Noninvasive evaluation of systolic pressures of pulmonary artery and right ventricle using contrast-enhanced doppler echocardiography: Comparative study using sonicated albumin or glucose solution

Evaluation of pulmonary arterial pressure is essential for the diagnosis and management of patients with congenital heart disease; it is usually done by cardiac catheterization. An alternative, noninvasive method may be clinically more useful. The purpose of this study was to assess the usefulness of the noninvasive determination of systolic pressure of the pulmonary artery and right ventricle by contrast-enhanced Doppler echocardiography. We selected 30 pediatric patients (28 with trivial or nonsignificant tricuspid regurgitant Doppler signals and 2 with significant tricuspid regurgitant Doppler signals) aged 2 months to 21 years. The flow velocity of tricuspid regurgitation was measured with continuous-wave Doppler of the right ventricular inflow view or left parasternal or apical four-chamber view before and after injection of two types of contrast medium (hand-agitated 5% glucose or sonicated albumin). The systolic pressure of the pulmonary artery was assessed as the estimated right ventricular systolic pressure (albumin method) minus the peak pressure gradient across the pulmonary valve (nonenhanced Doppler method). After injection of hand-agitated 5% glucose and sonicated albumin, trivial tricuspid regurgitation signals were enhanced in 25 of 28 patients (89%). In two patients, spectral envelopes were well defined enough to obtain the peak systolic velocity of the tricuspid regurgitation jet without contrast medium injection. Peak velocity was not altered by injection of contrast medium in these patients. There was significant correlation between the estimation by contrast-enhanced Doppler using hand-agitated 5% glucose and the cardiac catheterization measurement of the transtricuspid pressure gradient (r= 0.88). The transtricuspid pressure gradients obtained by continuous-wave Doppler during sonicated albumin enhancement corresponded closely to those measured by cardiac catheterization (r = 0.95). Pulmonary arterial and right ventricular systolic pressures measured by Doppler using sonicated albumin and those obtained by cardiac catheterization were highly correlated (right ventricle, r = 0.96; pulmonary artery, r = 0.95). In conclusion, this technique may be a valuable noninvasive method for determining accurate right ventricular and pulmonary arterial systolic pressures.     

Echocardiography for the Diagnosis of Congenital Cardiac Anomalies with Multiple Lesions

The purpose of this study was to determine the sensitivity and specificity of echocardiography for the diagnosis of congenital cardiac abnormalities with multiple lesions. The study was carried out on 80 patients (ages 1 day to 14 years). After clinical evaluation all patients were studied by echocardiography. Cardiac catheterization and angiocardiography were performed, and echocardiographic findings were compared with those obtained by cardiac catheterization. The sensitivity and specificity of echocardiographic diagnosis were determined based on the false-negative and false-positive results. Of the 80 patients, 19 had double-outlet right ventricle, 17 transposition of the great arteries, 10 common atrium, 9 atrioventricular septal defect, 7 single ventricle, 7 corrected transposition, 6 tricuspid atresia, 3 Ebstein's anomaly, and 2 cor triatriatum. All of these entities were visualized correctly by echocardiography (sensitivity 100%, specificity 100%). There were also 12 instances of atrial isomerism with one false-negative diagnosis, 6 pulmonary atresia with two false-negative diagnoses, and 5 total anomalous pulmonary venous connections with one false-negative diagnosis. The total number of individual cardiac lesions was 291. Nineteen false-negative and four false-positive echocardiographic diagnoses were obtained (sensitivity 93%, specificity 99%). It is concluded that double-outlet right ventricle, transposition of the great arteries, atrioventricular septal defect, single ventricle, corrected transposition, and tricuspid atresia can be accurately diagnosed by echocardiography. However, the role of echocardiography is limited for evaluation of right ventricular outflow tract and small patent ductus arteriosus, especially when associated with pulmonary hypertension.     

Idiopathic Enlargement of the Right Atrium

A case of aneurysmal enlargement of the right atrium was found accidentally during a routine examination. The patient was asymptomatic and free of palpitations or proven rhythm disturbances. The results of echocardiography, magnetic resonance imaging, and cardiac catheterization excluded cardiac malformation, which could have caused secondary enlargement of the right atrium. A partial pericardial defect as a likely cause of herniation of the right atrium was ruled out by magnetic resonance imaging. In keeping with these results, isolated aneurysmal enlargement of the right atrium was diagnosed.     

Doppler Echocardiography with Extended Transesophageal Atrial Pacing: Predicting the Efficacy of Permanent Atrial Pacing in the Patient with a Small Left Ventricle and Sinus Node Dysfunction

A 2100-g neonate underwent a two-ventricular surgical repair of a right ventricle-dominant unbalanced atrioventricular septal defect associated with the heterotaxy syndrome and sinus node dysfunction. Postoperative congestive heart failure persisted despite bradycardia management by temporary ventricular pacing. Spectral Doppler echocardiographic analysis of pulmonary venous inflow and aortic outflow patterns demonstrated significant improvement with transesophageal atrial pacing. Extended transesophageal pacing was performed for two days, resulting in dramatic clinical improvement. This is the first report of extended transesophageal atrial pacing complementing Doppler echocardiography predicting an improved outcome with permanent atrial pacing.     

Effects of Age and Respiration on Right Ventricular Diastolic Filling Patterns in Normal Children

Right ventricular diastolic filling was assessed in 88 normal Chinese children using Doppler echocardiographic interrogation of diastolic transtricuspid valve flow. Any influences of age and respiration on right ventricular diastolic filling were also investigated. The results showed that age-dependent differences were apparent for filling times, associated with the decrease in heart rate with increasing age. In addition, peak transtricuspid flow velocities were markedly greater in inspiration than in expiration, with corresponding increases in filling times and velocity–time integrals. The influence of age and respiration on transtricuspid flow parameters should be considered in the evaluation of right ventricular diastolic function by Doppler echocardiography. We believe that measurements should be standardized for respiratory phase and that right ventricular diastolic function parameters should be taken at end-inspiration and end-expiration, respectively.     

Utility of Intraoperative Transesophageal Echocardiography in the Assessment of Residual Cardiac Defects

To investigate the accuracy of immediate postbypass transesophageal echocardiography in the assessment of residual cardiac defects, we compared intraoperative transesophageal echocardiograms with intra/postoperative data in 86 patients, aged 4 days to 30.7 years (median = 1.4 years), at risk for a total of 174 postoperative lesions: right (n= 55) or left (n= 26) ventricular outflow tract obstruction, ventricular septal defect (n= 65), aortic (n= 12) or mitral regurgitation (n= 8), or mitral stenosis (n= 8). Accuracy of intraoperative transesophageal echocardiography was evaluated based on comparison with (1) immediate post-bypass left (n= 4) or right (n= 9) ventricular outflow tract pressure gradients by pullback in the operating room, (2) direct surgical inspection of residual ventricular septal defects (n= 3), (3) pulmonary artery oxygen saturation (n= 49), (4) right ventricular outflow tract pullback gradient (n= 24), and (5) transthoracic echocardiogram (n= 51) performed within 40 days of surgery. The results indicate that intraoperative transesophageal echocardiography agreed with intra/postoperative data in 87% of patients at risk for right ventricular outflow tract obstruction, 96% at risk for left ventricular outflow tract obstruction, 97% at risk for ventricular septal defect, and 100% at risk for aortic regurgitation, mitral regurgitation, or mitral stenosis. Significant residual lesions led to immediate surgical revision in 11 cases: 3 ventricular septal defects, 6 right and 2 left ventricular outflow tract obstructions. Of these, intraoperative transesophageal echocardiography confirmed and quantified suspected residual lesions in 7 and identified unsuspected lesions in 4 cases. Immediate postbypass transesophageal echocardiography proved reliable for assessing residual ventricular septal defect, mitral stenosis, and mitral or aortic regurgitation. Although accurate for assessment of the left and right ventricular outflow tracts in most patients, transesophageal echocardiography may not reliably reflect the severity of obstruction in all cases.     

A Comparison Between MUGA and Echocardiography in Patients with Muscular Dystrophy in the Early Detection of Cardiac Involvement

Muscular dystrophies are a group of sex-linked diseases with frequent myocardial involvement. In this study 14 patients with Duchenne Muscular Dystrophy (DMD), 7 with Becker Muscular Dystrophy (BMD), and 8 female carriers who were asymptomatic were evaluated with echocardiography and multigated radionuclide ventriculography (MUGA). All showed predominant systolic and minor diastolic left ventricular dysfunction determined both by echocardiography and MUGA when compared with healthy controls. In conclusion, it is recommended that DMD, BMD, and female carriers be evaluated and closely monitored for cardiac functions. Though MUGA and echocardiography are both effective and sensitive techniques, echocardiography is more convenient for availability and serial evaluation.     

Doppler Echocardiographic Evaluation of Right Ventricular Diastolic Function in Children

Right ventricular diastolic function was evaluated by flow velocity pattern in the right ventricular inflow tract by means of pulsed Doppler echocardiography. Traditionally used to evaluate this function are peak velocities obtained during early diastole (peak E wave) and during atrial contraction (peak A wave), their ratio (peak E/A ratio), and the deceleration half-time. We conducted pulsed Doppler echocardiographic studies of right ventricular inflow and outflow patterns in 171 children (105 normal children and 66 children who were undergoing total surgical repair of congenital heart defects without sequelae). Results showed that summation flow was present in the right ventricular inflow tract in 43 (25%) of the 171 subjects, which made it difficult to separate the peak E wave from the peak A wave. We noted the presence of antegrade late diastolic flow (DW) in the right ventricular outflow tract of all subjects. DW, measured in 121 subjects in whom both E and A waves were detected in the right ventricular inflow tract, showed a highly significant correlation (p < 0.0001) with A waves in the right ventricular inflow tract. The ratio of DW to right ventricular outflow tract velocities during systole (SW) showed a highly significant (p < 0.0001) correlation with E/A ratio. When evaluating right ventricular diastolic function by pulsed Doppler, especially in children, the analysis of right ventricular outflow tract patterns is helpful in addition to that of inflow tract patterns. The DW and DW/SW ratio may present good alternatives to traditional parameters in children.     

Serial Pulsed Doppler Assessment of Pulmonary Artery Pressure in Very Low Birth-Weight Infants

We assessed pulmonary artery pressure (PAP) during the early neonatal period in very low birth-weight (VLBW) infants using serial echocardiographic measurements of the ratio of the pulmonary artery acceleration time to the right ventricular ejection time corrected by heart rate [AT:RVET(c)]. Eighty-four VLBW infants weighing less than 1500 g were examined using serial color Doppler echocardiography from 3 hours to day 7 after birth. The AT:RVET(c) of infants born after 30 weeks of gestation showed a rapid, significant increase during the early neonatal period, whereas those of the groups born at less than 30 weeks showed no significant increase before day 14. At 24 hours after birth, the AT:RVET(c) values of VLBW infants did not correlate well with either the ratio of the right preejection period to the right ventricular ejection time on M-mode echocardiography or the pressure gradient between the right ventricle and the right atrium, as estimated by tricuspid regurgitation on pulsed Doppler echocardiography. The AT:RVET(c) value for the chronic lung disease (CLD) group did not differ significantly from that for the oxygen-dependent group at any assessment point. During the early neonatal period, the AT:RVET(c) of VLBW infants, as calculated by pulsed Doppler echocardiography, differed with their gestational age and did not appear to correlate well with PAP. Our data also suggest that AT:RVET(c) values may not be a good predictor of the subsequent occurrence of CLD in VLBW infants.     

Generation of Reactive O2 Species in the Myocardium of Newborn Lambs Following Intrauterine Increase in Right Ventricular Pressure

Fetuses with pulmonary stenosis and constriction of the ductus arteriosus or the recipient twin in the context of a twin-to-twin transfusion syndrome may present with severe right ventricular myocardial dysfunction. Free O₂ radicals are known to be increased in hypertrophied adult myocardium secondary to an increase in endocavitary pressure. This study investigates whether products of reactive O₂ species generation are abnormally elevated in the myocardium of fetuses with increased right ventricular pressure. Banding of the main pulmonary artery was performed in five fetal lambs at 90 to 100 days of gestation. Three other animals had a sham intervention and were used as controls. Postoperative observation lasted on average 42 days (range 33–49 days). The levels of hydroperoxides were found to be significantly higher in the right ventricle of the stenosed lambs (6.6 ± 3.5 nmol/mg protein) compared to the left ventricle of the same lambs (0.7 ± 0.7 nmol/mg protein), and compared to the right (0.12 ± 0.1 nmol/mg protein) and the left (0.5 ± 0.8 nmol/mg protein) ventricles of the controls. It is concluded that during fetal life, an increase in right ventricular pressure is associated with a marked accumulation of products of reactive O₂ species generation in the right ventricular myocardium.     

Estimation of Right Ventricular Free-Wall Mass Using Two-Dimensional Echocardiography

Echocardiographic methods based on geometric models have long been in use for estimating left ventricular mass, but there is currently no similar method for estimating right ventricular (RV) free-wall mass. We hypothesized that a one-quarter prolate ellipsoid model could be used with two-dimensional echocardiography to approximate RV mass. Over a 2-year period 39 patients who had both a complete cardiac magnetic resonance imaging (MRI) scan and an echocardiogram within 2 weeks of each other were retrospectively analyzed. MRI-derived RV mass was used as the standard for comparison. Echocardiographic RV mass was estimated using three equations based on the geometric model. Linear regression analysis was performed to determine the correction factors used in the final formulae. The formula with the lowest standard error of the estimate was then prospectively analyzed for accuracy using a separate group of 88 subjects. The most accurate echocardiographic equation derived was RV mass = 5.84 (apical four-chamber RV cavity planar area) (RV free-wall thickness) + 1. Compared to MRI-RV mass the correlation coefficient was 0.97 and the standard error of the estimate was 16.8%. The positive and negative predictive values for diagnosing RV hypertrophy were 95% and 88%, respectively. We conclude that RV free-wall mass can be estimated by two-dimensional echocardiography using a one-quarter prolate ellipsoid shell model.     

Acute loads applied to the right ventricle: Effect on left ventricular filling dynamics in the presence of an open pericardium

To determine whether diastolic ventricular interdependence mechanisms would act in the presence of an open pericardial sac, as during cardiac surgery, moderate acute right ventricle afterload increases were applied to eight dogs with the chest and pericardium open while left ventricular filling dynamics were being assessed by Doppler echocardiography. Dogs were studied under basal conditions and after acute banding of the main pulmonary artery tightened to produce a 100% increase in right ventricular systolic pressure. With banding, the left ventricular filling velocity ratio (E/A), as assessed by Doppler echocardiography of mitral inflow, changed from a baseline value of 1.32 ± 0.05 to 1.16 ± 0.03 (p < 0.02), suggesting a restrictive pattern to early left ventricular filling, which is differed to that during the second half of diastole. Isovolumic relaxation time, measured as the time interval between aortic valve closure and mitral valve opening, assessed by M-mode echocardiography of both valves, was prolonged, though not significantly, from 63.3 ± 2.5 ms to 69.4 ± 2.9 ms, by banding of the pulmonary artery. E wave deceleration time, a filling variable influenced by chamber pressure/volume relations, was shortened by pulmonary artery banding, changing from 75.1 ± 1.7 ms to 68.0 ± 1.8 ms (p < 0.01). It was concluded that pressure loads applied to the right ventricle restricted early left ventricular filling. Prolonged relaxation and altered pressure–volume chamber relations were the diastolic interdependence mechanisms involved that proved to be acting even under open pericardium conditions.     

Balloon Dilatation of the Pulmonary Valve in a Patient with Pulmonary Atresia and Intact Ventricular Septum Using a Commercially Available Radiofrequency Catheter

Using a commercially available 5F deflectable radiofrequency catheter, we have succeeded in percutaneous valvotomy of an imperforate pulmonary valve and consecutive balloon dilatation in a baby with pulmonary atresia and intact ventricular septum. After the procedure, right ventricular systolic pressure fell from 125 mmHg to 65 mmHg, and right ventriculography demonstrated anterograde blood flow into the pulmonary arteries. There were no major complications. Doppler echocardiography at 1 year after the procedure demonstrated a pressure gradient across the pulmonary valve of 20 mmHg with mild pulmonary and tricuspid regurgitations.     

The Range of Normal Values of Cardiovascular Structures in Infants, Children, and Adolescents Measured by Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is a powerful diagnostic technique and research tool for assessment of congenital heart disease due to its ability to accurately assess anatomy, function, and flow in any orientation in the thorax. However, little data exist on normative reference values for cardiac structures, except in small study populations, and even fewer data exist for pediatric populations. In this review, MRI acquisition and analysis methods for assessment of aortic size, pulmonary artery size, and right and left ventricular function, volume, and mass are presented along with reference data obtained in pediatric populations by MRI. Where MRI data are not available, reference data obtained by echocardiography or angiography are included.     

Distinguishing Cardiac Features of a Novel Form of Congenital Muscular Dystrophy (Salih CMD)

The cardiac features of a novel form of congenital muscular dystrophy (Salih CMD) are described in two adolescent siblings. The patients presented with severe hypotonia at birth, associated with delayed development. They could walk independently and managed to maintain walking after 13 years of age. Their muscle immunohistochemistry differed from that seen in Duchenne and Becher muscular dystrophy (DMD and BMD), severe childhood autosomal recessive muscular dystrophy (SCARMD) due to sarcoglycan deficiency (sarcoglycanopathies), and lamininα2 (merosin)-deficient CMD. However, both patients had associated cardiomyopathy. Electrocardiography (ECG) in Salih CMD was characterized by delayed atrioventricular (AV) conduction, left anterior fascicular block (left axis deviation), and left atrial enlargement without evidence of atrial dysarrhythmia. Echocardiography showed features of severe left ventricular dysfunction with estimated left ventricle ejection fraction (LVEF) of 25% at 16 years-of-age in the older patient. A year later, multigated aquisition MUGA scan showed LVEF of 21% and dilatation of the right ventricle. Echocardiography and MUGA scan were normal in the younger patient at 15 years-of-age. ECG, echocardiography, and MUGA scan are effective techniques for diagnosing and monitoring the cardiomyopathy in Salih CMD. They can also distinguish it from features seen in the other common forms of MD, including DMD, BMD, and sarcoglycanopathies.     

Balloon Angioplasty of Right Ventricular Outflow Tract Conduits

Palliation of complex congenital heart disease, requiring reconstruction of the right ventricular outflow tract (RVOT), is standard practice. Survival of the homograft is a limiting factor. We examined the role of balloon angioplasty (BAP) in prolonging conduit life. Twelve patients underwent 15 BAP procedures between February 1989 and October 1997. The median age at conduit insertion was 28 months with detection of a significant echo gradient 42 months later. Calcification of homografts, with attendant obstruction and valve dysfunction, was present in all patients. BAP was performed within 1 month of echocardiography and reduced the gradient from a median of 57 to 38 mmHg (p < 0.0005). Echocardiographic follow-up showed persistent gradients (median 68 mmHg) and 11/12 patients went on to conduit replacement after BAP. Only one patient had replacement deferred as a result of BAP. Complications requiring intervention occurred in 20% of the procedures and included bleeding and an unusual balloon fracture. Although BAP can reduce the pressure gradient across the RVOT conduit, the effect is transient and the delay of surgery is not due to improved hemodynamic function. Approximately 10% of cases will benefit from BAP alone, but given the high rate of complications, we do not recommend this procedure as a means of prolonging conduit life.     

Congenital Aneurysm of the Muscular Interventricular Septum in a Fraternal Case Diagnosed by Fetal Echocardiography

Two siblings with aneurysms of the muscular ventricular septum are presented. Case 1 (the older brother) underwent fetal echocardiography at 26 weeks of gestation. Initially, it was thought that he had a muscular ventricular septal defect; however, postnatal echocardiography revealed an aneurysm of the muscular portion of the ventricular septum. Retrospective review of the 26-weeks gestation fetal echocardiogram confirmed this diagnosis. Case 2 (a younger brother of the first case) was also diagnosed as having an aneurysm of the ventricular septum by fetal echocardiography at 28 weeks of gestation. Postnatal echocardiography confirmed this diagnosis.     

Circulatory System in Children with Localized Scleroderma

The circulatory system was studied in 43 children (ages 3–18 years, mean 10.6 years; 32 girls, 11 boys) suffering from localized cutaneous forms of scleroderma. The following studies were undertaken: general pediatric examination, cardiologic examination including routine electrocardiogram (ECG), 24-h Holter ECG monitoring, echocardiography plus Doppler study, and a treadmill exercise test. Three children found to have congenital heart malformations were excluded from the study. Children with localized scleroderma were often lighter and shorter than their appropriate controls. The most common ECG abnormality was incomplete right bundle branch block, but other ECG and Holter abnormalities were found as well. Abnormal echocardiographic results were obtained in 16 cases. The abnormalities concerned valvar function (in all heart valves but predominantly in the mitral valve). It was found that the children suffering from scleroderma had different indices than controls for left ventricular mass index, mitral valve function and left ventricular filling. During the exercise test (conducted according to Bruce's protocol) we found no difference between patients and controls.     

Successful Treatment of Postoperative Right Ventricular Heart Failure with the HIA-Medos-Assist System in a 2-Year-Old Girl

One year after total correction of tetralogy of Fallot, reoperation was performed in a 2-year-old infant because of an aneurysm of the right ventricular outflow tract. After removal of the aneurysm, massive right ventricular failure occurred. Maximal medical inotropic support could not reestablish sufficient right ventricular function. Therefore, it was decided to implant the new HIA-Medos system as a right ventricular assist. In the postoperative period, echocardiographic controls showed increasing contractility of the right ventricle. The assist system was removed after 3 days and the infant was discharged in good condition on the 22nd postoperative day.     

Left Ventricular Diastolic Functions in Juvenile Rheumatoid Arthritis

Cardiac involvement as pericarditis, myocarditis, and endocarditis is common in juvenile rheumatoid arthritis (JRA). Though there are many reports concerning systolic and diastolic functions of adults with rheumatoid arthritis, there are no studies on children with JRA. Thirty patients with JRA without any cardiac symptoms and 30 sex- and age-matched controls were included in the study. M-mode and pulsed-wave Doppler echocardiography were performed on each participant to assess the systolic and diastolic functions of the left ventricle. Left ventricular end-systolic diameter and volume were larger and ejection fraction and fractional shortening were decreased in the JRA group. Among the diastolic parameters, increased late flow velocity, decreased early flow velocity, and prolonged isovolumic relaxation time reflected an abnormal relaxation form of diastolic dysfunction. Mortality rate is increased in adults with rheumatoid arthritis, and ischemic heart disease is the leading cause of cardiovascular mortality. The abnormal relaxation form of diastolic dysfunction found in children with JRA is seen in ischemic heart disease. These children can therefore be candidates for ischemic heart disease in the future even though they are fully asymptomatic at present. In conclusion, children with JRA should be assessed for systolic and diastolic functions with serial echocardiography. In this way it may be possible to reduce the mortality and morbidity of the disease from cardiac causes.