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.

Noninvasive diagnosis of partial anomalous left pulmonary artery.

The branching patterns of the pulmonary arteries may vary, with one or more lobes of the left lung being supplied by a branch originating from the right pulmonary artery-a condition termed partial anomalous left pulmonary artery. If this anomalous branch courses anterior and inferior to the trachea, it is unlikely to result in airway obstruction. It is important that this anomaly not be confused with pulmonary artery sling, where the anomalous branch courses posterior to the trachea, encircling it almost completely. Partial anomalous left pulmonary artery has previously been diagnosed with angiography or by direct visualization during surgery. We present the first cases of noninvasive diagnosis of this anomaly with the use of echocardiography and magnetic resonance imaging. The complementary roles of these two modalities in detecting the anomaly and defining the spatial relationship of the anomalous pulmonary artery to the trachea are emphasized.

Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela.

OBJECTIVE: We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing. BACKGROUND: Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects. METHODS: A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB. RESULTS: Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%). CONCLUSIONS: Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Reliability of intraoperative transesophageal echocardiography during Tetralogy of Fallot repair.

UNLABELLED: There is limited information available concerning the accuracy of intraoperative transesophageal echocardiography (TEE) in predicting the extent of residual abnormalities after recovery from surgical repair of tetralogy of Fallot. Therefore, we investigated differences between the results of final postbypass TEE and those of postrecovery (mean, 6 days after surgery) transthoracic echocardiography in a total of 28 consecutive pediatric patients who underwent repair of tetralogy of Fallot with biplane or multiplane TEE. Both postbypass and postrecovery echocardiographic examinations included measurements of the right ventricle (RV)-main pulmonary artery (PA) and the main PA-branch PA peak instantaneous gradients, the degree of pulmonary valvar insufficiency, and color Doppler interrogation of the ventricular septum for residual defects. The RV-main PA gradient did not change significantly: 15 +/- 13 vs 18 +/- 14 mmHg (postbypass versus postrecovery, mean +/- SD). None of the patients had a decrease of > or = 10 mmHg; and only one patient had an increase of > or = 15 mmHg. There also was no change in the degree of pulmonary insufficiency (3.0 +/- 1.2 versus 3.1 +/- 1.1, using a scale of 0 to 4). Only one of the seven very small (< or = 2 mm) residual ventricular septal defects was not discovered during postbypass TEE. However, postrecovery transthoracic echocardiography detected significant branch PA stenosis (peak gradient, > or = 15 mmHg) in five patients (18%) that was not detected during postbypass TEE (P < 0.03). Of the branch PA stenoses that were not detected during TEE, four were left and one was right. CONCLUSIONS: Postbypass TEE after tetralogy of Fallot repair reliably predicts residual postrecovery hemodynamic abnormalities, except for branch PA stenosis.

Magnesium supplementation in the prevention of arrhythmias in pediatric patients undergoing surgery for congenital heart defects.

BACKGROUND: The efficacy of magnesium in the prevention of arrhythmias in pediatric patients after heart surgery remains unknown. Therefore we prospectively examined the effect of magnesium treatment on the incidence of postoperative arrhythmias in pediatric patients undergoing surgical repair of congenital heart defects. METHODS AND RESULTS: Twenty-eight pediatric patients undergoing heart surgery with cardiopulmonary bypass were prospectively, randomly assigned in a double-blind fashion to receive intravenous magnesium (magnesium group, n = 13; 30 mg/kg) or saline (placebo group, n = 15) immediately after cessation of cardiopulmonary bypass. Magnesium, potassium, and calcium levels were measured at defined intervals during surgery and 24 hours after surgery. Continuous electrocardiographic documentation by Holter monitor was performed for 24 hours after surgery. Magnesium levels were significantly decreased below the normal reference range for patients in the placebo group compared with the magnesium group on arrival in the intensive care unit and for 20 hours after surgery. Magnesium levels remained in the normal range for patients in the magnesium group after magnesium supplementation. In 4 patients in the placebo group (27%), junctional ectopic tachycardia developed within the initial 20 hours in the intensive care unit. No junctional ectopic tachycardia was observed in the magnesium group (P =.026). CONCLUSIONS: Although this study was originally targeted to include 100 patients, the protocol was terminated because of the unacceptable incidence of hemodynamically significant junctional ectopic tachycardia that was present in the placebo group. Thus low magnesium levels in pediatric patients undergoing heart surgery are associated with an increased incidence of junctional ectopic tachycardia in the immediate postoperative period.

Pediatric cardiac auscultation.

Murmurs will be a frequent finding during the well child pediatric exam and perhaps more frequent during the evaluation of an acute illness, but most of these murmurs are innocent. Understanding the variety of causes of innocent murmurs should help identify them as such. However, referral to the pediatric cardiac specialist is appropriate in newborns and small infants, when the findings are not entirely consistent with an innocent murmur, or when there are other reasons to suspect heart disease.

Right ventricular volumes revisited: a simple model and simple formula for echocardiographic determination.

Our objective was to establish a crescentic model of the right ventricle as the basis of a reported 2/3 (Area)(Length) empirical formula for volume. This formula has been investigated by others without cognizance of its connection to a clear geometric model. The particular model, an ellipsoidal shell or difference of ellipsoids, has been investigated by several groups by using different volume formulas. Accordingly, we obtained echocardiographic images in 2 orthogonal planes from 7 patients and 4 volunteers. Specified area and length measurements from these images were used to calculate right ventricular volumes. These volumes were compared with values determined through multislice, magnetic resonance imaging with summation of lumen areas, a widely accepted standard. Obtained high correlations compared favorably with those of previous investigators who used equivalent but less well understood methods. We conclude that the ellipsoidal shell model of the right ventricle provides a simple area-length formula for the determination of lumen volume with echocardiography.

The effect of indomethacin tocolysis on fetal ductus arteriosus constriction with advancing gestational age.

OBJECTIVE: Our purpose was to determine whether continuing exposure to indomethacin tocolysis is associated with an increased incidence of constriction of the human fetal ductus arteriosus with advancing gestational age. STUDY DESIGN: Fetal echocardiograms were reviewed in 61 cases in which the pregnant women were treated for preterm labor with indomethacin (25 mg orally every 6 hours). Density function analysis and regression analysis were used to assess the effect of indomethacin tocolysis on ductal constriction with advancing gestational age. RESULTS: A total of 193 fetal echocardiograms were obtained for 72 fetuses. Ductal constriction developed in 50% of the fetuses ranging from 24.7 to 35.0 weeks' gestation. Fetuses with indomethacin-induced ductal constriction demonstrated a greater increase in systolic flow velocities with advancing gestational age compared with the nonconstricted group (p < 0.05). Constriction was detected at a mean gestational age of 30.9 +/- 2.3 weeks at an average of 5.1 +/- 6.0 days after initiation of therapy. Ductal constriction occurred by 31 weeks' gestation in 70% of the affected fetuses. After discontinuation of indomethacin therapy, all follow-up echocardiograms demonstrated a return to nonconstricted ductal flow velocities. No significant adverse neonatal outcomes were attributed to indomethacin use. CONCLUSIONS: A dramatic yet reversible increase in the incidence of indomethacin-induced ductal constriction occurs at 31 weeks' gestation. However, ductal constriction can occur at any gestational age. With indomethacin tocolysis, weekly fetal echocardiography is warranted for the duration of therapy.

Incidence of femoral vein occlusion after catheter ablation in children: evaluation with magnetic resonance angiography.

Catheter ablation in children requires placement of multiple large femoral venous sheaths and catheters. Magnetic resonance angiography (MRA) was used to evaluate the effect of indwelling lines on femoral venous blood flow. Between October 1993 and February 1994 a total of 17 patients scheduled for catheter ablation underwent venous MRA. Two-dimensional time-of-flight MRA was performed 12-70 hours after catheterization on all patients. All patients received intravenous heparin during the procedure and had aspirin therapy instituted after ablation. Eighteen catheter ablations and MRA studies were performed on the 17 patients (one patient underwent repeat ablation). There were 7 females and 10 males, with a mean age of 14.8 +/- 4.2 years (range 8-21 years). Patients had three venous sheaths inserted in the left femoral vein (5F, 6F, and 7F with external diameters measuring 1.7, 2.0, and 2.3 mm, respectively) and one sheath in the right femoral vein (7F). Four patients (22%) had altered venous flow (two complete obstructions and two partial obstructions) following catheterization. None of these patients experienced symptoms or complications. It was concluded that there is an increased incidence (22%) of venous obstruction following catheter ablation, but there are no related complications. Venous MRA provides a rapid, noninvasive method for evaluating venous flow abnormalities and possibly detects patients at risk for complications.

Correlation of pediatric echocardiographic Doppler and catheter-derived valvar aortic stenosis gradients and the influence of aortic regurgitation.

This report suggests that in the absence of aortic regurgitation, Doppler peak and mean gradients are useful predictors of catheter peak-to-peak aortic stenosis gradients >50 mm Hg; however, in the presence of aortic regurgitation, the predictive value diminishes dramatically, but improves when electrographic data are incorporated. We present potentially useful equations to help predict the need for interventional catheterization for valvar aortic stenosis.

Right ventricular volume estimation using an ellipsoidal shell model and single-plane magnetic resonance imaging.

RATIONALE AND OBJECTIVES: To investigate whether accurate right ventricular volumes could be obtained using an ellipsoidal shell model with magnetic resonance (MR) image measurements from a single imaging plane. METHODS: An initial retrospective patient study included 10 patients with congenital cardiac defects who had undergone same-day or next-day radiographic contrast ventriculography. An expanded study included MR scans of a total of 29 patients with congenital cardiac defects. Magnetic resonance scans of 10 healthy volunteers were also included in part of the study. Right ventricular volumes were calculated from (1) model-based calculations using single-plane cine MR imaging, and (2) multislice calculations based on contrast angiography. RESULTS: Regression of angiography-based volumes against MR-based volumes showed high correlation (r = 0.97, see = 12.5 mL) and slope near unity. Regression of right against left stroke volumes, both calculated from MR data, showed excellent correlation (r = 0.90, see = 11.6 ml) and slope near unity. CONCLUSIONS: The ellipsoidal shell model can be used to reliably estimate right ventricular volume using single-plane MR images.

Right ventricular volume estimation with an ellipsoidal shell model and two-plane magnetic resonance imaging.

In patients with congenital and other heart disease, measurement of right ventricular (RV) volumes would be as useful as left ventricular (LV) volume measurement has been for diseases of the LV. Model-based techniques have had limited success. Simpson's rule (multislice) techniques require lengthy data collection and reduction. We investigated a technique for volume estimation with a new but simple geometric model. A retrospective patient study compared RV volumes from model-based calculations with dual-plane cine magnetic resonance (MR) imaging and multislice calculations with biplane cineangiography. Linear regression showed high correlation (r = 0.98, standard error of the estimate = 11.8 ml) between the two techniques, with a slope near unity. Comparison of calculated right and left stroke volumes also showed an excellent correlation (r = 0.93, standard error of the estimate = 10.4 ml) and a slope near unity. It is concluded that the ellipsoidal shell model can be used to estimate RV volume reliably and practically with dual-plane MR imaging.

T-cell lymphoma in a child after heart transplantation.

Lymphoproliferative disease remains a small but worrisome problem after organ transplantation. This disorder is often a B-cell proliferation associated with Epstein-Barr virus. This article describes the unusual association of Epstein-Barr virus with a T-cell lymphoma in a child after heart transplantation and ultimately an atypical rejection episode with an increased number of eosinophils.

Immunosuppressive treatment for myocarditis and borderline myocarditis in children with ventricular ectopic rhythm.

OBJECTIVES: To ascertain the responsiveness to immunosuppressive treatment of myocarditis and borderline myocarditis in children with ventricular ectopic rhythm (that is, all ventricular arrhythmia except benign premature ventricular contractions). To determine the impact of the diagnostic information provided by an endomyocardial biopsy specimen in these patients. BACKGROUND: The therapeutic value of performing an endomyocardial biopsy in children with ventricular ectopic rhythm is not established. In turn, the treatment of myocarditis with immunosuppressive drugs is also controversial. METHODS: The case notes and endomyocardial biopsy findings of all children with ventricular ectopic rhythm and a biopsy diagnosis of myocarditis were reviewed. RESULTS: Ten (14%) of 69 patients with ventricular ectopic rhythm and an anatomically normal heart had histological evidence of myocarditis or borderline myocarditis. Eight patients received corticosteroids and efficacy was judged by regular 24 hour Holter monitoring. Total resolution of arrhythmia was seen in four, improvement in two, and no change in two patients. At follow up (8-39 months, mean 22 months), arrhythmia recurrence was seen in the two patients who showed an improvement but not resolution during treatment. Both received azathioprine with further reduction in ectopy rates. Patients who responded to treatment were symptomatic (six of six patients) at presentation compared with those who did not respond to treatment (none of two patients) who were not symptomatic. Five patients had a repeat biopsy specimen taken which confirmed histological improvement. CONCLUSIONS: Steroid treatment seems to benefit a subset of children with ventricular ectopic rhythm and a biopsy diagnosis of myocarditis or borderline myocarditis. Because it can identify a treatable cause for the ventricular arrhythmia, endomyocardial biopsy is a valuable investigation in these patients.

Resolution of atrial standstill in a child with myocarditis.

Atrial standstill is a rare disorder usually seen in adults with extreme myocardial disease. Etiologies described in the literature have included muscular dystrophy, familial amyloidosis, and rarely myocarditis. These etiologies usually lead to permanent atrial standstill and require ventricular pacing. We present a case of an 11-year-old black female who developed atrial standstill secondary to biopsy proven acute necrotizing myocarditis. Absence of atrial function was confirmed by surface electrocardiogram, echocardiogram, and an invasive electrophysiology study. Atrial function returned within 3 days of initiation of methyl-prednisolone. In cases of atrial standstill due to myocarditis, a delay in the placement of a permanent pacemaker with or without a trial of methylprednisolone may prove beneficial.

Cardiomyopathy and myocarditis in children with ventricular ectopic rhythm.

OBJECTIVE: The objective of this study was to evaluate the histologic features of the myocardium in children with abnormal ventricular ectopic rhythm but a structurally normal heart. BACKGROUND: Abnormal ventricular ectopic rhythm in children with a structurally normal heart is an uncommon but serious condition. Previous studies in adults with these findings have shown that approximately 10% have "primary electrical disease" and that 40% to 100% of these have abnormal histologic findings. METHODS: Endomyocardial biopsy samples were obtained prospectively in 33 subjects presenting with ventricular ectopic rhythm but a structurally normal heart by physical examination and noninvasive studies. Biopsy specimens were evaluated for histologic changes consistent with dilated cardiomyopathy or myocarditis and these results were compared with noninvasive and invasive clinical findings. RESULTS: Of the 33 subjects, 16 (48%) had normal myocardial histologic features (Group A), 14 (42%) had changes similar to the histologic features seen with idiopathic dilated cardiomyopathy (Group B) and 3 (9%) had lymphocytic myocarditis (Group C). Presenting clinical symptoms, surface electrocardiograms (ECGs), exercise stress testing and electrophysiologic stimulation tests failed to predict the biopsy results. Twenty-four-hour ambulatory ECGs showed a statistical difference between sustained and nonsustained ventricular tachycardia in Group A versus Group B (p less than 0.007), with Group A having more sustained ventricular tachycardia. Left ventricular function measured by fractional shortening on echocardiography did not differ between groups, but left ventricular end-diastolic dimension was greater in the subjects with abnormal histologic findings (Group B) (p less than 0.03). CONCLUSIONS: These results provide evidence that approximately 50% of children with abnormal ventricular ectopic rhythm but a structurally normal heart may have subclinical cardiomyopathy or unsuspected myocarditis.

Myocardial necrosis in a newborn after long-term maternal subcutaneous terbutaline infusion for suppression of preterm labor.

We report a case of myocardial necrosis in a newborn after treatment of the mother with long-term subcutaneous terbutaline. No such serious side effects in the fetus have previously been reported. We speculate that this myocardial damage was due to beta-sympathomimetic therapy.