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Biomedical subjects

C Wren

Publications and source records attributed to C Wren.

At least 19 recordsLinked to original sources

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.

Anti-Arrhythmia Agents

Antenatal diagnosis of congenital heart disease and Down's syndrome: the potential effect on the practice of paediatric cardiology.

OBJECTIVE: To predict the effect of antenatal ultrasound screening for congenital heart disease and maternal serum screening of Down's syndrome on the practice of paediatric cardiology and paediatric cardiac surgery. DESIGN: A retrospective and prospective ascertainment of all congenital heart disease diagnosed in infancy in 1985-1991. SETTING: One English health region. PATIENTS: All congenital heart disease diagnosed in infancy by echocardiography, cardiac catheterisation, surgery, or necropsy was classified as "complex", "significant", or "minor" and as "detectable" or "not detectable" on a routine antenatal ultrasound scan. RESULTS: 1347 infants had congenital heart disease which was "complex" in 13%, "significant" in 55%, and "minor" in 32%. 15% of cases were "detectable" on routine antenatal ultrasound. Assuming 20% detection and termination of 67% of affected pregnancies, liveborn congenital heart disease would be reduced by 2%, infant mortality from congenital heart disease by 5%, and paediatric cardiac surgical activity by 3%. Maternal screening for Down's syndrome, assuming 75% uptake, 60% detection, and termination of all affected pregnancies, would reduce liveborn cases of Down's syndrome by 45%, liveborn cases of congenital heart disease by 3.5%, and cardiac surgery by 2.6%. CONCLUSIONS: Screening for congenital heart disease using the four chamber view in routine obstetric examinations and maternal serum screening for Down's syndrome is likely to have only a small effect on the requirements for paediatric cardiology services and paediatric cardiac surgery.

Cardiac Surgical Procedures

Differences in amiodarone, digoxin, flecainide and sotalol concentrations between antemortem serum and femoral postmortem blood.

1. The concentrations of amiodarone/desethylamiodarone, digoxin, flecainide and sotalol were measured in serum collected immediately prior to death and in postmortem blood collected from the femoral vein and artery of an 18-year-old male with congenital heart disease who developed a fatal arrhythmia. 2. The concentrations of all four drugs in the sample collected during life were consistent with the dosage given and in the range accepted for normal therapy. 3. There were no differences in amiodarone/desethylamiodarone, flecainide and sotalol concentrations in arterial or venous postmortem blood. 4. The concentrations of desethylamiodarone, digoxin, flecainide and sotalol but not amiodarone, were higher in postmortem blood than in antemortem serum. The flecainide concentration was significantly greater than the upper limit associated with toxicity in life. Without knowledge of the true concentration measured in life, this apparently high, toxic concentration would have suggested that death could have resulted from arrhythmogenic/proarrhythmic effects of the drug in excess. 5. These results further demonstrate the hazards in interpreting postmortem blood concentrations following suspected drug intoxication.

Adolescent

Death in infancy from unrecognised congenital heart disease.

This study was undertaken to identify all congenital heart disease in infancy, including deaths before diagnosis, to provide a truer picture of the spectrum of congenital heart disease and to assess the 'treatability' of those dying before diagnosis. All births, infant deaths, and surviving babies with congenital heart disease in one health region in 1985-90 were identified and were classified as 'complex', 'significant', or 'minor'. Of the 1074 infants diagnosed in infancy, 185 died and 56 of these (30%) died undiagnosed. Severe non-cardiac malformations were present in 29 of the 56 while 27 were otherwise normal. Cardiovascular abnormalities in the latter group were complex in 13/27 and significant in 14/27. Identification of undiagnosed cardiovascular anomalies will improve epidemiological evaluation of congenital heart disease and, more importantly, earlier recognition of treatable abnormalities may reduce mortality.

Abnormalities, Multiple

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.

Aorta, Thoracic

End-on aortogram: improved identification of important coronary artery anomalies in tetralogy of Fallot.

OBJECTIVE: To identify coronary artery anomalies in patients with tetralogy of Fallot with an aortogram taken with steep caudal and left oblique angulation ("end-on" aortogram). DESIGN: Prospective evaluation of end-on aortogram in the preoperative angiographic assessment of consecutive patients with tetralogy of Fallot. SETTING: Regional paediatric cardiology centre. PATIENTS: 34 patients, aged 3 months to 12 years (median age 9 months). METHODS: An aortogram was performed with steep caudal (38 degrees-45 degrees) and left oblique (0 degrees-30 degrees) angulation under general anaesthetic as part of routine preoperative angiographic assessment. RESULTS: The origins and courses of the coronary arteries were visualised in all patients and important coronary artery anomalies were identified in four patients: single left coronary artery; single right coronary artery (two patients); separate high origin of left anterior descending. These anomalous coronary vessels crossed the right ventricular outflow tract. CONCLUSIONS: It is important to identify preoperatively coronary arteries that may interfere with right ventricular outflow tract reconstruction. An aortogram with steep caudal and left oblique angulation is useful in identifying anomalous coronary arteries and more importantly it defines the relation of these vessels to the right ventricular outflow tract.

Aortography

Ondine's curse and neurally mediated syncope--a new and important association.

A 6-year-old boy with congenital central hypoventilation syndrome (Ondine's curse) presented with presyncope. Investigation revealed a diagnosis of neurally mediated syncope. This previously unreported association provides strong evidence that autonomic dysfunction is implicated in both these conditions.

Autonomic Nervous System

Endocardial pacemakers in children: lead length and allowance for growth.

Permanent endocardial pacing in small children is feasible but is limited by two problems: sufficient extra lead has to be left within the heart to allow for growth and the excess has to be coiled behind the pacemaker, limiting the benefit from smaller generators. The required intravascular lead length in 120 children and adults was measured on posteroanterior chest X ray and was correlated with standing height. Measurements were made from the mid-point of the left clavicle to the apex of the right ventricle in a curve simulating the usual endocardial lead position. In 60 children, aged 2.0-15.9 years, intravascular lead length (range 15.5-29.0 cm) correlated well with height (0.83-1.70 m), r = 0.91. In 60 adults, mean age 54.9 years, intravascular lead length (25.5-35.6 cm) also correlated well with height (1.45-1.85 m), r = 0.71. In 20 adults the excess extravascular lead length, measured during pacemaker implantation via the subclavian route, was 15.1-33.7 cm and was inversely correlated with height. A child's eventual adult height can be predicted and, using our data, the extra length of lead necessary to allow for growth can be computed. Available endocardial pacing leads are usually 58- to 64-cm long. The excess extravascular lead is a major practical difficulty in children. Shorter leads would avoid the problem of excess lead and facilitate long-term pacing in small children.

Adolescent

Cardiac abnormalities in end stage renal failure and anaemia.

Thirteen anaemic children on dialysis were assessed to determine the incidence of cardiac changes in end stage renal failure. Nine children had an increased cardiothoracic ratio on radiography. The electrocardiogram was abnormal in every case but no child had left ventricular hypertrophy as assessed by voltage criteria. However, left ventricular hypertrophy, often gross, was found on echocardiography in 12 children and affected the interventricular septum disproportionately. Cardiac index was increased in 10 patients as a result of an increased left ventricular stroke volume rather than heart rate. Left ventricular hypertrophy was significantly greater in those on treatment for hypertension and in those with the highest cardiac index. Abnormal diastolic ventricular function was found in 6/11 children. Children with end stage renal failure have significant cardiac abnormalities that are likely to contribute to the high cardiovascular mortality in this group. Anaemia and hypertension, or its treatment, probably contribute to these changes. Voltage criteria on electrocardiogram are of no value in detecting left ventricular hypertrophy. Echocardiography must be performed, with the results corrected for age and surface area, in order to detect and follow these abnormalities.

Adolescent

Ambulatory blood pressure monitoring.

Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.

Adolescent

Stenting of the arterial duct combined with banding of the pulmonary arteries and atrial septectomy or septostomy: a new approach to palliation for the hypoplastic left heart syndrome.

OBJECTIVE: To assess the feasibility of pulmonary artery banding, atrial septectomy or septostomy, and percutaneous stenting of the arterial duct in babies with the hypoplastic left heart syndrome. PATIENTS: Four infants with hypoplastic left heart syndrome. SETTING: Two supraregional paediatric cardiac centres. METHODS: Ductal patency was maintained initially with prostaglandin E. Banding of the proximal branch pulmonary arteries was performed through a median sternotomy and open atrial septectomy was performed if balloon septostomy was not. Stainless steel stents (Johnson & Johnson) mounted in a balloon catheter were implanted into the arterial duct under radiographic control and expanded to a diameter of approximately 8 mm, prostaglandin treatment was then stopped. RESULTS: All the patients survived the immediate postoperative period and maintenance of wide ductal patency was achieved in three of the four patients by stent implantation. Two weeks after the procedure two babies died of right ventricular failure and respiratory infection: some distal ductal constriction had occurred in one where the stent was not quite sufficiently distally placed. One child was discharged home 15 days after treatment and was well at follow up at age 16 weeks and one was stable but required diuretic therapy five weeks after the procedure. CONCLUSIONS: This new approach is technically feasible. At least in the short term it seems to offer hope of effective palliation for the hypoplastic left heart syndrome and it warrants further study.

Cardiac Catheterization

Endocarditis with acute mitral regurgitation caused by Fusobacterium necrophorum.

Infective endocarditis is uncommon in young children, especially in the absence of structural heart disease. We report the case of a 2-year-old boy who presented with acute rupture of the mitral valve chordae 6 weeks after an episode of Fusobacterium necrophorum septicemia. His heart had been structurally normal before. Mitral valve replacement was successfully performed. This is the first recorded case of endocarditis in a child caused by necrobacillosis.

Bacteremia

Atrial flutter in the fetus and young infant: an association with accessory connections.

OBJECTIVE: To highlight the association between atrial flutter and accessory connections in the fetus and young infant. DESIGN: A retrospective review from January 1985 to January 1990. PATIENTS: Fetuses, neonates, and young infants with atrial flutter. RESULTS: Four fetuses and five infants presented with atrial flutter. In two fetuses and one infant sinus rhythm returned spontaneously. The other six required cardioversion. Three of them developed orthodromic atrioventricular re-entry tachycardia and each had evidence of an accessory connection. CONCLUSIONS: Because atrial flutter in the fetus and neonate is rare, the high incidence of accessory connections in this group points to a possible aetiology of "idiopathic" atrial flutter in this age group.

Atrial Flutter