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Mutations in sarcomeric proteins can lead to either hypertrophic or dilated cardiomyopathy depending on their effects on the structural and functional properties of the contractile unit of the heart. Mutations in cardiac troponin T, which binds the calcium-responsive troponin complex to α-tropomyosin, have been shown to result in cardiac hypertrophy or cardiac dilatation and heart failure, depending on the nature of the specific mutation. In this study, we report the identification of a novel cardiac troponin T mutation (A171S) leading to dilated cardiomyopathy and sudden cardiac death. In contrast to prior described mutations, the A171S mutation results in a significant gender difference in the severity of the observed phenotype with adult males (over 20 years of age) demonstrating more severe ventricular dilatation [left ventricular end diastolic dimension (LVEDD) 7.1 vs. 5.1cm; P =0.01, t test] and left ventricular dysfunction [left ventricular shortening fraction (LVSF) 21 vs. 34%; P =0.04, t test] than adult females. The described mutation substitutes a hydrophilic amino acid for a hydrophobic one in a highly conserved domain involved in the interaction between troponin T and α-tropomyosin. Interestingly, four previously described mutations within 12 amino acids of A171 lead to a hypertrophic phenotype, suggesting that further characterization of the functional consequences of the A171S mutation may lead to a better understanding of the pathophysiology of DCM and of the functional differences between HCM- and DCM-causing mutations in cardiac troponin T.

L-Transposition of the great arteries (L-TGA) is characterized by atrioventricular and ventriculoarterial discordance such that the morphologic right ventricle and tricuspid valve directly provide systemic cardiac output. The ability of the right ventricle to support the systemic circulation is often complicated by associated cardiac defects which provide numerous potential mechanisms for the development of ventricular dysfunction. Theoretical risk factors for right ventricular failure include volume overload, systemic afterload, conduction and rhythm disturbances, associated left ventricular pressure and geometry, coronary artery anomalies, surgical injury, pregnancy, hypoxemia, and advancing patient age. The high prevalence of associated lesions including anomalies of the conduction system and tricuspid valve predispose these patients to systemic right ventricular failure which is likely to alter survival in this uncommon form of congenital heart disease.

We studied three pediatric patients with protein-losing enteropathy in conjunction with univentricular hearts and right atrial to pulmonary artery anastomosis (Fontan operation) before and during heparin therapy. Each patient showed dramatic improvements in symptoms, marked elevations in serum albumin levels, and quantitative reversal of enteric protein loss within a few weeks of beginning therapy. These findings suggest that heparin may be an important treatment for this poorly understood condition.

Whereas multiple and different cardiac abnormalities may be accompanied by hypoplasia of the left heart, the postnatal pathophysiologic changes which accompany these abnormalities are very similar. In the fetus, hypoplasia of the left ventricle does not result in any complications, but the post-natal physiologic changes lead to severe hemodynamic and circulatory complications which in the absence of treatment are fatal. The major physiologic changes are those related to the decrease in pulmonary vascular resistance, spontaneous constriction or closure of the ductus arteriosus, and restriction of the obligatory left-to-right shunt which must exist through an interatrial communication. The clinical features are closely related to the dominance and severity of the physiologic changes and the balance between the systemic and pulmonary vascular resistance. Presentation may be with respiratory distress, congestive heart failure, vascular collapse, or less frequently with severe cyanosis. The presence of mild hypoxemia, normal or reduced Pa CO 2 and very low pH are characteristic features of infants with hypoplastic left heart syndrome. Early post-natal detection of these infants may be enhanced by screening all newborns discharged from the nursery with measurement of systemic arterial oxygen saturations by a pulse volume oximeter.

Between January 1990 and February 1993, 73 patients underwent first-stage reconstruction for hypoplastic left heart syndrome at the University of Michigan Medical Center. During this period, surgical reconstruction remained essentially constant and consisted of a pulmonary artery–to–aorta anastomosis with allograft augmentation of the ascending, transverse, and proximal descending aorta, restriction of pulmonary blood flow with a polytetrafluoroethylene shunt from the innominate artery to the central pulmonary artery confluence, and atrial septectomy. Hospital survival was 62 of 73 patients, 85% (70% confidence limits: 80% to 89%). These results stand in marked contrast to those obtained during the earlier years of our experience from 1986 to 1989 when only 21 of 50 patients (42%, 70% confidence limits: 35% to 49%) survived ( p = 0.001). Among the most recent group of patients, only 2 of 7 patients older than 1 month of age at operation survived, whereas 60 of 66 (91%, 70% confidence limits: 87% to 94%) patients younger than 1 month of age survived ( p = 0.0001). Anatomic subtype and ascending aortic diameter were not predictive of survival. Actuarial survivals for those patients younger than 1 month of age at the first-stage operation, including hospital deaths and subsequent operative procedures, were 81%, 74%, and 74% at 6 months, 1 year, and 2 years, respectively. These results indicate that survival for patients after first-stage reconstruction for hypoplastic left heart syndrome has significantly improved in recent years. Older age was a strong risk factor, with a hospital survival of 91% for those patients undergoing first-stage palliation within the first month of life. These data have important implications for the type of operative intervention and its timing. (J THORAC CARDIOVASC SURG 1994;107:934-40)

Although the early mortality for repair of truncus arteriosus has decreased in the modern era, routine correction in the neonate has not been widely adopted. To assess the results of our protocol of early repair, we reviewed 46 neonates and infants undergoing repair of truncus arteriosus at the University of Michigan Medical Center from January 1986 to January 1992. Their ages ranged from 1 day to 7 months (median 13 days) and weights from 1.8 kg to 5.4 kg (mean 3.1 kg). Repair was performed beyond the first month of life in only 8 patients, because of late referral in 7 and severe noncardiac problems in 1. Associated cardiac anomalies were frequently encountered, the most common being interrupted aortic arch (n = 5), nonconfluent pulmonary arteries (n = 4), hypoplastic pulmonary arteries (n = 4), and major coronary artery anomalies (n = 3). Truncal valve replacement was performed in 5 patients with severe regurgitation, 3 of whom also had truncal valve systolic pressure gradients of 30 mm Hg or more. The truncal valve was replaced with a mechanical prosthesis in 2 patients and with a cryopreserved homograft in 3 patients. Right ventricle-pulmonary artery continuity was established with a homograft in 41 patients (range 8 mm to 15 mm), a valved heterograft conduit in 4 (range 12 mm to 14 mm), and a nonvalved polytetrafluoroethylene tube in the remaining patient (8 mm). There were 5 hospital deaths (11%, 70% confidence limits 7% to 17%). Multivariate and univariate analyses failed to demonstrate a relationship between hospital mortality and age, weight, or associated cardiac anomalies. Only 1 death occurred among 9 patients with interrupted aortic arch or nonconfluent pulmonary arteries. Hospital survivors were followed-up from 3 months to 6.3 years (mean 3 +/- 0.4 years). Late noncardiac deaths occurred in 3 patients, all within 4 months after the operation. Actuarial survival was 81% +/- 6% at 90 days and beyond. Despite the prevalence of major associated conditions, early repair has resulted in excellent survival. We continue to recommend repair promptly after presentation, optimally within the first month of life.

An assessment of late morbidity and mortality is essential before arterial repair can be considered truly corrective for patients with transposition of the great arteries. We describe the early and intermediate-term results in 126 patients who underwent arterial repair. Operation was performed at a median age of 6 days, with 76 patients operated on within the first 7 days of life. Coronary artery anatomy differed from the usual arrangement in 37 patients. Simultaneous procedures included ventricular septal defect closure (35) and repair of interrupted aortic arch (2) or coarctation (5). Hospital mortality was seven of 126 (5.5%), with three deaths among the most recent 100 patients (3%). There were one late, noncardiac death and one late death after reoperation. Reoperation for pulmonary artery stenosis was required in 10 of the first 63 patients (16%), all of whom underwent pulmonary artery reconstruction with separate patches for closure of the coronary excision sites. Of the last 63 patients, all of whom underwent pulmonary artery reconstruction with a single pantaloon-shaped pericardial patch, one (2%) required reoperation for pulmonary artery stenosis. Doppler flow studies and echocardiography performed in 115 of 119 surviving patients at a mean of 12 months after repair demonstrated normal left ventricular function, minimal left ventricular outflow gradients, and no more than trivial aortic regurgitation. Peak gradient across the right ventricular outflow tract was 19 +/- 3 mm Hg in patients with separate pulmonary artery patches and 5 +/- 2 mm Hg in those with a single pantaloon patch (p = 0.0001). Follow-up is 96% complete from 1 month to 8 years after operation (mean 2.5 years). The actuarial survival rate at 5 years, including operative mortality, was 92%. All patients are in sinus rhythm, and none requires antiarrhythmic medications. These data suggest that pulmonary artery reconstruction with a single pantaloon patch may be associated with a decreased requirement for reoperation. Intermediate-term survival and functional results are excellent after arterial repair for transposition of the great arteries.

Necrotizing enterocolitis is common in preterm and low birth weight infants but rare beyond the neonatal period. Various infectious agents including bacterial and viral organisms have been implicated in its pathogenesis. Rotavirus has recently been shown to be associated with necrotizing enterocolitis. In this report we describe two irlfants with congenital cardiac disease who developed ficlminating necrotizing enterocolitis after cardiac catheterization. Both infants were beyond the newborn period and developed enterocolitis during an epidemic of rotaviral injection. We postulate a relationship between rotavirus infection and the development of necrotizing enterocolitis in older infants with congenital heart disease after cardiac catheterization. (J Interven Cardiol 1991 :4:2)

The acute hemodynamic effects of captopril were evaluated at cardiac catheterization in 16 children (age, 0.3-18 years) with cardiomyopathy. Twelve children had congestive cardiomyopathy, whereas four had restrictive cardiomyopathy. Hemodynamic measurements were obtained 30 and 60 minutes after the oral administration of captopril (0.5 mg/kg). Blood pressures were measured in the aorta, pulmonary artery, right atrium, and pulmonary capillary wedge position; cardiac outputs were measured by the thermodilution technique. Hemodynamic data could not be obtained after the administration of captopril in one child with congestive cardiomyopathy because of an immediate, severe hypotensive response. In 11 of 12 children with congestive cardiomyopathy, cardiac index increased by 22%, from 2.3 to 2.8 l/min/m2 (p less than 0.05), and stroke volume increased by 22%, from 23 to 28 ml/m2 (p less than 0.05). Systemic vascular resistance decreased from 32 to 21 units.m2 (p less than 0.01), but the mean aortic pressure did not change significantly. In contrast, four children with restrictive cardiomyopathy had no change in cardiac output after captopril, but there was a trend toward significant arterial hypotension (mean aortic pressure decreased from 78 to 59 mm Hg). Thus, captopril acutely reduced systemic vascular resistance and increased both cardiac output and stroke volume in children with congestive cardiomyopathy. In children with restrictive cardiomyopathy, however, captopril did not affect cardiac output, but it did decrease aortic pressure. These data indicate that captopril may benefit children with a congestive cardiomyopathy but that captopril probably should not be used in children with restrictive disease.

A large number of patients with congenital cardiac disease have a repaired but not cured malformation. Although some mild cardiac defects may heal spontaneously, others persist or progress with advancing age. Among those with a major or complex defect repaired by interventional and/or surgical procedures, few are cured. Whereas major cardiac defects often occur as an isolated anomaly, many patients have serious extracardiac congenital defects, systemic syndromes, genetic abnormalities, or other handicaps. In caring for the patient, the pediatric cardiologist, in addition to directing cardiac therapy, is often called upon to coordinate the diverse care, plan, and guide for the patient’s future. It is a chronic disorder often recognized in the fetus, proceeding through infancy, childhood, and into adulthood, thus requiring long-term care. The medical and surgical therapy is usually provided by subspecialist colleagues within the field. However, delivery of appropriate, comprehensive, and optimal care requires a “quarterback” cardiologist concerned with diverse, frequently inevitable issues, such as prematurity, nutrition, growth, or genetic screening. Important concomitant problems may be related to associated extracardiac anomalies, exercise capacity, school, health or life insurance, employment, pregnancy, and family life. A primary care physician might be uncomfortable advising on many of these issues and the responsibility falls to the cardiologist. Anticipated medical advances may further impact the care and require yet greater coordination of services and close empathetic attention. These changes may include further cardiologist subspecialization, primary care provided by nurse clinicians, fetal cardiac intervention, increase in regionalization of specialty care, or more complex laboratory procedures—all not infrequently replacing the careful medical history and physical examination.

Shone's anomaly, a congenital cardiac malformation, consists of multiple levels of left heart obstruction including supravalvar mitral ring, parachute mitral valve, subaortic stenosis, and coarctation. The prognosis for patients with Shone's anomaly is poor. To assess operative results and late outcome, we reviewed the records of 30 consecutive patients seen with Shone's anomaly at our institution between 1966 and 1989. Anatomical diagnoses in these patients were supravalvar mitral ring (22 patients), mitral valve abnormalities including parachute mitral valve, fused chordae, or single papillary muscle (26 patients), subaortic gradients (26 patients), and coarctation (29 patients). Nineteen patients had all four lesions. Other common defects were bicuspid aortic valve (19 patients) and ventricular septal defect (20). Two patients were treated medically. The other 28 patients required 84 operative procedures with 18 patients undergoing more than one procedure. Operations included coarctation repair (28 patients), mitral valve repair or replacement (11), ventricular septal defect closure (8), subaortic resection (8), and complex left ventricular outflow tract reconstruction or bypass (4). Age at first operation ranged from 7 days to 7 years (median age, 3 months). There were no operative deaths at the first operation. However, mortality rose to 24% (4/17) after the second operation. All operative deaths were secondary to severe mitral valve disease. The survivors have been followed from 1 to 16 years (mean follow-up, 6 +/- 1 years). There were no late or sudden deaths. Morbidity has included stroke (1), gastrointestinal bleeding (2), permanent heart block (1), and persistent congestive heart failure (6).(ABSTRACT TRUNCATED AT 250 WORDS)

This retrospective study was designed to evaluate the effectiveness of subcutaneous heparin therapy for the treatment of protein-losing enteropathy (PLE) associated with single-ventricle palliation and to evaluate the side effects of long-term heparin use. PLE affects 4% to 13% of Fontan operative survivors. Five-year survival after onset of PLE is only 46% to 59%. We studied a cohort of patients with single-ventricle palliation who developed PLE and were treated with subcutaneous heparin. Seventeen patients were included in the study. Symptoms of PLE appeared on average 43 months after surgical palliation. At diagnosis of PLE, mean albumin level was 2.0 +/- 0.4 g/dl. At cardiac catheterization, mean systemic venous pressure was 11.6 mm Hg. Subjective symptomatic improvement on heparin therapy occurred in 13 patients (76%). Three patients (18%) went into clinical remission. Compared with the period before initiation of heparin, there was no significant difference in the number of hospital admissions (p = 0.99) or albumin infusions (p = 0.88) during the first year of heparin therapy. Five patients had x-rays of their thoracolumbar spine, and 9 patients had bone mineral analyses; all scans were grossly abnormal. In conclusion, subcutaneous heparin therapy leads to subjective improvement of PLE symptoms in most patients; however, it does not change the need for frequent albumin infusions and does not increase the rate of remission above that for standard medical therapy.

Objective. Patient-activated transtelephonic electrocardiographic event monitors (TTMs) are often used for the evaluation of children and adolescents with suspected arrhythmias. Since their introduction 25 years ago, there has been little inquiry quantifying the usefulness of TTMs for pediatric patients. The objective of this study was to measure the utility of TTMs for children and adolescents with symptoms of a possible cardiac rhythm disturbance. Methods. Medical records of all patients who received TTMs from C.S. Mott Children’s Hospital Electrocardiography Laboratory between February 1, 1993, and October 31, 2000, were reviewed. Patients with pacemakers, known arrhythmias, or age older than 18 years were excluded. Indications for monitoring included palpitations with or without other symptoms (N = 420), chest discomfort (N = 43), and presyncope or syncope (N = 32). Results. A total of 495 studies (patient mean age: 10.2 ± 4.3 years; range: 0.1–17.9 years; 48% male) met inclusion criteria. Monitoring was performed for 1 to 1021 consecutive days (mean: 103 ± 97). Fifty-two percent (N = 257) of patients failed to transmit an electrocardiogram while experiencing symptoms. Fewer boys transmitted electrocardiograms (N = 100/238). Of 238 symptomatic patients, 15% (N = 35; mean age: 11.4 ± 4.7 years; range: 0.1–17.4 years; 51% male) had supraventricular tachycardia (SVT). No other significant arrhythmia that may warrant treatment was identified. All patients with SVT had palpitations. No patients with isolated chest discomfort, presyncope, or syncope had SVT (N = 75). SVT was documented more frequently in patients with postevent (N = 35/464) than loop recorders (N = 0/31). Of those with SVT, 71% (N = 25) and 91% (N = 33) transmitted events within 4 and 16 weeks, respectively. Follow-up for 1 to 108 months (mean: 32 ± 25; median: 26) in 53% (243 of 460) of patients without SVT uncovered a 3% (N = 7) rate of subsequent SVT detection. The overall sensitivity of the TTM test was 83% (35 of 42) for detection of SVT. The sensitivity of studies theoretically limited to 4 and 16 weeks would be 60% (25 of 42) and 79% (33 of 42), respectively. The negative predictive value of the TTM study was 99% in our patient population. The negative predictive value of tests theoretically limited to 4 and 16 weeks would be 96% and 98%, respectively. TTM studies of 2 weeks’ duration were most cost-effective in terms of total diagnostic yield. In contrast, studies of 4 weeks’ duration were most cost-efficient for SVT detection. Conclusions. TTMs are useful for the evaluation of children and adolescents with palpitations but not with isolated chest pain, syncope, or presyncope. In this study, girls were more likely to transmit events. The sensitivity of TTMs for detection of SVT was 83%. The negative predictive value of the TTM test was 99%. Monitoring for longer than 16 weeks did not increase test sensitivity. Studies of 4 weeks’ duration proved most cost-effective for SVT detection.

To determine the prevalence of malnutrition among hospitalized children with congenital heart disease by age, disease process, and clinical status.Cross-sectional, retrospective chart review.Pediatric cardiology units at a 150-bed tertiary care teaching hospital in Ann Arbor, Mich.Patients (n = 160) were randomly selected from consecutive admissions to the Pediatric Cardiology and Thoracic Surgery Services during a 1-year period.None.Acute and chronic malnutrition, assessed by comparing the patients' weight and height with established means.Acute and chronic malnutrition occurred in 33% and 64% of the patients, respectively. Age, diagnostic category, and symptoms were associated with malnutrition. Eighty percent of infants presented with acute malnutrition compared with 18% of patients of other ages (P.001). Malnutrition affected 60% of patients with left-to-right shunts, 53% of patients with complex heart disease, and no patients with primary rhythm disturbances. Acute malnutrition affected 11% and chronic malnutrition affected 50% of patients with left-sided heart obstruction. Acute or chronic malnutrition occurred in 70% or more of patients with cyanosis and/or congestive heart failure but in only 30% of patients with neither (P.001).Malnutrition in hospitalized children with congenital heart disease remains common, highlighting the importance of nutritional screening and intervention.

Today's health care environment prompted implementation of a case management model by pediatric nurse practitioner clinical nurse specialists to promote the organization of resources for optimal care of children with heart disease. Evaluation of this pilot program suggests that achievement of expected outcomes within an appropriate length of stay was facilitated, that parents were ready for discharge, and that readmissions were infrequent. In addition, patient and system variances resulting in delay of discharge and discharge preparation needs were identified. The pediatric nurse practitioner as case manager may have a significant impact on the quality and cost of care for hospitalized children.

BACKGROUND Percutaneous balloon valvuloplasty has proven to be acutely effective in the treatment of congenital valvar aortic stenosis; however, the intermediate- and long-term effectiveness of the procedure remain to be documented. METHODS AND RESULTS To assess the intermediate-term effectiveness of balloon valvuloplasty, repeat catheterization was performed in 27 of 30 children 1.7 +/- 0.1 years after balloon valvuloplasty for congenital aortic stenosis (AS). In 33 children the peak AS gradient was reduced acutely by 55% from 77 +/- 4 to 35 +/- 3 mm Hg (p less than 0.001), and left ventricular systolic pressure was reduced from 176 +/- 4 to 138 +/- 4 mm Hg (p less than 0.001). Despite a technically adequate valvuloplasty procedure, three patients had inadequate relief of obstruction and required complex surgical intervention. Twenty-seven of the 30 patients available for late reevaluation (90%) enrolled in the follow-up study. The peak AS gradient remained significantly reduced compared with that present before valvuloplasty (29 +/- 3 versus 77 +/- 4 mm Hg, p less than 0.001). Furthermore, there was no difference in peak AS gradient at follow-up compared with that immediately after valvuloplasty. The greatest increase in gradient at reevaluation was 14 mm Hg. Twenty of 27 patients (74%) had no change in the degree of aortic insufficiency at follow-up compared with that present before valvuloplasty. At follow-up, 16 patients had no aortic insufficiency at all, and only two had moderate-to-severe (3-4+) insufficiency. Femoral artery injury was documented in four patients, three of whom were under 12 months of age at valvuloplasty. CONCLUSIONS Balloon aortic valvuloplasty provides safe and effective intermediate-term gradient relief without early restenosis in children and adolescents with congenital AS.

We defined the natural history of scoliosis in congenital heart disease (CHD) with respect to the risk of progression and indications for treatment. We reviewed radiographs of 48 children with CHD and scoliosis. Thirty-seven had developmental scoliosis (77%), and 11 (23%) had congenital scoliosis. Children with congenital scoliosis can be managed in the same way as children without CHD. Developmental curves less than 30 degrees in children aged greater than 10 years showed no progression. Developmental curves greater than 30 degrees with onset in children aged less than 10 years and progression greater than 9 degrees per year require treatment.

There are approximately 500,000 adults with congenital heart disease in the United States, and each year another 10,000 children who have undergone surgical repair reach adulthood1. The largest diagnostic category among patients undergoing repair is isolated ventricular septal defect, followed by tetralogy of Fallot. In classic tetralogy of Fallot, an anterior displacement of the infundibular septum results in a large ventricular septal defect and the development of infundibular pulmonary stenosis. Right ventricular hypertrophy is caused by right ventricular hypertension associated with both the ventricular septal defect and the pulmonary stenosis. Aortic override onto the right ventricle is the fourth . . .

In an attempt to determine if percutaneous arterial catheterization rather than open arteriotomy or the use of an antiplatelet agent, aspirin, would reduce the incidence of arterial thrombosis after cardiac catheterization, 95 children were studied. After measuring the amplitude of pulsations by oscillometry on the day of admission, the children were randomly divided into two groups. One received aspirin 15 mg. per kilogram of body weight per dose for 5 doses and the other served as a control. Method of arteriotomy—percutaneous or open surgical incision—was left to the discretion of the catheterizer. Repeat oscillometric measurements were obtained before discharge. Percutaneous catheterization was associated with a significantly fewer number of diminished pulses (p =

The most recent postoperative echocardiographic examinations of all children who underwent arterial switch repair of transposition of the great arteries from August 1985 to December 1987 were reviewed. The patients included 35 children whose age at operation was 12 ± 16 days and whose weight was 3.6 ± 0.4 kg. Thirty-three patients are alive and well; 1 died intraoperatively and 1 died immediately postoperatively. The time of the follow-up echocardiographic examination ranged from 1 day to 2.5 years (mean 9.2 months) with 11 patients examined >1 year after surgery. Complete examination of the repair site was possible in all patients. Echocardiographic visualization of distortion of the great arteries at the suture lines was seen in all patients; however, Doppler evidence of hemodynamically significant obstruction at the repair site was uncommon. On Doppler examination in the surviving 33 patients, 16 had no supravalvular pulmonary stenosis and 14 had mild to moderate supravalvular pulmonary stenosis with peak systolic pressure gradients ranging from 16 to 56 mm Hg (mean 31). Three patients had severe supravalvular pulmonary stenosis and peak systolic pressure gradients of 66, 74 and 77 mm Hg (2 have had reoperation, 1 is awaiting surgery). On Doppler examination, 4 patients had mild supravalvular aortic stenosis with peak systolic gradients ranging from 10 to 29 mm Hg. Doppler gradients were confirmed in 10 patients who had catheterization 12 ± 3 months after surgery. Three patients had mild pulmonary regurgitation by Doppler examination, 5 had mild aortic regurgitation, 4 had mild tricuspid regurgitation and 2 had mild mitral regurgitation. In all 33 patients, ventricular dimensions, left ventricular shortening fraction (42 ± 6%) and rate-corrected mean velocity of circumferential fiber shortening (1.25 ± 0.24 circumference/s) were normal.

Twenty-nine children were evaluated prospectively for the presence of an aortic aneurysm at the repair site 1 to 19 years after patch aortoplasty repair of coarctation of the aorta. In each child, noninvasive evaluation included a chest X-ray film, computed tomography of the chest and two-dimensional echocardiography. The presence and size of an aortic aneurysm were determined quantitatively by measuring the ratio of the diameter of the thoracic aorta at the repair site to the diameter of the aorta at the diaphragm (aortic ratio). An aortic ratio of ≥1.5 was judged abnormal and was shown to be significantly greater than the aortic ratio of a normal control group. An aortogram was obtained in each child if any noninvasive screening test was found to be abnormal. As assessed by the aortogram, the prevalence of aortic aneurysm was 24% in this patient group. The sensitivity of echocardiography and chest computed tomography for detecting an aneurysm was 71% and 66%, and the specificity 76% and 85%, respectively. The chest X-ray film was 100% sensitive and 68% specific in determining the presence of an aneurysm. Although the data are not statistically significant, they suggest that children undergoing patch aortoplasty as the primary procedure (rather than a reoperation after earlier resection), and children in whom a Dacron patch is utilized may be at increased risk for aneurysm formation. Thus, in a prospective manner, this study has documented that aortic aneurysm occurs commonly after patch aortoplasty for coarctation in childhood, that the chest X-ray film provides a sensitive screening test and that the aneurysm may be evaluated quantitatively (by measuring the aortic ratio) with echocardiography or chest computed tomography.

Cardiovascular abnormalities were present in 11 of 48 (23%) patients with congenital diaphragmatic hernia. Cardiac abnormalities included congenital heart disease, compression of a major vascular structure, cardiac malposition, and abnormalities in pulmonary circulation. The differential diagnosis between isolated congenital diaphragmatic hernia and coexisting cardiac abnormality may be difficult and may require echocardiographic or invasive studies. Mortality in infants with diaphragmatic hernia and cardiovascular abnormalities is 73% in contrast to 27% in those without cardiac abnormalities.

The development of systemic hypertension, in an eight-year-old girl, after resection of a large arteriovenous malformation, is described. The hypertension was related to an elevated plasma renin activity and was controlled with propranolol. A possible mechanism for the rise in plasma renin activity is postulated.

The lungs of ten newborn infants who died of hypoplastic left ventricle syndrome were studied by a morphometric technique that (1) determined the percentage wall thickness of injected pulmonary arteries, (2) determined the ratio between the number of alveoli per high-power field and the number of corresponding arteries, and (3) examined in detail the extension of medial smooth muscle to the vessels at the periphery of the acinus. The findings in the lung were related to the gross cardiac morphological changes and to echocardiographic and hemodynamic findings. The echocardiograms of eight neonates demonstrated small left ventricles. The aortic root was hypoplastic in seven and the left atrium was small in three of the eight. Pulmonary artery hypertension and elevation of the left atrial pressure were present in all infants in whom measurements were obtained. The mean percentage wall thickness of all vessels was greater in afflicted infants than in normal age-matched control subjects. There was a normal ratio between the number of alveoli per high-power field and the number of corresponding arteries, and all infants had extension of muscle to the peripheral vessels at the alveolar duct and alveolar wall levels. The pulmonary vascular abnormalities observed in the neonate with hypoplastic left ventricle syndrome may represent persistence of fetal vascular abnormalities associated with the abnormal fetal circulatory hemodynamics resulting from the malformation. These abnormalities may influence the success of surgery proposed for hypoplastic left ventricle syndrome.

To determine the diagnostic value of exerciseinduced R-wave changes in adolescents with congenital heart disease, the responses of 50 adolescents without significant heart disease were compared with those of 72 patients with either a left ventricular (LV) pressure or volume overload lesion. Among the pressure overload group, 24 patients had valvular aortic stenosis (AS) and 27 had coarctation of the aorta. The volume overload group included 12 patients with mitral regurgitation (MR) and 9 with aortic regurgitation (AR). Severity of the cardiac lesion was assessed using cardiac catheterization in patients with AS, physical examination in patients with coarctation of the aorta and clinical or angiographiec criteria, or both, in patients with valvular regurgitation. The R wave was measured in 10 consecutive QRS complexes in leads II, aVF and V 5 at rest, maximal exercise and 1-minute recovery. At maximal exercise, control subjects had a mean decrease in amplitude (ΔR) of −3.6 mm (p

A retrospective review of 149 episodes of bacterial endocarditis (BE) in 141 patients under 25 years of age, at The Children's Hospital Medical Center from 1933 through June of 1972, demonstrates increasing survival and a distinct change in the frequency of underlying congenital heart disease and rheumatic heart disease (RHD). Certain forms of congenital heart disease such as tetralogy of Fallot, small ventricular septal defect, and aortic stenosis are at particular risk for BE. Following BE, patients with ventricular septal defect and tetralogy of Fallot have less morbidity and higher survival rates than children with aortic outflow lesions. over the entire time period, alpha Streptococcus is the most common pathogen and Staphylococcus aureus, second most frequent organism. Surgical correction in patients with congenital heart disease may offer the best form of prevention.

Simultaneous red blood cell (RBC) and plasma volume determinations were obtained in 16 patients with cystic fibrosis (CF) and moderately severe pulmonary involvement. Hypervolemia with an increase in both RBC and plasma volumes was observed. Changes in blood volume were marked when values were indexed by weight but less significant when indexed by height. Decreasing systemic arterial oxygen saturation was associated with a progressive increase in RBC mass, hematocrit value, and hemoglobin level and a decrease in mean corpuscular hemoglobin concentration. RBC and total blood volumes were highest in patients with cor pulmonale and congestive heart failure. However, the compensatory polycythemic response in patients with CF was inadequate when compared with the response to hypoxemia in patients with cyanotic congenital heart disease. The insufficient oxygen-carrying capacity may compromise tissue oxygen delivery and necessitate treatment.

A perforated intracardiac prosthesis, and patch infundibuloplasty and annuloplasty were employed for the surgical management of an infant with tetralogy of Fallot, pulmonary atresia, and severe hypoplasia of the pulmonary arteries. This approach provides a means of decompression of the right ventricle in the immediate postoperative period. It allows sufficient systemic cardiac output while increasing pulmonary blood flow to relieve severe hypoxemia and cyanosis. In addition, the high risk of further compromise to the diminutive pulmonary arteries by a palliative shunt is avoided. A physiological basis for the use of this technique is discussed.

The etiology of chronic congestive heart failure (CHF) after repair of tetralogy of Fallot was determined in 102 patients consecutively catheterized 1 to 12 years postoperatively. Chronic CHF was observed in 36/102 patients. The most prevalent abnormality leading to congestive failure (31/36) was a large residual ventricular septal defect alone or in combination with other lesions. All postoperative patients with pulmonary to systemic flow ratios greater than 2:1 (25/102) had congestive failure and evidence of biventricular dysfunction. Significant tricuspid regurgitation (N = 11) and persistent systemic to pulmonary artery shunts (N = 6) contributed to volume overload and congestive failure in the patients with large residual ventricular septal defect. Isolated severe residual right ventricular outflow tract obstruction was a common cause of chronic CHF. Pulmonary artery hypertension was present in 20/36 patients with CHF. The increased pulmonary pressure was not wholly due to an increased pulmonary flow since 7/20 patients had pulmonary vascular resistance greater than 3 mm Hg/L/min/m2. Our findings indicate that persistent or chronic congestive heart failure in postoperative tetralogy of Fallot patients requires bilateral cardiac catherterization since an identifiable and surgically correctable lesion is nearly always present.

The prevalance and sequelae of infectious sinusitis in a hospitalized group of children with and without congenital heart disease (CHD) were studied. Sinusitis was more common (1% versus 0.3%) in the CHD group and occurred predominantly (90%) in the cyanotic patients. It was associated with subacute bacterial endocarditis in 20% (5 of 20) and brain abscess in 15% (3 of 20) of the CHD cases. It is postulated that proliferation and distension of the venous channels and marrow spaces in patients with cyanotic CHD enhances the hematogenous spread of bacteria from the paranasal sinuses.

Little research exists on the relationship between congenital heart disease (CHD) and thanatological variables. Many social, physical and psychological characteristics render patients with CHD rich sources of data which might be used to develop improved techniques of patient and parent management. Relevant aspects include erroneous ideas about CHD, patient's physical appearance and will to live, parental guilt and the use of prostheses and other devices. These are discussed.

The clinical course of five infants with hepatic hemangioendothelioma is reviewed. Hemodynamic abnormalities observed at cardiac catheterization included an increased cardiac output (range, 9.2 to 10.5 liters/min/sq m) with over 50% of this output being shunted through the arteriovenous malformation, an elevated right and left end diastolic pressure (8 to 10 mm Hg and 9 to 15 mm Hg respectively), a small systolic pressure gradient across the pulmonary outflow tract (4 to 6 mm Hg), and mild elevation of pulmonary artery pressure (range, 35/16 to 37/12 mm Hg). All four patients treated with prednisone improved while on therapy; three are well one to three years after cessation of therapy. One patient died from unrecognized congestive heart failure following discontinuation of prednisone and another before prednisone was started. We conclude that prednisone in high doses (2 to 4 mg/kg/day) with the addition of digitalis and diuretics for control of congestive heart failure is an effective treatment regimen for infants with hepatic hemangioendothelioma.

Parents of infants with serious congenital heart defects have misconceptions and negative feelings which may threaten their ability to provide optimal care for their infant. In an effort to increase knowledge and promote a more positive, less anxious attitude among these parents, a videotape entitled ‘Your Baby with a Congenital Heart Defect’ was developed and evaluated. Forty-three parents of thirty infants who required cardiac catherization in the first 8, weeks of life were randomly assigned to experimental (N = 23) or control (N = 20) groups. In the videotape viewed by the experimental parents, three families of cardiac infants related common feelings, problems and infant care experiences. The control group viewed a videotape describing the cardiac anatomy and functional changes associated with defects. Post-videotape questionnaires demonstrated significantly greater knowledge of the infant's behavior and needs in the experimental parents compared to controls (P < 0.0001). In comparison to the control group, parents in the experimental group had fewer misconceptions related to the danger of cyanosis (P < 0.001), the risk of sudden death (P < 0.01) and vulnerability to infections (P < 0.001) after viewing the videotape. The experimental group parents also tended to report less negative feelings toward the infant (P = 0.02). We conclude that viewing the videotape on infant care improved parental attitude and their understanding of the behavior and needs of the neonate with congenital heart disease.

No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACTS) with those generated by the atrial pacing method (TSACTN). In this study, TSACT in 55 patients, age 0.2-18.5, was measured using both techniques. TSACTN was performed at a mean 90% (TSACTN-90) (n = 32) or a mean 95% (TSACTN-95 and (n = 38) of sinus cycle length (SCL). When data generated during determination of TSACTN-90 and TSACTS were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACTS (128 +/- 40 ms) and TSACTN-90 (126 +/- 74 ms) were not significantly different. Coefficient of correlation was r = 0.82, p less than 0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACTS and TSACTN-90. In contrast, when values generated during TSACTN-95 and TSACTS were compared, TSACTS exceeded TSACTN-95 (137 +/- 38 vs 105 +/- 58 ms; p less than 0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong (r = 0.82, p less than 0.001). Despite a good correlation between TSACTN-90 and TSACTS, individual differences in magnitude and direction were noted between the two techniques. In summary, TSACTN-90 approximates TSACTS in children. TSACTN-90 is preferable to TSACTN-95, probably due to more complete sinus node capture during atrial pacing. However, the behavior of the sinus node in response to extrastimuli (single or train) precludes favoring one technique over the other. More precise evaluation of sinoatrial conduction will require direct recording of sinus node activity.

To assess left ventricular (LV) diastolic filling in children with pressure overload hypertrophy, 12 patients with LV outflow obstruction (7 with aortic valve stenosis and 5 with aortic coarctation) and 12 healthy, age-matched control subjects were examined. Each child underwent M-mode echocardiography and pulsed Doppler examination of the LV inflow. The patients with LV outflow obstruction had cardiac catheterization and balloon angioplasty. Their echo/Doppler examinations were performed in the catheterization laboratory before and immediately after balloon angioplasty. From the M-mode echocardiogram, the LV cavity dimensions and wall thicknesses, LV mass and shortening fraction were measured. The following measurements were made from the Doppler recording: peak velocities at rapid ventricular filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, total area under the Doppler curve, percent of the total Doppler area occurring in the first one-third of diastole (0.33 area fraction), percent of the total area occurring under the E wave (E area fraction), percent of the total area occurring under the A wave (A area fraction) and the ratio of E area to A area.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular (LV) apical aneurysms were observed in 16 of 50 (32%) children (average age 8 years) consecutively catheterized after surgical repair of congenital heart disease. The LV apex was vented by a sump during cardiopulmonary bypass in each. The aneurysms varied in size, but were generally small. Average dimensions were 7.5 X 6.8 mm in the anteroposterior projection and 8.9 X 5.7 mm in the left anterior oblique projection. The LV apex wall was thinner in patients with aneurysms than in age- and lesion-matched controls. All of the LV aneurysm patients were asymptomatic during average follow-up of 4 years. Nevertheless, such aneurysms are anticipated to represent a potential source of cardiovascular complications and, when possible, alternate methods for venting the left ventricle are recommended.

Balloon angioplasty was attempted in 13 children with peripheral pulmonary arterial (PA) stenosis. In 5 patients, angioplasty was successful in relieving the peripheral PA stenosis as judged by an increase in PA size of more than 75% over the predilatation size and a more than 50% reduction in the distal PA to main PA peak systolic pressure gradient. Each child has been followed for 6 to 30 months. All remain well, without signs of subsequent deterioration, and follow-up angiograms in 2 patients (at 10 and 12 months) showed persistence of anatomic and hemodynamic improvement. In 8 patients, angioplasty was unsuccessful: In 4 patients, stenosis at the site of a previous systemic-to-PA shunt could not be dilated and in 4 patients, angioplasty could not be performed because of technical difficulties. Thus, we could not dilate the stenosis in more than 60% of the patients; we also had a significant complication with the angioplasty procedure (perforation of a distal branch of the right pulmonary artery). Thus, although balloon angioplasty was not effective in all patients, it did provide significant improvement in some patients in whom traditional operative management is usually unsuccessful.

Cardiovascular malformations were present in 48 of 326 (14.7%) patients with tracheoesophageal fistula. The most common cardiac lesion was ventricular septal defect. When tracheoesophageal fistula or esophageal atresia was associated with other gastrointestinal anomalies, tetralogy of Fallot and atrial septal defect were very frequent; when skeletal anomalies were present, the cardiac malformations were usually complex. The hospital mortality in infants with tracheoesophageal fistula and cardiovascular malformations is 79% in contrast to 23% for infants without cardiac abnormalities.

The acute hemodynamic effects of verapamil were evaluated in nine children with hypertrophic cardiomyopathy. Verapamil, 0.1 mg/kg, was administered as an i.v. bolus over 2 minutes, followed by a 20-minute continuous infusion of 0.007 mg/kg/min. Hemodynamic measurements were obtained at rest in nine patients and at maximal supine bicycle exercise in seven before and 15 minutes after verapamil. At rest, verapamil increased the mean cardiac output from 3.3 +/- 0.9 to 3.7 +/- 0.9 l/min/m2 (+/- SD) (p less than 0.02) and decreased left ventricular end-diastolic pressure from 19.3 +/- 8.1 to 14.5 +/- 6.9 mm Hg (p less than 0.006). In six patients with resting left ventricular outflow tract obstruction, the systolic pressure gradient decreased from 17.5 +/- 7.2 to 5.2 +/- 4.5 mm Hg (p less than 0.04). Repeat supine bicycle exercise testing after verapamil showed increases in total work performed (1743 +/- 1284 to 3168 +/- 1643 kg-m, p less than 0.006) and maximal cardiac index during exercise (6.5 +/- 1.3 to 7.8 +/- 1.8 l/min/m2, p less than 0.05), and decreases in maximal exercise left ventricular end-diastolic pressure (29.1 +/- 10.1 to 19.3 +/- 10.4 mm Hg, p less than 0.002) and left ventricular systolic outflow tract gradient (31.2 +/- 10.5 to 1.75 +/- 1.7 mm Hg, p less than 0.04). These results suggest that verapamil may be an effective therapeutic agent for the treatment of hypertrophic cardiomyopathy in children.

The course and prognosis of 16 infants and children with sick sinus syndrome associated with cardiac surgery is reviewed. The dysrhythmia was observed most ofter after extensive atrial reconstructive surgery in patients with transposition of the great arteries and with atrial septal defect. In 12 (75%) of the patients, sick sinus syndrome was detected in the immediate postoperative period. Tachyarrhythmias and bradyarrhythmias were presnet in 12 and isolated bradyarrhythmias in four. Temporary pacing was used in two and permanent pacing was required in five. Death in two non-paced patients was attributable to arrhythmias. Postmortem examination in one patient revealed a suture in the sinoatrial node. Careful attention to the anatomy of the sinoatrial node, its artery and the internodal tracts during surgery may prevent the development of sick sinus syndrome. In patients with dysrhythmia, a careful search should be undertaken to document the abnormal rhythm with the use of Holter monitoring. The insertion of a pacemaker is indicated in patients with tachyarrhythmias requiring cardioversion or antiarrhythmic drug therapy and those without adequate lower escape mechanisms.

To assess the usefulness of the Doppler mean gradient as a noninvasive indicator of the need for intervention, 33 children (ages 3 months to 20 years) with valvular aortic stenosis (AS) underwent a 2-dimensional and Doppler echocardiographic examination a median of 1 day before cardiac catheterization. The clinical decision for intervention was based on finding a catheterization peak-to-peak pressure gradient of greater than 75 mm Hg or from 50 to 75 mm Hg in the presence of symptoms or an abnormal exercise treadmill test result. Of the 33 patients, 23 required intervention. The decision for intervention was compared to the Doppler mean gradient, and the Doppler peak and mean gradients were compared to the catheterization peak-to-peak gradient. All 12 patients with a Doppler mean gradient greater than 27 mm Hg had intervention and had a catheterization peak-to-peak gradient of greater than or equal to 75 mm Hg. All 3 patients with a Doppler mean gradient less than 17 mm Hg had no intervention and had a peak-to-peak gradient less than 50 mm Hg. The remaining 18 patients with Doppler mean gradients between 17 and 27 mm Hg comprised an intermediate group in whom the Doppler mean gradient alone did not predict the need for intervention. From a chi-square table, a Doppler mean gradient greater than 27 mm Hg predicted the need for intervention with 100% specificity (no false positives) and 52% sensitivity (11 false negatives).(ABSTRACT TRUNCATED AT 250 WORDS)

We prospectively examined the usefulness of electrocardiography, chest radiography, and M-mode echocardiography in discriminating between the presence and absence of heart disease in 280 children older than one month and newly referred for evaluation of a heart murmur. After taking a history and performing a physical examination but before reviewing diagnostic tests, we categorized the children as having "no heart disease" (142), "possible heart disease" (34), or "definite heart disease" (104). Among the children initially thought to have no heart disease, the diagnosis was changed after a review of diagnostic tests in eight--three with mitral-valve prolapse, two with possible cardiomyopathy, and three with no heart disease on follow-up. Among those initially thought to have possible heart disease, the tests changed the diagnosis to definite heart disease in four, of whom only one had heart disease (mitral-valve prolapse) on follow-up. In no case did a review of tests change the diagnosis of definite heart disease. We conclude that the results of diagnostic tests are unlikely to change the clinical diagnosis of no heart disease or definite heart disease, when made by a qualified pediatric cardiologist in children newly referred for evaluation of a heart murmur.

Surgical repair was performed on 8 patients with tetralogy of Fallot and congenital or acquired absence of the left pulmonary artery. Prior palliative systemic-pulmonary artery shunts had been performed in the 5 patients with acquired absence of the pulmonary artery, and in none was repair of the damaged pulmonary artery possible. A valve-containing conduit (Hancock) was used in each patient to prevent pulmonary valvular regurgitation during the early postoperative period. All patients survived operation and have exhibited marked symptomatic and hemodynamic improvement. This contrasts with the poor results of corrective operation previously reported in patients in this diagnostic category. We believe that the present improved results are due in large part to the valved conduit, and we therefore recommend its use during repair in children or adults with tetralogy and a single pulmonary artery.

To assess the flow characteristics of homograft valved conduits in the immediate postoperative period, 69 children with 71 homograft conduits underwent 2-dimensional and Doppler echocardiographic examination at 1 to 40 days (mean 8) after surgery. Of the 71 conduits studied, 19 were aortic and 52 were pulmonary homograft valved conduits. Two aortic homograft valved conduits were inserted in the aortic position, whereas all remaining homografts were placed in the pulmonary position. On the immediate postoperative echocardiogram, 25 (35%) of the conduit valves had no regurgitation and 44 (62%) had 1+ (mild) regurgitation. Two pulmonary valved conduits (3%) in the pulmonary position had 2+ (moderate) regurgitation and right ventricular dimensions >95% for body surface area. The peak velocity across the homograft valve was normal ( 2.6 m/s in the immediate postoperative period. To assess the fate of homograft valved conduits in the intermediate-term follow-up period, 38 children with 38 conduits had a repeat echocardiogram at 6 to 25 months (mean 15 ± 6) after surgery. Of the 38 conduits examined, 10 (26%) had no regurgitation, 25 (66%) had 1+ regurgitation and 3 (8%) had 2+ regurgitation. Progression of the amount of regurgitation occurred in 11 (29%) patients. At the follow-up examination, peak velocity was ≤1.4 m/s across 34 conduit valves, between 1.4 and 2.6 m/s across 3 valves and >2.6 m/s across 1 valve. This latter patient had a 3.2-m/s jet across the proximal insertion of the conduit and no further increase across the valve itself. Thus, no patient had evidence of conduit valve stenosis. Of the 38 patients, 9 had Doppler evidence of obstruction at the conduit insertion (8 at the distal end and 1 with the aforementioned proximal obstruction). Most obstructions were of mild to moderate severity and only 2 patients (5%) had severe conduit stenosis. Thus, in the immediate postoperative period, normally functioning homograft valved conduits frequently have mild regurgitation (62%) and rarely have moderate or severe regurgitation (3%), with peak velocities reaching Thus, in the immediate postoperative period, normally functioning homograft valved conduits frequently have mild regurgitation (62%) and rarely have moderate or severe regurgitation (3%), with peak velocities reaching

Transluminal balloon valvuloplasty was used in the treatment of congenital valvar pulmonary stenosis in 19 children, aged 5 months to 18 years. The right ventricular (RV) systolic pressure and RV outflow tract gradient decreased significantly immediately after the procedure (95 +/- 29 vs 59 +/- 14 mm Hg, p less than 0.01, and 78 +/- 27 vs 38 +/- 13 mm Hg, p less than 0.01). Seven of these patients were evaluated at cardiac catheterization 1 year after balloon valvuloplasty. No significant change occurred in RV systolic pressure or RV outflow tract gradient at follow-up evaluation compared with measurements immediately after balloon valvuloplasty (60 +/- 5 mm Hg vs 56 +/- 12 mm Hg and 39 +/- 5 vs 38 +/- 10 mm Hg). In addition, follow-up evaluation was performed using noninvasive methods and included electrocardiography (n = 13), vectorcardiography (n = 11) and Doppler echocardiography (n = 11) Doppler echocardiography in 11 patients 15 +/- 9 months after balloon valvuloplasty showed a continued beneficial effect with a mild further decrease in RV outflow tract gradient. Thus, balloon valvuloplasty is effective in the relief of pulmonary stenosis.

The incidence and possible causes of paradoxical hypertension were evaluated in eight children who underwent balloon dilatation and seven children who underwent surgical repair of coarctation of the aorta. Both procedures resulted in a significant reduction in the coarctation gradient. Both systolic and diastolic blood pressures increased in the surgical group after repair, whereas systolic pressures decreased and diastolic pressures remained unchanged after balloon angioplasty. In the surgical group, but not in the balloon angioplasty group, plasma catecholamines and plasma renin activity rose during the first 2 days after relief of the coarctation. The data presented in this report support the hypothesis that the sympathetic nervous system and the renin angiotensin system are important mediators of the paradoxical hypertension that occurs after surgical repair of coarctation. Furthermore, balloon angioplasty of coarctation of the aorta does not stimulate either system and thus paradoxical hypertension is not a complication of this procedure.

To assess the long-term results of left ventricular outflow tract reconstruction utilizing an apical left ventricular to aortic valved (porcine) conduit the clinical and hemodynamic data were reviewed from 24 patients who had placement of an apico-aortic conduit. Eighteen of the patients are asymptomatic and taking no cardiac medications. Three patients were reoperated on, one patient 1.5 years after his original operation for subacute bacterial endocarditis and two patients 3 to 4 years after their original operation for severe conduit valve insufficiency. None of the patients is taking anticoagulants and no thromboembolic events have occurred. Postoperative catheterization has been performed 1 to 1.5 years (mean 1.2) after repair in 15 of 21 patients. The rest left ventricular outflow tract gradient has decreased from 102.5 +/- 20 mm Hg preoperatively to 14.8 +/- 9.9 mm Hg postoperatively (probability [p] less than 0.001). Some degree of conduit obstruction was demonstrated by catheter passage in 11 of the 15 patients. In these 11 patients, the obstruction occurred at three distant sites: at the egress of the left ventricle in 9, at the porcine valve in 5 and at the aortic to conduit junction in 1. Isometric exercise in five and supine bicycle exercise in six patients increased the left ventricular outflow tract gradient by 2.5 +/- 1.1 and 20.8 +/- 11.8 mm Hg, respectively, despite an increase in cardiac index of 1 +/- 0.3 and 3.7 +/- 0.4 liters/min per m2, respectively. The data suggest that a left ventricular to aortic conduit is an effective form of therapy for severe left ventricular outflow tract obstruction.