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.

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.

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.

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.

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.

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.

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.

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.