Transposition of the great arteries, interrupted inferior vena cava and intestinal atresia: a new association?

We present a neonate with transposition of the great arteries, ventricular septal defect, inferior vena caval interruption with azygous continuation and intestinal atresia. This concurrence of anomalies has not been previously reported.

Mutations in cardiac T-box factor gene TBX20 are associated with diverse cardiac pathologies, including defects of septation and valvulogenesis and cardiomyopathy

The T-box family transcription factor gene TBX20 acts in a conserved regulatory network, guiding heart formation and patterning in diverse species. Mouse Tbx20 is expressed in cardiac progenitor cells, differentiating cardiomyocytes, and developing valvular tissue, and its deletion or RNA interference-mediated knockdown is catastrophic for heart development. TBX20 interacts physically, functionally, and genetically with other cardiac transcription factors, including NKX2-5, GATA4, and TBX5, mutations of which cause congenital heart disease (CHD). Here, we report nonsense (Q195X) and missense (I152M) germline mutations within the T-box DNA-binding domain of human TBX20 that were associated with a family history of CHD and a complex spectrum of developmental anomalies, including defects in septation, chamber growth, and valvulogenesis. Biophysical characterization of wild-type and mutant proteins indicated how the missense mutation disrupts the structure and function of the TBX20 T-box. Dilated cardiomyopathy was a feature of the TBX20 mutant phenotype in humans and mice, suggesting that mutations in developmental transcription factors can provide a sensitized template for adult-onset heart disease. Our findings are the first to link TBX20 mutations to human pathology. They provide insights into how mutation of different genes in an interactive regulatory circuit lead to diverse clinical phenotypes, with implications for diagnosis, genetic screening, and patient follow-up.

Outcomes following surgery for congenital heart disease in low-birthweight infants

AIM

To describe cardiac surgery, survival and outcomes for low-birthweight (< or = 2500 g) infants undergoing surgery for congenital heart disease.

METHODS

Using data from a prospectively collected population-based database of admissions to neonatal intensive care units in New South Wales and the Australian Capital Territory, we identified all low-birthweight infants undergoing cardiac surgery between 1992 and 2001. Infants with only a persistent ductus arteriosus were excluded. Two-year cardiac and neurodevelopmental outcome data were sought from hospital medical records.

RESULTS

A total of 121 low-birthweight infants underwent cardiac surgery, of whom 34% had a congenital syndrome or non-cardiac birth defect. Most (81%) underwent a palliative surgical procedure in the neonatal period. There were 19 early (15.7%) and 19 late deaths giving a 2-year mortality of 31%. Factors associated with mortality included birthweight below 1500 g (P = 0.006), low weight at surgery (P = 0.028) and Apgar score at 1 min (P = 0.019). No single factor predicted 30-day mortality. By 2 years of age, 27 (33% of survivors) were known to have neurodevelopmental delay. Although 22 children are known to be developing normally, the neurodevelopmental status of 34 children was not known.

CONCLUSIONS

These surgical data were comparable to previous single-institution studies. This group had a high risk of disability due to prematurity, low birthweight and associated conditions. There is a need to prospectively assess and manage neurodevelopmental outcomes in this group.

Contrast echocardiography: potential for the in-vivo study of pediatric myocardial preservation

BACKGROUND

Myocardial contrast echocardiography (MCE) has been used successfully during adult cardiac surgery to image myocardial perfusion. Recently it has been suggested this technique is capable of detecting microvascular injury and inflammation because sonicated albumin microbubbles adhere to activated neutrophils and, in the presence of denuded or inflamed endothelium, they persist within the microvasculature rather than passing unimpeded, which results in profound slowing of their transit rates. The technique has not previously been used during congenital heart surgery; however significant potential is suggested in this setting in which myocardial inflammation may contribute to postoperative myocardial dysfunction, a leading cause of morbidity and mortality. We have performed a preliminary study to assess the safety and feasibility of MCE in the pediatric intraoperative environment and to examine myocardial transit rates.

METHODS

Sonicated albumin microbubbles were injected with cardioplegia during bypass in 16 children (aged 3 weeks to 8.5 years). Images were collected using transesophageal echocardiography. Complications, post-bypass electrocardiographic, echocardiographic, and outcome data were recorded. Myocardial transit rates were calculated using videointensity analysis, assessed for reproducibility and correlated with demographic and intraoperative variables and postoperative outcome.

RESULTS

The technique was performed safely, with good reproducibility. Myocardial persistence of microbubbles, which occurred in 6 patients, was associated with crystalloid cardioplegia, prolonged preischemic bypass (r = 0.72, p = 0.004), or ischemic time (r = 0.69, p = 0.002).

CONCLUSIONS

Intraoperative MCE shows potential as an in vivo technique for the study of pediatric myocardial preservation.

Balloon dilatation of aortic stenosis in infants younger than 6 months of age: intermediate outcome

The objectives of this study were to review the outcome of balloon dilatation of critical/severe aortic valve stenosis in patients younger than 6 months of age, with particular emphasis on subdivisions of age at intervention, and to identify factors that might influence outcome. From 1988 to 1998, 42 patients underwent dilatation. Patients were divided into three groups (group 1: 1-7 days, n = 16; group 2: 8-30 days; n = 10; group 3: 1-6 months, n = 16). Medical records and echocardiograms were reviewed retrospectively for presentation, clinical course, and left ventricular, aortic valve, and Doppler flow parameters. Median follow-up was 53 months (range, 6 months to 10 years). Of 16 group 1 patients, 11 (70%) had, respiratory distress requiring ventilator support, 12 (80%) received prostaglandin, and 5 (30%) received inotropic support. Nine (56.2%) patients died and 7 (44%) required reintervention. Of 10 group 2 patients, 4 (40%) were ventilated, 2 (20%) received prostaglandin, and 3 (30%) received inotropic support. Three (30%) patients died and 5 (50%) required reintervention. Of 16 group 3 patients, only 1 had symptoms (respiratory distress) at presentation. One (6%) patient died and 4 (15%) required reintervention. The overall actuarial survival rate at 10 years was 72% (88% at 10 years for indexed aortic annulus > 25 mm/m2. Freedom from reintervention was 70% and 21% at 5 and 10 years, respectively (80 and 33% at 5 and 10 years, respectively, for indexed aortic annulus > 25 mm/m2). The actuarial survival rates at 10 years for groups 1, 2, and 3 were 42%, 65%, and 93%, respectively. Predictors of death included young age at presentation, and multivariate analysis of left heart measures yielded an 83% positive prediction of outcome. An improved chance of survival was associated with indexed aortic valve annulus > 25 mm/m2. Patients with critical aortic stenosis who require balloon dilatation within the first month of life, but especially within the first week, have a poorer outcome than those requiring the procedure later, and this can be accounted for by a tendency toward less favorable anatomical features. Many will require repeat intervention.

Gregg's congenital rubella patients 60 years later

BACKGROUND

In 1941, a Sydney ophthalmologist, Norman McAlister Gregg, correctly identified the link between congenital cataracts in infants and maternal rubella early in pregnancy. Fifty of Gregg's subjects with congenital rubella, born in 1939-1944, were reviewed in 1967 and again in 1991. We reviewed this cohort in 2000-2001, 60 years after their intrauterine infection.

METHODS

The subjects underwent full clinical assessment, plus pathology tests, an ophthalmological and cardiological review (including electrocardiography and echocardiography) and HLA histocompatibility testing.

RESULTS

Since they were first seen in 1967, 10 have died (cardiovascular causes [4], malignant disease [4], AIDS [1], and hepatitis C-related cirrhosis [1]). All surviving men came for review (19) and 13 women (eight women declined). Echocardiography showed mild aortic valve sclerosis in 68%. The prevalence of diabetes (22%), thyroid disorders (19%), early menopause (73%) and osteoporosis (12.5%) was increased compared with the Australian population; 41% had undetectable levels of rubella antibodies. The frequency of HLA-A1 (44%) and HLA-B8 (34%) antigens was increased, and the haplotype HLA-A1, B8, DR3, said to be highly associated with many autoimmune conditions, was present in 25%.

CONCLUSIONS

This cohort of people with congenital rubella has illuminated our understanding of viral teratogenesis.

Comparative analysis of pattern, management and outcome of pre- versus postnatally diagnosed major congenital heart disease: a population-based study

OBJECTIVES

Most pregnant women in New South Wales undergo obstetric ultrasound examination, including some assessment of fetal cardiac anatomy. We aimed to review the spectrum of cardiac defects, management and outcome data of all fetuses with diagnosis of major congenital heart disease between 1994 and 1996 and compare them to major congenital heart disease in infants born during the same 3-year study period.

METHODS

Descriptive comprehensive study of the New South Wales population. Study centers included the single fetal echocardiographic referral service and the two pediatric cardiac centers of New South Wales.

RESULTS

Ninety-seven fetuses and 562 infants with major congenital heart disease were identified (240,000 livebirths), resulting in a prenatal detection rate of 15%. Anomalies detectable by cardiac four-chamber views were diagnosed at an average rate of 30% (68/229) in utero. By contrast, lesions associated with abnormal ventricular outflow and great artery views were detected in only 6.7% (29/430; P < 0.0001) of cases prior to birth. Of the 97 fetuses, 29 were aborted, 16 died in utero, and 9 died early postnatally without treatment. Within 2 weeks of age, 23% with fetal and 40% (P < 0.05) with infant major congenital heart disease diagnosis required an intervention, mainly for patent ductus arteriosus dependent lesions. Postnatal survival was similar for the fetal and infant series up to 2 years of age: 77% (95% confidence interval 64-90%) vs. 85% (95% confidence interval 82-88%).

CONCLUSIONS

Prenatal diagnosis has important implications for pregnancy outcome, in particular for univentricular lesions. However, the present mode of obstetric routine ultrasound scanning fails to identify most ductus arteriosus dependent cardiac lesions with a predictable need for early postnatal intervention.

Three-dimensional quantitative echocardiographic assessment of ventricular volume in healthy human fetuses and in fetuses with congenital heart disease

The purpose of this study was to evaluate the feasibility of three-dimensional freehand echocardiographic assessment of ventricular volumetry in healthy fetuses and in fetuses with congenital heart disease. The study was approved by the hospital institutional review board. After echocardiographic examination by conventional ultrasonographic equipment interfaced with a magnetic tracking system, three-dimensional cardiac data were collected prospectively in 57 fetuses. Ventricular volumes were determined from three-dimensional data sets, and 22 fetuses with congenital heart disease were compared with 29 healthy fetuses. A multiple regression analysis of covariance was performed to assess between-group differences. Gated three-dimensional volume data sets enabled assessment of ventricular volumes in 51 of the 57 fetuses. Both fetuses with and without congenital heart disease had exponential increases in cardiac volumes during gestation. In fetuses with congenital heart disease and a marked inequality of ventricular size but no heart failure, the combined end-diastolic and stroke volumes of both ventricles were found to be significantly reduced compared with controls with no disease and fetuses with other types of congenital heart disease. Three-dimensional imaging can provide estimates of ventricular volume changes in fetal hearts with abnormal ventricular morphology that cannot easily be performed by two-dimensional echocardiography, and it may provide insight into evolving congenital heart disease.

Communicating hydrocephalus secondary to a cardiac tumour compressing the superior vena cava

An infant developing communicating hydrocephalus as a result of a rare cardiac tumour compressing the superior vena cava is reported. The development and regression of the hydrocephalus parallels the degree of obstruction to venous outflow. This finding is reviewed in the light of previous studies and case reports, and it is argued that the hydrocephalus is secondary to a reversible defect in cerebrospinal fluid absorption caused by the reversal of the normal cerebrospinal fluid to sagittal sinus pressure gradient.

Transesophageal echocardiographic guidance of blade atrial septostomy in children

Transesophageal echocardiography (TEE) was used to guide blade atrial septostomy in children requiring decompression of right or left atrium. In conjunction with biplane fluoroscopy, TEE was used to position the blade septostomy catheter and to monitor the pullback from left atrium to right atrium. Subsequent balloon dilatation of atrial septum was also carried out under TEE control. The use of TEE monitoring facilitated the procedure by providing optimal views of intracardiac structures while also limiting the total radiation exposure.

Simplified single patch technique for the repair of atrioventricular septal defect

OBJECTIVE

Because of the complexity of traditional 1- and 2-patch techniques for the repair of complete atrioventricular septal defect, we modified our repair technique to avoid the use of any ventricular septal patch material. We report our prospective experience with this simplified 1-patch technique.

METHOD

Forty-seven consecutive patients between May 1995 and August 1998 underwent repair with the use of this technique without modification. Repair was done in all patients by direct suturing of the common atrioventricular valve leaflets to the crest of the ventricular septum. No division of valve leaflets was necessary. A single pericardial patch was used to close the defect in the atrial septal component. Follow-up included electrocardiography and echocardiographic assessment of ventricular function, atrioventricular valve function, and adequacy of the left ventricular outflow tract.

RESULTS

There were 2 deaths (4%), only 1 cardiac related, in the series. There were 17 male patients and 30 female patients. Mean age at repair was 5.6 months (median, 3.4 months). Associated lesions were repaired in 19 patients (40%). Mean follow-up was 1.85 years (median, 1.9 years). There was no heart block. There were no significant residual ventricular septal defects detected and no left ventricular outflow tract obstruction seen on echocardiography in any patient to date. Mitral valve status after operation was assessed as no incompetence in 13 patients (28%), minimal in 19 patients (40%), mild in 12 patients (26%), and moderate in 3 patients (6%).

CONCLUSION

The repair of complete atrioventricular septal defect by direct suturing of the atrioventricular valve leaflets to the crest of the ventricular septum with a single-patch technique greatly simplifies the repair and does not lead to left ventricular outflow tract obstruction nor interfere with valve function.

Supraventricular electrical interaction in conjoined twins with common coronary sinus

Conjoined twins with echocardiographic evidence of continuity of the coronary sinuses had identical heart rates on ECG. Both had broad, polyphasic QRS complexes, and various imaging modalities were unable to determine whether there was ventricular myocardial continuity. Administration of adenosine demonstrated that the broad polyphasic complexes were a "fusion" of the twins' individual QRS complexes, which could be clearly distinguished after administration of the drug. Ventricular pacing resulted in dissociation of the individual QRS complexes, thus demonstrating an absence of ventricular myocardial continuity. This was confirmed when the twins were successfully separated at the age of 10 months.

Myocardial infarction complicating neonatal enterovirus myocarditis

A 10-week-old, 31-week gestation preterm boy re-presented with heart failure after an initial episode of neonatal aseptic meningitis with positive CSF enterovirus polymerase chain reaction. Investigation demonstrated global myocardial dysfunction with left ventricle posterolateral myocardial infarction. The boy's heart failure was controlled with medical treatment but his myocardial dysfunction persisted 9 months after presentation.

Adenosine in the management of supraventricular tachycardia in children

OBJECTIVE

To assess the efficacy and safety of adenosine in the management of supraventricular tachycardia in children.

METHODOLOGY

A review of 43 children with supraventricular tachycardia who received intravenous adenosine between June 1992 and July 1995.

RESULTS

Thirty-five patients had re-entrant supraventricular tachycardia and eight patients had atrial tachydysrhythmias. Reversion to sinus rhythm occurred in 75% of episodes in all patients treated for supraventricular tachycardia, and in 96% of episodes in patients with re-entrant supraventricular tachycardia. Early re-initiation of supraventricular tachycardia after reversion to sinus rhythm occurred in 25% of episodes. Sixteen percent of patients reverted with the recommended 0.05 mg/kg starting dose, and 35% reverted with a dose of 0.1 mg/kg. Four patients were given adenosine as a diagnostic procedure to elicit occult pre-excitation. The most common side effects were brief feelings of discomfort. No serious side effects occurred.

CONCLUSION

Adenosine is safe and effective in the management of supraventricular tachycardia in children. A commencing dose of 0.1 mg/kg is appropriate.

Internal mammary artery grafting in a neonate for coronary hypoperfusion after arterial switch

Coronary hypoperfusion may occur after the arterial switch operation, especially when coronary anatomy is complicated. We report successful use of the left internal mammary artery graft for a neonate with coronary hypoperfusion after the arterial switch operation for transposition of great arteries with intramural left coronary artery. Internal mammary arteriography showed a patent graft 19 months after operation.

Evaluation of a staged treatment protocol for rapid automatic junctional tachycardia after operation for congenital heart disease

OBJECTIVES

This study sought to 1) develop an efficient treatment protocol for postoperative automatic junctional tachycardia (JT) using conventional drugs and techniques, and 2) identify clinical features associated with this disorder by analyzing a large study group.

BACKGROUND

Postoperative JT is a transient arrhythmia that may be fatal after operation for congenital cardiac defects. Its precise cause is unknown. A variety of palliative treatments have evolved, but because of a low incidence of JT, large studies of the most efficient therapeutic sequence are lacking.

METHODS

A protocol for rapid JT (>170 beats/min) was adopted in 1986, and was tested in 71 children between 1986 and 1994. Staged therapy involved 1) a reduction of catecholamines; 2) correction of fever; 3) atrial pacing to restore synchrony; 4) digoxin; 5) phenytoin or propranolol or verapamil; 6) procainamide or hypothermia; and 7) combined procainamide and hypothermia. Effective therapy was defined as a sustained reduction of JT rate <170 beats/min within 2 h. Clinical profiles of the study group were contrasted with all patients without JT from this same era to identify features associated with JT.

RESULTS

Of the multiple treatment stages, only correction of fever and combined procainamide and hypothermia appeared to be efficacious. By refining the protocol to eliminate nonproductive stages, the time to JT control was significantly shortened for the last 30 patients. Treatment was ultimately successful in 70 of 71 children. Postoperative JT was strongly associated with young age, transient atrioventricular block and operations involving ventricular septal defect closure.

CONCLUSIONS

A staged approach to therapy, with emphasis on combined hypothermia and procainamide in difficult cases, appears to be an effective management strategy for postoperative JT. These results may also serve as comparison data for evaluation of newer and promising JT options, such as intravenous amiodarone. Trauma to conduction tissue may play a central role in the etiology of this disorder.

Echocardiographic assessment of aortic root dimensions in normal children based on measurement of a new ratio of aortic size independent of growth

Two-dimensional echocardiography is commonly used as a method of monitoring aortic root dimensions in children with connective tissue disease. Measurements are usually standardized to body surface area (BSA) to account for growth. However, there are several theoretical and practical disadvantages to adopting this approach, and there has been little investigation of alternative methods of standardization. This study of 48 normal children and adolescents (age range 2 weeks to 23 years) was performed to determine the relation of 2-dimensional echocardiographic aortic root dimensions to indexes of body size and growth, and to examine a simple means of internally standardizing aortic root measurements to create an index of aortic root size independent of growth. Maximal diameters in the parasternal long-axis view were recorded at 4 levels: annulus, sinuses of Valsalva (SOV), supraaortic ridge (SAR), and ascending aorta (AAO). Ratios of aortic root size were created by internally standardizing aortic root diameters to aortic annular size. All diameters correlated closely with age, height, weight, and BSA (all r > 0.87). Linear regression in each case showed a significant positive slope (all p < 0.0001). The best predictor of aortic dimensions was height, with r values of 0.93 for annulus, SOV, and AAO, and 0.95 for SAR. Ratios of SOV/annulus, SAR/annulus, and AAO/annulus remained constant, with no correlation with age or any growth parameters. Mean values and 95% confidence limits were: SOV/annulus 1.37 (1.18-1.56); SAR/annulus 1.11 (0.95-1.28); and AAO/annulus 1.16 (0.97-1.35). Standardization to height, or the use of internally standardized aortic root ratios, provides a simple and accurate alternative to standardization to BSA for assessing aortic root dimensions in normal growing children.

Amiodarone management of junctional ectopic tachycardia after cardiac surgery in children

OBJECTIVE

To assess the effectiveness and safety of amiodarone in the treatment of junctional ectopic tachycardia (JET) after open heart surgery in children.

PATIENTS

Between January 1990 and December 1991, 16 consecutive patients aged 6 days to 14 years with JET associated with significant haemodynamic impairment after cardiopulmonary bypass were treated with amiodarone as the principal antiarrhythmic drug.

INTERVENTIONS

Amiodarone 5 mg/kg was administered intravenously over one hour and the same dose was subsequently infused over 12 hours. This was reviewed every 12 hours and repeated as necessary until a satisfactory heart rate and stable haemodynamics were achieved. Atrial pacing was used whenever possible to provide atrioventricular synchrony.

RESULTS

Except for one patient with a JET rate of 160/min, the maximum JET rate ranged from 180/min to 245/min with a mean(SD) of 200 (20)/min. After amiodarone, the heart rates reduced to a mean(SD) of 170 (20), 164 (27), 158 (27), 157 (24), and 153 (19)/min at two, four, eight, 12, and 24 hours respectively. A reduction in tachycardia rate allowing atrial pacing was achieved in 10 patients by two hours. Haemodynamic variables improved in most patients with an increase in mean systolic blood pressure by an average of 15 mm Hg and a decrease in atrial filling pressures by an average of 3.5 mm Hg at four hours after amiodarone administration. There were three deaths: one was a moribund patient who died soon after the onset of JET and the other two deaths were not directly related to JET.

COMPLICATIONS

Late bradycardia with hypotension was recorded in one patient. Asymptomatic late sinus bradycardia was seen in several others.

CONCLUSIONS

Amiodarone can be used safely and effectively to control JET with haemodynamic improvement in most patients. The addition of atrial pacing confers the advantage of atrioventricular synchrony.

Salvage of infected truncus repair using rifampicin-impregnated gelatin-sealed graft

An infant suffered sternal infection and ventricular septal patch dehiscence after a truncus arteriosus repair. Successful reoperation used rifampicin-impregnated gelatin-sealed Dacron to repair the recurrent ventricular septal defect and replace the contaminated conduit. This was an effective solution to a potentially lethal surgical complication.

Prenatal diagnosis of hypoplastic left heart syndrome

Over a 21-month period 200 fetal echocardiographic studies were performed on pregnancies at high risk for congenital heart disease referred to the NSW Fetal Echocardiography Service. Four cases of hypoplastic left heart syndrome were diagnosed in-utero during this period. These cases demonstrated the heterogeneity of this lesion, its known association with other defects and chromosomal anomalies, and evidence of in-utero evolution. Hypoplastic left heart syndrome is reliably diagnosed by fetal echocardiography. This lesion is heterogenous and may evolve beyond the first trimester. Careful attention to ventricular function, endocardial echoes and Doppler flow may assist with diagnosis.

Minimally invasive management of transposition of the great arteries in the newborn period

This study reports on a predominantly noninvasive management program for neonatal transposition of the great arteries [TGA] incorporating balloon atrial septostomy [BAS] under echocardiographic control. BAS was performed in 25 consecutive patients presenting with TGA between April 1988 and April 1990. Structural and coronary anatomy was evaluated echocardiographically with angiographic supplementation only when additional data were required. This information was correlated, where possible, with direct anatomic findings and subsequent course. BAS was performed through the umbilicus in 17 patients (85% of patients in whom this approach was attempted). Thirteen patients did not require ventilation during BAS. There were minimal complications and satisfactory septostomies in all cases. Coronary anatomy was correctly predicted in all patients where anatomic correlation was available. Without invasive investigation 9 patients underwent neonatal arterial switch procedures and 2 underwent palliative procedures. BAS under echocardiographic control proved safe, effective, minimally traumatic and mostly possible via the umbilical vein. The umbilical vein, where patent, permitted rapid safe access for BAS. Echocardiographic diagnosis of the coronary artery, and structural and functional anatomy was reliable and allowed minimally invasive preoperative management in many patients.

Persistent ductus arteriosus in adults. A review of surgical experience with 25 patients

OBJECTIVE

To review the clinical features, operative details and course of adults with persistent ductus arteriosus.

DESIGN

Retrospective study. Information on subjects was obtained by case records review.

SETTING

The Cardiothoracic Unit, Royal Prince Alfred Hospital, Sydney.

PATIENTS

Twenty-five adults aged 16 years and over with persistent ductus arteriosus, from 1974-1990.

INTERVENTION

Surgical division or ligation of persistent ductus, via left thoracotomy or median sternotomy.

MAIN OUTCOME MEASURES

Preoperative clinical features; postoperative mortality and morbidity.

RESULTS

There was a high incidence of symptoms in this group of adults with persistent ductus arteriosus, many having anatomical (aneurysm, calcification) and/or haemodynamic (heart failure, pulmonary hypertension) complications. There was one death (mortality, 4%) of a young woman with significant preoperative pulmonary hypertension. The remaining 24 patients (96%) left hospital completely well between 4 and 12 days after surgery.

CONCLUSIONS

Persistent ductus arteriosus, although primarily a paediatric problem, may present in adulthood. Closure by operative means (or in selected cases, by interventional catheter) is warranted in all adult subjects with left to right shunt, other than for patients over 60 years of age with neither heart failure nor cardiomegaly.

Myocardial infarction in childhood: clinical analysis of 17 cases and medium term follow up of survivors

Between 1979 and 1989 17 patients aged two months to 12 years with acute myocardial infarction of any cause (other than after cardiac surgery) were seen at a children's hospital. Eight died from three days to three years after diagnosis (overall mortality 47%). The nine survivors, now aged 2-17 years, have been followed for one to 10 years (mean follow up five years) after infarction. The commonest causes of myocardial infarction in this series were anomalous origin of left coronary artery from the pulmonary artery (six patients (35%] and Kawasaki disease (five patients (27%]. The main symptoms of acute myocardial infarction were dyspnoea, vomiting, and difficulty feeding. Diagnosis was made in all patients by electrocardiography and confirmed by echocardiography, cardiac catheterisation, or at operation. All survivors were symptom free with excellent exercise capacity. The left ventricular ejection fraction in survivors ranged from 21% to 66%, and only one child was on regular cardiac medications. There were no cases of late sudden death. Twenty four hour Holter monitoring performed on survivors was normal (seven) or showed minor abnormalities only (one), suggesting that serious arrhythmia is rare after paediatric myocardial infarction. Myocardial infarction in children had a high early mortality; however, the incidence of serious arrhythmia was low in the survivors, who had a good exercise tolerance even when the left ventricular ejection fraction was low.

Congenital complete heart block in patients without anatomic cardiac defects

Forty-three patients with congenital complete heart block and an otherwise structurally normal heart were reviewed in an effort to better define the profile of an anatomically homogenous group and to identify factors that may predict the need for pacing. Fourteen patients (32%) developed "symptoms" during follow-up, including two with out-of-hospital cardiac arrest. Heart rate on electrocardiogram or Holter monitor did not clearly distinguish this subgroup. The presence of alternate "risk factors," such as atrial enlargement seen on electrocardiogram, cardiomegaly seen on x-ray film, or prolonged QT interval were independent predictors of symptoms and poor outcome (p less than 0.05). Ventricular ectopy determined on Holter monitoring was also common among the symptomatic group, although this finding was inconsistent. Prophylactic pacing is indicated in select patients with congenital complete heart block and otherwise normal anatomy. Surveillance for rick factors beyond rate criteria alone may refine this selection process.

Nitroprusside in children after cardiopulmonary bypass: a study of thiocyanate toxicity

Thiocyanate levels, an indicator of nitroprusside toxicity, were studied in 22 children after repair of structural heart disease during cardiopulmonary bypass. At the total dose (2.6 +/- 2.3 mg/kg) and time (34.4 +/- 19 h) ranges of this study, no evidence of toxicity was detected, despite this total dose exceeding recommended maximum in some patients. Nitroprusside infusion, as described, in children with normal hepatic and renal function is safe and may not warrant routine assessment of thiocyanate levels.

Effect of isolated right ventricular outflow obstruction on left ventricular function in infants

Resting left ventricular (LV) function was evaluated in 29 infants with isolated right ventricular (RV) outflow obstruction. Age-corrected cardiac index was significantly inversely correlated with the degree of obstruction (r = 0.59, p = 0.0001). Right ventricular hypertension resulted in septal displacement and altered LV geometry. The magnitude of RV outflow obstruction related closely to the degree of LV distortion. Septal displacement toward the LV free wall was associated with lower values for cardiac index, indexed LV end-diastolic volume, ejection fraction, ratio of early to atrial LV diastolic inflow and with a higher RV ejection fraction. The LV end-diastolic volume index and the ratio of early to atrial LV diastolic inflow correlated with the degree of obstruction and amount of septal displacement. Four infants evaluated during the development of supravalvar pulmonary stenosis demonstrated decreasing cardiac index during development of obstruction and significant increase in cardiac index after surgical relief. These findings indicate that significant RV outflow obstruction in infants is associated with a reversible alteration in LV function related to abnormal LV geometry and impaired LV diastolic filling.

Noninvasive estimation of the left ventricular pressure waveform throughout ejection in young patients with aortic stenosis

Validation of a totally noninvasive method for estimating instantaneous left ventricular pressure and constructing a pressure waveform throughout ejection in patients with aortic stenosis is reported. In 20 patients (aged 8.75 +/- 10 years) with congenital aortic stenosis (measured peak left ventricular pressure 120 to 260 mm Hg; transvalvular gradient 18 to 165 mm Hg), transaortic valve continuous wave Doppler ultrasound, indirect carotid pulse tracing, peripheral blood pressure and measured left ventricular pressure were recorded simultaneously at cardiac catheterization. Data were entered into a microcomputer using a digitizing tablet and the instantaneous Doppler gradient was calculated and added to instantaneous aortic pressure, derived from the time-corrected and calibrated carotid pulse tracing, to estimate instantaneous left ventricular pressure. Estimated left ventricular pressure waveforms reproduced measured left ventricular pressure closely. The mean error at peak left ventricular pressure was 0.2 +/- 4.8 mm Hg (r = 0.98, p = 0.001). The average error throughout ejection was 0.9 +/- 5.1 mm Hg. The error of estimated pressure was not related to age or the severity of aortic stenosis. The Doppler peak instantaneous gradient was observed to correlate closely (r = 0.97, p = 0.001) with peak to peak gradient. With this technique, the left ventricular pressure waveform throughout ejection can be accurately estimated noninvasively in patients with aortic stenosis. This methodology enables determination of mean, total and instantaneous systolic left ventricular pressure.

Balloon dilation of congenital aortic valve stenosis. Results and influence of technical and morphological features on outcome

We evaluated dilation technique (n = 80) and aortic valve morphology by two-dimensional echocardiography (n = 58) in patients with congenital aortic valve stenosis to determine their influence on outcome. Patients' age (9 +/- 9 years; range, 1 day-39 years) and a history of surgical valvotomy did not influence outcome. The number of dilating balloons (one vs. two) and balloon: annulus ratio based on the largest balloon used in each case (97 +/- 12%; range, 71-133%) did not demonstrably influence the percent reduction in valvar gradient. In contrast, with a balloon: annulus ratio greater than 100%, the incidence (26%) of significant, dilation-induced aortic regurgitation was higher than occurred when the ratio was equal to or less than 100% (11%). Fifty bicommissural and eight unicommissural valves were identified echocardiographically. Relief of obstruction was associated with apparent commissural division in 24 of 32 patients with suitable postdilation studies. The sites of fusion and stenosis relief did not influence percent reduction in valvar gradient. Substantial increases in aortic regurgitation (greater than three of five grades) occurred in three of eight unicommissural and one of 50 bicommissural valves. The presence of a thick valve was associated with a slightly lower gradient reduction (53 +/- 12%) than thin and pliant valves (63 +/- 24%) (p greater than 0.05). Unlike all other congenital lesions we have studied, dilation technique and balloon size appeared to have a lesser influence on percent reduction in valvar gradient in congenital aortic stenosis, although balloon: annulus ratio influences the increase in aortic regurgitation. Valve morphology appears to assist with predicting the outcome of dilation.

Myocardial performance after arterial switch operation for transposition of the great arteries with intact ventricular septum

Left ventricular dimensions, wall thickness, wall stress, and indexes of afterload, preload, contractility, and early diastolic function, as well as regional wall motion, were determined by echocardiographic methods in patients with transposition of the great vessels after arterial switch operation and in age-matched normal controls. In patients evaluated early after surgery, body surface area-adjusted left ventricular dimensions were smaller, and wall thickness was increased compared with controls. Ventricular performance (fractional shortening) was normal in most patients but was abnormally low in 10%. Nevertheless, contractility was normal or augmented in all subjects, with a mean value higher than the control group. The reduction in systolic function was related to altered loading conditions with a combination of reduced afterload and preload combined with augmented contractility. These altered myocardial mechanics appeared to be secondary to routine therapy with digitalis and diuretics. Diastolic function was also normal with differences in the rate of peak filling and rate of wall thinning entirely attributable to differences in ventricular size and function, and normalized indexes of diastolic function were not different between patients and controls. Patients evaluated late after repair were found to have normal regional wall motion with no evidence to suggest regional dysfunction as might be seen with regional ischemia. Ventricular size, wall thickness, systolic function, afterload, preload, contractility, and early diastolic function were indistinguishable from control values. Indexes of diastolic function demonstrated the same relation to age, body surface area, and ventricular size and function in both patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data

Although the short-term results of atrial level repair of transposition of the great arteries (TGA) are satisfactory, longer follow-up has disclosed a significant incidence of systemic right ventricular dysfunction and rhythm disturbances. The arterial switch operation (ASO) may represent a major improvement by restoring the left ventricle as the systemic ventricle and avoiding extensive atrial surgery. We have prospectively evaluated 49 consecutive survivors of ASO for TGA with intact ventricular septum (IVS) by clinical examination, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and invasive electrophysiologic studies. The mean length of follow-up has been 29 +/- 14 (SD) months after surgery. All children are currently asymptomatic and on no medications. Severe supravalvular pulmonary stenosis (greater than 60 mm Hg) was present in five children, all of whom have undergone reoperation. No patient has severe supravalvular aortic obstruction. Mild degrees of supravalvular pulmonary or aortic obstruction have not progressed. Seven children (14%) have trivial or mild aortic regurgitation. Two children have proximal occlusion of the left anterior descending coronary artery with adequate retrograde collateral perfusion. One child had an electrocardiographic pattern of inferior myocardial infarction without evidence of ventricular dysfunction. Systemic (left) ventricular function is normal as measured by end-diastolic pressure (mean 7 +/- 6 mm Hg), ejection fraction (mean 68 +/- 6%), end-diastolic volume (mean 101 +/- 22% of predicted normal), and cardiac index (mean 4.7 +/- 1.3 liters/min/m2). Only one patient has sinus node dysfunction. There have been no late deaths. These early results are encouraging. We conclude that the arterial switch operation is currently the procedure of choice for neonates with TGA and IVS.

Echo Doppler assessment of cardiac output and its relation to growth in normal infants

In a study of 38 normal infants, serial measurements of systemic (n = 169) and pulmonary (n = 143) blood flow were undertaken from the ages of 2 weeks to 12 months by 2-dimensional, M-mode and pulsed Doppler echocardiography. Cardiac output changed linearly (cardiac output = 0.3 X height -0.99 liter/min), and cardiac index was validated as a means for standardizing cardiac output in infants younger than 10 to 13 months of age. Infants younger than 2 months had lower cardiac indexes and stroke volume indexes (2.6 +/- 0.7 liters/min/m2 and 19 +/- 5 ml/m2, respectively) compared with those aged 12 months (3.2 +/- 0.7 liter/min/m2 and 25 +/- 5 ml/m2, respectively). Changes in cardiac output in individual infants over time suggest nonmorphometric modulating factors for cardiovascular function.

Primary left ventricular rhabdomyosarcoma in a child: noninvasive assessment and successful resection of a rare tumor

Rhabdomyosarcoma of the heart is a rare tumor, especially in childhood and particularly in the left ventricle. A primary tumor of this type was successfully resected after echocardiographic assessment alone in a young girl exposed prenatally to diphenylhydantoin. The patient is well and free of recurrence 2 1/2 years later.

Cardiac surgery in the first year of life: the effect on weight gains of infants with congenital heart disease

Forty-seven infants with ventricular septal defect (n = 17), tetralogy of Fallot (n = 7) and transposition of the great arteries (n = 23) who had 'corrective' surgery in the first year of life were reviewed with respect to birthweight and pre- and postoperative growth. The mean birthweight for each group was below that of the standard population. There was an overall decrease in growth velocity pre-operatively which was reversed after surgery. At follow up, 12-18 months later (means), most infants had regained at least their birthweight percentile, while the group with ventricular septal defect exceeded it. Consideration is given to the pathophysiological mechanisms contributing to these observations.

Fetal echocardiography: experience and reason

Improvements in echocardiographic techniques have allowed detailed study of the fetal heart by experienced paediatric echocardiographers. We report 40 studies in 36 fetuses from 18 to 38 weeks' gestation whose mothers were referred for the assessment of fetal hydrops or arrhythmia or because of a family history of congenital heart disease. Normal, or probably normal, cardiac structure was demonstrated in 29 studies and abnormal, or probably abnormal, structure in seven. In four studies the imaging was inadequate and an opinion was deferred until further study. In this series, the sensitivity and specificity of the technique was 100% and 95% respectively. Fetal echocardiography is useful in pregnancies at high risk of fetal heart disease and for the further study of developmental cardiology. The results of such studies include the optimal management of pregnancy and delivery of high-risk neonates, and the allaying of parental anxiety.

Infective endocarditis in childhood

A total of 37 cases of infective endocarditis, in children aged two days to 13 years, were seen from 1971 to 1983 at the Children's Hospital, Camperdown. Structural heart disease was known to preexist in 95%. Cyanotic congenital heart disease was present in 15 children, of whom 11 had been palliated by a systemic-to-pulmonary artery shunt. In five children, there was infection of a prosthetic valve. Identifiable precipitants of infection were rare. In particular, no child had had a preceding dental procedure within three months, while only 19% had had recent cardiac surgery. Organisms were identified by blood culture in 92%, the majority being streptococci (43% of cases) and staphylococci (27% of cases). While 59% of all organisms were penicillin sensitive, six of the seven early postoperative children were infected with organisms not sensitive to antibiotics, given for wound infection prophylaxis in the perioperative period. The overall death rate was 13.5%. Of the children infected with Staphylococcus aureus, 40% died, while no child with Streptococcus viridans endocarditis died. Of the survivors, four needed urgent valve replacement, and three had major central nervous system complications. Using these figures, a current profile of patients with infective endocarditis is presented.

Pulmonary sequestration in a newborn mimicking cardiac disease: a trap for diagnosis

A case of pulmonary sequestration in a neonate presenting with hyperdynamic circulation and a murmur is reported. Clinical, radiographic and echocardiographic data suggested the diagnosis and this was confirmed by angiography. The surgical findings were those of sequestration of the right lower lobe, in conjunction with an accessory right lung complete with bronchial and vascular supply arising from the region of the lower oesophagus. Pulmonary sequestration may mimic primary cardiovascular disease in the neonate.

Generalized arterial calcification of infancy: three case reports, including spontaneous regression with long-term survival

Generalized arterial calcification in infancy is a rare disorder in which death usually occurs in infancy, the diagnosis generally being made at autopsy. Three patients are reported. The diagnosis was made during life in two, enabling new information to be collected. Cardiac catheterization in one provided evidence suggesting stiffness of pulmonary and systemic arterial walls. Another is a long-term survivor with spontaneous regression of calcification. The third case, diagnosed at necropsy, was associated with endocardial fibroelastosis.

Prophylaxis of bacterial endocarditis. Awareness of need

The parents or guardians of attenders at a paediatric cardiac clinic were surveyed over five months. Ninety-six patients who were at risk of bacterial endocarditis were identified. In 46% of these, the parents or guardians had insufficient knowledge to ensure that their children will receive prophylaxis at times of risk. A first language other than English, a lower level of education of the main family wage- earner , lack of exposure to previous dental extractions and non-cardiac operations, and a child aged less than five years--all correlated with poor knowledge of prophylaxis. Means of achieving greater awareness of need and efficacy of protection are suggested.