Interventional catheterization procedures performed via the arterial route are well recognized therapies which are being employed with increasing frequency. This review summarizes our experience with local arterial complications of such procedures performed on 44 patients in our institution since 1985. A total of 51 balloon dilations were performed. All patients were heparinized during the procedure. Twenty-one procedures (41%) were followed by clinical evidence of reduced arterial circulation to the affected leg more than four hours after the procedure. Continuing infusion of heparin was used in 17 patients, with return of the pulse concerned in six, while two further patients developed evidence of arterial obstruction after an interval (having initially been found to have ‘satisfactory’ pulses at the end of the procedure). The final infant, whose femoral artery had been torn and could not be repaired, was observed without continuing heparinization. Streptokinase and/or tissue plasminogen activator was employed in eight patients, with resultant success in four. The remaining three, and three who failed thrombolytic therapy, underwent embolectomy. The incidence of arterial damage was related to the size of the catheter (assessed by the size of sheath required to introduce the collapsed balloon, indexed to body surface area) and to low weight or young age at the time of the procedure. No relationship could be established with other variables, including operator, type of catheter, or year or duration of procedure. At long-term follow-up, 11 (22%) patients still have absent or reduced pulses in the leg concerned. Arterial damage following interventional catheterization procedures remains a frequent occurrence despite increasing experience and technical improvements.

We report a case of right aortic arch and isolation of the left brachiocephalic artery. Stenosis of the left pulmonary artery, ventricular septal defect and left superior caval vein draining to the right atrium via the coronary sinus were also present in a 13-month-old asymptomatic girl with Down's syndrome. To our knowledge, this association of lesions has not previously been described.

Pericardial effusion requires attention because of its underlying pathology and its potential for producing hemodynamic compromise. It was our hypothesis that the etiology of and danger from large pericardial effusions are different at different ages. We reviewed the clinical data on 44 consecutive patients seen between 1986 and 1993. All (age range 0-19 years) had a large pericardial effusion identified by echocardiography, and 38 had fluid available for analysis, pericardiocentesis in these cases being undertaken on the basis of the clinical decision of the attending physician. History, physical examination, chest x-ray, electrocardiogram, and echocardiographic Doppler findings were evaluated retrospectively. Of the patients, 17 presented with tamponade. Of the 14 patients aged less than one year, 12 had tamponade (85%), whereas in the 30 patients older than one year, only five (16%) had tamponade. Surgical drainage was needed in seven patients. Typical physical and electrocardiographic findings (distant heart sounds, pericardial friction rub, decreased QRS voltage, and ST-T wave abnormalities) were present in less than half the patients. Etiologies of the effusion included infection in 10 (four less than one year old, and six greater than one year of age). Among these, two unusual pathogens were detected: Mycobacterium avium-intracellulaire and Candida tropicalis. In eight patients, the effusion was due to trauma (six less than one year old, and two older than one year), and in 11 it was due to post-pericardiotomy syndrome (two less than one year of age and nine older than one year). Malignancy was the cause in six (all older than one year of age), radiation in two, and collagen vascular disease, drug induced, and uremia in one each, all older than one year. Only three patients had idiopathic effusions (6%). These data suggest that, unlike adults, an etiologycan be found in most children with large pericardial effusions. Those less than one year of age are much more likely to present in cardiac tamponade.

Although ventricular septal defect is the most common form of congenital heart disease, its epidemiology is not completely understood. The Baltimore-Washington Infant Study, a case-control study of congenital cardiovascular malformations, enrolled 4,390 case infants during the study period 1981–1989. Ventricular septal defect, the most common malformation, was present in 1,465 (33%) of affected infants. The purpose of this report was to describe the epidemiological characteristics of membranous and muscular ventricular septal defects, the most common types of ventricular septal defects. Membranous ventricular septal defects (n=895) and muscular ventricular septal defects (n=429) accounted for 90% of all ventricular defects. During the study, prevalence increased from 0.9 to 2.1 /1000 live births. Associated non-cardiac defects, such as chromosomal defects, genetic syndromes, and defects of other organs were more common among infants with ventricular septal defect than among control infants, and more common among infants with membranous ventricular defect (20.8%) than among those with muscular defects (7.5%). Infants with ventricular septal defects and non-cardiac defects had increased mortality in comparison to infants with isolated ventricular septal defects or controls. Epidemiological information derived from population-based studies provide valuable data for counseling families and may allow for examination of etiologic factors.

Despite early arterial switch repair of complete transposition of the great vessels, significant physiologic aberrations may still occur. Two cases of vascular disease in the left pulmonary arterial system are described and potential mechanisms are discussed. We conclude a small number of children with simple transpostion may develop asymmetric patterns of pulmonary blood flow without evidence of anatomic narrowing of either arterial vessel.

Between 1981 and 1990, 765 symptomatic neonates with major congenital heart malformations were admitted into the Grantham Hospital. This represented an incidence of 10 per 10,000 live births for Hong Kong. The figure was comparable to those reported for Caucasians. Among the 744 Oriental neonates, obstruction of the pulmonary outflow tract occurred most frequently (281, 37.8%), followed by left ventricular outflow tract obstruction (169, 22.7%), left-to-right shunting (115, 15.5%), complete transposition (92, 12.4%), common mixing situations (62,8.3%), and miscellaneous causes (25, 3.3%). When compared with the available reports from the West, Chinese neonates had a high preference for pulmonary outflow tract obstruction (p<0.005), especially the anomaly of pulmonary atresia and intact ventricular septum. This correlated well with cyanosis as the commonest neonatal presentation (64%). Contrary to previous reports that aortic coarctation was rare among Orientals, this abnormality was observed frequently in our study. The rare occurrence of critical aortic valvar stenosis among Chinese, however, was supported by our present analysis. Other lesions, such as left-to-right shunting and complete transposition, showed no significant racial difference in the frequency of occurrence. Such knowledge concerning the pattern of congenital heart disease amongst Oriental neonates can facilitate early diagnosis and timely referral of babies to the appropriate center for management.

A patient with complete transposition and a ventricular septal defect was clinically improved by an atrial septectomy at nine years but continued sepsis in the thoracotomy scar resulted in blood-stream infection with Staphylococcus aureus at the age of 24 years. A deep nylon suture was found and removed at surgical exploration. Five months later she again became febrile and had a vasculitic skin rash which responded to antibiotic therapy. At that time she was cyanosed and had a restricted exercise tolerance and was found to have aneurysmal dilatation of the pulmonary trunk. A year later she had acute chest pain with increased breathlessness, fever, hepatomegaly and pulmonary regurgitation. The fever did not respond to antibiotic therapy and she died suddenly following removal of a Hickman line. At postmortem examination, there was found to be a false aneurysm in the mediastinum due to rupture of the aneurysmal pulmonary trunk. No evidence of infection was found and it was considered that the low grade pyrexia had been due to the large hematoma within the false aneurysm.

There are limited reports in the literature that address the unique issues related to cardiac catheterization on extracorporeal membrane oxygenation. Since 1990, cardiac catheterization has been performed on nine patients on extracorporeal membrane oxygenation. The median age was 10 months (range four days to 18 years) and the median weight was 4 kg (range 2.3–73.8 kg). The indications for catheterization were to relieve pulmonary edema in five patients with severe left ventricular dysfunction, and in one instance each, evaluation of probable anomalous left coronary artery, tetralogy of Fallot associated with a diaphragmatic hernia, possible pulmonary venous abnormalities, and postoperative evaluation after an arterial switch. Venous access was obtained through a preexisting femoral venous line in six patients, and through a cutdown of the saphenous or femoral vein in the other three. Interventional catheterization procedures were performed in six of the nine patients in this group. These consisted of blade atrial septostomy followed by balloon septostomy or dilation of the atrial septum in four patients, balloon septostomy alone in one, and placement of a catheter from the left atrium to the circuit used for extracorporeal oxygenation in another. A transseptal puncture was performed in five of them. Adequate decompression of the left atrium with relief of pulmonary edema was achieved in five patients. Six of the nine children in this group died, although there were no complications or deaths related to the catheterization. Children in cardiopulmonary failure on extracorporeal support represent a population at high risk. Diagnostic cardiac catheterization and atrial septostomy to decompress the left heart, when indicated, can be performed safely in such patients.

A case of left ventricular obstruction is reported in a fetus of 21 weeks gestation. Obstruction to the left ventricular inflow and outflow tracts was documented by prenatal echocardiography and, at autopsy, the cause was found to be a large blood cyst. It is likely that the associated hypoplasia of the left heart was a result of reduced blood flow beyond this obstructive lesion.

Long-term follow-up studies after intraatrial repair for complete transposition have shown postoperative morphologic and hemodynamic abnormalities in many patients which often require reevaluation and therapeutic intervention. The purpose of this study was to assess, using magnetic resonance imaging, the presence and extent of late postoperative complications in a large cohort of 44 patients undergoing repair with the Mustard procedure. Of these 34 had an intact ventricular septum with or without obstruction of the left ventricular outflow tract, while 10 had an associated ventricular septal defect. Transverse spin-echo and gradient-echo images were acquired of the entire heart from the diaphragm to the bifurcation of the pulmonary trunk. Additional oblique images were acquired for better visualization of venous connections. Abnormal findings were diagnosed by visual inspection of spin-echo and gradient-echo images, and diagnoses were compared to previous findings at cardiac catheterization. On magnetic resonance imaging, a baffle leak was seen in eight patients, two had pulmonary venous obstruction, four had obstruction at the caval veins, 23 had obstruction of the left ventricular outflow tract and 18 had tricuspid regurgitation. Cardiac catheterization showed a leak across the baffle in 16, pulmonary venous obstruction in two, obstruction at the caval veins in four, obstruction of the left ventricular outflow tract in nine, and tricuspid regurgitation in nine. We conclude that combined spin-echo and gradient-echo magnetic resonance imaging provides extensive noninvasive assessment of postoperative sequels and residuals in patients after the Mustard procedure for complete transposition.

The arterial switch operation is the treatment of choice for complete transposition, and for the Taussig-Bing anomaly, with good early and mid-term results. This retrospective study examined the findings obtained at routine follow-up cardiac catheterization after primary arterial switch repair. We catheterized 111 patients after a mean of 16.9 months after surgery. These included 67 patients with an intact ventricular septum, 33 with a ventricular septal defect, and 11 with the Taussig-Bing anomaly. Right ventricular pressures were mildly elevated (mean 33.9±10.2 mm Hg) in the overall group with a mean pressure ratio between right and left ventricles of 0.34±0.1. Of the patients 74% had gradients across the right ventricular outflow tract of under 20 mm Hg, while three (2.7%) had gradients over 30 mm Hg. A significant gradient across the left ventricular outflow tract occurred in one patient (0.9%), while significant neo-aortic stenosis was not seen. The neo-aortic root remained dilated, with mild aortic valvar incompetence being seen in 12%, with none having higher grades of regurgitation. Left ventricular ejection fraction was normal in all patients, while left ventricular end-diastolic pressure was elevated in 38%. Coronary arterial stenosis was not seen, but one patient (0.9%) had left ventricular apical dyskinesia. Overall, therefore, we conclude that cardiac hemodynamics and ventricular systolic function after primary arterial switch are good. Minor gradients to the pulmonary arteries, and mild neo-aortic valvar incompetence were commonly noted. Left ventricular end-diastolic pressure was elevated in over a third of the patients. These subclinical and subtle abnormalities warrant ongoing follow-up to determine their long-term significance.

We report an unusual case with discordant atrioventricular and ventriculoarterial connections. In addition to the commonly associated intracardiac anomalies ofventricular septal defect and subpulmonary tissue tags, a supravalvar ring was present above the left-sided, morphologically tricuspid valve. This case highlights the value of color flow Doppler echocardiography in making the diagnosis, particularly as the supravalvar ring was seen poorly angiographically.

Adenosine, when given as an intravenous bolus, has been shown to produce atrioventricular nodal block in humans. To examine the effect of adenosine on conduction across both accessory pathways and the atrioventricular node in children, we reviewed our experience with adenosine administered during both atrial and ventricular pacing in 42 patients with atrioventricular resting tachycardia and in eight patients with atrioventricular nodal reentry tachycardia. Adenosine was administered as a mean bolus of 195 μg/kg/dose during both atrial and ventricular pacing, examining antegrade and retrograde conduction before and after radiofrequency ablation. In those patients with persistent or intermittent pre-excitation, anomalous ventricular activation was either unchanged (n=8) or increased (n=11). Retrograde conduction (either through the accessory pathway alone in three, or across both the accessory pathway and the atrioventricular node in 19) persisted in 92% of the 24 patients studied. Adenosine produced either first or third degree antegrade heart block in all patients studied without pre-excitation (those with either dual atrioventricular nodal pathways or concealed accessory pathways). Adenosine produced retrograde block in all of the eight patients with dual atrioventricular nodal pathways. In contrast, retrograde conduction persisted in 82% (14/17) of patients with concealed accessory pathways (p=0.001). When used to examine retrograde conduction, adenosine was a sensitive (82%) and highly specific (producing retrograde atrioventricular block in all patients with dual atrioventricular nodal pathways) predictor of tachycardia supported by a concealed accessory pathway. Adenosine yielded a sensitivity and specificity of 96% and a positive predictive value of 99.5% for the success of ablation of accessory pathways. These data indicate that the pattern of adenosine-induced changes in either antegrade or retrograde atrioventricular conduction, or conduction in both directions, in young patients with supraventricular tachycardia is related to the mechanism of the tachycardia. Adenosine, therefore, is a useful adjunct in the electrophysiologic evaluation of supraventricular tachycardia in children.

Atrial correction for complete transposition involves a potential risk of later development of right ventricular dysfunction. To determine the reasons contributing to such systemic ventricular failure, radioisotope first-pass and SPECT perfusion studies at rest after one dose of Technetium-99m MIBI were performed in 26 asymptomatic patients, 5.9±2.7 years after a Mustard or Senning repair. Mean age at operation was 4.3±4.3 years. All patients were followed with 24-hour Holter monitoring and echocardiography. Normal perfusion was observed in 11 patients with a mean age at operation of 2.25±1.8 years and mean right ventricular ejection fraction of 49.0±8.7%. Perfusion defects were found in 15 patients with a mean age at operation 5.8±4.8 years (p<0.05) and mean right ventricular ejection fraction of 43.2±9.3% (NS). In the group of older patients, 10 had extensive perfusion defects with significantly lower right ventricular ejection fraction (39.7±9.3%, p<0.05) and even older mean age at the surgery (7.1±5.6 years p<0.02). Mild or moderate tricuspid regurgitation was found significantly more frequently in those patients with perfusion defects (73%) than in the group of younger patients (36.3%), p<0.05. There was no difference in the frequency and type of arrhythmias, nor in the extent of follow-up, between the two groups. We conclude that, in patients undergoing surgery at an older age, it is more common to find perfusion defects and, often, lower right ventricular ejection fraction. Perfusion abnormalities found in such asymptomatic patients may be a result of several factors: impaired right ventricular function as a consequence of pressure and volume overload, enhanced myocardial fibrosis, or long-lasting preoperative hypoxemia and tricuspid valvar dysfunction secondary to ventricular dilation. We suggest that the perfusion defects observed in this study may be a better indicator of systemic ventricular impairment.

We performed ten operations in children using a lower mid-line incision and limited minimal sternotomy. The skin incision is made from the level of nipples to the lower end of the xiphoid process, and only the body of the sternum is cut vertically. There was neither operative mortality nor complications. The upper limit of the scar was, at the most, 1 cm beyond the level of the nipples, and was difficult to observe in typical open-necked shirts. We believe our method is suitable in fulfilling the cosmetic needs for eligible children.

Second degree atrioventricular block is uncommon in children. In order to evaluate its outcome, and to find early prognostic factors, we reviewed the history and evolution of 21 children with this arrhythmia discovered on their surface electrocardiogram. Twenty-four-hour monitoring displayed variations in the conduction patterns in almost all children, from long PR interval to complete heart block alternating in the same patient. At follow-up (nine months to 19 years), 13 children (62%) had received implantation of a pacemaker because of progression either to complete atrioventricular block or to severe ventricular bradycardia. Atrioventricular conduction improved on exercise in 11 children, but this did not predict a favorable outcome since four of them required pacing. In contrast, deterioration during sinus acceleration in four patients predicted further aggravation. A supra-Hisian location of the block did not protect against the occurrence of syncope in the two patients who underwent His recordings. Finally, the outcome was not linked to age at diagnosis. Second degree atrioventricular block, therefore, should be considered a serious disease because of its trend to worsen towards complete block and/or severe complications. Close follow-up, including repeated 24-hour monitoring, is the most effective way to unmask such a progression and to avoid its clinical consequences.

A case is reported where unguarding of the tricuspid orifice was associated with Uhl's malformation. Echocardiographic features of the condition permitted the diagnosis during life. A therapeutic plan is proposed which involves surgical closure of the unguarded tricuspid orifice.