Kalim U. Aziz

Echocardiographic assessment of the relation between left ventricular wall and cavity dimensions and peak systolic pressure in children with aortic stenosis

Echocardiographic measurements of the left ventricular end diastolic minor axis and posterior and septal wall thickness were obtained in 19 children with congenital aortic stenosis with left ventricular peak systolic pressures ranging from 110 to 225 mm Hg at cardiac catheterization. From these measurements were derived (1) the left ventricular peak circumferential wall stress, (2)the end-diastolic h/r ratio (that is, mean of septal and posterior wall thickness (h) to minor semiaxis (r) ratio), and (3) the LVM/LVV ratio (that is, left ventricular mass (LVM) to left ventricular end-diastolic volume (LVV) ratio). The peak stress was found to be within the normal range and independent of the left ventricular peak systolic pressure. The end-diastolic h/r and LVM/LVV ratios had highly significant linear relations to the left ventricular peak systolic pressure. It is concluded that these easily determined echocardiographic measurements provide a useful noninvasive means of assessing left ventricular peak systolic pressure in patients with aortic stenosis without myocardial decompensation.

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

Abstract 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.

Bronchopulmonary circulation in d-transposition of the great arteries: Possible role in genesis of accelerated pulmonary vascular disease

Hemodynamic and angiograhic data from 209 patients with d-transposition of the great arteries were reviewed to estimate the incidence of prominent bronchopulmonary circulation and to explore its role in the genesis of accelerated pulmonary vascular disease in these patients. The degree of bronchopulmonary circulation was assessed visually by considering the extent of the pulmonary arterial opacification and the circulation to the left atrium. An initial survey study revealed a marked degree of collateral circulation in 20 of 138 patients with d-transposition having cardiac catheterization before age 2 years at the Hospital for Sick Children, Toronto, between 1967 and 1972. Detailed analysis of 71 additional patients with d-transposition aged 1 week to 72 months (mean 17 months) studied at Childrens Memorial Hospital, Chicago, between 1967 and 1974 showed collateral circulation of marked degree in 23 and of mild degree in 14. The bronchopulmonary collateral vessels were more freqently demonstrated in the patients with intact ventricular septum than in those with ventricular septal defect or left ventricular outflow tract stenosis. In a prospective study in 12 of 15 patients during cardiac catheterization the functional patency of the bronchopulmonary collateral circulation was demonstrated by obstructing pulmonary blood flow in the right or left pulmonary artery, or both, with an inflated balloon and obtaining from the pulmonary arterial segment distal to the occlusion blood with an oxygen saturation similar to that of the aorta. A hypothesis is presented concerning the role of systemic hypoxemia and local pulmonary hypoxemia induced by way of the bronchopulmonary collateral vessels and the bronchial arterial vasovasorum in promoting pulmonary vasoconstriction. It is suggested that increased pulmonary blood flow and pressure due to the physiologic features of ventricular septal defect, patent ductus arteriosus or transposition of the great vessels, in the face of this regionally increased hypoxemia results in accelerated pulmonary vascular disease.

Two-dimensional echocardiographic features of interruption of the aortic arch.

The 2-dimensional echocardiographic features of interruption of the aortic arch are presented based on analysis of the echocardiograms and angiograms from 8 infants: 2 with type A and 6 with type B interruption. Each infant had a patent ductus arteriosus, 6 had a conoventricular septal defect with leftward deviation of the conal septum, 1 had truncus arteriosus with truncal valve stenosis, and 1 had a distal aortopulmonary septal defect with an intact ventricular septum. Echocardiographic images obtained from the suprasternal notch or from a high parasternal approach demonstrated the interruption of the aortic arch and continuation of the patent ductus arteriosus into the descending aorta. These findings were compared with those in infants with aortic atresia and a hypoplastic ascending aorta or discrete coarctation of the aorta with tubular hypoplasia of the aortic arch. Types A and B interruption of the aortic arch were easily differentiated and the caliber of the patent ductus arteriosus was assessed. The characteristic conoventricular septal defect was readily visualized froma an apex 2-chamber view or from a subcostal sagittal plane view. With this information subsequent angiography can be more expeditiously performed in this group of critically ill infants.

Echocardiographic features of total anomalous pulmonary venous drainage into the coronary sinus

Echocardiograms were obtained from five infants with total anomalous pulmonary venous drainage to the coronary sinus or the portal system or the superior vena cava and from one child with a secundum atrial septal defect and a large coronary sinus due to persistence of the left superior vena cava. The results demonstrate that an enlarged coronary sinus is positioned consistently posterior to the left atrium in approximately the same horizontal plane as the aortic valve. Echocardiographically the coronary sinus can be located as an echo complex behind the left atrium by using the aortic root as a reference point. The echo complex can be differentiated from the other spurious echoes in the left atrium by its characteristic phasic motions. The additional demonstration of the enlarged common pulmonary venous chamber behind the right atrium confirms the diagnosis of anomalous pulmonary venous drainage to the coronary sinus. For other types of anomalous pulmonary venous return, anatomic diagnosis with single crystal M mode echocardiography is not always possible because of the positional variability of the common pulmonary venous chamber in relation to the left atrium.

Echocardiographic assessment of left ventricular outflow tract in d-transposition of the great arteries.

Abstract The left ventricular outflow tract in 38 patients (aged 0.3 to 13 years) with complete d-transposition of the great arteries, 31 with intraatrial (Mustard) repair, was quantitated with echocardiography, and the findings were correlated with hemodynamic and angiographic data. The left ventricular outflow tract (LVO) was measured on the echocardiogram as an anteroposterior dimension between the closure point on the mitral valve below the pulmonary arterial root (PA) and the left endocardial surface of the interventricular septum. This measurement was expressed as an LVO/PA ratio and on the basis of these measurements three groups were recognized. Group I consisted of 14 patients who had an unobstructed left ventricular outflow tract and no significant pressure differences between the pulmonary artery and left ventricle. In Group II, the 16 patients had evidence of dynamic obstruction and mild to moderate pressure differences between the pulmonary artery and left ventricle, characterized in the echocardiogram by LVO/PA ratios comparable with those of Group I, but with an abnormally prominent early posterior systolic septal bulge in the left ventricular outflow tract, abnormal systolic anterior motion of the mitral valve and coarse fluttering of the pulmonary valve. In Group III the eight patients had anatomically fixed stenosis of the left ventricular outflow tract and severe left ventricular outflow pressure gradients characterized in the echocardiogram by a reduced LVO/PA ratio and fine vibrations of the pulmonary valve. Angiographically discrete or long segmental narrowing of the left ventricular outflow tract correlated well with the echocardiographic data. Echocardiographic measurements of left ventricular posterior wall thickness also correlated well with the severity of left ventricular outflow stenosis in these three groups. The echocardiogram provides clinically useful quantitative and qualitative analysis of the left ventricular outflow tract in patients with complete transposition of the great arteries.

Echocardiographic assessment of discrete subaortic stenosis in childhood

Abstract The validity of Laplaces relation for assessing peak left ventricular pressure has previously been demonstrated in children with congenital aortic valve s tenosis by using the echocardiographically determined end-diastolic h 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 w ith left ventricu l ar outflow tract obstruction is presented: LVP = 312.23 ( h r ) ± 28.01 ( h r ) . 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 ( LVOT 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 a ted with the severity of stenosis. It is concluded that the end-diastolic h r ratio and the VOT 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.

Two dimensional echocardiographic evaluation of mustard operation for d-transposition of the great arteries

Two dimensional sector scan echocardiography was used to evaluate the morphologic characteristics of the surgically revised atria in 17 patients with d-transposition of the great arteries who had undergone the Mustard operation. Echocardiographic imaging of the atria was obtained from various planar projections. Dimensional measurements of various segments of the systemic and pulmonary venous atria were obtained in each patient. Correlative hemodynamic, angiographic, postmortem and echocardiographic data showed that seven patients (Group I) had no structural abnormalities of the atria. These 7 patients served as controls for 10 other patients with structural abnormalities of the surgically created atria. One patient (Group II) showed stenosis of the junction of the superior vena cava and systemic venous atrium compared with findings in the control group. Three patients (Group III) had significantly reduced echocardiographic dimensions of the junction of the anterior and posterior segments of the pulmonary venous atrium. Six patients (Group IV) had increased echocardiographic dimensions of all components of the pulmonary venous atrium due to tricuspid regurgitation. These data show that qualitative and quantitative two dimensional sector echocardiography can reliably detect structural abnormalities of the surgically revised atria after the Mustard operation.

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.

Echocardiographic features of supracristal ventricular septal defect with prolapsed aortic valve leaflet

Abstract Anatomically diagnostic echocardiographic features of a supracristal ventricular septal defect with prolapsed right coronary aortic leaflet are described in four children aged 2 to 10 years. Both single crystal M mode as well as 80 ° phased array sector scan techniques were used. The echographic features in the M mode scan from the aorta to the left ventricle in three of four patients included (1) the position of the ventricular septal defect as a clear space between the interrupted septal echoes below the aortic root, and (2) the prolapsed right coronary aortic leaflet as anomalous linear echoes in the right ventricular outflow tract. Angiographic, intraoperative and echocardiographic contrast studies were used to establish the diagnosis. On sector scanning using the long axis view, the supracristal ventricular septal defect was recognized as a clear space between the top of the ventricular septum and the anterior segment of the aortic root in three of four patients. The right coronary aortic leaflet was seen to prolapse into the right ventricular outflow tract through this defect, and its motion could be clearly followed during systole and diastole. It is concluded that echocardiography provides anatomic diagnosis of this lesion. Furthermore, the severity and progression of this lesion can be assessed by quantitation of the left ventricular size and performance.