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Sudden Infant Death Syndrome (SIDS) is the most common cause of death in children between 1 and 6 months of age. Recent data suggest that a prolonged QTc interval on the 12-lead electrocardiogram (ECG) is associated with SIDS. Prone body position during sleep is also known to be a risk factor for SIDS; this has prompted the American Academy of Pediatrics to promote the "Back to Sleep" campaign. We postulated that the QTc interval in infants might change as a function of body position, linking the observations relating body position and QTc interval to SIDS. We recorded ECGs in a group of infants in both the supine and prone position to determine if the QTc interval and QT dispersion differ between the 2 positions. Forty-seven standard 12-lead EGGs and high-amplitude, rapid-sweep 12-lead EGGs were performed on 45 healthy infants (mean age 26 +/- 40 days) in both the supine and prone positions. The infants were asleep in a quiet, restful state. The ECGs were reviewed by 2 investigators blinded to the position of the infants during recording. Measurements included the average QTc interval (using Bazett's correction) and QT dispersion (the difference between the longest and the shortest QT intervals on a standard 12-lead EKG). The study was designed to detect a 3% difference in QTc interval with 80% power and alpha = 0.05. All subjects had telephone or clinical follow-up at 1 year. The average QTc interval was 403 +/- 20 milliseconds (msec) in the supine position and 405 +/- 27 msec in the prone position (p = NS). The QT dispersion was 20 +/- 12 msec in the supine position and 22 +/- 13 msec in the prone position (p = NS). One infant in the study group died of SIDS at the age of 3 months. The EGG of this patient revealed a QTc interval of 382 msec in the supine position and 407 msec in the prone position; the QT dispersion was 34 msec in the supine position and 34 msec in the prone position. We found no difference in QTc interval or QT dispersion as a function of body position in healthy infants resting quietly. Prolongation of the QTc interval is unlikely to explain the increased risk for SIDS associated with prone body position in the general population of healthy infants, unless patients with long QT syndrome are somehow more influenced by body position than normal patients are.

Pediatric cardiologists and cardiologists who examine adults frequently receive referrals of adolescents and young adults with chest pain. Chest pain in this age group is most likely noncardiac in origin, which often creates a diagnostic dilemma for the consultant in terms of the etiology and extent of evaluation. This review presents the noncardiac and cardiac etiologies of chest pain in adolescents and young adults, as well as the key features of a patient's history and physical examination that help delineate cardiac from noncardiac chest pain. In addition, we present recommendations for the cardiac consultant regarding the evaluation and management of adolescents and young adults referred with the complaint of chest pain.

Anomalous left coronary artery (ALCA) from the pulmonary trunk presents in early infancy with a clinical picture of failure to thrive, congestive heart failure (CHF), angina-like episodes, and mitral insufficiency. These manifestations which are due to myocardial ischemia may change in the presence of an associated lesion. We present a case and review two previous reports of a patent ductus arteriosus (PDA) associated with this anomaly. Although signs and symptoms are not as clear due to the less impaired coronary perfusion and the presence of a PDA, the presence of mitral insufficiency should raise the possibility of an anomalous coronary artery and, therefore, a cardiac catheterization and angiocardiography are recommended in anticipation of reparative surgery.

The first superior vena cava-pulmonary artery shunt (Glenn shunt) in our series was performed in February 1958. From then through September 1988, 91 patients have undergone this procedure for a wide variety of congenital defects. We here report follow-up data available on all patients. Ages ranged from 2 days to 46 years (mean 6.8). Diagnoses were as follows: tricuspid atresia, 27; single ventricle, 22; tetralogy of Fallot, 14; D-transposition of the great arteries, ventricular septal defect, and pulmonary stenosis, 9; D-transposition, 5; Ebstein's anomaly, 4; pulmonary atresia + intact septum, 4; and others, 6. The hospital mortality rate was 7.7% (one death in the last 53 patients, 1.9%). Five deaths occurred in patients less than 6 months old. There were 20 late deaths (22%) with actuarial survival rates of 84% and 66% at 10 and 20 years, respectively. Pulmonary arteriovenous fistula formation was seen in 18 patients (19.7%), six of whom have undergone therapeutic embolization with improvement in saturation. The prevalence of pulmonary arteriovenous fistula increases with time after shunt. No long-term shunt thrombosis or stricture formation was seen. Fifty percent of shunts were still functioning at 20 years. Palliation was limited because of decrease in blood flow to the contralateral pulmonary artery, collaterals between the inferior and superior venae cavae, and pulmonary arteriovenous fistula formation. Improvement in saturation was obtained in eight otherwise inoperable patients by creation of a right axillary arteriovenous fistula up to 19 years after the Glenn shunt. Three patients had conversion of a Blalock-Taussig shunt to a Glenn shunt with improvement in congestive heart failure. Twenty-six patients have undergone a Fontan procedure with two deaths. Compared with the group having a Fontan procedure without a prior Glenn operation, there was no difference in early or late mortality. Thirty years after a Glenn shunt, the first patient in this series is working full time after having undergone a modified Fontan procedure in 1981. We conclude that the Glenn connection, usually with supplemental procedures to enhance oxygenation, has provided excellent physiologic palliation with low mortality up to 30 years with no late thrombosis or stricture formation. The incidence of pulmonary arteriovenous fistula increases with time and can be effectively treated with embolization. Physiologic repair after the Glenn shunt carries a low mortality. Although currently used infrequently, superior vena cava-pulmonary artery shunting remains a useful method of palliation in selected patients.(ABSTRACT TRUNCATED AT 400 WORDS)

A protocol is presented that facilitates early extubation following pediatric cardiothoracic operations. A total of 197 consecutive patients were managed according to this protocol. Fifty percent of the patients were less than 3 years old. Cardiopulmonary bypass was required in 113 (57%) of the surgical procedures. Extubation immediately following the surgical procedure was accomplished in 142 (72%) of the patients. Pulmonary complications occurred in 8 of these 142 patients (6%) and in 10 (18%) of the 55 patients requiring postoperative mechanical ventilation. Of the patients having early extubation, 5 (4%) required reintubation. One death in this group was unrelated to pulmonary function. There were 16 deaths among the 55 patients managed with mechanical ventilation. Carefully conducted early extubation provided specific advantages over routine postoperative mechanical ventilation. Modern techniques of anesthesia and surgical repair of congenital heart disease can decrease the requirement for postoperative mechanical ventilation and the potential for related complications.

Fetal echocardiography has been a useful technique for demonstrating the anatomy of the developing human heart. M-mode echocardiography may be used to provide rhythm diagnosis in the absence of high-fidelity transabdominal fetal electrocardiograms. The information so generated may be applied to plan the management of pregnancy and delivery in a population at "high risk" for structural or functional heart disease and may provide the impetus for developing in utero treatment programs. For this reason, a high degree of sensitivity and specificity must be asked of the technique and of the personnel performing the examination. "Major" malformations which impart marked hemodynamic and structural alterations on the fetal heart may be reliably diagnosed. Diseases which must be identified on the basis of direct recognition of subtle abnormalities of structure, with little impact on fetal flow patterns (e.g. mild semilunar valve stenosis of perimembranous ventricular septal defect) have been more problematic. Before effective screening and treatment programs for the fetal heart can be developed, a cooperative effort between cardiologists and perinatologists is essential in order to gain facility with imaging as well as familiarity with the natural history of these conditions.

As a first step in a multicenter, collaborative project to study the role of indomethacin in the management of patent ductus arteriosus in premature infants, a diagnostic scheme was developed, on an a priori basis, by a consensus of the participating neonatologists and pediatric cardiologists. The scheme, which utilizes clinical and noninvasive findings, was designed to detect infants with a "hemodynamically significant" patent ductus arteriosus (PDA). Among 1,689 infants with birth weight less than 1,750 g who were monitored during the first year of the study, 342 (20.2%) met the criteria for PDA. Rates were higher for smaller infants (42% with birth weight less than 1,000 g) than for larger infants (7% with birth weight 1,500 to 1,750 g). Although study protocol did not require a direct procedure to confirm the diagnosis of PDA, a marked decrease in the presence of most criteria was noted following surgical ligation of the ductus. Although the echocardiographic criterion (ratio of left atrium to aorta [LA/Ao] greater than or equal to 1.15) proved to have a low specificity for PDA, the data suggest that the overall scheme led to a very low rate of false-positive diagnosis. Following the application of the scheme for 1 year at 13 clinical centers, it has been shown to be a highly acceptable means of detecting infants with PDA.

The effect of transthoracic direct current countershock on the myocardium of 21 newborn piglets was studied. Myocardial damage was quantified by measuring the myocardial uptake of technetium-99m pyrophosphate injected 24 hours after countershock. Substantial myocardial damage occurred in animals given greater than 150 joules/kg but not at lower energy doses. Damage occurred in both ventricular free walls, but more frequently in the right ventricle. The epicardial half of the myocardium was more severely affected than the endocardial half. The relationship between myocardial damage and total countershock energy dose was well modeled by an exponential function. Transthoracic direct current countershock appears unlikely to cause myocardial damage in newborn piglets unless greatly elevated energy doses are employed.

Accessory mitral valve tissue, a rare cause of left ventricular outflow tract obstruction, can be difficult to diagnose preoperatively and confusing even at surgery. The reported case illustrates how preoperative evaluation can be made using two-dimensional echocardiography combined with Doppler flow analysis. The intraoperative technique for removing the accessory tissue without causing damage to the native mitral valve is discussed.

Recurrence risks for primary congenital heart lesions are well defined. An infant with hypoplastic left heart syndrome is observed to have a short neck with a full skin fold on the right side, unilateral single palmar crease, and whorls on all ten fingers. She was found to have the Ullrich-Turner syndrome with mosaicism 45,X/46,XX/47,XXX. We believe the cardiac malformation was secondary to her aneuploidy. This could have important implications for prediction of recurrence risks to the parents. Chromosomal tests may be indicated for infants were severe congenital cardiac lesions, based on subtle clinical findings.

Small myocardial specimens were obtained from 12 patients undergoing coronary reconstructive surgery and from 12 patients undergoing surgical correction for cyanotic congenital heart defects. The specimens were analyzed for LDH isozyme distribution. A control analysis was performed on myocardial specimens obtained at the time of surgical correction for acyanotic congenital heart defects in seven patients with normal coronary arteries. There was a 42% increase in the proportion of A subunits in the hearts of coronary patients as compared to controls. This represented a shift toward an anaerobic isozyme distribution. There was no change in the percentage of A units from the hearts of cyanotic patients as compared to acyanotic hearts of the same age. Cardiac muscle from patients with coronary vascular disease had an altered LDH subunit composition. Such an alteration was not present with chronic systemic hypoxia. These deficiencies may or may not be related to differing local metabolic responses to the two conditions. However, in the clinical situations, ischemic heart muscle may be oxygen deprived to the point of lactic acid production while hypoxic heart muscle usually is not. Consequently, these findings may represent a compensatory cellular mechanism which provides for continued energy production during chronic ischemia by enhancing glycolysis.

The effect of physical training on the exercise performance of 26 patients following surgical repair of tetralogy of Fallot (16 patients) and ventricular septal defect (ten patients) was evaluated. Base line exercise testing was performed on a bicycle ergometer using the technique of Godfrey. Patients were placed on a six-week alternate day submaximal interval home exercise program of varying duration and intensity. Work loads at 50%, 60%, and 70% maximum oxygen consumption were selected to maintain heart rates between 130 and 160 beats per minute. Subjects completed an average of 18 of the possible 21 training sessions (range 11 to 21). A 25% improvement (p less than .001) was noted in maximum work capacity (747 to 935 km). Sixty-five percent of the patients performed at less than expected maximum work capacity prior to training, but only 31% performed at less than expected maximum work capacity after training. Repeat testing at work loads of one-third, one-half, and two-thirds the original maximum work capacity revealed improved aerobic efficiency as manifested by significantly decreased oxygen consumption and heart rate at each level of work. No significant difference was noted in maximum oxygen consumption. It is concluded that physical training can improve the exercise performance of patients after surgical repair, permitting the individuals to function at levels of activity at, or closely approaching, normal.

The clinical, roentgenographic, hemodynamic, and angiographic features of a patient with a right cervical aortic arch and retroesophageal aortic obstruction associated with a ventricular septal defect are presented. Surgical relief of the aortic obstruction was successfully achieved by placement of a bypass graft between the left common carotid artery and the descending thoracic aorta.

Congenital cardiac defects are not common, but their serious consequences make early detection and treatment essential. In developing a set of workable criteria for selective screening of serious abnormalities, the authors used commercially available ultrasound equipment in more than 500 high-risk pregnancies. Possible future applications include elucidation of causes of fetal cardiac defects.

We studied the acute effects of increasing hemoglobin concentration and hematocrit on the pulmonary and systemic circulations of nine infants with large left-to-right shunts. After isovolemic exchange transfusion, which was designed to raise hemoglobin but keep blood volume constant, a consistent rise in systemic and pulmonary vascular resistances occurred. This rise was comparable to those previously found in isolated circulations showing a linear relation between hematocrit and loge of the vascular resistance. These changes in resistance were accompanied by decreases in systemic and pulmonary blood flow and a marked decline in left-to-right shunt. Despite the decrease in systemic blood flow, there was no decline in systemic oxygen transport, and there may have been a marginal decrease in left ventricular stroke work. These observations help explain why the newborn with a large ventricular septal defect and a high hemoglobin concentration does not have clinical signs of a large left-to-right shunt, and also suggest that the postnatal decline in hematocrit has a substantial role in the normal fall in pulmonary vascular resistance after birth.

While four patients with d-transposition of the great arteries who had a Mustard operation before 2 years of age developed severe pulmonary venous obstruction 2, 3 1/2, 3 9/12, and 5 years following their operation, initial postoperative catheterization (less than 1 year) revealed only minimal pulmonary artery wedge and right ventricular end-diastolic pressure differences, with normal peak systolic pulmonary artery pressures. Serial clinical examination, including height and weight percentiles, chest X-rays, electrocardiograms, and the presence of a continuous murmur in one patient suggested development of pulmonary venous obstruction. Repeat catheterizations demonstrated pulmonary artery pressures greater than or equal to systemic and pulmonary artery wedge minus right ventricular end-diastolic differences greater than 13. Successful relief of the pulmonary venous obstruction included insertion of a Dacron patch to enlarge the pulmonary venous atrium, incision of the obstructing orifice, and repair of associated intra-atrial defects. Operation and postoperative course have been unremarkable. It is concluded that pulmonary venous obstruction can be both an early and progressively late sequela of the Mustard operation. Serial examinations with a high index of suspicion should allow repeated catheterizations to document the occurrence. Operative revision of the obstruction appears to be effective with minimal risk.

Fetal echocardiographic studies were performed in 71 patients referred for evaluation of cardiac rhythm disturbances at 24 to 40 weeks' gestation. After 2-dimensional echocardiographic study of cardiac structure was performed, M-mode echocardiograms were analyzed for measurement of cardiac rate, atrioventricular contraction sequence, atrioventricular valve motion, and duration of postectopic pauses. Arrhythmias were diagnosed in 59 patients. In 34 patients with isolated ectopic beats, the arrhythmia resolved during later pregnancy in 26 or within the first 5 days of life in 8. Six patients had mild sinus bradycardia and 8 had frequent sinus pauses; all 14 had resolution of the arrhythmia during pregnancy. Sustained arrhythmias occurred in 11 patients. Deaths occurred when there was associated fetal congestive heart failure (hydrops fetalis), structural heart disease, or both. M-mode echocardiography diagnosed supraventricular tachycardia in 3 fetuses. The echocardiogram was used thereafter for monitoring transplacental digoxin therapy.

The sequence of events leading to the development of acute obstruction in two infants with coarctation has been defined by clinical, hemodynamic, and angiographic studies. One infant had normally related great arteries and an isolated coarctation, while the other infant had transposition with a hypoplastic right ventricle, a ventricular septal deffect, narrowing of the aortic isthmus, and a localized site of coarctation. In each instance, a posterior aortic shelf--the basic pathologic lesion in coarctation--could be observed angiographically. Signs of aortic obstruction were absent, however, as long as the ductus arteriosus was widely patent. Following ductal obliteration, femoral pulsations diminished, a peak systolic pressure difference was recorded between the ascending and descending aorta, and a discrete area of juxtaductal coarctation was seen. The basic malformation (posterior aortic curtain) would appear to exist in utero, possibly as an aortic branch point. This lesion is nonobstructive as long as blood can traverse the aortic isthmus through the aortic end of the ductus into the descending aorta. Postnatally, as the ductus arteriosus undergoes constriction at its aortic insertion, signs of acute aortic obstruction may b =ecome apparent. Normal femoral arterial pulsations during the newborn examination do not definitively exclude coarctation. Pediatricians should recheck at 2 weeks of age if the infant is asymptomatic or sooner if there are signs of cardiac failure to establish the presence or absence of this defect.

During obstetrical ultrasound examinations, 200 M-mode and 35 real-time two-dimensional echocardiographic studies were performed on 180 fetuses of high-risk pregnancies. Fetal gestational ages ranged from 18 to 41 weeks. M-mode "sweeps" demonstrating mitral- and septal-aortic fibrous continuity were obtained in 115 studies. Paradoxic septal motion in 50 fetuses suggested relarive right ventricular volume loading. Congenital cardiac malformations were accurately diagnosed in a 34-week fetus with pulmonary atresia and hypoplastic right ventricle and in a 28-week fetus with a univentricular heart. Congenital complete atrioventricular block was diagnosed in a 28-week fetus and atrial flutter with variable atrioventricular block was diagnosed in a 38-week fetus. The use of echocardiographic studies to evaluate cardiac structure and rhythm in utero assists in counseling prospective parents and in planning postnatal management for their offspring.

A 3-month-old infant is described in whom a persistent left superior vena cava impinged on the posterior wall of the left atrium, producing a subdivided left atrium with left-to-right shunting and congestive heart failure. To our knowledge, this anomaly has not previously been reported. The preoperative diagnosis, surgical management, and embryological implications are discussed.

Extraction of circulating vasoactive hormones by the lung may influence systemic vasomotor tone. Since this process occurs in the pulmonary microcirculation, we evaluated the effects of pulmonary artery hypertension (PAH) secondary to congenital heart disease (CHD) on this metabolic function of lung. Eleven patients with varying congenital cardiac lesions were studied preoperatively and postoperatively. Five had normal pulmonary artery pressure (PAP) (group I), and six had PAH with peak systolic PAP greater than 40 mm Hg (group II). PA and postpulmonary arterial blood samples were collected before and after surgery at the time of pressure measurements. Norepinephrine (NE) and epinephrine (EPI) levels were determined by radioenzymatic assay. Preoperatively, circulating NE levels were higher (P less than 0.05) and NE extraction measured was lower (P less than 0.01) in group II patients as compared with group I. Extraction increased in group II postoperatively after PA pressures were reduced, becoming equivalent to group I postoperative values. EPI extraction was negligible in either group at any time. These data demonstrate that lungs of children are capable of selective catecholamine uptake and that elevated PAP occuring with CHD is associated with a decrease in this capability and an increase in circulating NE levels. Additionally, the decrease in NE extraction observed with PAH is reversible once PAP is reduced by surgical repair of the cardiac defect.

Thirteen fetuses with nonimmune hydrops (22 to 39 weeks of gestation) were evaluated with two-dimensional and M-mode echocardiography. Ten fetuses had cardiovascular abnormalities resulting in heart failure, and three had noncardiac causes of hydrops. In three cases, hydrops was caused by supraventricular tachycardia. One of these fetuses responded to cardioversion at birth, another responded to transplacental digoxin therapy, and the third died with atrial flutter and high-grade atrioventricular block before delivery. There were no cases of "idiopathic" hydrops. Our results show that fetal echocardiography is useful in determining cardiac causes of in utero heart failure resulting in hydrops fetalis. The fetal echocardiogram may also be used in monitoring transplacental therapy of heart failure.

The current approach to the perioperative management of the infant and child with congenital heart disease has been discussed. The major focus has been on potential problems of oxygen transport as they relate to vital organ system function. Management strategies for specific defects or perioperative problems have also been considered as well as the newer on-line monitoring techniques, while stressing the importance of careful clinical evaluation. The ultimate surgical outcome is dependent not only on the adequacy of repair or palliation but on the treatment of potential life-threatening situations that may take place during the critical postoperative period.

Effects of phenylephrine hydrochloride on the degree of hypoxia were studied in six cyanotic patients with tetralogy of Fallot. Baseline aortic and right atrial oxygen saturations, blood gas tensions, pH, and indicator-dilution curves were obtained under stable conditions. Phenylephrine was infused while systemic arterial pressure was monitored continuously. Aortic and right atrial blood samples were measured at each 10 mm Hg systolic pressure increment and decrement and analyzed for pH, PO2, PCO2, and oxygen saturation. A 40 mm Hg peak systolic aortic pressure rise was the arbitrary end point for phenylephrine infusion and the indicator-dilution curve repeated. Aortic oxygen tensions rose in all from 4 to 28 mm Hg (mean, 14 mm Hg). The net right-to-left shunt decreased from 10% to 40% (mean, 25%) with phenylephrine infusion as compared to the shunt under basal conditions. The presumed mechanism related to the increase in systemic vascular resistance relative to right ventricular outflow obstruction with resultant augmentation of pulmonary blood flow. It is concluded that acutely raising systemic vascular resistance in patients with tetralogy of Fallot using phenylephrine infusion has a beneficial effect on systemic arterial oxygen level and might be the medical treatment of choice for protracted hypoxic spells.

Although pulmonary regurgitation is generally well tolerated, reconstruction of the right ventricular outflow tract and insertion of a pulmonary valve are indicated in some patients. This procedure was performed in 12 patients, ages 1 1/2-17 years (mean 10 years). Seven had tetralogy of Fallot; of these, one underwent primary repair with Glenn shunt takedown and six underwent repeat operations after previous repairs. Of these six, the major indication for reoperation was right ventricular outflow tract obstruction in four, tricuspid and pulmonary regurgitation in one, and a residual ventricular septal defect and patent shunt in one. Three had absent pulmonary valve syndrome and two had pulmonary atresia. There were no early complications or deaths in this series during a mean follow-up of 28 months. Repeat cardiac catheterization was performed in eight patients and revealed that the preoperative right ventricular-pulmonary artery gradient was reduced from 58 +/- 25 mm Hg to 11.6 +/- 7 mm Hg at rest postoperatively and was located at the level of the valve. This gradient increased with exercise or isoproterenol infusion to 31 +/- 9 mm Hg. Our experience suggests that right ventricular outflow tract reconstruction with porcine valve insertion can be safely performed with good hemodynamic results. This technique allows insertion of a larger porcine valve and avoids kinking and compression of a conduit behind the sternum.

Severe congenital mitral stenosis in the infant poses a difficult problem. We present the case history of an infant in whom a left atrial--left ventricular apical conduit was used to bypass a severely hypoplastic mitral valve. Associated coarctation of the aorta, patent ductus arteriosus, and ventricular septal defect were corrected at the same time. This method of circumventing the mitral valve offers a new approach to the relief of congenital mitral hypoplasia in small infants.

The clinical, angiographic, and pathologic features are presented for a case of d-transposition of the great arteries with atresia of the mitral and pulmonary valves and two well-developed ventricles. The morphologic left ventricle appeared to be functioning as a systemic ventricular aneurysm, and this may have led to the patient's death. A possible explanation for this anomaly is given.

The magnitude of ventricular hypertrophy in response to afterloading is determined by wall stress, with wall thickness increasing in proportion to ventricular load until systolic wall stress is normalized. With use of echocardiographic measurements of left ventricular end-systolic wall thickness (Ws) and cavity transverse dimension (Ds), the pressure constant k was calculated in 16 patients without left heart obstruction according to the formula k = P-Ds/Ws. The mean value for k was 225 +/- 6.7 (standard deviation) mm Hg. From this value, left ventricular pressure was estimated in 13 patients with aortic stenosis aged 4 to 17 years using the formula P = k-Ws/Ds. No subject had evidence of cardiac failure. Peak systolic aortic pressure difference (delta P) was calculated by subtracting cuff-measured brachial arterial peak systolic pressure from the estimated left ventricular pressure. Excellent correlation was obtained between the estimated delta P and that found at cardiac catheterization (r = 0.89). In two patients, echocardiographic data predicted significant obstruction in the presence of normal electrocardiographic, vectorcardiographic and vector lead tracings. Echocardiography offers a noninvasive method for estimating the severity of aortic stenosis, in the absence of myocardial failure; it appears to be more sensitive than other currently employed techniques.

Reported clinical experience with prosthetic valve replacement in children have suggested a high operative mortality. We placed 25 valves in 24 children with one operative death. There has been one late death related to pacemaker malfunction, but the remainder of the patients have generally done extremely well. The children have not undergone elective anticoagulation, and the long-term embolism rate has not exceeded the incidence of systemic embolization in adults who have been controlled on warfarin sodium (Coumadin) therapy. The objective of prosthetic valve replacement is myocardial preservation. We believe that valve replacement with currently available prostheses should be undertaken in any child with valvular malfunction who is not well controlled with good medical management.

The Fontan procedure was initially proposed for tricuspid atresia (TA). We describe our experience with modifications of this operation and its application to previously uncorrectable congenital lesions. From 1975 to 1979, 26 patients have undergone a Fontan-like procedure, at a mean age of 14 years (range: 3 months to 23 years). Nineteen patients had TA, one patient had mitral atresia, four patients had a univentricular heart, one patient had a "criss-cross" heart, and one patient had pulmonary atresia. Previous procedures included eight Glenn shunts, 18 systemic to pulmonary artery (PA) shunts, two PA bands, and two atrial septectomies. Thirteen patients underwent right atrial (RA) to PA connections, with a valved conduit in nine patients and without in four. Two patients had simultaneous Glenn shunts. Thirteen had RA to right ventricular (RV) conduits, with a valve in 12 patients and without in one. There were five early deaths (<30 days, 19%) and no significant difference between the RA to PA connection (four deaths of 13) versus the RA to RV connection (one death of 13). The mortality rate was higher in patients undergoing RA to PA connection without valved conduit (one death of nine with a valve, three deaths of four without, p < 0.05), while the Glenn shunt did not affect mortality (one death of seven with, three of six without, p < 0.1). There were no late deaths (mean follow-up: 24 months). Seven patients underwent recatheterization with a mean RA pressure of 14 mmHg (range: 9--25 mmHg). Thus, the "Fontan" procedure can be done with an acceptably low mortality with good functional results, both for TA and other complex lesions.

This report describes a case of corrected transposition of the great arteries (TGA) in which a classic subaortic membrane resulted in significant obstruction to outflow from the morphologically right ventricle. To our knowledge, discrete subaortic obstruction has not been previously reported with corrected TGA.

The major attempt in this monograph has been to provide a systematic approach to OT in the infant under normal and abnormal conditions based on an appreciation of pathophysiologic mechanisms. This has included a consideration of oxygen uptake, gas transfer from the lungs to the circulation, oxygen delivery to the tissues, and various adaptive responses. We have discussed disorders involving the control of respiration, the upper and lower airways, lung parenchyma, pulmonary circulation, heart, and the oxygen carrier, hemoglobin, that may impair OT to tissues, and how compensation for these conditions can be achieved. The clinical presentation in each of these pathologic processes represents the net effect of the lesion on the multiple steps involved in the transport of oxygen to the tissues and the adaptation provided by the lungs, heart, circulation, and hematologic system. These must be taken into account in developing a plan for medical and/or surgical treatment that is focused on improving the supply of oxygen to the various organ systems of the body.

The use of surface-induced profound hypothermia with limited cardiopulmonary bypass and circulatory arrest markedly diminished the need for mechanical ventilation for patients undergoing cardiac surgery. Eleven of twenty-two patients were extubated in the operating room and five more patients within 70 minutes postoperatively. Five patients required mechanical ventilation. Four of the five were extubated within 24 hours (mean, 19.05 hours); only one patient required mechanical ventilation greater than 24 hours. This experience would indicate that as the age of surgery is decreased, in conjunction with improved technics of cardiac surgery and anesthesia, the need for mechanical ventilation should be diminished.

Experience with four children undergoing apicalaortic shunts for relief of aortic valvular disease is reported. All children tolerated the procedure uneventfully, and postoperative cardiac catheterization in three revealed restoration of normal hemodynamics. In one unique case severe aortic regurgitation in a two year old boy was managed by suture closure of the aortic valve producing total left ventricular output through the apical-aortic conduit.

In the foregoing discussion we have attempted to provide an overview of much of the information available on the effects of changes in systemic oxygen transport on the neonatal and young subject. Using data synthesized from both human and animal studies, we have described the normal developmental changes and the findings of studies in which oxygen transport has been acutely altered by experimental means. This was intended to highlight the potentially delicate balance that can occur between oxygen supply and utilization during the critical period of rapid growth after birth. Finally, using the left-to-right shunt as an example, we have tried to show how a common pathologic condition can impair oxygen transport at multiple sites, and how normal development can make matters worse. It is anticipated that from an understanding of both normal and abnormal physiology, we will be able to develop rational approaches to the management of infants in whom the oxygen transport system has been stressed beyond its reserve.