia. There were two sudden deaths in Group 1 (4%) and one nonsudden death in Group 2 (2.5%). The absolute difference in mortality between groups was therefore 1.5% (95% confidence limits -6% to +9%), excluding a clinically significant difference in outcome. All but 1 of the 39 patients with complex ventricular arrhythmia are alive and well, including those with elevated (> or = 60 mm Hg) right ventricular pressure.

CONCLUSIONS

Nonsustained ventricular arrhythmia on ambulatory ECG does not identify patients at high risk for sudden death after repair of tetralogy of Fallot. There does not appear to be any advantage in potentially dangerous long-term antiarrhythmic therapy for asymptomatic postoperative patients.

Tricuspid atresia presenting in infancy. Survival and suitability for the Fontan operation

BACKGROUND

The Fontan operation is the usual goal of therapy for children with tricuspid atresia. The influences of morphology and different management strategies on survival and subsequent suitability for this procedure are crucial but unstudied in an unselected population during the Fontan era.

METHODS AND RESULTS

The fates of 237 consecutive infants with tricuspid atresia were reviewed (1972-1987; median follow-up, 8.0 years). Overall actuarial survival was 72% at 1 year, 53% at 5 years, and 46% at 10 years. Univariate risk factor analysis established that discordant ventriculoarterial connections (24% of the group; relative risk, 2.7), pulmonary atresia (14%, 2.3), aortic arch obstruction (7%, 2.9), and subaortic stenosis (8%, 4.2) were associated with poor survival, whereas pulmonary stenosis (60%, 0.52), balanced pulmonary blood flow (9%, 0.25), and older age at presentation (33%, 0.42) were beneficial. Multivariate analysis allowed the creation of predictive patient-specific survival curves and two additive indexes. Survival was worse for patients who underwent banding of the pulmonary trunk with aortic arch repair than for other individual palliative procedures (p < 0.001). On retrospective review, 204 patients (86%) were judged suitable for a future Fontan procedure at presentation. However, 99 (48%) of these are known to have died before a Fontan operation or became unsuitable for such surgery during follow-up, mostly because of death after palliative surgery (23 patients, 11%), sudden death (18 patients, 9%), and new adverse features (32 patients, 16%) such as subaortic stenosis, pulmonary arterial distortion, and ventricular dysfunction.

CONCLUSIONS

Management in infancy must aim to ensure survival and maintain suitability for a Fontan-type operation. The accumulating incidence of adverse events with increasing age would argue in favor of undertaking definitive surgery in early childhood in most patients.

Double-inlet ventricle presenting in infancy. II. Results of palliative operations

The influence of palliation on survival was studied in 191 consecutive infants, presenting at under 1 year of age, with double-inlet ventricle (1973 to 1988, median follow-up 8.5 years). Palliative operations were performed on 154 occasions in 121 patients (63%). Survival after a systemic-pulmonary arterial shunt (n = 57) and banding of the pulmonary trunk (n = 35) was comparable (84% and 77% at 1 year, 62% and 45% at 5 years), but those who underwent repair of aortic arch obstruction fared worse (n = 18, 44% and 22% at 1 and 5 years, p less than 0.001). The remainder did not undergo an operation because of balanced physiology (n = 17, 9% of entire group), complex anatomy (n = 32, 15%), or irreversible low output (n = 19, 12%). Palliative surgery, overall, had a deleterious effect on immediate survival (greater than 1 month relative risk 6.6, p less than 0.001), but, in the survivors, medium-term outcome was improved (greater than 6 months, 0.68, p less than 0.05). This effect was most marked for those undergoing a systemic-pulmonary artery shunt (less than 1 month, 2.52; greater than 6 months, 0.43); by contrast, after banding of the pulmonary trunk, with or without additional repair of the aortic arch repair, medium-term risk was not altered (greater than 6 months, 1.13 and 0.91, respectively). These data will assist the clinician in making decisions concerning the management of infants with double-inlet ventricle and in the judicious use of palliative surgery.

Double-inlet ventricle presenting in infancy. III. Outcome and potential for definitive repair

The fate of 191 infants with double-inlet ventricle was studied to determine the influence of morphologic characteristics at presentation and subsequent management on the potential for, and timing of, definitive repair by the Fontan operation or ventricular septation. At presentation, 136 patients (71%) were potential candidates for a Fontan procedure. Actuarial survival was better than for those deemed unsuitable for either definitive option (n = 55; 68% versus 28% at 1 year; p less than 0.001), but still, only 78 patients (57%) were known to be alive and suitable candidates at 2 years of age. This was largely due to death after presentation with low cardiac output (n = 19) and at palliative operation (20 of 98 surgically treated patients). The adverse events of late sudden death (n = 14) and the development of new features precluding a Fontan operation (n = 18) mostly occurred before 4 years of age (n = 22). Patients requiring no operation and those who underwent a systemic-pulmonary arterial shunt fared better than those who underwent isolated banding of the pulmonary trunk (9/13 and 25/42 alive and suitable versus 14/33; p less than 0.05), and than those who required aortic arch repair together with banding (1/12; p less than 0.01), because of the development of subaortic stenosis in the latter group. In contrast, only 43 patients (23% of all 191 patients) had morphologic features that were additionally compatible with future ventricular septation. Actuarial survival free of adverse events for these 43 patients was similar to that of the 136 patients considered suitable for a Fontan operation. Thus management in infancy must be aimed at maintaining potential for a future Fontan operation, which itself should not be delayed, for most patients, beyond 3 years of age, because of the prevalence of adverse events with increasing age.

Double-inlet ventricle presenting in infancy. I. Survival without definitive repair

Survival before definitive operations was studied in 191 infants with double-inlet ventricle presenting before 1 year of age (1973 to 1988, median follow-up 8.5 years). The morphologic spectrum was broad, with a great prevalence of associated lesions. The actuarial survival rate before definitive repair was 57% at 1 year, 43% at 5 years, and 42% at 10 years, worse than prior reports because of the younger age at entry into our series. Analysis of univariate risk factors established that right atrial isomerism (18% of the group, relative risk 2.9), common atrioventricular orifice (42%, 2.0), pulmonary atresia (20%, 3.4), obstruction of the systemic outflow tract (18%, 2.5), and extracardiac anomalous pulmonary venous connection (13%, 3.1) were strongly associated with poorer survival. Pulmonary stenosis (40%, 0.35), balanced pulmonary blood flow (9%, 0.40), and presentation at an older age (3%, 0.42 to 0.18) were beneficial (p less than 0.05 to 0.0001). Multivariate analysis allowed the creation of patient-specific curves for prediction of survival for different anatomic and physiologic variants of double-inlet ventricle. A simple additive index was then derived from the multivariate Cox coefficients to enable stratification of risk for these morphologic subgroups of patients and so assist in the making of clinical decisions in infancy.

Evaluation of a diagnostic algorithm for heart disease in neonates

OBJECTIVE

To develop, test, and validate an algorithm for diagnosing disease in neonates during an over the telephone referral to a specialist cardiac centre.

DESIGN

A draft algorithm requiring only data available to a referring paediatrician was generated. This was modified in the light of a retrospective review of case records. A questionnaire to elicit all the data required by the algorithm was then generated. There followed a prospective three phase evaluation during consecutive over the telephone referrals. This consisted of (a) a conventional phase with unstructured referral consultations, (b) a phase with referrals structured around the questionnaire but independent of the algorithm, and (c) a validation phase with the algorithm (and its previous errors) available during the referral consultation.

SETTING

59 paediatric centres in south east England and a central specialist paediatric cardiology unit.

PATIENTS

Consecutive neonates (aged less than 31 days) referred with suspected heart disease. The retrospective review was of records of 174 neonates from 1979. In the prospective evaluation (1987-90) the conventional phase comprised 71 neonates (over 5.5 months), the structured phase 203 neonates (over 14 months), and the validation phase 195 neonates (over 12 months).

MAIN OUTCOME MEASURES

Diagnostic accuracy (assigning patients to the correct diagnostic category (out of 27)), of the referring paediatrician, the specialist after the referral consultation, and the algorithm as compared with the definitive diagnosis by echocardiography at the specialist centre, and score for the appropriateness of management in transit.

RESULTS

Simply structuring the consultation by questionnaire (that is, proceeding from the conventional phase to the structured phase) improved the diagnostic accuracy of both paediatricians (from 34% (24/71 cases) to 48% (97/203) correct) and specialists (from 54% (38/71 cases) to 64% (130/203) correct). The algorithm (structured phase) would have been even more accurate (78% (158/203 cases); p less than 0.01). Management scores in the structured phase were also better than in the conventional phase (80%(162/203 cases)v 58% (41/71) appropriate; p less than 0.01). Management scores would have improved to 91% appropriate (185/203; p less than 0.001) had the algorithmic diagnoses dictated management. The superiority of the algorithm was maintained but not bettered in the validation phase.

CONCLUSIONS

Applying the algorithm should reduce the morbidity and mortality of neonates with critical heart disease by aiding clinicians in therapeutic decisions for in transit care.

Is banding of the pulmonary trunk obsolete for infants with tricuspid atresia and double inlet ventricle with a discordant ventriculoarterial connection? Role of aortic arch obstruction and subaortic stenosis

Banding the pulmonary trunk may exacerbate or promote the development of subaortic stenosis in patients with double inlet ventricle or tricuspid atresia with a dominant left ventricle and discordant ventriculoarterial connection and, therefore, may be an inappropriate palliative procedure for such patients. To examine this possibility, 102 consecutive infants were studied who presented with this anatomy between 1972 and 1987. Obstruction of the aortic arch was present in 52 patients. In 28 patients (17 with aortic arch obstruction), subaortic stenosis was already apparent at presentation. Of the remaining 74 patients, 19 received no palliative surgery and 55 underwent banding of the pulmonary trunk either with (n = 22) or without (n = 33) aortic arch repair. Outcome was significantly worse in patients with associated aortic arch obstruction. All such patients either died or developed subaortic stenosis by 3 years of age (survival free of subaortic stenosis 0 of 22 versus 22 of 33 for patients with isolated banding of the pulmonary trunk, p less than 0.001). After isolated banding, there was a lower ratio of the ventricular septal defect to ascending aorta diameters at presentation in the patients who developed subaortic stenosis than in the patients who did not (0.60 +/- 0.08 versus 1.03 +/- 0.15, p less than 0.001). Of the latter, 18 (95%) of 19 patients fulfilled criteria for a Fontan procedure at recatheterization. Thus, the presence of aortic arch obstruction is associated with rapid development of subaortic stenosis after banding of the pulmonary trunk. Alternative initial surgery, even though high risk, may be indicated. In the absence of such obstruction, banding the pulmonary trunk can be performed at reasonable risk and, provided that the ventricular septal defect is of adequate size, satisfactorily prepares most patients for a later Fontan procedure.

Normal values for noninvasive estimation of left ventricular contractile state and afterload in children

The outcome and suitability for therapeutic interventions in children with congenital heart disease depend frequently on left ventricular function. Congenital heart disease is characterized by changes in loading conditions, making it difficult to assess ventricular contractility using conventional load-dependent indexes. Two-dimensional and M-mode echocardiography and arterial blood pressure were used to study left ventricular morphometrics and contractility in 44 normal children, aged 2 to 12 years. Left ventricular end-systolic and end-diastolic length, diameter, wall thickness, volume and mass all showed linear increases with body surface area (p less than 0.001 in all). Shortening and ejection fractions, velocity of circumferential fiber shortening, morphometric ratios and endocardial meridional and circumferential stress (mean 46 and 115 g/cm2, respectively) all remained constant. A load-independent measure of the normal resting left ventricular contractile state was determined by relating the rate-corrected velocity of circumferential fiber shortening to end-systolic endocardial meridional and circumferential stress; there was an inverse linear correlation (r = -0.641 and -0.557 respectively, p less than 0.001). These data provide a quantitative basis for assessment of myocardial hypertrophy, afterload and contractile state in childhood.

Impact of Fontan operation on left ventricular size and contractility in tricuspid atresia

Left ventricular dimensions and contractility were determined by echocardiography in 33 patients with tricuspid atresia in 1985 and again in 1988. Eight patients remained palliated throughout the 3-year period; neither the left ventricular end-diastolic diameter (153 +/- 15% of normal vs. 157 +/- 19%, p = NS) nor a load-independent index of contractility (rate-corrected velocity of shortening [VCFc]/end-systolic meridional stress [ESSM]) changed. Eleven patients underwent a Fontan operation during the study and were reevaluated at least 6 months after surgery; left ventricular dimension decreased (130 +/- 15% vs. 114 +/- 19%, p less than 0.001), and the contractility index VCFc/ESSM improved (p less than 0.05). Fourteen patients had undergone a Fontan operation 0.9-9.5 years (mean, 4.2 years) before initial examination in 1985. Over the 3-year period, left ventricular dimensions did not change (121 +/- 17% vs. 118 +/- 11%, p = NS), but the contractility index showed significant improvement (p less than 0.01). Eight additional patients were studied just before and after a Fontan operation to examine the early effects of surgery. Left ventricular dimensions decreased from 130 +/- 14% to 100 +/- 13% by 10 days p less than 0.001) with no further change at 2 months. An inappropriate degree of ventricular hypertrophy was observed in only the early postoperative period. Successful Fontan repair results in rapid reduction of left ventricular size, followed by regression of hypertrophy to a normal mass-to-volume ratio. Operating at more favorable dimensions and loading conditions results in an early increase in left ventricular contractility, which further improves in the medium term follow-up.

Combining clinical judgement and statistical data in expert systems: over-the-telephone management decisions for critical congenital heart disease in the first month of life

When a new-born baby with congenital heart disease is referred to a regional specialist centre, the transportation management is crucial but must be decided on the basis of clinical information obtained over the telephone. We consider algorithmic and naive statistical approaches to helping in this decision, and on the basis of preliminary results the relative strengths and weaknesses are discussed. A synthesised logical and probabilistic approach appears to have the best potential and could be implemented on hand-held computers.

Arrhythmia and prognosis in infants, children and adolescents with hypertrophic cardiomyopathy

In adults with hypertrophic cardiomyopathy, the annual mortality rate from sudden death is 2 to 3%, and the finding of nonsustained ventricular tachycardia during electrocardiographic (ECG) monitoring provides a marker of the patient who is at increased risk. In the young, the annual mortality rate from sudden death is even higher, approximately 6%, but the prognostic significance of arrhythmia is unknown. To determine the prevalence of arrhythmia and its relation to prognosis, 2 days of ECG monitoring was performed in 6 infants, 14 children and 33 adolescents with hypertrophic cardiomyopathy receiving no cardioactive medications. An additional 1 to 9 days (median 2) of monitoring was performed in 29 patients. All patients had sinus rhythm; 4 adolescents had episodes of paroxysmal supraventricular tachycardia, a child with the Wolff-Parkinson-White syndrome had symptomatic reentrant atrioventricular tachycardia and 5 adolescents had asymptomatic nonsustained ventricular tachycardia. During follow-up of 1 week to 7 years (median 3 years), five patients died suddenly and two had successful resuscitation from out-of-hospital ventricular fibrillation; none of these seven patients had ventricular arrhythmias during 2 to 7 days (median 3) of ECG monitoring. The two patients with ventricular fibrillation, the five with ventricular tachycardia, the one with Wolff-Parkinson-White syndrome and the seven with recurrent syncope or adverse family history, or both, received low dose amiodarone. None of these "high risk" patients died during 6 months to 6 years (median 3 years) of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Left-ventricular cavity dimensions in children with normal and dilated hearts

Studies were carried out to find how left-ventricular length and length/diameter ratio relate to body size and degree of dilation. By use of M-mode and two-dimensional echocardiography, diastolic cavity long axis (Led), diastolic cavity diameter (Ded), systolic cavity long axis (Les), systolic cavity diameter (Des), fractional L shortening (SFL), and fractional D shortening (SFD) were measured in children, adolescents, and young adults between two and 23 years of age, with body-surface area (BSA) between 0.5 and 2.1 m2 and with a variety of volume loads and SFD values. In normal subjects, Led/Ded was about 1.9. Regardless of age and pathology (in this age range), Led correlated consistently with BSA (Led = 3.9 + 3.2 BSA), indicating that the long axis changes rather little with pathological dilation. A plot of Led/Ded vs BSA/D2ed (in m2/cm2) formed a straight-line relation: Led/Ded = 0.77 + 16.4 BSA/D2ed. Similar relations were found for end-systolic dimensions. End-systolic L/D ratio exceeded end-diastolic L/D ratio to a degree that depended on both end-diastolic L/D ratio and SFD:Les/Des = Led/Ded + (0.22 + 2.67 Led/Ded)(SFD)2. Relations like these may be useful in the interpretation of echocardiographic images. The results suggest that left-ventricular L/D ratio may be influenced by myocardial anisotropy (dominance of hoop over meridional fiber orientation tending to promote prolate shape especially during systole) and external factors that antagonize extension of the long axis.

Left ventricular wall stress and contractile function in transposition of the great arteries after the Rastelli operation

Left ventricular wall stress and contractile function were determined by echocardiographic methods in 11 patients studied 0.7 to 13.8 years (mean +/- standard error of the mean = 5.6 +/- 1.2 years) after undergoing the Rastelli operation for transposition of the great arteries associated with ventricular septal defect and left ventricular outflow tract obstruction. Age at operation ranged from 4.6 to 11.3 years (mean +/- standard error of the mean = 7.4 +/- 0.7 years). Data were compared with data of 24 normal subjects of similar age and heart rate. Left ventricular end-diastolic dimension and end-diastolic volume were significantly higher than normal, averaging 134% +/- 8% of normal dimension (p less than 0.004) and 106 +/- 13 ml/m2 versus a normal volume of 60 +/- 3 ml/m2) (p less than 0.007). In addition left ventricular wall mass was 215 +/- 40 gm/m2 versus a normal value of 72 + 6 gm/m2 (p less than 0.004). Both meridional and circumferential end-systolic and peak systolic stress values were not significantly different between normal subjects and Rastelli patients. Estimates of ventricular pump function including shortening fraction, rate-corrected velocity of circumferential fiber shortening, and ejection fraction were all depressed when compared with normal values. Velocity of fiber shortening, evaluated as a function of end-systolic stress, demonstrated abnormal contractile function in eight of 11 (73%) patients. These data indicate that left ventricular function is usually abnormal and residual left ventricular dilation and wall hypertrophy remain despite successful use of the Rastelli operation for repair in patients with transposition of the great arteries, ventricular septal defect, and left ventricular outflow tract obstruction.

Left ventricular wall stress and contractile function in childhood: normal values and comparison of Fontan repair versus palliation only in patients with tricuspid atresia

Left ventricular wall stress and contractile function were determined by echocardiographic methods in 23 patients with tricuspid atresia after palliation only (group 1), in 19 patients after Fontan repair (group 2), and in 24 age-matched normal subjects. End-diastolic dimension was increased above normal in both groups with tricuspid atresia (group 1 [mean +/- SEM] 141 +/- 4%, group 2 129 +/- 5% of normal; both p less than .001) but were not different from each other. Left ventricular end-diastolic volume and wall mass also were increased above normal in both groups (group 1, 126 +/- 9 ml/m2 and 194 +/- 19 g/m2, respectively, p less than .001 and p less than .004; group 2, 80 +/- 7 ml/m2 and 128 +/- 10 g/m2, p less than .02 and p less than .001), and group 2 patients showed significantly lower values than group 1 patients (p less than .001 and p less than .004). Meridional end-systolic stress was increased above normal in both groups with tricuspid atresia but was not different between groups (normal, 43 +/- 3 g/cm2; group 1, 56 +/- 54 g/cm2, p less than .02; group 2, 59 +/- 7 g/cm2, p less than .001). Contractile function estimated by rate-corrected circumferential fiber shortening velocity was abnormal in nine of 23 (39%) group 1 patients and in five of 19 (26%) group 2 patients (percentages not different from each other by nonparametric testing). Contractile function was depressed in one of 11 group 1 patients under 5 years old and in eight of 12 over 5.3 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal thyroid function: prematurity, prenatal steroids, and respiratory distress syndrome

Indices of thyroid function were measured in 97 preterm infants at birth and at 5, 10, and 15 days of age. Triiodothyronine uptake, free thyroxine index, thyroxine, free thyroxine, triiodothyronine, reverse triiodothyronine, and thyroxine binding globulin values at birth correlated with gestational age, whereas thyroid stimulating hormone values did not. Treatment with steroids prenatally had no apparent effect on thyroid function at birth or postnatally. Infants developing respiratory distress syndrome had normal values for all indices at birth. These infants had significantly lower thyroxine, free thyroxine index, free thyroxine, and triiodothyronine values at 5 days of age, while thyroid stimulating hormone values remained normal. This alteration in thyroid function was interpreted as being secondary to respiratory distress syndrome. Gestational maturity and respiratory distress syndrome, if present, must be taken into account when evaluating thyroxine variables in preterm infants, whereas measurement of thyroid stimulating hormone as the screen for congenital hypothyroidism circumvents these considerations.

Neonatal thyroid function: influence of perinatal factors

Indices of thyroid function were measured in 229 healthy term neonates at birth and at 5, 10, and 15 days of age. Results were analysed to assess whether maternal diabetes mellitus, toxaemia of pregnancy, intrapartum fetal distress, duration of labour, method of delivery, asphyxia at birth, race, sex, birthweight, birth length, head circumference, or method of feeding influenced any index. Thyroxine, the free thyroxine index, and free thyroxine concentrations at birth correlated with birthweight. Method of delivery influenced mean thyroxine and free thyroxine index values at birth and at age 5 days. Mean values of triiodothyronine, reverse triiodothyronine, thyroxine binding globulin, and thyroid stimulating hormone were not affected by any of the perinatal factors studied. Birthweight and perhaps method of delivery should be taken into account when interpreting neonatal thyroxine parameters but determination of thyroid stimulating hormone as a screen for congenital hypothyroidism in healthy term neonates circumvents these considerations.

Thyroid hormone concentrations and free thyroxine status in neonatal venous and capillary serum pairs

The levels of thyroid hormones in paired venous and capillary serum samples taken from 68 healthy full-term neonates were determined by radioimmunoassay. Compared with capillary values, total thyroxine (T4), thyrotropin (TSH) and thyroxine-binding globulin (TBG) each showed a significant decrease in venous serum. The mean venous and capillary concentrations of tri-iodothyronine (T3), reverse tri-iodothyronine (rT3) and free thyroxine (fT4) were not significantly different; however, in each case the fitted linear relationship suggested that venous and capillary values were not concordant (P less than 0.02, P less than 0.01, P less than 0.05 respectively). Both the T3 uptake test and the free thyroxine index (FTI) were significantly higher in venous serum, while the ratios of T4 to TBG in paired samples were equivalent. These results suggest that consistent sample collection and assay methods should be applied when assessing neonatal thyroid status, particularly if comparison of results is intended.

Cleft palate and gonadotrophin deficiency

A boy who had previously had a cleft lip and palate repaired and bilateral orchiopexies presented at 16 years of age with delayed puberty. Isolated gonadotrophin deficiency and testicular hyporesponsiveness to human chorionic gonadotrophin were found. The possibility of bilateral cryptorchidism due to gonadotrophin deficiency should be considered in boys with either cleft lip or palate, or both.

Endocrine influences on serum acid-ethanol soluble non-suppressible in insulin-like activity (NSILA-S)

Serum levels of the acid-ethanol soluble component of non-suppressible insulin-like activity (NSILA-S) have been measured by bioassay in patient with hyperprolactinaemia, hypothyroidism, thyrotoxicosis and diabetes mellitus, and in normal subjects administered prednisone, oestrogens of androgens. Hyperprolactinaemia per se did not influence serum NSILA-S, however when GH was deficient prolactin hypersecretion may have maintained serum NSILA-S. Thyroid hormones, insulin and steroids did not appear to influence serum NSILA-S. These results suggest that regulation of the serum concentration of NSILA-S is not a common effector mechanism by which these hormones influence statural growth in man.

The occurrence of a distinct high molecular weight form of serum non-suppressible insulin-like activity

Gel filtration of acromegalic or normal serum at acid pH gave two distinct species of non-suppressible insulin-like activity (NSILA), one of high MW and the other of low MW (approximately 7000 daltons). The acid-stable high MW form remained high MW on rechromatography in acid. Gel filtration of serum at neutral pH however, gave only high MW activity, which remained high MW when rechromatographed under neutral conditions but split into both high and low MW forms when rechromatographed in acid. These results indicate that there are at least two circulating forms of NSILA--a low MW form which circulates in serum bound to a carrier protein in an acid-labile high MW complex and a species which circulates only as a stable, discrete high MW protein.

Serum levels of the acid-ethanol soluble component of non-suppressible insulin-like activity in untreated and treated streptozotocin-diabetic rats

Streptozotocin-diabetic rats suffered growth failure and had reduced serum levels of the acid--ethanol soluble component of non-suppressible insulin-like activity (NSILA-S) compared with normal rats. Chronic insulin substitution (6 weeks) resulted in a normalization of serum levels of NSILA-S; this was accompanied by a normal increase in weight. Insulin therapy for 3 days resulted in a partial recovery of serum levels of NSILA-S and a slight but significant accompanying gain in weight. Short-term administration of GH also resulted in a partial recovery of the serum level of NSILA-S, in spite of continued uncontrolled diabetes. These results demonstrate that, in the rat, insulin as well as GH contributes to the regulation of serum levels of NSILA-S.

Acid-ethanol-extractable nonsuppressible insulin-like activity (NSILA-S) during pregnancy and the puererium, and in cord serum at term

A longitudinal study of serum NSILA-S during normal human pregnancy and the puerperium has demonstrated that levels rose progressively during pregnancy and returned to nonpregnant values about 48 h after delivery. Low concentrations were defined within the feto-placental circulation at term. Cord arterial and venous levels were equivalent, but there was no significant correlation between these and matched maternal values.

Changes in NSILA-S in response to somatotropin administration and hypophysectomy

The effects on the serum levels of NSILA-S of the administration of human GH (hGH) or of hypophysectomy have been studied. hGH given im (5 mg daily for 3 days) raised the NSILA-S levels of three GH-deficient subjects into the normal range. Significant elevations of NSILA-S were also seen in three normal subjects given im GH. In the same groups of three normal and three GH-deficient subjects, 5 mg hGH administered iv induced an elevation of NSILA-S within 15-60 min. Hypophysectomy in three acromegalics and one subject with a chromophobe adenoma was followed by significant falls of serum NSILA-S. These studies provide further evidence of the dependence of NSILA-S levels on GH.

A bioassay for NSILA-S in individual serum samples and its relationship to somatotropin

A practical bioassay for the acid-ethanol soluble non-suppressible insulin-like activity (NSILA-S) of individual serum samples has been developed utilizing the incorporation of 14C-glucose into the lipid faction of isolated adipocytes. NSILA-S activity was correlated with somatotropin status. Thus, the mean potencies (+/-SD) relative to an extract of pooled normal human serum were: normal samples 1.11 +/- 0.14, acromegalic 2.91 +/- 0.72, and somatotropin deficient 0.13 +/- 0.06. This variation in NSILA-S was not due to variability in extraction recoveries. The within assay precision was 9% (coefficient of variation) and the between assay 23%. This method allows the simultaneous extraction and processing of relatively large numbers of samples, and compares favorably with other more complex methods. Because of the evidence that NSILA-S may be related to the somatomedins, the present method should provide a simpler and more reliable alternative to the cartilage bioassays used to measure somatomedin activity.