Double outlet right ventricle {S,D,L} with subaortic ventricular septal defect and pulmonary stenosis: Report of six cases

The clinical, hemodynamic, angiocardiographic and pathologic findings are presented in an infrequent but surgically correctable type of double outlet right ventricle. This study is based on six cases, one with autopsy confirmation. In all, the viscera and atria were in situs solitus (S). A ventricular d-loop was present (D). There was l-malposition of the great arteries, the aorta being to the left of, and anterior to, the pulmonary artery (L). Hence, this anomaly may conveniently be represented as double outlet right ventricle {S,D,L}. The ventricular septal defect was subaortic because the aorta was anterior and leftward, adjacent to the ventricular septum. A bilateral conus was present beneath both the aortic and pulmonary valves, preventing any semilunar-atrioventricular fibrous continuity. The subpulmonary conus was poorly expanded, resulting in pulmonary infundibular and valvular (annular) stenosis.The clinical features were those of cyanosis, clubbing and accentuation of the second heart sound in the pulmonary area (related to aortic valve closure). There was a systolic ejection murmur along the upper left sternal border, related to pulmonary outflow tract stenosis. Selective right and left ventricular angiocardiography was diagnostic.Relatively early surgical correction is suggested to minimize the progression of pulmonary infundibular stenosis and to avoid acquired atresia. In this malformation, pulmonary outflow tract reconstruction is more difficult than in tetralogy of Fallot because of the rather posterior location of the pulmonary outflow tract, and because the right coronary artery crosses the stenotic pulmonary outflow tract in front of the pulmonary valve.     

Congenital mitral valve anomalies in transposition of the great arteries

In 165 hearts with transposition of the great arteries, including 16 with a ventricular septal defect and overriding pulmonary trunk and 5 with a so-called posterior transposition, the left ventricle was studied with emphasis on the morphology of the mitral valve. Distinct mitral valve anomalies were found in 36 cases (22 percent), and four categories of anomalies could be identified. Group A Included 16 specimens with a cleft anterior mitral valve leaflet. The cleft was complete or partial. Partial clefts continued as a fibrous cord within the leaflet. In eight cases the cleft was situated posterior or lateral to the pulmonary ostlum; in these cases the left ventricular outflow tract was not narrowed. Severe outflow tract stenosis was present in another eight cases in which the cleft was located anterior to the pulmonary ostlum, usually in combination with a ventricular septal defect, and in four of these specimens there was straddling of the mitral valve.

Group B included eight hearts with an abnormal size or position of the mitral valve, or both, the valve being hypoplastic or rotated clockwise, or both. Group C comprised seven hearts showing redundant left ventricular structures involving the mitral valve, among which were anomalous tissue strands, subpulmonary rings and redundant valve tissue. Group D included five specimens with deficient papillary muscles.

It is concluded that an abnormal mitral valve is not unusual in hearts with transposition of the great arteries. The findings are notably Important for those patients for whom anatomic surgical correction of the transposition is considered. In comparison with the venous baffle procedure, this operation makes greater demands on the structure of the mitral valve because the pressure in the left ventricle remains at systemic level. Thorough Investigation of mitral valve anatomy and function is necessary before anatomic correction is considered.     

Masked subaortic stenosis in ostium primum atrial septal defect: Recognition and treatment

Five patients with ostium primum atrial septal defect (ASD) and a cleft mitral valve had no hemodynamic evidence of left ventricular (LV) outflow tract obstruction on preoperative cardiac catheterization. After surgical closure of the ASD and repair of the mitral cleft, all 5 patients manifested subaortic stenosis with pressure gradients ranging from 10 to 120 mm Hg. Postoperative LV angiograms revealed systolic narrowing of the outflow tract, and the same outflow tract dynamics were recognized on reviewing the preoperative angiograms and echocardiograms. Persistence or exaggeration of the characteristic diastolic “goose-neck” deformity during LV systole in atrioventricular canal defects is diagnostic of a potential or actual subaortic obstruction. This diagnostic sign is also readily recognizable by 2-dimensional echocardiography, and when present, the surgeon should be alerted to explore the LV outflow tract because the outflow tract anatomy is not readily apparent at operation aimed solely at closing the ASD and repairing the cleft mitral valve.     

Echocardiographic assessment of discrete subaortic stenosis in childhood

The validity of Laplace's relation for assessing peak left ventricular pressure has previously been demonstrated in children with congenital aortic valve $\text{s}$tenosis by using the echocardiographically determined end-diastolic $\text{h}\text{r}$ ratio (that is, the ratio of mean left ventricular septal and posterior wall thicknesses to half the minor left ventricular cavity axis). This report examines the applicability of this ratio to the preoperatlve assessment of left ventricular pressure in 17 children with discrete subaortic stenosis. Because the regression equation derived from previously published data on patients with aortic valve stenosis and the present data on children with subaortic stenosis were similar, a pooled estimate of peak left ventricular pressure (LVP) in children $\text{w}$ith left ventricu$\text{l}$ar outflow tract obstruction is presented: $\text{LVP}\text{= 312.23 (}\text{h}\text{r}\text{) ± 28.01 (}\text{h}\text{r}\text{)}$.Additionally, the left ventricular outflow tract was measured as the anteroposterior dimension between the first recognizable closure point of the mitral valve and the interventricular septum and expressed as the left ventricular outflow tract/aortic root dimension ($\text{LVOT}\text{Ao}$) ratio. This ratio was tower in patients with subaortic stenosis than in control subjects and was helpful in differentiating patients with mild stenosis from those with more severe stenosis. The prevalence of echocardiographically observed features such as early systolic closure of the aortic valve and fluttering of the aortic valve leaflets could not be correl$\text{a}$ted with the severity of stenosis. It is concluded that the end-diastolic $\text{h}\text{r}$ ratio and the $\text{VOT}\text{Ao}$ ratio are quantitatively useful in the assessment of subaortic stenosis, whereas the commonly present motion abnormalities of the aortic valve are not indicative of the severity of the subaortic lesion.     

False diagnosis of subpulmonary obstruction by echocardiography in d-transposition of the great arteries

Twenty-one consecutive children (aged 3 to 14 months) with d-transposition of the great arteries were evaluated with standard M mode echocardiography at the time of hospital admission for routine preoperative cardiac catheterization. At catheterization, 6 of the 21 were found to have a systolic pressure gradient between the body of the left ventricle and the main pulmonary artery. Echocardiographic systolic anterior mitral valve motion was noted in nine patients, including five who did not have a left ventricular to pulmonary arterial systolic pressure gradient. Diastolic approximation of the anterior mitral leaflet to the septum was noted in 14 (9 without a gradient), pulmonary valve flutter was also present in 14 (9 without a gradient) and there was premature systolic pulmonary valve closure in 6 (3 without a gradient). Echographic left heart dimensions were not different in patients with a left ventricular outflow pressure gradient than in those without, but patients with systolic anterior mitral valve motion and diastolic approximation of the mitral leaflet to the septum did have smaller left ventricular and pulmonary root dimensions than did those without these echocardiographic findings. Echocardiographic findings that have been described as suggesting left ventricular outflow obstruction in patients with d-transposition of the great arteries appear to be more related to the size and configuration of the left ventricle than to the presence or absence of obstruction.     

Positional abnormalities of atrioventricular valves in transposition of the great arteries including double outlet right ventricle, atrioventricular valve straddling and malattachment.

Positional abnormalities (straddling or overriding) of the atrioventricular (A-V) valves were studied using angiographic, sector scan echocardiographic and postmortem anatomic data in 10 patients with transposition of the great arteries including double outlet right ventricle. Group I included six patients with tricuspid valve abnormalities. This group was further classified into: (a) patients with anular straddling and abnormal attachment of portions of the tricuspid leaflets in the left ventricle (malattachment) or on the ventricular septum, or both (four patients with d-transposition of the great arteries and hypoplastic right ventricle); and (2) patients with malattachment of portions of the tricuspid valve leaflet to the crest or left ventricular surface of the septum (septal malattachment) without significant anular straddling (two patients with d-transposition of the great arteries).Group II included four patients with mitral valve abnormalities without significant anular straddling, further classified into: (1) patients with septal malattachment of the portions of the mitral valve to the crest and right ventricular surface of the ventricular septum (two patients with double outlet right ventricle); and (2) patients with ventricular malattachment of portions of the mitral valve leaflets to the papillary muscles in the right ventricle (two patients with ventricular septal defect and discordant criss-cross atrioventricular connections).On the basis of these observations and reported experience, two main types of positional abnormalities of the A-V valves were recognized: (1) anular straddling in which the A-V anulus straddled the ventricular septum above the contralateral ventricle, together with ventricular leaflet malattachments, and (2) leaflet malattachment of either the septal or ventricular type without significant straddling of the valve anulus. Angiocardiography and sector scan echocardiography helped to identify these abnormalities of the A-V valves.     

Relation of the echocardiographic estimate of left ventricular size to mortality in infants with severe left ventricular outflow obstruction

The relation of left ventricular size, as estimated with echocardiography, to mortality was evaluated in three groups of infants with severe left ventricular outflow obstruction. Group I consisted of 17 patients with combined aortic and mitral stenosis or atresia associated with definite hypoplasia of the left ventricle. Group II consisted of eight patients with the primary diagnosis of severe aortic stenosis. Group III consisted of 12 patients with severe coarctation of the aorta. The left ventricular enddiastolic dimension measured with M mode echocardiography and the cross-sectional area of the left ventricular cavity as seen in the parasternal long axis view of the two dimensional echocardiogram were used as indexes of left ventricular volume.All patients with symptomatic outflow obstruction and a left ventricular end-diastolic dimension of less than 13 mm died in infancy. However, five patients with a hypoplastic left ventricle proved at angiography or at autopsy, or both, were found to have a ventricular end-diastolic dimension of 13 mm or greater. Two dimensional echocardiography showed that the left ventricle in these patients was foreshortened and spherical in shape. The cross-sectional area of the left ventricle of each patient in group I was less than 1.6 cm². This was below the range of cross-sectional areas found in a group of normal infants (1.8 to 3.5 cm² ± 2 standard deviations about the mean). Three patients in groups II and III had a slightly reduced left ventricular area (1.7 cm²) and none of these patients survived infancy.Measurement of the cross-sectional area of the left ventricle is a useful method of determining left ventricular size in infants suspected of having the hypoplastic left ventricle syndrome. Patients who have reduced left ventricular volume as assessed by this technique are at very great risk even if surgical relief of the outflow obstruction is attempted.     

Clinical manifestations of dynamic left ventricular outflow tract stenosis in infants with d-transposition of the great arteries with intact ventricular septum

Four infants with d-transposition of the great arteries and intact ventricular septum who manifested early clinical symptoms and deterioration due to dynamic left ventricular outflow stenosis are presented. All four had an anatomically adequate atrial septal defect, made at the initial balloon atrial septostomy, that was later confirmed intraoperatively. Two infants continued to have a low arterial oxygen saturation level because of inadequate interatrial mixing, and one of these had severe persistent cyanosis and was treated with the Mustard operation at age 4 days. The other two infants subsequently presented with hypercyanotic spells at age 3 months. All four infants had features of dynamic left ventricular outflow stenosis on hemodynamic, angiocardiographic and echocardiographic studies. The left ventricular outflow pressure gradient was shown to increase after administration of isoproterenol in one infant, and relief of a cyanotic spell with reduction of left ventricular systolic pressure was achieved in another after intravenous administration of propranolol. The Mustard operation relieved symptoms in all infants. The effect of left ventricular outflow tract stenosis on the mechanisms responsible for interatrial mixing in d-transposition of the great arteries with intact ventricular septum is discussed.     

Left ventricular outflow tract obstruction in complete transposition of the great arteries with intact ventricular septum. A cross sectional echocardiography study

The roles of posterior bulging of the interventricular septum (septal bulge) and of systolic septal mitral apposition in patients with simple transposition of the great arteries are not known. Cross sectional echocardiograms of 40 such patients were reviewed (after exclusion of those with fixed left ventricular outflow tract obstruction) and haemodynamic findings were compared with long and short axis measurements within the left ventricle. There was no significant correlation between the degree of septal bulge and systolic gradient across the left ventricular outflow tract, but septal bulge correlated weakly with systolic right ventricular pressure and inversely with pulmonary arteriolar resistance index. Systolic left ventricular outflow gradient was inversely related to the minimum systolic distance between the anterior mitral leaflet and interventricular septum. No patients without complete systolic apposition of the anterior mitral leaflet and interventricular septum had a left ventricular outflow gradient greater than 20 mm Hg. Conversely, even when cross sectional echocardiography showed apparently total obstruction of the left ventricular outflow tract at some time in systole there was often no significant gradient detected during haemodynamic study. In the short axis cuts closeness of the papillary muscles to the interventricular septum or to each other was unrelated to systolic gradient. This study shows that (a) cross sectional echocardiography can identify fixed obstruction of the left ventricular outflow tract in simple transposition of the great arteries; (b) the degree of septal bulge, unless complicated by fibrous thickening of the anterior mitral leaflet and interventricular septum, is unrelated to the gradient across the left ventricular outflow tract; (c) the absence of systolic septal/mitral apposition excludes a significant gradient at that site across the left ventricular outflow tract; and (d) papillary muscle geometry is unrelated to dynamic gradients across the left ventricular outflow in this condition.     

Left ventricular outflow tract obstruction in complete transposition of the great arteries with intact ventricular septum. A cross sectional echocardiography study.

The roles of posterior bulging of the interventricular septum (septal bulge) and of systolic septal mitral apposition in patients with simple transposition of the great arteries are not known. Cross sectional echocardiograms of 40 such patients were reviewed (after exclusion of those with fixed left ventricular outflow tract obstruction) and haemodynamic findings were compared with long and short axis measurements within the left ventricle. There was no significant correlation between the degree of septal bulge and systolic gradient across the left ventricular outflow tract, but septal bulge correlated weakly with systolic right ventricular pressure and inversely with pulmonary arteriolar resistance index. Systolic left ventricular outflow gradient was inversely related to the minimum systolic distance between the anterior mitral leaflet and interventricular septum. No patients without complete systolic apposition of the anterior mitral leaflet and interventricular septum had a left ventricular outflow gradient greater than 20 mm Hg. Conversely, even when cross sectional echocardiography showed apparently total obstruction of the left ventricular outflow tract at some time in systole there was often no significant gradient detected during haemodynamic study. In the short axis cuts closeness of the papillary muscles to the interventricular septum or to each other was unrelated to systolic gradient. This study shows that (a) cross sectional echocardiography can identify fixed obstruction of the left ventricular outflow tract in simple transposition of the great arteries; (b) the degree of septal bulge, unless complicated by fibrous thickening of the anterior mitral leaflet and interventricular septum, is unrelated to the gradient across the left ventricular outflow tract; (c) the absence of systolic septal/mitral apposition excludes a significant gradient at that site across the left ventricular outflow tract; and (d) papillary muscle geometry is unrelated to dynamic gradients across the left ventricular outflow in this condition.     

The association of fixed and dynamic left ventricular outflow obstruction.

Twelve patients were investigated echocardiographically and angiographically and were shown to have severe fixed obstruction to the left ventricular outflow tract. Eight had valvular stenosis, and four had discrete subvalvular membranes. Two of the patients had additional dynamic obstruction of the left ventricular outflow tract. This was recognized preoperatively by echocardiography because of abnormal systolic motion of the mitral leaflet. At the time of definitive surgery for relief of the fixed obstruction, the additional dynamic obstruction was identified and treated, since persistent residual obstruction may lead to death in the immediate postoperative period or to long-term symptoms. The dynamic left ventricular outflow obstruction is probably a result of the hypertrophy produced by the fixed obstruction.     

Early systolic closure of the aortic valve in patients with hypertrophic subaortic stenosis and discrete subaortic stenosis. Correlation with preoperative and postoperative hemodynamics

Patterns of motion of the aortic valve were analyzed with echocardiography in 9 patients with discrete subaortic stenosis and 31 patients with idiopathic hypertrophic subaortic stenosis, 22 with and 9 without a resting intraventricular pressure gradient. The intention was to determine whether the early systolic closure of the aortic valve was a sensitive indicator of a resting pressure gradient across the left ventricular outflow tract. All 9 patients with discrete subaortic stenosis and the 22 patients with idiopathic hypertrophic subaortic stenosis with a resting pressure gradient showed early systolic closure of the aortic valve; however, the 9 patients without a resting gradient had normal motion of the aortic valve. Measured values for O-ESC (the interval from the opening point of the aortic valve to the point of early systolic closure of the aortic valve) in 9 patients with discrete subaortic stenosis and in 22 with idiopathic hypertrophic subaortic stenosis averaged 0.05 ± 0.01 (standard deviation) second and 0.14 ± 0.04 second for each group, respectively (P < 0.01). Twelve patients with idiopathic hypertrophic subaortic stenosis underwent operation to alleviate left ventricular outflow tract obstruction. In eight of these patients the resting pressure gradient was completely abolished and early systolic closure of the aortic valve was no longer present. The results indicate that in idiopathic hypertrophic subaortic stenosis, early systolic closure of the aortic valve is recorded only when there is a significant intraventricular pressure gradient at rest. The time of occurrence of early systolic closure differentiated patients with discrete subaortic stenosis from those with idiopathic hypertrophic subaortic stenosis in all observations.     

Systolic closure of aortic valve in patients with prosthetic mitral valves.

Systolic closure of the aortic valve was found in 10 of 36 patients who underwent mitral valve replacement. Eight patients had early systolic closure, and two had mid-systolic closure. The left ventricular outflow tract dimension on M-mode and two dimensional echocardiograms, left ventricular posterior wall and septal thickness, left ventricular dimensions in systole and diastole, aortic valve opening, and mitral to aortic valve distance were not significantly different between patients with and without systolic closure of the aortic valve. Two of the 10 patients with systolic aortic valve closure were catheterised and in neither was there a gradient between the left ventricle and the aorta. The two patients with mid-systolic closure, however, were the patients who had the narrowest left ventricular outflow tract which could cause significant distortion of blood flow. Systolic closure of the aortic valve in patients with mitral valve replacement is probably not caused by left ventricular outflow tract obstruction, though abnormalities in laminar flow from the left ventricular outflow tract may be involved.     

Origin of the basal systolic murmurs in mitral stenosis. A study with intracardiac phonocardiography

In order to study the origin of the basal systolic murmurs in mitral stenosis, left and right heart catheterization was performed in 18 patients with mitral stenosis using intracardiac phonocardiography. Our data revealed that the basal systolic murmurs originated in the aorta, the pulmonary artery, and the outflow tract of the right ventricle.In 14 cases, we noted the maximal ejection systolic murmur in the aorta near the aortic valve. However, in two cases, there was a loud systolic murmur in the pulmonary artery. These murmurs occurred in early to mid-systole and were crescendo-decrescendo in configuration. The pitch of the murmur ranged from low to medium frequency in the majority of cases. They are produced by the turbulence of blood flow in the aorta and the pulmonary artery.A late systolic murmur was also recorded in the outflow tract of the right ventricle in two patients. This is thought to occur due to functional or relative infundibular stenosis of the right ventricle. It differs in location and timing from those in the aorta and the pulmonary artery. The outflow tract of the right ventricle is regarded as the third origin of the basal systolic murmur in mitral stenosis.     

Doppler color flow mapping studies of jet formation and spatial orientation in obstructive hypertrophic cardiomyopathy

To help clarify the mechanism of outflow tract obstruction and systolic anterior motion of the anterior leaflet of the mitral valve and their relation to the geometry of the left ventricle, we studied left ventricular outflow tract flow in 20 patients with hypertrophic cardiomyopathy (HCM) using two-dimensional Doppler flow mapping. We compared our results with outflow tract flow in 10 patients with isolated valvular aortic stenosis, (AS) and with those in 10 healthy volunteers. In HCM, a 94- to 145-degree angle (mean 111.4 +/- 11.9 degrees) developed between the direction of left ventricular outflow tract flow acceleration and aortic valve outflow, resulting in posterolaterally directed left ventricular outflow jets. The angle of the outflow jet and the peak velocity of the jet measured with continuous wave Doppler (as an indicator of the severity of obstruction) correlated well (r = -0.81, SEE = 7.8 degrees). Jet narrowing during ejection measured just proximal to the point of systolic anterior motion was 42 +/- 11% in HCM and was weakly correlated with peak jet velocity (r = 0.61, SEE = 8.9 degrees). Aliasing of left ventricular outflow occurred proximal to systolic anterior motion of the mitral valve, and color M-mode demonstrated temporal and spatial flow acceleration proximal to systolic anterior motion, providing evidence for obstruction at that site. In AS, left ventricular outflow tract jets were more parallel to the axis of aortic outflow (129 to 153 degree, 138.4 +/- 8.1 degrees). Jet narrowing was only 8 +/- 5% compared to HCM (both p less than 0.05), and flow acceleration occurred proximal to the stenotic valve.(ABSTRACT TRUNCATED AT 250 WORDS)     

Echocardiographic characterization of the reversible cardiomyopathy of hypothyroidism

Nineteen patients with untreated hypothyroidism were evaluated by M-mode echocardiography. Asymmetric septal hypertrophy (ASH), defined as a ratio of interventricular septal thickness to left ventricular posterior wall thickness (IVS/LVPW) equal to or greater than 1.3, was identified in 17 cases. Additional abnormalities recognized by echocardiography included reduced amplitude of systolic septal excursion (SSex) [13 patients], reduced per cent of systolic septal thickening (%SST)[19 patients], reduced left ventricular outflow tract dimension (LVOT)[five patients] and systolic anterior motion of the mitral valve (SAM)[five patients]. These findings are similar to some of the echocardiographic features of idiopathic hypertrophic subaortic stenosis (IHSS). In 10 patients who returned to euthyroid state with L-thyroxine therapy, these abnormalities resolved. We conclude that long-standing hypothyroidism leads to a reversible cardiomyopathy, manifested by asymmetric septal hypertrophy with or without other echocardiographic features of a hypertrophic obstructive cardiomyopathy. This previously unrecognized features of hypothyroidism has important diagnostic and therapeutic implications.     

Dynamic left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve in the absence of asymmetric septal hypertrophy

Systolic anterior motion of the anterior mitral valve leaflet and asymmetric septal hypertrophy are the principal components of the dynamic subaortic stenosis in hypertrophic obstructive cardiomyopathy. Mitral valve systolic anterior motion without septal hypertrophy or left ventricular outflow tract obstruction has been described, but asymmetric septal hypertrophy is supposedly a consistent feature of dynamic subaortic stenosis. We describe two patients with syncope, chest pain and the typical systolic murmur of hypertrophic subaortic stenosis whose echocardiograms showed mitral valve systolic anterior motion but not asymmetric septal hypertrophy. Normal septal thickness on echo was confirmed by intravenous indocyanine green to identify the right septal endocardium. At catheterization, left ventricular outflow tract gradients were provoked, and neither patient had interventricular septal hypertrophy on biventricular cineangiography. These findings in two cases suggest that mitral valve systolic anterior motion can be the only definable anatomic abnormality associated with symptomatic dynamic left ventricular outflow tract obstruction and that asymmetric septal hypertrophy is not a necessary component of this condition.     

Echocardiographic localization of interatrial baffle after mustard operation for dextrotransposition of the great arteries

The position of the interatrial baffle was determined by echocardiography in 11 patients with complete transposition of the great arteries who had undergone the Mustard operation. The location of the interatrial baffle and the newly created systemic venous atrium and the pulmonary venous atrium behind the pulmonary arterial root was established by echocardiographic contrast studies during cardiac catheterization. Angiographic analysis indicated that the segments of the systemic and pulmonary venous atria seen behind the pulmonary arterial root in the echocardiogram were, respectively, the superior limb of the systemic venous atrium and the posterior segment of the pulmonary venous atrium. The area of mitral-pulmonary valve continuity in the echocardiogram was used as a reference point for dimensional measurements of the systemic and pulmonary venous atria. It is suggested that longitudinal measurements of these structures by echocardiogram may help evaluate their growth in size. Fine to coarse fibrillatory movements of the atrioventricular valves and, more frequently, of the mitral valve were seen in the majority of patients.     

Functional aortic valve atresia in transposition of the great arteries

The criterion for the diagnosis of functional atresia of a patient semilunar valve is met when the pressure in a ventricle remains lower than that in the related great artery throughout systole so that no forward flow can occur. Functional pulmonary valve atresia has been well recognized in infants with normally related great arteries and massive tricuspid valve incompetence. The cardiac physiology and anatomy of an infant with transposed great arteries and functional aortic valve atresia is reported for the first time. The peak systolic pressure in the right ventricle was 30 mm Hg and in the aorta 64 mm Hg. The causes for right ventricular incompetence were abnormalities of the tricuspid valve and hypoplasia of the ventricular free wall. Three other cases with similar ventricular anatomy and physiology but with anatomic atresia of the aortic valve are reviewed. The possibility that under these physiologic circumstances during fetal life functional atresia develops first, and that anatomic fusion of idle semilunar cusps develops as a secondary phenomenon, is discussed.     

Prediction of pulmonary arterial pressures from electrovectorcardiographic data in pediatric patients with rheumatic mitral valve disease.

The Frank vectorcardiogram (VCG) and the electrocardiogram (ECG) were used to predict pulmonary arterial pressures in 30 pediatric patients with rheumatic mitral valve disease. The patients' ages ranged from eight to 14 1/2 years. Eleven were male and 19 were female. Sixteen had mitral stenosis, eight had mitral regurgitation and six had mitral stenosis and regurgitation. Mean pulmonary arterial wedge pressure ranged from 5-32 mmHg. All patients underwent complete catheterization and angiocardiographic study. None had significant gradient across the right ventricular outflow tract. Right maximum spatial vector (Rmsv) was calculated using Frank VCG.R in V1 and S in V5 of ECG were also measured. Rmsv, RV1, and SV5 were correlated with pulmonary arterial pressures (systolic, diastolic and mean). Pulmonary artery systolic pressure and Rmsv bear the best correlation (r=0.773). The correlation coefficient for pulmonary artery diastolic pressure and Rmsv was 0.698. Rmsv as calculated from Frank VCG is useful in prediction of pulmonary arterial pressures (systolic and diastolic) in pediatric patients with rheumatic mitral valve disease.