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Objectives: The purpose of this study was to characterize left ventricular (LV) mechanics during acute rheumatic fever (ARF) and to define factors influencing remodeling after the acute event., Background: Acute rheumatic fever is associated with varying degrees of valvulitis and myocarditis, but the impact of these factors on LV mechanics is poorly defined., Methods: Echocardiograms and clinical data were reviewed in 55 patients aged 11.2 +/- 2.6 years during ARF. Valve regurgitation was absent or mild in 33 (group I) and moderate or severe in 22 (group II). Forty-two children (75%) underwent a further examination after ARF., Results: Group I patients demonstrated a mildly elevated LV size during ARF and had normal indexes at follow-up. Group II patients demonstrated a markedly elevated LV size (end-diastolic dimension z-score 3.6 +/- 1.8, p < 0.01 compared with the normal population) and decreased shortening fraction (z-score -0.8 +/- 1.4, p < 0.05). The stress-velocity index, a z-score describing the velocity of shortening-afterload relationship, was normal in group II patients with mitral regurgitation (-0.2 +/- 1.2, p = NS) but was depressed in those with aortic regurgitation or both (- 1.4 +/- 1.4, p < 0.01). At follow-up the stress-velocity index remained depressed (-1.2 +/- 1.0, p < 0.01) and had deteriorated in those treated nonsurgically compared with those treated surgically (interval change nonsurgical -0.7 +/- 1.2 vs. surgical 1.3 +/- 1.3, p = 0.005)., Conclusions: The evolution of contractile dysfunction during and after ARF is dependent on the degree and type of valve regurgitation and may be influenced by surgical intervention. These findings suggest that mechanical factors are the most important contributors to myocardial damage during and after ARF.

Objectives: The present study was undertaken to determine the independent risk factors for early mortality in the current era after arterial switch operation (ASO)., Background: Prior reports on factors affecting outcome of the ASO demonstrated that abnormal coronary arterial patterns were associated with increased risk of early mortality. As diagnostic, surgical and perioperative management techniques continue to evolve, the risk factors for the ASO may have changed., Methods: All patients who underwent the ASO at Children's Hospital, Boston between January 1, 1992 and December 31, 1996 were included. Hospital charts, echocardiographic and cardiac catheterization data and operative reports of all patients were reviewed. Demographics and preoperative, intraoperative and postoperative variables were recorded., Results: Of the 223 patients included in the study (median age at ASO = 6 days and median weight = 3.5 kg), 26 patients had aortic arch obstruction or interruption, 12 had Taussig-Bing anomaly, 12 had multiple ventricular septal defects, 8 had right ventricular hypoplasia and 6 were premature. There were 16 early deaths (7%), with 3 deaths in the 109 patients considered "low risk" (2.7%). Coronary artery pattern was not associated with an increased risk of death. Compared with usual coronary anatomy pattern, however, inverted coronary patterns and single right coronary patterns were associated with increased incidence of delayed sternal closure (p = 0.003) and longer duration of mechanical ventilation (p = 0.008). In a multivariate logistic regression model using only preoperative variables, aortic arch repair at a separate procedure before ASO and smaller birth weight were independent predictors of early mortality. In a second model that included both pre- and intraoperative variables, circulatory arrest time and right ventricular hypoplasia were independent predictors of early death., Conclusions: The ASO can be performed in the current era without excess early mortality related to uncommon coronary artery patterns. Aortic arch repair before ASO, right ventricular hypoplasia, lower birth weight and longer intraoperative support continue to be independent risk factors for early mortality after the ASO.

Objectives: The purpose of the study was to assess the effects of maternal HIV-1 (human immunodeficiency virus) infection and vertically transmitted HIV-1 infection on the prevalence of congenital cardiovascular malformations in children., Background: In the United States, an estimated 7000 children are born to HIV-infected women annually. Previous limited reports have suggested an increase in the prevalence of congenital cardiovascular malformations in vertically transmitted HIV-infected children., Methods: In a prospective longitudinal multicenter study, diagnostic echocardiograms were performed at 4-6-month intervals on two cohorts of children exposed to maternal HIV-1 infection: 1) a Neonatal Cohort of 90 HIV-infected, 449 HIV-uninfected and 19 HIV-indeterminate children; and 2) an Older HIV-Infected Cohort of 201 children with vertically transmitted HIV-1 infection recruited after 28 days of age., Results: In the Neonatal Cohort, 36 lesions were seen in 36 patients, yielding an overall congenital cardiovascular malformation prevalence of 6.5% (36/558), with a 8.9% (8/90) prevalence in HIV-infected children and a 5.6% (25/449) prevalence in HIV-uninfected children. Two children (2/558, 0.4%) had cyanotic lesions. In the Older HIV-Infected Cohort, there was a congenital cardiovascular malformation prevalence of 7.5% (15/201). The distribution of lesions did not differ significantly between the groups., Conclusions: There was no statistically significant difference in congenital cardiovascular malformation prevalence in HIV-infected versus HIV-uninfected children born to HIV-infected women. With the use of early screening echocardiography, rates of congenital cardiovascular malformations in both the HIV-infected and HIV-uninfected children were five- to ten-fold higher than rates reported in population-based epidemiologic studies but not higher than in normal populations similarly screened. Potentially important subclinical congenital cardiovascular malformations were detected.

Objectives: We reviewed our institutional experience with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) after dual coronary repair to assess preoperative variables predictive of outcome, the time course for postoperative recovery of cardiac function, the short- and long-term complications and our experience with left ventricular assist devices (LVAD) in these patients., Background: Outcome after surgical repair of ALCAPA remains incompletely defined., Methods: The surgical records and echocardiograms of 42 patients were reviewed. Left ventricular function was assessed by fractional shortening z-score (FSz) and stress-velocity index., Results: The overall survival rate was 86%. All six patients who died were < 1 year old and died within 3 days of the operation. More severe preoperative mitral regurgitation (MR) was associated with increased mortality, but age, body surface area, preoperative FSz and end-diastolic dimension were not. We used an LVAD for 7 of 28 patients who underwent repair for ALCAPA since its introduction at our institution, with a survival of 5 of 7 patients. The degree of MR improved in 62% of patients and remained unchanged in 38%. Complications included supravalvar pulmonary stenosis (16 of 21 patients) and baffle leaks (11 of 21 patients) with the intrapulmonary baffling technique. Supravalvar pulmonary stenosis developed in 1 of 11 patients after direct coronary reimplantation. Left ventricular function became normalized in all 28 patients with follow-up past 1 year, regardless of preoperative FSz. Of 13 patients who underwent serial postoperative echocardiography, the average time to normalization of function was 2 to 7 months., Conclusions: The degree of preoperative MR was predictive of outcome, whereas the severity of preoperative cardiac dysfunction and ventricular dilation were not. Mild and moderate MR tended to improve without mitral valvuloplasty. Complete recovery from myocardial dysfunction is expected after dual coronary repair of ALCAPA.

Objectives: We report the clinical course and unique hemodynamic findings after placement of a supraannular mitral valve prosthesis., Background: Children with symptomatic mitral valve disease whose annulus is too small for the smallest prosthesis are difficult to manage. One option is valve replacement with a prosthesis positioned entirely within the left atrium (LA)., Methods: We reviewed 17 patients (median age 10 months) with symptomatic mitral valve disease who underwent placement of a supraannular valve prosthesis between 1980 and 1994., Results: The actuarial survival rates were 88% at 1 month and 71%, 62% and 53% at 1, 2 and 10 years, respectively. Preoperative hemodynamic data (mean +/- SD)) compared with those after placement of the supraannular mitral prosthesis were as follows: "a" wave to left ventricular end-diastolic pressure gradient 17 +/- 5 versus 4 +/- 4 mm Hg (p = 0.003), mean LA pressure 25 +/- 6 versus 20 +/- 6 mm Hg (p = 0.07), "a" wave 30 +/- 6 versus 19 +/- 5 mm Hg (p = 0.006), "v" wave 28 +/- 5 versus 30 +/- 9 mm Hg (p = 0.31), mean pulmonary artery pressure 54 +/- 19 versus 42 +/- 15 mm Hg (p = 0.07) and left ventricular end-diastolic pressure 14 +/- 5 versus 16 +/- 4 mm Hg (p = 0.12)., Conclusions: Supraannular mitral valve replacement provides relief of mitral stenosis or mitral regurgitation. However, LA to left ventricular early diastolic gradients with large atrial "v" waves contribute to elevated mean LA pressures in the absence of prosthetic valve obstruction or regurgitation. As a result of this unexpected finding, associated left heart obstructive lesions and pulmonary and left ventricular end-diastolic hypertension, the outlook remains poor.

Objectives: This study was designed to define patterns of pulmonary artery and aortic growth in fetuses with tetralogy of Fallot and to determine the potential for in utero progression of right ventricular outflow tract obstruction., Background: Despite an abundance of reports documenting the prenatal diagnosis of tetralogy of Fallot, there is little information about its course in utero., Methods: Pulmonary artery and ascending aortic diameters were measured from prenatal and postnatal echocardiograms of 16 fetuses with tetralogy of Fallot, initially studied at 23.6 +/- 6.0 (mean +/- SD) weeks of gestation. Fetuses were classified retrospectively as having mild and severe tetralogy of Fallot according to whether the pulmonary artery circulation was (severe, n = 5) or was not (mild, n = 11) ductus arteriosus dependent at birth., Results: Initial main pulmonary artery diameter was small for gestational age in 9 fetuses, large in 2 and normal in 5 compared with data from 57 gestational age-adjusted normal fetal studies; it was significantly smaller in the group with severe tetralogy of Fallot (p = 0.05). The initial main pulmonary artery/aortic diameter ratio was also smaller for the group with severe tetralogy of Fallot (0.50 +/- 0.15 vs. 0.73 +/- 0.14 in the group with mild tetralogy of Fallot, p = 0.01). Initial aortic and branch pulmonary artery diameters tended to be normal or near normal for age. In eight fetuses serially studied, main and branch pulmonary artery growth was normal or reduced during prenatal follow-up. Pulmonary artery growth was most reduced in two fetuses in the group with severe tetralogy of Fallot, resulting in pulmonary artery hypoplasia at birth. Two fetuses with valvular pulmonary atresia at birth had previously shown anterograde pulmonary outflow in midgestation, suggesting progression of pulmonary outflow obstruction., Conclusions: The postnatal spectrum of pulmonary artery size in tetralogy of Fallot can be attributed to variable patterns of growth in utero. Main pulmonary artery size, main pulmonary artery/aortic diameter ratio and pattern of pulmonary artery growth may be predictive of the severity of postnatal pulmonary outflow obstruction. Pulmonary atresia can develop in utero in some fetuses with tetralogy of Fallot.

Objectives: This study attempted to determine the effect of young age on changes in coronary conductance and capillary density with left ventricular pressure overload hypertrophy. Mechanisms responsible for age differences in perfusion capacity were examined., Background: Hypertension in adults causes alterations in the coronary vasculature, resulting in diminished coronary perfusion capacity and myocardial ischemia. These processes are worsened in adults by advanced age. Young age may provide advantages in coronary adaptation to hypertension., Methods: Coronary conductance was examined in conscious chronically instrumented 10-week old lambs and adult sheep with progressive ascending aortic stenosis of 6-week's duration and age-matched control sheep by means of the microsphere technique and vasodilators. Capillary density was measured post-mortem., Results: Adult sheep with aortic stenosis had a decrease in left ventricular subendomyocardial capillary density by 17% and maximal coronary conductance with adenosine by 67%. In the nonhypertrophied right ventricle, maximal coronary conductance was depressed by 47%, whereas capillary density was normal, implying an effect of coronary hypertension on resistance vessels. In contrast, lambs with aortic stenosis maintained normal left ventricular capillary density, maximal coronary conductance and coronary reserve and had relatively little impairment of conductance in the right ventricular coronary bed (-15%, p = NS). Similar responses were found with other vasodilators, isoproterenol and chromonar., Conclusions: Young age confers advantages to coronary adaptation to left ventricular pressure overload, including angiogenesis proportionate to hypertrophy, resulting in normal capillary density and coronary conductance. There is also less hypertension-induced impairment of coronary conductance distinct from the effects of hypertrophy.

Objectives: The reliability of two-dimensional echocardiography for determining the proximal coronary artery anatomy in d-loop transposition of the great arteries was investigated in 406 infants who underwent surgical repair at one institution., Background: The origin and proximal course of the main coronary arteries can affect the surgical results of the arterial switch operation. Preoperative determination of the coronary artery anatomy appears to be advantageous for the surgeon., Methods: All infants with d-loop transposition who underwent a two-dimensional echocardiogram and primary surgical repair at our institution between 1987 and 1992 were identified, and the echocardiographic, operative and, when available, autopsy reports were reviewed for coronary artery anatomy, presence of a ventricular septal defect and the spatial relation between the arterial roots. The two-dimensional echocardiographic findings were compared with surgical or autopsy findings. The relation between proximal coronary artery anatomy and 1) a ventricular septal defect, and 2) the spatial orientation of the arterial roots was investigated. Twenty-seven infants diagnosed with an intramural coronary artery were not included because they are the subjects of another report., Results: Excluding intramural coronary artery patterns, 10 different types of coronary artery anatomy were seen in these 406 patients. The coronary arteries were imaged adequately in 387 (95%) of the 406 patients. The coronary artery anatomy was determined correctly by two-dimensional echocardiography in 369 (95.4%) of the 387 patients, with 18 errors in diagnosis. During the most recent 2.5 years, 193 (98.5%) of 196 patients were diagnosed correctly, with three diagnostic errors. Patients with a ventricular septal defect or side-by-side great arteries are more likely to have an unusual coronary pattern., Conclusions: Echocardiography appears to be highly reliable for determining proximal coronary artery anatomy in d-loop transposition of the great arteries. An unusual coronary artery pattern is more likely in patients with side-by-side great arteries or posterior aorta or a ventricular septal defect, or both.

Objectives: This study was conducted to determine the prevalence of myocardial perfusion abnormalities at rest and exercise and to assess exercise capacity in children after the arterial switch operation., Background: There have been sporadic reports of myocardial ischemia or sudden death in children after the arterial switch operation for transposition of the great arteries, possibly related to inadequate coronary perfusion due to kinking or stenosis of the translocated coronary arteries., Methods: Myocardial perfusion at rest and peak exercise was assessed using the scintigraphic agent technetium-99m methoxyisobutyl isonitrile (sestamibi). Exercise capacity was determined with a modified Bruce protocol. Ambulatory electrocardiographic (ECG) Holter monitoring was performed. Ventricular function, contractility and wall motion were assessed echocardiographically., Results: Twenty-three children (aged 4.2 to 7.9 years) underwent evaluation. Abnormalities were found on the rest perfusion scans in 22 children (95.6%). The left ventricular myocardium was divided into 13 segments for analysis. Of 299 rest segments, 225 (75.3%) were normal, 11 (3.7%) showed mild defects, 45 (15%) moderate defects and 18 (6%) severe defects at rest. At peak exercise, 237 segments (79.3%) were normal, 24 (8%) showed mild defects, 33 (11%) moderate defects and 5 (1.7%) severe defects. Compared with rest studies, myocardial perfusion grade at exercise was unchanged in 246 segments (82.3%), improved in 42 (14%) and worsened in 11 (3.7%). All patients had normal exercise tolerance without symptoms or ischemic ECG changes. No ventricular tachycardia was seen on Holter monitoring. All patients had a shortening fraction > or = 27%. Left ventricular contractility was normal in 12 children in whom it was assessed. Regional wall motion was normal in 17 children with adequate echocardiographic images for this analysis., Conclusions: Myocardial perfusion scan abnormalities assessed by technetium-99m sestamibi are common after an arterial switch operation. These abnormalities are of uncertain clinical significance and generally lessen with exercise. The normal exercise tolerance without symptoms or ECG changes suggests that myocardial perfusion is adequate during the physiologic stress of exercise in children up to 8 years after an arterial switch operation.

Objectives: This study was designed to identify preoperative echocardiographic predictors of left ventricular outflow tract obstruction after repair of interrupted aortic arch and ventricular septal defect closure., Background: Left ventricular outflow tract obstruction becomes apparent in nearly 50% of patients after repair of interrupted aortic arch and ventricular septal defect closure but is seldom recognized preoperatively., Methods: We analyzed the preoperative echocardiograms of all patients with interrupted aortic arch who had postoperative echocardiographic or catheterization data available. Thirty-seven infants (aged 1 day to 10 months, median 5 days) were included. Off-line measurements were performed on hard copies of selected images. The cross-sectional area (indexed to body surface area) and diameters (indexed to the square root of body surface area) of the left ventricular outflow tract; ascending and descending aorta; ventricular septal defect; and mitral, aortic and pulmonary valves were compared with outcome by using analysis of variance. Outcome was classified according to development of postoperative left ventricular outflow tract Doppler gradient (Group 1 < or = 20 mm Hg, Group 2 > 20 mm Hg)., Results: The cross-sectional area of the left ventricular outflow tract was significantly smaller in patients who did than in those who did not develop subaortic obstruction ([mean +/- SD] 0.64 +/- 0.25 vs. 1.7 +/- 1.01 cm2/m2, p < 0.004). Left ventricular outflow tract and aortic valve diameters and aortic valve area were not predictive of postoperative left ventricular outflow tract obstruction. Incidence of postoperative left ventricular outflow tract obstruction was lower (p < 0.03) in interrupted aortic arch type A (0 of 6) than in type B (15 of 31). The incidence of aberrant right subclavian artery was lower (p < 0.02) in Group 1 (6 of 22) than in Group 2 (10 of 15)., Conclusions: The preoperatively measured cross-sectional area of the left ventricular outflow tract is significantly smaller in patients with interrupted aortic arch who develop subaortic obstruction postoperatively, with a left ventricular outflow tract area < or = 0.7 cm2/m2 being a sensitive predictor. Aortic arch anatomy (i.e., type of interrupted aortic arch and presence of aberrant right subclavian artery) is also predictive of postoperative left ventricular outflow tract obstruction, possibly by influencing the volume of blood flow across the left ventricular outflow tract. These data should enable preoperative identification of infants who may require surgical relief of subaortic stenosis.

Objectives: Using a new mapping system that allows the simultaneous acquisition of data from 25 right atrial bipolar electrodes during cardiac catheterization, we mapped normal sinus rhythm and atrial reentrant tachycardia in 24 sheep (20 to 49 kg) and 7 pigs (25 to 35 kg)., Background: Rapid, high resolution mapping during cardiac catheterization may shorten ablation procedures and permit ablation of otherwise refractory arrhythmias., Methods: A flexible, elliptic, basket-shaped recording catheter has five spokes, each with 10 electrodes arranged as 5 bipolar pairs. Catheter shape, electrode spacing and introduction technique were modified in response to the results of experiments in the first 23 animals. In the most recent eight animals, retraction of a string attached to the distal tip distended the basket, providing safe tissue contact. Filtered (30 to 250 Hz) bipolar recordings from all 25 electrode pairs, as well as a surface electrocardiogram, were recorded and digitized at 1,000 Hz using custom software. An activation map was digitally constructed and superimposed on anteroposterior and lateral fluoroscopic catheter images. Bipolar recordings were made in normal sinus rhythm (31 animals), with adequate signals recorded from > 95% of electrode pairs. Rapid burst pacing and intentional right atrial air embolus (30 to 50 ml) induced sustained atrial reentrant tachycardia in five animals, which was also adequately recorded., Results: Catheter positioning and complete atrial mapping required < 10 min after venous access in the most recent eight experiments. The catheter was left in position for up to 4 h. Postmortem evaluation revealed minor superficial abrasion of the venae cavae or right atrial endocardium in six animals and moderate abrasion in two. No other damage was observed., Conclusions: This new system may ultimately assist in mapping simple or complex atrial arrhythmias during cardiac catheterization.

Objectives: We investigated whether mortality in totally anomalous pulmonary venous connection could be predicted from preoperative individual pulmonary vein size., Background: Some infants with this anomaly die with or without surgical repair because of stenosis of individual pulmonary veins., Methods: Individual pulmonary vein, vertical vein and pulmonary venous confluence diameters were retrospectively measured from preoperative echocardiograms in 32 infants with totally anomalous pulmonary venous connection presenting to Children's Hospital, Boston over a 4 1/2-year period. Data on body surface area, other cardiac anomalies, presence of initial pulmonary venous obstruction and early surgery and outcome were also recorded., Results: Of 32 patients, 6 (18.8%) died before hospital discharge, and 8 (25.0%) died subsequently. Six (75.0%) of the eight patients who died late had individual pulmonary vein stenosis at sites remote from the surgical anastomosis to the left atrium. The remaining 18 patients (56.3%) are alive at a mean follow-up period of 9.7 months. A Cox proportional hazards model revealed that small sum of individual pulmonary vein diameters (p = 0.0004), small confluence size (p = 0.02) and presence of heterotaxy syndrome (p = 0.008) were each significant univariate predictors of survival. Multivariate analysis showed that small pulmonary vein sum was a strong predictor of survival (p = 0.008), independent of the presence of heterotaxy syndrome. An analysis stratified by the presence of heterotaxy syndrome showed that the predictive effect of small pulmonary vein sum on survival was strongest in patients without heterotaxy syndrome., Conclusions: These data show that individual pulmonary vein size at diagnosis is a strong, independent predictor of survival in patients with totally anomalous pulmonary venous connection. In patients with this anomaly and small individual pulmonary veins, the anomaly may not be correctable by surgical creation of an anastomosis between the pulmonary venous confluence and the left atrium.

Objectives: We sought to study the range of conal morphology in transposition of the great arteries with ventricular septal defect and their embryologic and surgical implications., Background: Conal anatomy in transposition of the great arteries and ventricular septal defect is variable and might affect surgical repair., Methods: Conal anatomy was explored using two-dimensional echocardiography in 119 patients with transposition of the great arteries and a large ventricular septal defect who presented between 1984 and 1991. The influence of conal anatomy on surgical technique was determined by review of the operative reports. Specimens of transposition of the great arteries with unusual conal anatomy were selected from the Cardiac Registry for comparison with the echocardiograms., Results: One hundred five patients (88.2%) had subaortic conus only with no subpulmonary conus (Group 1). Subarterial conus was present bilaterally in eight patients (6.7%) (Group 2). Four patients (3.4%) had only subpulmonary conus with no (or minimal) subaortic conus (Group 3). Among these four patients, the aorta was posterior to the pulmonary artery in one patient, side by side relative to the pulmonary artery in two patients and slightly anterior in the fourth patient. Subarterial conus was absent bilaterally in two patients (1.7%) (Group 4); the aorta was slightly posterior in one and side by side with the pulmonary artery in the other., Conclusions: This variability of conal anatomy in transposition of the great arteries with ventricular septal defect implies four mechanisms by which transposition can occur. The conal anatomy appeared to affect surgical repair in Groups 1 and 2 insofar as it influenced ventricular outflow tract obstruction. In Groups 3 and 4, an arterial switch operation was performed in four of the six patients. The posterior location of the aorta obviated the need for the Lecompte maneuver in two of these four patients. In the remaining two cases in Groups 3 and 4, the condition was repaired by directing the left ventricular outflow across the ventricular septal defect to the aorta using a patch, with or without placement of a conduit from the right ventricle to the pulmonary artery.

Background: Anomalous origin of the left coronary artery from the pulmonary trunk is difficult to diagnose reliably by two-dimensional echocardiography. Therefore, Doppler color flow mapping was tested in 29 patients with dilated cardiomyopathy or anomalous left coronary artery, or both., Methods and Results: All patients with anomalous left coronary artery (10 patients) or dilated cardiomyopathy (27 patients) (excluding those with other known causes for cardiomyopathy) examined between January 1988 and May 1991 were identified. The direction of flow in the three main segments of the left coronary system was determined by Doppler color flow mapping. In all 10 patients with anomalous left coronary artery, flow mapping demonstrated an abnormal jet from the left coronary artery into the pulmonary trunk and retrograde flow in at least two segments of the left coronary system. The diagnosis was confirmed in all 10 patients at operation. Doppler color flow mapping, performed in 19 of the 27 patients with dilated cardiomyopathy, demonstrated anterograde flow in at least one segment of the left coronary system in 16 of the 19 patients; flow direction was not determined in the other 3 patients. Coronary artery anatomy was confirmed by aortic root or left ventricular angiography in 14 patients and at autopsy in 1 patient and was not directly confirmed in 4 patients. Left ventricular function spontaneously improved to normal in three of the latter four patients, a clinical course not consistent with anomalous left coronary artery. The left coronary artery appeared to arise from the aortic root by two-dimensional echocardiographic imaging alone in all patients with dilated cardiomyopathy and in 5 of 10 patients with anomalous left coronary artery (50% false negative diagnoses)., Conclusions: Detection of an abnormal jet into the pulmonary trunk and retrograde flow in the left coronary system by Doppler color flow mapping is reliable for diagnosing anomalous left coronary artery whereas two-dimensional echocardiographic imaging alone is often inconclusive or misleading. Determining flow direction in the left coronary system in patients with dilated cardiomyopathy is useful for excluding anomalous left coronary artery but is technically more difficult to document in this condition than in anomalous left coronary artery.

Somatic growth is associated with alterations in myocardial mechanics in children with heart disease and in most animal models of congenital heart disease. However, the effect of age and body size on myocardial contractility and loading conditions in normal infants and children is not known. Therefore, 256 normal children aged 7 days to 19 years (34% less than 3 years old) were evaluated with noninvasive indexes of left ventricular contractility and loading conditions. Two-dimensional and M-mode echocardiographic recordings of the left ventricle were obtained with a phonocardiogram, indirect pulse tracing and blood pressure recordings. Left ventricular dimensions, wall thickness and pressure measurements obtained from these data were used to calculate peak and end-systolic circumferential and meridional wall stress and mean and integrated meridional wall stress. Velocity of shortening adjusted for heart rate was compared with end-systolic stress to assess contractility independently of loading status. The subjects were stratified for gender and each of the derived variables was related to age and body surface area. Ventricular shape, assessed as the major/minor axis ratio, and the circumferential/meridional stress ratio were found to be invariant with growth. The ratio of posterior wall thickness to minor axis dimension did not change with age, despite the normal age-related increase in blood pressure. The increase in pressure despite unvarying ventricular shape and wall thickness/dimension ratio resulted in a substantial increase in wall stress that was most dramatic during the first few years of life. In association with the increase in afterload, systolic function decreased with age. However, the age-related decrease in the velocity of shortening was greater than that expected from the increase in afterload alone, indicating a higher level of contractility in infants and children during the first years of life than in older subjects. The process of normal growth and development, similar to that in children with heart disease, is associated with a rapid decrease in the trophic response to hemodynamic loads, resulting in an age-associated increase in wall stress. There is a similar but somewhat more rapid decrease in contractility, with the highest values seen in the youngest patients.

Bulboventricular foramen obstruction may complicate the management of patients with single left ventricle. Bulboventricular foramen size was measured in 28 neonates and infants greater than 5 months old and followed up for 2 to 5 years in those patients whose only systemic outflow was through the foramen. The bulboventricular foramen was measured in two planes by two-dimensional echocardiography, its area calculated and indexed to body surface area. One patient died before surgical treatment. The mean initial bulboventricular foramen area index was 0.94 cm2/m2 in 12 patients (Group A) in whom the foramen was bypassed as the first procedure in early infancy. The remaining 15 patients underwent other palliative operations but the bulboventricular foramen continued to serve as the systemic outflow tract. There was one surgical death. Six (Group B) of the 14 survivors developed bulboventricular foramen obstruction during follow-up (mean initial bulboventricular foramen area index 1.75 cm2/m2). The remaining eight patients (Group C) did not develop obstruction during follow-up and had an initial bulboventricular foramen larger than that in the other two groups (mean initial bulboventricular foramen area index 3.95 cm2/m2). All patients with an initial bulboventricular foramen area index less than 2 cm2/m2 who did not undergo early bulboventricular foramen bypass developed late obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

The records of 23 infants who underwent surgical repair of isolated totally anomalous pulmonary venous connection were reviewed to assess the accuracy of pre- and postoperative echocardiographic diagnoses. Preoperative echocardiographic diagnoses were accurate in 22 of 23 patients, including the sites of connection of the individual pulmonary veins. Cardiac catheterization in 13 patients confirmed the echocardiographic findings. Analysis of multiple pre- and postoperative variables revealed no statistically significant difference between the infants with and without catheterization, although there was a tendency toward a higher mortality rate in the catheterized group. Postoperative echocardiographic examination revealed obstruction to pulmonary venous return in 7 of 19 patients. Catheterization confirmed the echocardiographic findings, localizing the obstruction in one patient. The size of the venoatrial anastomosis was measured on postoperative echocardiograms performed on 14 patients. The cross-sectional area of the anastomosis was less than 0.3 cm2/m2 of body surface area in the four patients with obstruction of the anastomosis, and greater than 0.95 cm2/m2 in all long-term survivors examined. Two-dimensional echocardiography with pulsed Doppler examination and Doppler color flow mapping is an excellent means of diagnosing totally anomalous pulmonary venous connection. The connections of the individual pulmonary veins can be identified in nearly all cases. Surgical repair can usually be undertaken on the basis of echocardiographic diagnosis alone. Echocardiography also provides an extremely accurate method of evaluating surgical repair and of identifying and localizing postoperative obstruction to pulmonary venous return.

The echocardiographic anatomy of double-inlet single left ventricle was studied in 57 patients, aged 1 day to 27 years (mean 6 years); the variables examined included morphology, size and function of the atrioventricular (AV) valves and ventricular septal defect and their relation to pulmonary stenosis, aortic stenosis and aortic arch obstruction. The visceroatrial situs was solitus and the heart was in the left side of the chest in all 57 patients. A d-loop ventricle was present in 21 patients and an l-loop ventricle in 36. The great arteries were normally related (Holmes heart) in 8 patients and transposed in 49. In all hearts, the right AV valve was anterior to the left AV valve. In 53 patients, the tricuspid valve (right valve in d-loop and left valve in l-loop) was closer to and had attachments on the septum. The tricuspid valve straddled the outflow chamber in eight patients. No significant difference was noted in the mean AV valve diameter when comparing mitral and tricuspid valves within the same group or between the groups with a d- or l-loop ventricle. The right AV valve diameter had a significant direct correlation with the aortic valve diameter and the size of the ventricular septal defect regardless of ventricular loop. Both AV valves were functionally normal in 34 patients. Among patients with AV valve dysfunction, the tricuspid valve tended to be stenotic in patients with an l-loop ventricle and regurgitant in patients with a d-loop ventricle. Mitral valve dysfunction was uncommon. The ventricular septal defect (46 patients) was separated from the semilunar valves in 24 patients (muscular defect) and adjacent to the anterior semilunar valve as a result of hypoplasia or malalignment, or both, of the infundibular septum (subaortic defect) in 19 patients. Multiple defects were present in three patients. The defect was unrestrictive in 26 patients, restrictive in 23 and could not be evaluated in 8. Pulmonary artery banding had been performed in 8 of the 26 patients with an unrestrictive defect and in 10 of the 23 patients with a restrictive defect. Only 4 of 19 subaortic defects compared with 16 of 24 muscular defects were restrictive. The size of the defect was significantly correlated with the measured pressure gradient. Among patients with transposition, only 2 of 13 with pulmonary stenosis had a restrictive ventricular septal defect compared with 15 of 30 without pulmonary stenosis. In patients with transposition, the defect size was significantly smaller when coarctation was present.

Between January 1983 and October 1989, 290 patients underwent an arterial switch operation for transposition of the great arteries; 30 (10.3%) of the patients had abnormalities of the left ventricular outflow tract or mitral valve, or both. These abnormalities included isolated pulmonary valve stenosis (n = 9), septal (dynamic) subpulmonary stenosis (n = 5), anatomic (fixed) subpulmonary stenosis (n = 7), abnormal mitral chordae attachments (n = 2) or a combination of abnormalities (n = 7). There were two early deaths, one of which was due to previously unrecognized mitral stenosis and a subpulmonary (neo-aortic) membrane and one late death due to presumed coronary obstruction. Of the nine patients with pulmonary valve abnormalities due to either a bicommissural (n = 5) or a thickened tricommissural (n = 4) valve, only one underwent valvotomy. Peak systolic ejection gradients in these nine patients measured preoperatively ranged from 0 to 50 mm Hg. At follow-up study 5 to 30 months postoperatively, the neo-aortic valve gradient was less than or equal to 15 mm Hg in all patients; three patients had mild neo-aortic regurgitation. Preoperative gradients may overestimate the degree of obstruction because of the increased pulmonary blood flow present in transposition. No patient with "dynamic" subpulmonary obstruction before the arterial switch operation had a surgical procedure performed on the left ventricular outflow tract; none had evidence of subaortic obstruction after the arterial switch.(ABSTRACT TRUNCATED AT 250 WORDS)

The velocity of circumferential fiber shortening (Vcf) is an index of myocardial performance which, although sensitive to contractile state, has limited usefulness because of its dependence on left ventricular loading conditions. This study investigated the degree and velocity of left ventricular fiber shortening as it relates to wall stress in an attempt to develop an index of contractility that is independent of preload and heart rate while incorporating afterload. Studies were performed in 78 normal subjects using M-mode echocardiography, phonocardiography and indirect carotid pulse tracings under baseline conditions. In addition, studies were performed on 25 subjects during afterload augmentation with methoxamine, 8 subjects before and during afterload challenge after increased preload with dextran and 7 subjects with enhanced left ventricular contractility with dobutamine. The relation of end-systolic stress to the velocity of fiber shortening and to the rate-corrected velocity of shortening (corrected by normalization to an RR interval of 1) was inversely linear with correlation coefficients of -0.72 and -0.84, respectively. Alterations in afterload, preload or a combination of the two did not significantly affect the end-systolic wall stress/rate-corrected velocity of shortening relation, whereas during inotropic stimulation, the values were higher, with 94% of the data points above the normal range. Age did not appear to affect the range of normal values for this index. In contrast, the end-systolic wall stress/fractional shortening relation was not independent of preload status, responding in a manner similar to that seen with a positive inotropic intervention. Thus, the velocity of circumferential fiber shortening normalized for heart rate is inversely related to end-systolic wall stress in a linear fashion. Accurate quantitation can be performed by noninvasive means and a range of normal values determined. This index is a sensitive measure of contractile state that is independent of preload, normalized for heart rate and incorporates afterload. In contrast, the end-systolic wall stress/fractional shortening relation is dependent on end-diastolic fiber length in the range of physiologically relevant changes in preload.

The potential existence of a specific uremia-associated myocardial depressant factor was explored by evaluating nine pediatric subjects (3 to 21 years) without evidence of coronary artery disease or long-standing hypertension 1) before entering a dialysis program, 2) while undergoing a long-term dialysis regimen, and 3) after successful renal transplantation. Myocardial contractility was quantitated with load-independent indexes using the end-systolic pressure-dimension relation (Emax) and the relation of rate-corrected velocity of shortening to end-systolic wall stress. Myocardial loading status was determined by the direct measurement of afterload (end-systolic wall stress) and the functional quantitation of preload (differences between the relation of fractional shortening and velocity of shortening to end-systolic stress). Most patients (55%) were found to have abnormal ejection phase indexes of ventricular function either before or after entry into dialysis. However, contractility was normal in all subjects at each of their evaluations, and no change in contractility was found after dialysis or transplantation. Loading status was highly variable and usually abnormal before transplantation and accounted entirely for the abnormalities of fractional shortening and velocity of shortening. Transplantation invariably resulted in normalization of loading status and ejection phase indexes of ventricular function. In these children and young adults with uremia, abnormal ejection phase indexes of ventricular function were frequent and caused by associated abnormalities in ventricular loading. Contractility, however, was normal and no evidence of a uremia-associated myocardial depressant was found.

Pressure overload hypertrophy of the left ventricle is associated with abnormal left ventricular early diastolic filling. The roles of the extent of cardiac hypertrophy, depressed left ventricular systolic function and aging in the pathogenesis of left ventricular diastolic dysfunction have not, however, been fully defined. To determine the relative importance of these factors in the pathogenesis of diastolic dysfunction in pressure overload hypertrophy, 16 children and 25 adults with aortic stenosis were compared with 48 normal children and adults, using rates of left ventricular early diastolic filling and wall thinning derived from M-mode echocardiography. Left ventricular early diastolic filling and wall thinning rates were significantly depressed in both children and adults with aortic stenosis as compared with values in normal subjects. Filling and thinning rates correlated negatively with age, left ventricular peak systolic pressure and wall thickness in all subjects. Furthermore, the effect of age on diastolic function appeared to be mediated by age-related increases in systolic pressure and wall thickness. In adults with aortic stenosis, early diastolic filling and wall thinning rates were depressed to a similar extent in subjects with normal and abnormal systolic function; thus, diastolic dysfunction does not appear to be a manifestation of abnormal systolic loading and ejection performance. These results suggest that extent of hypertrophy itself plays a dominant role in the mechanism of impaired left ventricular early diastolic filling in pressure overload due to aortic stenosis.

Between December 1981 and April 1984, five children ranging in age from 1 month to 5 1/2 years examined by two-dimensional echocardiography appeared to have a double orifice mitral valve. The diagnosis was verified in one patient at surgery, one patient by angiography and one patient by necropsy. Associated malformations included mitral stenosis and regurgitation, coarctation of the aorta, ostium primum and secundum atrial septal defect, ventricular septal defect and hypoplastic left heart syndrome. Three varieties of double orifice mitral valve were observed: an incomplete bridge type (one patient), in which a small strand of tissue connected the anterior and posterior leaflets at the leaflet edge level; a complete bridge type (three patients), in which a fibrous bridge divided the atrioventricular orifice completely into equal or unequal parts and a hole type (one patient), in which an additional orifice with subvalvular apparatus occurred in the posterior commissure of the mitral valve. These three types could be distinguished by sweeping the transducer in cross-sectional view from the apex toward the base of the heart. Both orifices could be seen throughout the scan in the complete bridge type while in the incomplete bridge type the two orifices could be seen only at the level of the papillary muscles. In the hole type, the second orifice was seen at about midleaflet level. In all three types, the chordae surrounding each orifice attached to only one papillary muscle. Congenital mitral stenosis or regurgitation was evident in three patients. The type of the double orifice mitral valve did not predict the presence or severity of symptoms.

Validation of a totally noninvasive method for estimating instantaneous left ventricular pressure and constructing a pressure waveform throughout ejection in patients with aortic stenosis is reported. In 20 patients (aged 8.75 +/- 10 years) with congenital aortic stenosis (measured peak left ventricular pressure 120 to 260 mm Hg; transvalvular gradient 18 to 165 mm Hg), transaortic valve continuous wave Doppler ultrasound, indirect carotid pulse tracing, peripheral blood pressure and measured left ventricular pressure were recorded simultaneously at cardiac catheterization. Data were entered into a microcomputer using a digitizing tablet and the instantaneous Doppler gradient was calculated and added to instantaneous aortic pressure, derived from the time-corrected and calibrated carotid pulse tracing, to estimate instantaneous left ventricular pressure. Estimated left ventricular pressure waveforms reproduced measured left ventricular pressure closely. The mean error at peak left ventricular pressure was 0.2 +/- 4.8 mm Hg (r = 0.98, p = 0.001). The average error throughout ejection was 0.9 +/- 5.1 mm Hg. The error of estimated pressure was not related to age or the severity of aortic stenosis. The Doppler peak instantaneous gradient was observed to correlate closely (r = 0.97, p = 0.001) with peak to peak gradient. With this technique, the left ventricular pressure waveform throughout ejection can be accurately estimated noninvasively in patients with aortic stenosis. This methodology enables determination of mean, total and instantaneous systolic left ventricular pressure.

Obstruction of systemic ventricular inflow and outflow is considered uncommon in corrected transposition of the great arteries (S,L,L). Between 1979 and 1985, 42 patients with corrected transposition and two ventricles and atrioventricular valves underwent two-dimensional echocardiography. Obstruction of right ventricular inflow and outflow was present and diagnosed by two-dimensional echocardiography in 5 of the 42 patients. A supratricuspid stenosing ring, recognized in the apical or subxiphoid four chamber view as a bright, linear structure on the left atrial side of the tricuspid valve, occurred in two patients. Subaortic obstruction due to infundibular hypertrophy with or without displaced muscle bundles was seen in three patients. Subxiphoid long- and short-axis views and parasternal long-axis views best displayed these features. Aortic coarctation was present in four cases and could be diagnosed using modified suprasternal notch views. Thus, systemic ventricular inflow and outflow obstruction may be more common in corrected transposition than previously believed (occurring in up to 10 to 15% of patients). The mechanisms producing the obstruction appear to be characteristic of the left atrium and right ventricle irrespective of location or connections. Echocardiography appears to be an excellent technique for diagnosing these associated lesions in corrected transposition.

Physiologic hypertrophy resulting from intense athletic participation has been reported to result in normal, reduced and augmented overall left ventricular performance. Rather than representing true differences in left ventricular contractility, these data may reflect the variable degree of ventricular dilation and increased wall thickness that occur with different types of exercise. As such, the resultant altered loading conditions may diminish the ability of the usual indexes of left ventricular function to accurately assess the left ventricular contractile state. Therefore, three groups of elite athletes with distinct patterns of myocardial hypertrophy were investigated utilizing recently developed load-independent contractility indexes. Age-matched control subjects (n = 33) were compared with 11 swimmers, 11 long-distance runners and 11 power lifters. Rest echocardiogram, phonocardiogram and calibrated carotid pulse tracing were used to calculate left ventricular dimensions, wall thickness, mass, fractional shortening, velocity of shortening and mean, peak and end-systolic wall stresses and the stress-time and minute stress-time integrals. Compared with control subjects, all athletes had increased left ventricular mass, even when values were normalized for body surface area. Runners had a dilated left ventricular and normal wall thickness, swimmers had a mildly dilated ventricle with increased wall thickness and power lifters had normal cavity size with markedly increased wall thickness. Peak systolic wall stress was normal in runners and swimmers and reduced in power lifters, whereas end-systolic stress was low in swimmers and power lifters and normal in runners. The minute stress-time integral, a measure of myocardial oxygen consumption, was normal in runners and swimmers but was significantly reduced in lifters.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical pulmonary stenosis or atresia with intact ventricular septum represents a congenital cardiac lesion for which the long-term prognosis appears to depend partly on the size of the right ventricle. Thus, the capability of noninvasive assessment of right ventricular size to predict operative outcome was examined in 15 infants (aged 1 to 30 days, mean 5.6) with severe right ventricular outflow tract obstruction (either critical pulmonary stenosis [7 patients] or pulmonary atresia with intact ventricular septum [8 patients]). Using echocardiography in two orthogonal subxiphoid views, right ventricular volume, wall thickness, area change fraction, ejection fraction and tricuspid anulus dimension were measured. All patients with a normalized right ventricular enddiastolic volume of less than 5 ml/m2 and a normalized tricuspid anulus dimension of less than 1.0 cm/m2/3 required a shunt operation. Only one patient with a volume of more than 6 ml/m2 and a normalized tricuspid anulus dimension of more than 1.4 cm/m2/3 required more than relief of right ventricular outflow tract obstruction. In this patient, residual severe pulmonary stenosis necessitated the shunt procedure. One patient with a volume of more than 6 ml/m2 had an anulus diameter of less than 1.4 cm/m2/3 and one patient with an anulus diameter of more than 1.4 cm/m2/3 had a volume of less than 6 ml/m2; both required shunt procedures. It therefore appears that if either the ventricular volume or tricuspid anulus size is excessively small, a shunt procedure is necessary. Wall thickness, area change fraction and ejection fraction measurements were not significantly correlated with right ventricular volume or postoperative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular hypertrophy due to aortic stenosis, hypertension and other forms of heart disease is associated with abnormalities of diastolic function. It is uncertain whether these changes are an inherent consequence of the hypertrophic process or represent additional pathologic factors. To investigate this issue, echocardiographic indexes of left ventricular early diastolic function in highly trained athletes were compared with those in age-matched normal control subjects. Athletes were equally classified into two groups: 11 swimmers who had a pattern of myocardial hypertrophy with normal wall thickness to dimension ratio and 11 power lifters whose wall thickness to dimension ratio was increased. The peak rates of left ventricular dimension increase and wall thinning in swimmers and power lifters were greater than in control subjects despite significantly higher left ventricular wall thickness and left ventricular mass index in the athletes. This increase in diastolic function indexes was associated with greater ventricular size and systolic performance. Normalization of the peak rate of dimension increase for end-diastolic dimension and adjustment of the peak rate of wall thinning for the fractional systolic thickening resolved any differences between groups. Thus, after the effects of ventricular size and systolic function were taken into consideration, diastolic function was normal in these subjects with considerable physiologic hypertrophy. This is in contrast to the findings in patients with hypertrophy associated with left ventricular pressure or volume overload, and suggests that abnormalities of diastolic function seen in pathologic hypertrophy are due to factors other than cardiac hypertrophy itself.

Two-dimensional and Doppler echocardiography were compared with cardiac catheterization and angiography in the preoperative evaluation of ostium primum atrial septal defect. Preoperative echocardiographic examinations as well as operative reports of all patients (33 patients aged 2 months to 23 years at surgery) with ostium primum atrial septal defect or transitional atrioventricular (AV) canal defect having had echocardiography and surgical repair at The Children's Hospital, Boston from July 1983 to January 1986 were retrospectively reviewed. Original cardiac catheterization and angiographic reports also were reviewed. Preoperative echocardiography resulted in no false positive or false negative primary diagnoses when compared with the diagnoses obtained at preoperative angiography or surgery. Doppler assessment of mitral regurgitation correlated well with angiographic (93% agreement) and intraoperative (85% agreement) assessments of mitral regurgitation to within two diagnostic categories on the six level scoring system used. There was reasonably good agreement between the two-dimensional echocardiographic estimate of right ventricular systolic pressure and that measured at catheterization when expressed as percent of the simultaneous left ventricular pressure. Seven of nine ventricular septal defects observed intraoperatively were noted on preoperative echocardiography; five of these defects were detected on preoperative angiography. A variety of other surgically confirmed associated cardiovascular defects were observed by both preoperative techniques. However, echocardiography appeared to be superior to angiography for evaluation of AV valve morphology and papillary muscle architecture. This study implies that in children with typical clinical and two-dimensional echocardiographic and Doppler findings for ostium primum atrial septal defect or transitional AV canal defect, routine preoperative cardiac catheterization and angiography are unnecessary.

Anomalous connection of a coronary artery to a ventricle or pulmonary artery causes shunting of blood from the coronary circuit and may produce myocardial ischemia. Such a coronary anomaly may occur in isolation or with other defects. Doppler color flow mapping and two-dimensional echocardiography were used to diagnose anomalous coronary connections in 13 patients, 1 day to 7 years of age, over a 1 year period. The diagnoses were anomalous origin of the left coronary artery from the pulmonary trunk in five patients, a coronary artery to left ventricle fistula or coronary artery to pulmonary artery fistula in four patients with other complex defects, right ventricular sinusoids in two patients with pulmonary atresia and intact ventricular septum and an isolated coronary artery fistula in two patients. In all cases, the abnormal coronary connection was recognized on the basis of an abnormal, continuous or to and fro flow pattern in the fistula and its connections as demonstrated by scanning in multiple views with Doppler color flow mapping. The low spatial resolution of Doppler color flow mapping limits the anatomic detail available; nonetheless, it is a significant advance in the noninvasive diagnosis of abnormal coronary connections.