Thomas G. DiSessa

Two-dimensional echocardiographic assessment of left ventricular volumes and ejection fraction in children.

The ability of two-dimensional echocardiography to masure left ventricular volumes and ejection fraction was evaluated in 25 children with congenital heart disease. Dimensions and planimetered areas were obtained in the short-axis view at the mitral valve and high and low papillary muscle levels and in the apical two- and four-chamber views. Eight algorithms using five geometric models were assessed. Left ventricular end-diastolic volume, end-systolic volume and ejection fraction were compared with data from biplane cineangiocardiograms. The correlation varied with the algorithm used. Algorithms using short-axis views appeared superior to those using only apical long-axis views. Four algorithms estimated left ventricular volumes with equal accuracy (Simpsons rule, assuming the ventricle to be a truncated cone; Simpsons rule, assuming the ventricle to be a truncated ellipse; hemisphere cylinder; and ellipsoid biplane). The single algorithm that best estimated left ventricular ejection fraction was the ellipsoid biplane formula using the short-axis view at the papillary muscle level (r= 0.91, slope = 0.94, SEE = 6.7%). Thus, two-dimensional echocardiography can accurately assess left ventricular volumes and ejection fraction in children with congenital heart disease.

Echocardiography reveals a high incidence of bicuspid aortic valve in Turner syndrome

The most common cardiac defect in Turner syndrome has been described previously as coarctation of the aorta. We have evaluated 35 consecutive patients with Turner syndrome by clinical examination and by M-mode and two-dimensional echocardiography. Twelve patients (34%) had isolated, nonstenotic bicuspid aortic valve. A high correlation (82%) existed between the presence of a systolic ejection click and echocardiographic evidence of a bicuspid aortic valve. These data indicate that bicuspid aortic valve may be the most common cardiac anomaly in Turner syndrome.

The cardiovascular effects of dopamine in the severely asphyxiated neonate

The cardiovascular effects of dopamine were evaluated in 14 severely asphyxiated neonates. After a period of stabilization, either dopamine 2.5 micrograms/kg/minute or placebo was infused in a randomized double-blind protocol. In seven dopamine-treated infants, echocardiographically determined shortening fraction and mean velocity of circumferential fiber shortening increased when compared to preinfusion values (P less than 0.05). There was no significant change in these echo indices of cardiac function in the placebo-treated group. Systolic blood pressure rose in the dopamine group when compared to predopamine infusion values and to the postinfusion values of the placebo group (P less than 0.001 and 0.025, respectively). Diastolic blood pressure increased to a small degree in the dopamine group. There was no significant change in heart rate or echocardiographically measured systolic time intervals. Low doses of dopamine increase cardiac performance and raise systolic blood pressure in the severely asphyxiated neonate.

Closure of the patent ductus arteriosus with ligation and indomethacin: a consecutive experience.

This report summarizes a consecutive experience with 59 preterm infants with clinical, radiographic, and echocardiographic findings of a large patent ductus arteriosus. Thirty-five infants who met defined criteria received indomethacin, and 24 infants underwent PDA ligation. Analysis of the clinical course of these infants revealed no selective indomethacin morbidity and suggests that infants undergoing ligation require more prolonged ventilator therapy with increased exposure to FiO2 greater than or equal to 0.3. Mortality rates between ligated and pharmacologically treated groups were similar. This study documents that inhibition of prostaglandin synthesis to constrict and close the PDA in the premature infant is an effective alternative to operative closure.

Two-dimensional echocardiographic assessment of right ventricular volume in children with congenital heart disease

The ability of 2-dimensional echocardiography to measure right ventricular (RV) volume and ejection fraction was assessed in 22 children with congenital heart disease. From the apical 4 chambers 2-dimensional echocardiographic image, the long-axis length of the right ventricle was measured and the area planimetered. On the anteroposterior and lateral cineangiocardiographic planes, the right ventricle was separated into 2 parts: RV sinus and outflow tract. The longest length, inflow tract length, and area of the sinus were measured from biplane cineangiographic views. The echographic long-axis length correlated well with the longest length of the RV sinus measured from both anteroposterior and lateral cineangiographic views at both end-systole and end-diastole. Moreover, the echographic area correlated well with the sinus area obtained from both cineangiographic views. From these regression analyses, the echographic long axis length and area were corrected to the angiographic longest length and area of the sinus. The new corrected echographic longest length and area were applied to 3 formulas (2 biplane and 1 uniplane) to calculate the sinus volume of the right ventricle. Total RV volume was then derived from the sinus volume. RV volumes and ejection fraction determined by 2-dimensional echocardiography were compared with those obtained from biplane cineangiography using Simpsons rule method. All formulas tested predicted RV volumes and ejection fraction with equal accuracy. Thus, 2-dimensional echocardiography can assess RV volume and ejection fraction in children with congenital heart disease.

Systemic venous and pulmonary arterial flow patterns after Fontan's procedure for tricuspid atresia or single ventricle.

Despite increasing use of Fontan or modified Fontan repairs, the comparative hemodynamic efficacy of different types of connections are unresolved. Accordingly, we undertook a prospective study designed to determine postoperative flow patterns after Fontans operation. Seven subjects had tricuspid atresia and eight had single ventricle. Ages ranged from 5 to 38 years (mean 16.4). Ten subjects had nonvalved right atrial-to-pulmonary arterial connection, and four had nonvalved right atrial-to-right ventricular communication. A valved conduit established continuity between the right atrium and right ventricle in one subject. Doppler flow profiles were recorded in the pulmonary artery and in the superior and inferior venae cavae of each. A reference electrocardiogram was used for timing purposes. In 14 patients, forward flow in the pulmonary artery was biphasic. Flow began at the end of the T wave (early ventricular diastole), peaked at or before the P wave (atrial systole), and returned to baseline by the peak of the R wave. Forward flow recommenced at the peak of the R wave (ventricular systole) and returned to baseline at the end of the T wave. Flow in the superior vena cava varied, and could not be recorded in three subjects. Between the end of the P wave and peak of the R wave (atrial systole) flow was reversed in eight, absent in three, and forward in one patient. Forward flow occurred between the peak of the R wave and the end of the T wave and was either continuous or biphasic. Fourteen patients had adequate studies of inferior vena cava flow; reversed flow during atrial systole occurred in 10 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-dimensional echocardiographic assessment of left atrial size in children☆

The ability of 2-dimensional echocardiography (2-D echo) to estimate end-systolic left atrial (LA) size and volume was assessed in 140 infants and children. These subjects were divided into 2 groups. Group A included 91 patients with normal LA volume and Group B included 49 patients with LA volume overload. Five echocardiographic views (left parasternal long-axis, left parasternal short-axis, apical 4-chamber, apical 2-chamber and subcostal 4-chamber) were used. From these views, the LA long-axis and minor-axis lengths were measured and the area was planimetered. These echocardiographically derived measurements were compared with angiographically calculated LA volume. Although all echocardiographic measurements correlated well with angiographic LA volume measurements, the echocardiographic area tracked better than length measurements. Echo LA volume was calculated using 5 single-plane and 3 biplane area-length methods. LA volume calculated from either single- or biplane methods correlated well with angiographically determined LA volume. The degree of correlation depended on the method used. Echocardiographic area and estimated LA volume measured from the parasternal long-axis and apical 2-chamber views best separated patients with LA volume overload from normal. Two-dimensional echo using these views accurately segregated all patients with a LA volume greater than 180% of normal and 15 of 21 patients (71%) with an LA volume between 138% and 179% of normal. Thus, 2-D echo is useful in the evaluation of LA size and volume in infants and children.

Coarctation repair without cardiac catheterization in infants

Of 35 infants who underwent an operation for coarctation of the aorta, 15 did not undergo cardiac catheterization before surgery. The diagnoses in all uncatheterized patients were made by clinical examination, chest radiography, ECG, and two-dimensional echocardiography combined with pulsed Doppler echocardiography. Associated anomalies diagnosed by two-dimensional/Doppler echocardiography included a patent ductus arteriosus in all patients, bicuspid aortic valve in six, small ventricular septal defect in four, and complete common atrioventricular canal in one. In no instance was the diagnosis of coarctation in error. In addition, the clinical significance of the ventricular septal defect was judged correctly by two-dimensional echocardiography, and no patient required an early reoperation because of significant left-to-right shunt. Two significant lesions were missed in one patient each: mitral stenosis and aortic stenosis. These diagnoses were missed in patients who were first seen with either profound congestive heart failure or shock. Coarctation of the aorta and associated lesions can be diagnosed accurately by two-dimensional echocardiography. This permits proper patient management without the added risk of cardiac catheterization. Although mitral and aortic lesions may be missed because of low cardiac output, this does not result in management errors.

Two-dimensional echocardiographic evaluation of discrete subaortic stenosis from the apical long axis view

M-mode standard two-dimensional (2DE) left parasternal long axis echocardiographic examination of the left ventricular outflow tract (LVOT) was evaluated exclusively with respect to its utility in identifying discrete subaortic stenosis (SUB-AS). Important details of the anatomy of the subaortic area may also be obtained from 2DE apical long axis imaging. According, 18 patients with discrete SUB-AS were prospectively evaluated by M-mode and 2DE. The M-mode findings included narrowing of the LVOT and early systolic closure of the aortic valve. However, these findings were variable and highly dependent upon scan speed, fluid flow dynamics, and beam angulation. 2DE findings varied using the standard long axis view at the left parasternal border, depending upon the type of obstruction present. A discrete membrane produced linear echoes adjacent and parallel to the interventricular septum beneath the aortic valve. Fibromuscular obstruction produced a localized dense ridge of echoes in the LVOT. These findings were not apparent in five patients studied. In these patients, the 2DE apical long axis view was employed to image the subaortic area. From this tomographic corss-section a fibrous membrane was imaged as a linear echo parallel to the aortic valve. The membrane extended across the LVOT from the ventricular septum to the anterior leaflet of the mitral valve. The 2DE apical long axis view therefore provides an additional approach in the evaluation of patients with discrete SUB-AS.

152 TWO DIMENSIONAL ECHOCAEDIOGRAPHIC (2DE) ASSESSMENT OF RIGHT VENTRICULAR VOLUMES (RVV) AND EJECTION FRACTION (EF)

The ability of M-mode and 2DE to measure RVV and EF was assessed in 15 children without right ventricular outflow tract obstruction (RVOTO) (Group I). M-mode measurement of end diastolic dimension (RVEDD) was performed in the usual fashion. From the apical 4 chamber 2DE view the long axis of the right ventricle (RVLA) was measured from the apex to mid tricuspid valve, and area planed (RVA). From the anterior-posterior (AP) and lateral (lat) angio-graphic (angio) views the right ventricular body (RVB) longest length was measured, area planed, and volumes calculated using a Simosons Rule algorithm. Data were compared by linear regression analysis (r=correlation coefficient, a=slope). RVEDD by M-mode correlated poorly with angio data. The 2DE obtained RVLA length correlated well with the maximum angio obtained length from either the AP or Lat views at both end systole (ES) and end diastole (ED). 2DE RVA also correlated with the planed area obtained from either AP or Lat angio projections. To determine the relationship between RVB volume (RVBV) and total right ventricular volume (TRW), these volumes were separately assessed in 30 other children without RVOTO (Group II). A constant relationship existed between RVBV and TRVV such that RVBV/TRW=0.75. By 2DE RVBV was determined from the apical 4 chamber view by an area-length algorithm assuming an ellipsoid model. Accurate 2DE assessment of TRW and EF in Group I patients could be achieved by the equation, Volume = 1.34 X echo calculated RVBV; (EDV r=0.92, a=0.98; ESV r=0.84, a=0.95; EF r=0.80, a=1.19). Therefore, 2DE is able to accurately measure RVV and EF in patients without RVOTO.