Introduction: The first step in diagnosing congenital cardiac malformations is to assess the arrangement of the atrial appendages. In patients with abnormal lateralization of the organs of the body, the arrangement of atrial appendages is neither normal, nor a mirror image of normal. There are 2 categories of abnormal arrangement based on the morphology of the atrial appendices, namely right isomerism and left isomerism, and in almost all instances these are found in the setting of so-called heterotaxy syndromes. Objective: To evaluate the various congenital cardiac malformations those are associated with abnormalities of lateralization, and to discuss the diagnostic tools, therapeutic options, and outcome for these patients. Patients and methods: We studied 134 patients, who had been admitted to our department of paediatric cardiology with known abnormalities of lateralization and congenital cardiac defects between 1990 and 2003. The data relating to each patient was evaluated retrospectively. The arrangement of the atrial appendages was established echocardiographically, and/or angiographically, and/or on the basis of morphologic investigations during the operation. These studies showed that 43 (32.1%) of the patients had right isomerism, and 88 (65.7%) had left isomerism. In 2 (1.5%), there was mirror-imaged arrangement, while in the final patient (0.07%), we were unable to determine sidedness with certainty. The median age at diagnosis was 0.66 years, and the females outnumbered the males in a ratio of 3 to 1. Patients in the 2 isomeric groups were compared with regard to age, cardiac defects, diagnostic tools and outcomes. Results: The difference in mean ages of the two groups of patients was statistically significant, those with right isomerism being 1.0 minus or plus 1.5 years, as opposed to those with left isomerism being 3.3 minus or plus 4.7 years (P is less than 0.005). Of the patients with right isomerism, 32 (74.4%) had left-sided, and 11 (25.6%) right-sided hearts, whereas in those with left isomerism, the hearts were left-sided in 65 (73.9%), and right-sided in 21 (23.9%), with 2 (2.2%) positioned in the midline. Extracardiac totally anomalous pulmonary venous connection was more common in those with right isomerism, being found in 13 patients (30.2%) as opposed to 5 patients (5.7%) with left isomerism. In only 8 of those with right isomerism did we find two perforate atrioventricular valves (18.6%), this arrangement being found in 34 (38.6%) of those with left isomerism. Pulmonary atresia and stenosis were present in 40 (93.0%) of those with right isomerism, but also in 41 (46.6%) of the patients with left isomerism. Angiographic and echocardiographic investigations were concordant in about three-quarters of patients with both right and left isomerism. All patients with extracardiac totally anomalous pulmonary venous connection died. Overall, 22 of the patients with right isomerism died (51.2%), as opposed to 20 (22.7%) of those with left isomerism. Conclusion: Our experience confirms that patients with right isomerism have more complex cardiac defects than those with left isomerism. Overall, the presence of isomerism carries a poor prognosis, the more so for right isomerism, with this related to the complex cardiac abnormalities. In our cohort, extracardiac totally anomalous pulmonary venous connection with pulmonary arterial obstruction was always a fatal combination. The mapping of cardiac and abdominal morphologies is still essential for proper diagnosis of these syndromes, especially in fetal life.

Aim: Our aim was to perform a comparative, quantitative and qualitative, analysis of valvar echocardiographic findings in patients with acute rheumatic fever, with or without clinical manifestations of carditis, as compared to healthy controls. Methods and results: We analyzed cross-sectional Doppler echocardiographic images of 31 patients with acute rheumatic fever diagnosed according to the Jones criterions as modified in 1992. Of 31 patients, 22 presented with clinical carditis, while 9 had subclinical carditis. The patients, and a control group of 20 healthy individuals, underwent cardiac examination and echocardiographic assessment, assessing quantitative and qualitative findings of mitral and aortic valvar abnormalities. The leaflets of the mitral valve were statistically thicker in those with clinical and subclinical carditis when compared to controls (p less than 0.001). We observed a greater frequency of mitral variance, convergence of mitral flow, and aortic regurgitation for those with clinical and subclinical carditis when compared to controls (p less than 0.001, p less than 0.001 and p equal to 0.003, respectively). Patients with clinical and subclinical carditis had more quantitative and qualitative changes in the parameters than did the controls. Conclusion: Echocardiography is a sensitive method to detect valvar abnormalities in patients with acute rheumatic fever and carditis. Additionally, by using regular standardized criterions, abnormalities that lead to a diagnosis of subclinical carditis are found in those patients with acute rheumatic fever in the apparent absence of cardiac involvement.

Their perceptual and motor experiences determine the physical and motor development of children, and impact also on their emotional, psychosocial, and cognitive development. Our aim, therefore, was to evaluate motor development in children with congenitally malformed hearts compared to their healthy peers.

We compared 194 children, with a mean age of 10.0 years, and standard deviation of 2.7 years, representing the entire spectrum of congenital cardiac disease, to a control group of 455 healthy children, having a mean age 9.6 years, with standard deviation of 2.17 years. The bodily coordination test for children was used to examine motor development.

Of the children with congenitally malformed hearts, 26.8% showed moderate, and 31.9% had severe disturbances of motor development, compared to 16.5% and 5.5% of the control group, the p-value for these differences being less than 0.001. The mean motor quotient adjusted for age and gender was lower in the children with congenitally malformed hearts than in their healthy peers, at 79.6, with standard deviation of 18.9 as opposed to 96.6, with standard deviation of 15, this difference having a p-value of less than 0.001. Depending on the presence, and/or the degree, of residual sequels, the children with congenitally malformed hearts were divided into two subgroups, with either no or mild residual sequels, or with significant sequels. The mean motor quotient was lower in those with significant residual sequels, at 75, with standard deviation of 19.3, as opposed to 83, with standard deviation of 17.9, the p-value for this difference being less than 0.01. In both subgroups, the mean motor quotient was lower, with a p-value of less than 0.01, than in the control group.

Our findings show that children with congenitally malformed hearts have deficits in their motor development, these being found in the presence of no or mild sequels, as well as with significant residual sequels. Parental overprotection may contribute to these findings.

Introduction: A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy. Methods: We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation. Results: At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries. Conclusions: Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.

Objective: To assess a novel method for assessing risk and providing advice about activity to children and young people with congenital cardiac disease and their parents. Design and setting: Questionnaire survey in outpatient clinics at a tertiary centre dealing with congenital cardiac disease, and 6 peripheral clinics. Interventions: Children or their parents completed a brief questionnaire. If this indicated a desire for help, or a serious mismatch between advised and real level of activity, they were telephoned by a physiotherapist. Main measures of outcome: Knowledge about appropriate levels of activity, and identification of the number exercising at an unsafe level, the number seeking help, and the type of help required. Results: 253/258 (98.0%) questionnaires were returned, with 119/253 (47.0%) showing incorrect responses in their belief about their advised level of exercise; 17/253 (6.7%) had potentially dangerous overestimation of exercise. Asked if they wanted advice 93/253 (36.8%) said “yes”, 43/253 (17.0%) “maybe”, and 117/253 (46.2%) “no”. Of those contacted by phone to give advice, 72.7% (56/77) required a single contact and 14.3% (11/77) required an intervention that required more intensive contact lasting from 2 up to 12 weeks. Of the cohort, 3.9% (3/77) were taking part in activities that put them at significant risk. Conclusions: There is a significant lack of knowledge about appropriate levels of activity, and a desire for further advice, in children and young people with congenital cardiac disease. A few children may be at very significant risk. These needs can be identified, and clinical risk reduced, using a brief self-completed questionnaire combined with telephone follow-up from a suitably knowledgeable physiotherapist.

We report our initial experience in using the Amplatzer® vascular plug for closure of coronary arterial fistulas. The self-expanding, cylindrical, device is made from Nitinol wire mesh, and is available from 4 to 16 millimetres in diameter. We have now used the device to close fistulas in 3 patients, aged from 3 to 14 years, who presented with ratios of pulmonary-to-systemic flow from 1.5 to 3. In 2 patients, fistulas arising from the proximal right and left coronary arteries, with maximal diameters of 9 and 10 millimetres, respectively, had their narrowest diameter, of 6 millimetres, proximal to the entrance into the right atrium via a saccular aneurysm. The third fistula, with a maximal diameter of 16 millimetres, and with its origin from the circumflex coronary artery, entered the right atrium with nearly unrestricted flow, its narrowest diameter being 8 millimetres. For interventional closure, we chose plugs twice the diameter of the narrowest segment of the fistula, thus using 2 devices of 12 millimetres and one of 16 millimetres diameter. An arteriovenous loop was established through the fistula by snaring an exchange guide wire. Using a 7 or 8 French guide catheter inserted through the femoral vein, all plugs were placed at the narrowest segment of the fistula, leading to immediate complete closure of 2 fistulas. The third patient, with a fistula of the circumflex coronary artery, who received the largest plug initially had residual flow, but the fistula was found to be completely occluded at 12 months follow-up examination. We have demonstrated, therefore, safe and effective usage of the new vascular plug for transcatheter closure of moderate- to large-sized coronary arterial fistulas. The plug offers an alternative to cardiac surgery, or occlusion using coils.

Transcatheter closure of ventricular septal defects with the Amplatzer® Membranous VSD Occluder has yielded promising initial results, but disturbances of conduction, including complete heart block, have been reported. We report our experience with the Amplatzer occluder in 35 patients with a median age 4.5 years, the defects being sized angiographically at 4.4 plus or minus 1.1 millimetres, with a range from 3 to 8 millimetres, and the size of the occluder varying from 4 to 12 millimetres. Over a median follow-up of 2.5 years, the rate of complete closure was 87% and 91%, at 1 and 2 years respectively, while 2 patients required surgical closure of the defect subsequent to the insertion of the device. Persistent regurgitation across the tricuspid valve related to the occluder was observed in 3 patients, and in 6 patients across the aortic valve. Abnormalities of conduction related to the procedure were noted in 7 patients, one-fifth of the cohort. The disturbances were transient in 1 patient, but permanent in 6, in one of the latter progressing after 6 months from left bundle branch block to intermittent Mobitz II second-degree atrioventricular block in association with expansion of the occluder. We conclude that transcatheter closure of perimembranous ventricular septal defects with the Amplatzer occluder is effective with limited complications, but the incidence of immediate and progressive disturbances of conduction related to the proximity of conduction tissues to the rims of the occluder stress the importance of larger and longer studies to assess the safety of this procedure.

Objective: The frequency of residual shunting or recanalization was investigated in patients in whom a persistently patent arterial duct had been doubly ligated and transfixed during surgical closure. Methods: We investigated in retrospective fashion for any residual shunting 325 patients who, between January 1990 and December 2004, had undergone surgical double ligation and transfixion of a persistently patent arterial duct. Shunting was discovered in 10 patients, of whom four male and six female. Results: Of those with residual shunting. 4 patients had initially exhibited only persistent patency of the duct, while the other 6 had associated mild cardiac lesions. The mean age at operation was 5.5 years, with a range from 0.5 to 17.9 years. Postoperatively, the mean period for detecting the residual shunt was 22.8 months, with a range from 2 days to 72 months. The frequency of residual shunting amongst our patients, therefore, was 3.1%. We detected the residual shunt by colour-flow Doppler mapping in all patients, although a continuous murmur was heard in only one patient on physical examination. Conclusion: Our findings suggest that clinical sensitivity of detecting residual shunting subsequent to surgical closure of the persistently patent arterial duct is low, and hence that colour-flow Doppler interrogation should be a part of follow up. Residual shunting, or recanalization, may occur even after double ligation and transfixion of the duct. Since the residual flow may emerge after months, or even years, follow-up is needed for longer periods.

The coronary arteries, the vessels through which both substrate and oxygen are provided to the cardiac muscle, normally arise from paired stems, right and left, each arising from a separate and distinct sinus of the aortic valve. The right coronary artery runs through the right atrioventricular groove, terminating in the majority of instances in the inferior interventricular groove. The main stem of the left coronary artery bifurcates into the anterior descending, or interventricular, and the circumflex branches. Origin of the anterior descending and circumflex arteries from separate orifices from the left sinus of Valsalva occurs in about 1% of the population, while it is also frequent to find the infundibular artery arising as a separate branch from the right sinus of Valsalva.

Anomalies of the coronary arteries can result from rudimentary persistence of an embryologic coronary arterial structure, failure of normal development or normal atrophy as part of development, or misplacement of connection of a an otherwise normal coronary artery. Anomalies, therefore, can be summarized in terms of abnormal origin or course, abnormal number of coronary arteries, lack of patency of the orifice of coronary artery, or abnormal connections of the arteries.

Anomalous origin of the left coronary artery from the pulmonary trunk occurs with an incidence of approximately 1 in 300,000 children. The degree of left ventricular dysfunction produced likely relates to the development of collateral vessels that arise from the right coronary artery, and provide flow into the left system. Anomalous origin of either the right or the left coronary artery from the opposite sinus of Valsalva can be relatively innocuous, but if the anomalous artery takes an interarterial course between the pulmonary trunk and the aorta, this can underlie sudden death, almost invariably during or immediately following strenuous exercise or competitive sporting events. Distal anomalies of the coronary arteries most commonly involve abnormal connections, or fistulas, between the right or left coronary arterial systems and a chamber or vessel.

We discuss the current techniques available for imaging these various lesions, along with their functional assessment, concluding with a summary of current strategies for management.

We evaluated the concentrations of brain natriuretic peptide in the plasma as a marker of systolic ventricular function before and after maximal exercise in 15 surgically palliated patients with functionally univentricular hearts, with apparently good ventricular function. Of the patients, 6 with median age of 14.6 years, and a range from 12.5 to 17.9 years, had been palliated by construction of a total cavopulmonary connection, while the other 9 patients, with a median age of 32.1 years, and a range from 15.6 to 54.2 years, had undergone the classical Fontan procedure. We used 8 healthy individuals, with a median age of 13.9 years, and a range from 12.8 to 14.2 years, as a control group for the measurements of brain natriuretic peptide. The values of the peptide were significantly higher in those with the classical Fontan procedure, both before, when the median value was 131.8 nanogram per litre, with a range from 0.5 to 296.4, and after maximal exercise, when the median value was 108.1, with a range from 0.1 to 235.9. The comparable values in those with a total cavopulmonary connection were a median of 12.8, and a range from 0.5 to 39.1 before, and a median of 9.7, with a range from 2.7 to 26.2 after maximal exercise. The median value for the control group was 13.1, with a range from 2.6 to 38.7 before exercise (p = 0.016), and a median of 24.1, with a range from 5.8 to 66.7 after maximal exercise (p = 0.03), respectively. In the control subjects, the level of the peptide increased by a median of 9.7 nanograms per litre, with a range from 1.2 to 28.0 after maximal exercise (p = 0.008). The level was unchanged after maximal exercise in those with classical Fontan procedures and total cavopulmonary connections, with a difference between levels before and after exercise of a median of 5.9 nanogram per litre, and a range from −23.7 to 31.0 (p = 0.96), and a median of −1.0 nanogram per litre, with a range from −12.0 to 3.9 (p > 0.99), respectively. We conclude that maximal exercise did not increase the level of brain natriuretic peptide level in those patients with the classical Fontan procedure, nor those with a total cavopulmonary connection, findings which may indicate that systolic ventricular dysfunction is not the major cause of the decreased working capacity observed in patients with well functioning palliated functionally univentricular hearts.

We treated prospectively 14 patients with Eisenmenger's syndrome, with a mean age of 10 years, ranging from 3 to 18 years. Treatment continued for 12 months, and demonstrated a lasting symptomatic improvement, but no improvement in terms of mean saturation of oxygen over 24 hours. Exercise capacity, as judged by peak uptake of oxygen, worsened in the six patients able to perform a treadmill test. The symptomatic benefit from dual blockage of endothelin receptors in these patients may be due to mechanisms other than selective pulmonary vasodilatation alone.

We report our experience with implantation of stents for treatment of recurrent and native aortic coarctation in children weighing less than 20 kilograms. We treated 9 such patients between March, 2003, and January, 2006.

In 2 patients, the coarctation had not previously been treated, while in 7 it had recurred after surgery. The patients had a median weight of 14 kilograms, with a range from 5.5 to 19 kilograms. Balloon dilation was needed in 1 patient before the stent was implanted.

We used Palmaz Genesis XD stents in 7 patients, these having lengths from 19 to 29 millimetres, 1 Palmaz Genesis 124P stent, and 1 peripheral JoStent with a diameter of 6 to 12 millimetres. Implantation was effective in all patients. Immediately after implantation, the mean peak systolic gradient decreased from 30 millimetres of mercury, the range having been 15 to 50 mm, to 3 millimetres of mercury, with the final range from zero to 10 mm. There were no complications, with no observations of aneurysms, dissections, or dislocated stents. In 1 patient, the peripheral pulse was weak secondary to arterial access, but treatment with Heparin led to complete resolution. It was necessary to re-dilate the stent in another patient, while 2 others are scheduled for redilation because of growth-related restenosis. Our findings suggest that implantation of stents can produce excellent relief of the gradient produced by recurrent or native coarctation.

The process is safe and effective in patients weighing less than 20 kilograms.

Persistent patency of the arterial duct represents one of the most common lesions in the field of congenital cardiac disease. The strategies for management continue to evolve. In this review, we focus on management beyond the neonatal period. We review the temporal evolution of strategies for management, illustrate the currently available the techniques for permanent closure of the patent arterial duct, review the expected outcomes after closure, discuss the current controversy over the appropriate treatment of the so-called “silent” duct, and provide recommendations for the current state of management of patients with persistent patency of the arterial duct outside of the neonatal period.

At the Congenital Heart Institute of Florida, we now recommend closure of all patent arterial ducts, regardless of their size. Before selecting and performing the type of procedure, we explain the natural history of the persistently patent arterial duct to the parents or legal guardian of the child. Particular emphasis is placed on the risks of endocarditis, including the recognition that many cases of endocarditis may not be preventable.

The devastating effects of endocarditis, coupled with the perception of more anecdotal reports of endocarditis with the silent duct, as well as the low risk of interventions, has led us to recommend closure of the patent arterial duct in these situations. We now recommend intervention, after informed consent, for all patients with a patent arterial duct regardless of size, including those in which the patent duct is “silent”. We recognize, however, that this remains a controversial topic, especially given the new recommendations for endocarditis prophylaxis from American Heart Association.

Since 2003, our strategy for closure of the patent arterial duct has changed subsequent to the availability of the Amplatzer occluder. This new device has allowed significantly larger patent arterial ducts to be closed with interventional catheterization procedures that in the past would have been closed at surgery. During the interval between 2002 and 2006 inclusive, the overall surgical volume at our Institute has been stable. Over this period, the number of patients undergoing surgical ligation of the patent arterial duct has decreased, with this decline in volume most notable for the subgroup of patients weighing more than five kilograms. This decrease has been especially notable in thoracoscopic procedures and is attributable to the increased ability to close larger ducts using the Amplatzer occluder.

For infants with symptomatic pulmonary overcirculation weighing less than 5 kilograms, our preference is for the surgical approach. For patients who have ductal calcification, significant pleural scarring, or “window-like” arterial ducts, video-assisted ligation is not an option and open surgical techniques are used. When video-assisted ligation is possible, the approach is based on family and surgeon preference. When open thoracotomy is selected, we usually use a muscle-sparing left posterolateral thoracotomy.

For patients weighing more than 5 kilograms, we currently recommend percutaneous closure for all patent arterial ducts as the first intervention, reserving surgical treatment for those cases that are not amenable to the percutaneous approach. For symptomatic infants weighing greater than 5 kilogram with large ducts, we prefer to use the Amplatzer occluder. In rare instances, the size of the required ductal occluder is so large that either encroachment into the aorta or pulmonary arteries is noted, and the device is removed. The child is then referred for surgical closure. We can now often predict via echocardiography that a duct is too large for transcatheter closure, even with the Amplatzer occluder, and refer these patients directly to surgery.

For patients with an asymptomatic patent arterial duct, we prefer to wait until the weight is from 10 to 12 kilograms, or they are closer to 2 years of age. If the patent arterial duct is greater than 2.0 to 2.5 millimetres in diameter, our preference is to use the Amplatzer occluder. For smaller ducts, we typically use stainless steel coils. Using this strategy, we close all patent arterial ducts, regardless of their size.

We report the results of follow-up of the complete cohort of Norwegian children born in the period from 1987 through 1998 in whom there was the intention to treat surgically hypoplasia of the left heart using the Norwood sequence of operations. Of the 54 children, 21 are alive. Of these, 15 have been extensively studied, while the medical state of all the remaining survivors is known from reports from other hospitals. Of the survivors, the majority have reasonably acceptable cardiac and haemodynamic function, but significant neurological and neuropsychological morbidity is identified within the group as a whole, which requires special attention from qualified personnel of various kinds.

Background: In patients with discordant atrioventricular and ventriculoarterial connections, anatomic repair restores the morphologically left ventricle to its role in supporting the systemic circulation. In this study, we have evaluated the outcomes in the intermediate term for this complex surgical procedure. Methods: Between December 1984 and October 2003, 4 patients underwent an atrial switch operation concomitantly with a Rastelli operation, and 2 patients underwent an atrial switch operation and a patch-plasty of the pulmonary outflow tract for anatomic repair at a mean age of 3.3 plus or minus 2.1 years. All patients had intracardiac rerouting, connecting the morphologically left ventricle to the aorta. Results: There were no hospital deaths. In 5 patients, reoperation was needed, either for baffle complications, exchange of the conduit, repair of a residual ventricular septal defect, or relief of obstruction within the left ventricular outflow tract. Death occurred in 1 patient, from cardiac failure 6 months after correction. Mean follow-up time was 6.5 plus or minus 6.4 years, with a range from 6 months to 17 years. At follow-up, 1 patient presented with moderate tricuspid insufficiency, and 1 patient with mild obstruction of the pulmonary venous pathway. The remaining 3 patients showed good left and right ventricular function, and no, or mild tricuspid and mitral insufficiency. Conclusions: Anatomic repair can be performed with low hospital mortality. Restoration of the morphologically left ventricle into the systemic circulation in patients with discordant atrioventricular and ventriculoarterial connections is a demanding approach, associated with various reoperations over time. Despite this, the approach seems to be an appropriate solution for selected patients, since the majority of the patients show good left and right ventricular function, and no, or mild tricuspid and mitral insufficiency up to 17 years after correction.

Background: Nicotinamide adenine dinucleotide phosphate oxidase of the vascular cell membrane is an important source of reactive oxygen species. The aim of our study was to evaluate the possible influence of the p22phox C242T gene polymorphism on blood pressure and some markers of oxidative stress in children with tetralogy of Fallot. Methods: After surgical repair in early life, we recruited 38 children, aged 11.7 plus or minus 3.2 years, including 185 healthy individuals as controls for the purposes of establishing frequencies of alleles and genotypes. From this latter group, we matched a sub-sample of 53 healthy caucasian children, aged 11.0 plus or minus 1.0 years, in order to compare enzymic activities. Results: The children with tetralogy of Fallot showed significantly lower values of low-molecular-weight protein tyrosine phosphatase, particularly in carriers of CC genotype for the p22phox gene, with values of 145.2 plus or minus 77.4 μmol/g Hb/h, compared to controls, at 344.4 plus or minus 100.4 μmol/g Hb/h (p less than 0.001). Methemoglobin reductase activity in the patients with tetralogy was also lower in those with the CC genotype, at 9.8 plus or minus 3.2 μmol/g Hb−1 min−1 compared to 24.2 plus or minus 11.8 μmol/g Hb−1 min−1 as measured in the controls (p less than 0.01). Lower systolic (p less than 0.05) and diastolic (p less than 0.01) blood pressures were also observed in the patients with tetralogy of Fallot. Conclusions: Patients with tetralogy of Fallot having the CC genotype may be at a higher state of oxidative stress than T allele carriers, a finding which could have prognostic implications. Long term follow-up of these patients, however, may be necessary in order to draw definite conclusions.