For forty years, heparin has been used to temporarily inhibit normal coagulation so as to permit the use of extracorporeal circulation. It has proved effective in preventing gross thrombosis and has not been compromised by changes in adjunctive practices (such as profound hypothermia; circulatory arrest), new pharmacological therapies (such as anesthetics or antibiotics), devices (such as membrane oxygenators), or during use in patients at the extremes of age. Unfortunately, heparin has been and continues to be inefficient in preserving hemostatic function during cardiopulmonary bypass resulting in undesirable bleeding after surgery.

A ventricular septal defect is, almost always, an integral part of double outlet right ventricle and has been classified into the subaortic, subpulmonary, doubly committed and non-committed varieties. This study was performed to correlate the cross-sectional imaging characteristics of such ventricular septal defect in double outlet right ventricles using pathological specimens. The extent and the orientation of the outlet septum were the most important in the differentiation of the four varieties of ventricular septal defect. In the subaortic variety, the outlet septum fused with the left anterior margin of the defect, this being marked by the anterior limb of the septomarginal trabeculation. In the subpulmonary variety, the outlet septum fused with the right posterior margin of the defect, this being the posterior limb of the septomarginal trabeculation. The outlet septum was vestigial in case with doubly committed defects. In those with non-committed defects, the defect was not shown in those images or sections which demonstrated the outlet septum.

To identify the echocardiographic features and natural history of dilated cardiomyopathy in fetal life, we reviewed records of all fetal echocardiograms over the 10 year period 1980–1989 to identify cases of dilated cardiomyopathy without left ventricular outflow obstruction and conducted a retrospective review of the fetal echocardiograms and clinical course of those fetuses with dilated cardiomyopathy. In addition, all fetal losses, perinatal deaths and live-born infants presenting with dilated cardiomyopathy in the first seven days of life were identified from the British Columbia Pediatric Cardiovascular Pathology Registry and from inpatient records. The pathological findings and outcome for this group were also reviewed. Marked left ventricular dilatation and dysfunction without left ventricular outflow obstruction was diagnosed in five of 1,158 fetuses undergoing feta lechocardiography. These five fetuses were correctly distinguished from two others with critical aortic stenosis and severe left ventricular dysfunction. Two of the five fetuses had additional right ventricular dysfunction and dilatation and developed hydrops, while the remaining three with isolated severe left ventricular dysfunction did not and showed normal somatic growth. All fetuses were live-born with spontaneous labour occurring in four of five cases at a mean gestational age of 36.5 weeks. Four of the five infants died, with three deaths occurring in the first week of life. During the same 10 year period, two of 2450 autopsied stillbirths (both hydropic) were diagnosed with dilated cardiomyopathy. An additional 15 neonates (including the five identified by fetal echocardiography) were diagnosed in the first week of life with dilated cardiomyopathy, congenital myocarditis or endocardial fibroelastosis. Four were hydropic (all with associated right ventricular dysfunction). Only three of the 15 survive. Fetal echocardiography can accurately distinguish dilated cardiomyopathy from left ventricular outflow obstruction. In the absence of right-sided disease or premature closure of the oval fossa, severe left ventricular dysfunction is well tolerated in utero. The prognosis for fetal dilated cardiomyopathy is very poor.

A fenestration in the atrial septum may be temporarily beneficial in high–risk patients undergoing the modified Fontan operation. The venous system is decompressed into the left atrial cavities resulting in an improvement in the systemic output at the expense of a moderate arterial desaturation due to a right–to–left shunt. Two groups of patients undergoing the modified Fontan operation were compared. Those treated with the classic operation (non–fenestrated Fontan group, n=56) had lower prevalence of preoperative risk factors for the Fontan operation than those undergoing the Fontan operation with a fenestrated patch (n=91). Nevertheless, early results of mortality, repair take–down and morbidity (duration of pleuropericardial effusions) were comparable or better in the fenestrated Fontan group. By regression analysis the presence of a fenestrated patch was the major determinant in the reduction in the amount and duration of postoperative effusion. Of the early 73 survivors in the fenestrated Fontan group, fifty tolerated the closure of the fenestration, which occurred either spontaneously (five cases) or was achieved by a clamshell device during cardiac catheterization. Eleven patients failed the first attempt at fenestration closure, but this was successful at the second attempt a few months later. Coil embolization of arterial collaterals to the lung circulation and balloon dilatation of pulmonary artery stenoses were required in some cases. Other patients following the Fontan operation with a fenestrated patch showed an improvement of their ventricular function which was initially impaired. This favorable experience demonstrates the usefulness of the “fenestrated Fontan approach” in patients who are suboptimal candidates for the classic operation, provided that the preoperative risk factors are potentially reversible.

The debate concerning no flow versus low flow continues. Thus, it has not yet been possible to conclude whether limited period of total circulatory arrest, as opposed to maintained but reduced systemic flow, offers superior protection of the brain during cardiac surgery in children. While most previous work has focused on the hypothermic period of no versus low flow, less is known about the conditions during and after rewarming with full systemic flow. Some previous data, which related the ischemic marker creatine kinase BB during profound hypothermic procedures, suggested that neural dysfunction was aggravated by posthypothermic factors such as hyperglycemia, acidosis and anemia.

Thrombolysis was used in 13 procedures to treat eight patients with massive thrombosis of coronary aneurysms due to Kawasaki disease. The patients have now been followed for periods ranging from 2.5 years to 7.4 years subsequent to treatment. The procedures included intracoronary or intravenous infusion of urokinase and intravenous administration of tissue plasminogen activator. Thallium myocardial imaging, coronary arteriography and echocardiography were used for evaluation of the efficacy of the therapy and for follow-up studies. The latest time of treatment was 17 months after the onset of the disease. No new formation of massive thrombus was observed in any of the aneurysms. In five patients, eight of 13 procedures were judged to be successful. In the four patients with symptoms of myocardial ischemia, thrombolysis was undertaken immediately after the onset of symptoms. In the other patient, thrombolysis was attempted 36 days after the onset and produced remarkable improvement in the degree of ischemia. In the other four patients with no symptoms of ischemia, the therapy was undertaken when thrombus was detected in a coronary aneurysm. Aortocoronary bypass surgery was undertaken subsequent to the thrombolytic therapy in three patients, but proved satisfactory in only one patient. At follow-up, five patients have shown improvement in the degree of myocardial ischemia after treatment. Our results suggest that careful observation is needed to detect formations of thrombus in large coronary arteries for at least 1½ years after the onset of Kawasaki disease. Even if repeated thrombolytic therapy is required, it seems to be effective in checking the progression of ischemic heart disease.

We examined the echocardiograms of 40 patients with double oudet right ventricle, proven either at autopsy or during surgery. By way of the subcostal approach, it proved possible to determine the insertion of the outlet (infundibular) septum and to categorize the malformations within the classification proposed by de la Cruz and her colleagues. It was also possible to ascertain the relationships of the atrioventricular valves with one or with both infundibulums, and these features could be correlated with infundibular interrelationships. The interrelationship of the great arteries, in contrast, was not always in accordance with the infundibular interrelationships, indicating that the arterial interrelationship may not prove to be a good parameter for surgical decision-making. Of greatest importance was the visualization and echocardiographic appraisal of the spatial position and size of the ventriculoinfundibular fold, since this anatomic feature was the key to determining the optimal surgical approach. This is so because the ventriculoinfundibular fold constitutes one of the borders of the ventricular septal defect, and separates it from the plane of the leaflets of the arterial valves. Furthermore, the fold frequendy contributes to infundibular obstruction. Our echocardiographic studies, based on a better anatomic knowledge, permitted us to choose the most suitable surgical technique in our patients.

Because left ventricular mass may be important in judging feasibility of Fontan type of palliation in tricuspid atresia, this study was undertaken to generate data on left ventricular mass, volume and mass to volume ratio in newborns and infants with tricuspid atresia, native pulmonary stenosis and concordant ventriculoarterial connections prior to any surgical palliation to obtain values for “normal” left ventricular dimensions in tricuspid atresia. The left ventricle was evaluated in the apical two and four chamber view. From these two perpendicular imaging planes, we calculated mass as difference between epicardial and endocardial volume x 1.05 (specific gravity of heart muscle). Mass divided by volume at end-diastole yields the index: mass to volume. Data from 23 newborns and infants with tricuspid atresia were compared to data from 30 age-matched controls with normal hearts. In both patient and control groups, growth of the left ventricle was not linear but related to the 1.4 (volume) or 1.25 (mass) power of body surface area. The equation best describing relation between left ventricular volume and body surface area in normals is volume = 60.7(body surface area)1.4−0.2 ml; in patients with tricuspid atresia volume calculates as 96.7(body surface area)1.4+0.9 ml. In relation to normal infants, infants with tricuspid atresia had a left ventricular volume of 167 (135–206)% of normal and a left ventricular mass of 163 (132–201)% of normal. Left ventricular mass assessed in normals calculates as mass = 59.9(body surface area)1.25+1.3 grams; in patients with tricuspid atresia it calculates as mass= 117.5 (body surface area)1.25−0.9 grams. The index of left ventricular mass to volume in patients with tricuspid atresia measured 1.32, not significantly different from controls, in whom this index calculates as 1.34.

Selective coronary angiography was performed in 110 cases (aged 1–45 years) of tetralogy of Fallot. Anomalies of surgical importance were seen in 26 cases (23.6%). In 17 (15.4%) these anomalies existed alone, and in nine (8.2%) they coexisted with relatively minor anomalies. Isolated minor anomalies involving the terminal branches existed in 15 cases (13.6%). The coronary arterial anatomy was normal in the other 69 (62.7%) cases. Our study shows that coronary angiography can safely be performed in patients with tetralogy of Fallot, providing the surgeon with vital information for subsequent planning of the time and type of surgery required.

We studied the morphology of the aortic valves of 1,036 Syrian hamsters belonging to two families subjected to high endogamous pressure. Most (n=955) specimens were examined using a corrosion-cast technique. In the remaining 81 specimens, valvar morphology was assessed by means of a stereomicroscope, and in 18 of these cases a histologic study was also performed. In one of the families, a high proportion (30.5%) of hamsters had aortic valves with two leaflets, the aortic sinuses being oriented ventrodorsally. The percentage of such anomalous valves was found to be positively correlated with the inbreeding coefficient of specimens. In the other family, the occurrence of an aortic valve with two leaflets was a sporadic event. Stereoscopic and histologic observations demonstrated that, in 52 of 63 aortic valves with three leaflets, the ventral commissure between the right and left leaflets was partially fused, while in 10 other cases this commissure was completely fused. In addition, in nine of 18 aortic valves with two leaflets, there was a more or less well-developed raphe located in the ventral aortic sinus, approximately where the true ventral commissure would have been. Our observations suggest the existence of a continuous spectrum of aortic valvar morphology, ranging from a valve with three leaflets and no fusion of the ventral commissure to an aortic valve with two leaflets devoid of any raphe. This spectrum seems to be the result of the interaction of genetic and intrauterine environmental factors. Results of crosses between both related and unrelated hamsters suggest that the observed morphology in individuals is the result of quantitative inheritance.

In our first two experiments, we examined brain tissue pH and tensions of oxygen and carbon dioxide in dogs core cooled to 20°C. So as to evaluate the effects of 60 minutes of circulatory arrest, 120 minutes of low-flow perfusion (25 mI/kg/mm), and 120 minutes of moderate-flow perfusion (50 mi/kg/mm), all conducted with and without pulsatile assistance. We further determined the effects of blood gas strategy on the same variables with 60 minutes of circulatory arrest. In a third experiment, we directly observed microcirculation at the surface of the brain during profoundly hypothermic perfusion. In the fourth experiment, we measured cerebral blood flow, oxygen consumption, and excessive production of lactate. Profound anoxia occurred within 20 minutes of circulatory arrest, causing severe and progressive acidosis in the brain tissues along with hypercapnia. The inhalation of 5% or 7% carbon dioxide during core cooling made the brain unacceptably acidotic. The brain acidosis was mild with low flow perfusion, and slight with moderate-flow perfusion. Pulsatile assistance improved acidosis in the brain tissues at all rates of flow. It also improved the microcirculation, the patent number of arterioles and stabilized flow in bridging veins. Cerebral metabolism became aerobic without alterations in cerebral consumption of oxygen during low-flow perfusion. We recommend flow rates above 25% of normal, alpha-stat strategy, and pulsatile assistance for better protection of the brain during profound hypothermia.

Clinical and Doppler echocardiography were performed in 65 patients who had undergone ligation of the arterial duct between January 1978 and December 1991. Of the patients, 12 (18%) patients had residual patency as demonstrated by color Doppler, while three (4.6%) of these had continuous murmurs. There was no association between residual patency and the age at surgery, the weight at surgery or the follow-up interval.

Cardiopulmonary bypass has been extended to the very young patient undergoing operative correction of congenital heart defects. Growth and development of the central nervous, cardiovascular, pulmonary, and renal systems place significant metabolic and nutritional demands on cellular growth and repair. Immature homeostatic regulation and cellular function require modification of the approaches to preservation of organs and cardiovascular support used in older children and adults undergoing open-heart surgery. Aspects of newborn and infant physiology relevant to cardiopulmonary bypass and postoperative care are reviewed. Current approaches and future strategies designed to address the needs of the developing patient who requires cardiopulmonary bypass are discussed.

Embolization of major aortopulmonary collateral arteries by coils introduced via catheterization is a well-established procedure for the control of excessively high pulmonary blood flow in patients with tetralogy of Fallot and pulmonary stenosis or atresia. Under special circumstances, this procedure can be life-saving. Between October 1987 and February 1992, four patients with tetralogy of Fallot and pulmonary atresia and one patient with pulmonary stenosis rather than atresia underwent transcatheter embolization of major aortopulmonary collateral arteries as an emergency. Their ages ranged from 41 days to 13 years, with a mean of 45 months. Two patients had recently undergone surgical repair of tetralogy of Fallot while one had been palliated by enlarging the right ventricular outflow tract without closing the ventricular septal defect. All three had been dependent on mechanical ventilation in the postoperative period with signs of pulmonary congestion or intraparenchymal hemorrhage. Eight embolizations were attempted with 0.025 or 0.038 inch coils; seven collateral arteries were completely occluded and one was partially occluded. Thirteen coils were used in total. The systemic saturation rose in one postsurgical patient, with radiological evidence of decreased pulmonary congestion and regression of hemorrhage. In the other cases, the systemic saturation was unchanged. Peak pulmonary arterial pressures dropped in two patients but remained unchanged in three. Our experience suggests that embolization of major aortopulmonary collateral arteries can be beneficial in critical patients, thus avoiding the risks of surgical reexploration.

We report a case of an infant with isomerism of the right atrial appendages in whom a spleen-like nodule was found at post-mortem. The nodule, on histology, was found to be a fragment of liver. The cardiac lesions were typical of those associated with right isomerism, a complex generally described as the “asplenia syndrome.” The presence of either a spleen, or a nodule masquerading as a spleen, does not preclude an isomeric arrangement of the atrial appendages nor its commonly associated constellation of cardiovascular anomalies.

A patient with the rare combination of an unusual form of pulmonary atresia with intact ventricular septum and a Marfan-like disease is presented. She was extremely cyanosed in childhood but improved after construction of a left peripheral shunt at the age of nine years. She deteriorated gradually after the onset of atrial fibrillation at the age of 33, the subsequent course being complicated by a stroke and, finally, by intractable heart failure and death at the age of 39.

A complex case of congenital heart disease is presented which features isomerism of the left atrial appendages combined with bronchoatrial discordance and an anteriorly placed non-interrupted inferior caval vein draining to the left-sided atrium. This combination of anomalies has, as far as we are aware, not been described before. It emphasizes the importance of direct confirmation of atrial arrangement by atrial angiography or transesophageal echocardiography.

Isolated fetal pericardial effusion is generally held to have a good prognosis. We report a study of seven cases identified from a total of 504 fetuses scanned and followed with serial fetal scans.Our results show that it was associated with a poor fetal prognosis in six of the seven pregnancies. Probably due to the high incidence of mid-trimester abortion and the association with other abnormalities only evident postnatally, this has not, hitherto, been reported. We would advocate close follow-up and a guarded prognosis when isolated pericardial effusions are found on fetal scans.