Feasibility study of a novel approach to sore prevention in patients with spinal cord lesions: the computerized dynamic control Matrix 200 system

Objective: To evaluate the feasibility of a computerized mattress system based on a novel concept in sore prevention: continuous monitoring and adjustment of the interface pressure in small segments of contact between the skin and the supporting surface.

Design: A preliminary observational study.

Setting: The Spinal Department, Loewenstein Rehabilitation Hospital, Raanana, Israel.

Subjects: Twelve patients with spinal cord lesions.

Interventions: Patients were examined for signs of impending sores after lying on the mattress for up to 4 successive hours. The pressure within each of the mattress's air cells was continuously measured and adjusted.

Results: No evidence of redness or excessive perspiration was found in any of the areas considered to be high risk for bed sores. Maximal interface pressure was 22-30 mmHg in most of the examinations. Most of the patients felt comfortable on the mattress and the staff adapted easily to its operation.

Conclusions: The system is apparently safe, and at least as efficient as other existing means for preventing sores. In addition, it may allow for increased intervals between bed positionings. We conclude that this approach of pressure control has the potential to improve bed sore prevention in a rehabilitation hospital setting.

Safety and efficacy of carvedilol therapy for patients with dilated cardiomyopathy secondary to muscular dystrophy

BACKGROUND

By the age of 20 years, almost all patients with Duchenne's or Becker's muscular dystrophy have experienced dilated cardiomyopathy (DCM), a condition that contributes significantly to their morbidity and mortality. Although studies have shown carvedilol to be an effective therapy for patients with other forms of DCM, few data exist concerning its safety and efficacy for patients with muscular dystrophy. This study aimed to evaluate the safety and efficacy of carvedilol for patients with DCM.

METHODS

A clinical trial at an outpatient clinic investigated 22 muscular dystrophy patients, ages 14 to 46 years, with DCM and left ventricular ejection fraction (LVEF) less than 50%. Carvedilol up-titrated over 8 weeks then was administered at the maximum or highest tolerated dose for 6 months. Baseline and posttreatment cardiac magnetic resonance imaging (CMR), echocardiography, and Holter monitoring were recorded.

RESULTS

Carvedilol therapy was associated with a modest but statistically significant improvement in CMR-derived ejection fraction (41% +/- 8.3% to 43% +/- 8%; p < 0.02). Carvedilol also was associated with significant improvements in both the mean rate of pressure rise (dP/dt) during isovolumetric contraction (804 +/- 216 to 951 +/- 282 mmHg/s; p < 0.05) and the myocardial performance index (0.55 +/- 0.18 to 0.42 +/- 0.15; p < 0.01). A trend toward improved shortening fraction, E/E' ratio, and isovolumetric relaxation time also was observed. Two patients had runs of nonsustained ventricular tachycardia exceeding 140 beats per minute (bpm) before carvedilol administration. Ventricular tachycardia exceeding 140 bpm was not observed after carvedilol therapy. Carvedilol was well tolerated, and no serious adverse events were identified.

CONCLUSIONS

Carvedilol therapy appears to be safe for patients with DCM secondary to muscular dystrophy and produces a modest improvement in systolic and diastolic function.

Ventricular size and function assessed by cardiac MRI predict major adverse clinical outcomes late after tetralogy of Fallot repair

BACKGROUND

Factors associated with impaired clinical status in a cross-sectional study of patients with repaired tetralogy of Fallot (TOF) have been reported previously.

OBJECTIVES

To determine independent predictors of major adverse clinical outcomes late after TOF repair in the same cohort during follow-up evaluated by cardiac magnetic resonance (CMR).

METHODS

Clinical status at latest follow-up was ascertained in 88 patients (median time from TOF repair to baseline evaluation 20.7 years; median follow-up from baseline evaluation to most recent follow-up 4.2 years). Major adverse outcomes included (a) death; (b) sustained ventricular tachycardia; and (c) increase in NYHA class to grade III or IV.

RESULTS

22 major adverse outcomes occurred in 18 patients (20.5%): death in 4, sustained ventricular tachycardia in 8, and increase in NYHA class in 10. Multivariate analysis identified right ventricular (RV) end-diastolic volume Z >or=7 (odds ratio (OR) = 4.55, 95% confidence interval (CI) 1.10 to 18.8, p = 0.037) and left ventricular (LV) ejection fraction <55% (OR = 8.05, 95% CI 2.14 to 30.2, p = 0.002) as independent predictors of outcome with an area under the receiver operator characteristic curve of 0.850. LV ejection fraction could be replaced by RV ejection fraction <45% in the multivariate model. QRS duration >or=180 ms also predicted major adverse events but correlated with RV size.

CONCLUSIONS

In this cohort, severe RV dilatation and either LV or RV dysfunction assessed by CMR predicted major adverse clinical events. This information may guide risk stratification and therapeutic interventions.

Aortic stenosis: the spectrum of practice

There is significant variation in practice patterns in managing congenital aortic valve stenosis. Review of medical literature reveals no significant information regarding the current practice methods in the treatment of a simple lesion such as aortic stenosis (AS). Therefore, this survey-based study was conducted in an attempt to better understand the uniformity or heterogeneity of practice in treating AS. A questionnaire was prepared to evaluate the style of management of AS. This survey was designed to assess the practice of follow-up visitations, type and frequency of investigative studies, pharmacological therapy, and exercise recommendations. Questions about therapeutic intervention included those of timing and type of intervention. Questionnaires were sent to all academic pediatric cardiology programs in the United States (48 program) and selected international programs from Europe, Asia, and Australasia (19 program). The total number of surveys sent out was 67, and the total number of respondents was 25 (37%), 15 (31%) from the United States and 9 (53%) from outside the United States. The definition of moderate AS varied among respondents. The range provided for mild AS was identified as that with a peak-to-peak pressure gradient of < 25-30 mmHg, peak instantaneous Doppler gradient of < 36-50 mmHg, or mean Doppler gradient of < 25-40 mmHg. On the other hand, severe AS was defined as that with a peak-to-peak gradient of > 50-60 mmHg, peak instantaneous Doppler gradient of > 64-80 mmHg, or mean Doppler gradient of > 45-64 mmHg. In assessing follow-up patterns, 84% of respondents recommended seeing patients with mild AS annually, the longest time of follow-up listed in the questionnaire, whereas 20% suggested follow-up every 6 months. There was no consensus among survey centers regarding follow-up of patients with moderate AS. For severe AS, 16% recommend immediate intervention, 16% arrange follow-up every 6 months, and 56 and 28% recommend follow-up in 3 and 1 month(s), respectively. In making the decision to proceed with biventricular versus univentricular repair in patients with AS in the neonatal period, many factors were considered. Ninety-two percent of respondents rely on mitral valve z score, 84% on aortic valve z score, 52% on left ventricle length, 48% on the presence of antegrade ascending aorta flow, and only 32% considered significant endocardial fibroelastosis as a factor. Rhodes score was used by 20% of respondents in decision making regarding the approach to management of this subset of AS. This study shows that there is consensus in the management of mild and severe forms of AS. As expected, disagreement is present in the definition, evaluation, and therapy of moderate aortic valve stenosis. There is a tendency for catheter intervention except in the presence of dysplastic aortic valve or moderate to severe aortic regurgitation. There is also disagreement regarding methods used to determine biventricular versus univentricular repair of a borderline hypoplastic left heart.

Vascular tumors of the heart in infants and children: case series and review of the literature

Primary tumors of the heart are rare in children, of which vascular tumors comprise a small subgroup. We present the clinical, histopathologic, and imaging findings in six children with vascular tumors of the heart and review the findings of 36 previously published cases. We observed three intramuscular hemangiomas of the small-vessel type in older children, two congenital hemangiomas in infants, and one malignant polymorphous hemangioendothelioma. Intramuscular hemangiomas did not respond to corticosteroid and were biologically distinct from the congenital hemangiomas, both of which exhibited regression with pharmacotherapy. Age at diagnosis appears to predict histologic type, tumor location, and clinical presentation.

[Predictive factors of Doppler echocardiography in persistent pulmonary artery hypertension of the neonate]

INTRODUCTION

echocardiographic evaluation in neonates with persistent pulmonary artery hypertension is often limited to pressure measurements and analysis of pulmonary artery blood flow. The prognostic significance of a more detailed analysis, in particular of the extra-pulmonary shunt, is not known.

PATIENTS AND METHOD

we analysed retrospectively the echocardiographs of neonates with persistent pulmonary artery hypertension who were also entered in a randomised therapeutic trial of treatment with inhaled nitric oxide. Our aim was to identify the predictive echographic factors for extra-corporeal circulatory assistance, death and a good response to nitric oxide.

RESULTS

out of the 85 neonates studied, an extra-pulmonary right-left shunt across the foramen ovale or the ductus arteriosus was present in 80 patients (94%). Biventricular function was normal in the majority of patients while the cardiac index was reduced (< 2L/min/m2) in 61% of cases. With multivariate analysis, an exclusively right-left ductal shunt was a predictive factor for death (odds ratio 7.8; 95% confidence interval 1.2 to 52.8; p=0.04) while an exclusively left-right ductal shunt was at the limit of significance for circulatory assistance (odds ratio 0.13; 95% confidence interval 0.01 to 1.22; p=0.07). In the 40 patients randomised to receive nitric oxide, 28 responded positively with a reduction of at least 20% in the oxygenation index measured by post-ductal arterial gasometry. The existence of a left-right atrial shunt increased the risk of a poor response to nitric oxide (odds ratio 7.46; 95% confidence interval 1.23 to 45.1; p=0.028).

CONCLUSION

precise echocardiographic evaluation of these patients allows identification of prognostic factors and adjustment of vasodilator treatment.

Biatrial or left atrial drainage of the right superior vena cava: anatomic, morphogenetic, and surgical considerations--report of three new cases and literature review

Since the posterior wall of the right superior vena cava (RSVC) is contiguous with the anterior wall of the right upper pulmonary veins, a localized defect in this common wall may create a cavopulmonary venous confluence without eliminating the normal connection of the same right pulmonary veins with the left atrium (LA). Through this defect, blood of the unroofed right pulmonary veins will drain into the RSVC and right atrium (RA), and blood from the RSVC may shunt into the right pulmonary veins and LA. Hemodynamically, the RSVC will become biatrial. If the RSVC blood flows preferentially into the LA, its right atrial orifice will become stenotic or even atretic. If atretic, the normally positioned RSVC will drain entirely into the LA. In this report, we present the clinical and anatomical findings of two postmortem cases with biatrial drainage of the RSVC. We also document the clinical, echocardiographic, angiocardiographic, and surgical data of a living patient with left atrial drainage of the RSVC and tetralogy of Fallot with pulmonary atresia. The relevant literature and surgical treatment are reviewed, and the morphogenesis of the biatrial and left atrial RSVC is considered.

Use of tissue velocity imaging in the diagnosis of fetal cardiac arrhythmias

BACKGROUND

Precise diagnosis of cardiac arrhythmias in the fetus is crucial for a managed therapeutic approach. However, many technical, positional, and gestational age-related limitations may render conventional methods, such as M-mode and Doppler flow methodologies, or newer techniques, such as fetal electrocardiography or magnetocardiography, difficult to apply, or these techniques may be unsuitable for the diagnosis of fetal arrhythmias.

METHODS AND RESULTS

In this prospective study, we describe a novel method based on raw scan-line tissue velocity data acquisition and analysis. The raw data are available from high-frame-rate 2D tissue velocity images and allow simultaneous sampling of right and left atrial and ventricular wall velocities to yield precise temporal analysis of atrial and ventricular events. Using this timing data, a ladder diagram-like "fetal kinetocardiogram" was developed to diagram and diagnose arrhythmias and to provide true intervals. This technique was feasible and fast, yielding diagnostic results in all 31 fetuses from 18 to 38 weeks of gestation. Analysis of various supraventricular and ventricular arrhythmias was readily obtained, including arrhythmias that conventional methods fail to diagnose.

CONCLUSIONS

The fetal kinetocardiogram opens a new window to aid in the diagnosis and understanding of fetal arrhythmias, and it provides a tool for studying the action of antiarrhythmic drugs and their effects on electrophysiological conduction in the fetal heart.

Echocardiographic characteristics and outcome of straddling mitral valve

OBJECTIVES

This study sought to characterize the echocardiographic features of straddling mitral valve (SMV) and to determine its surgical implications and midterm outcome in a large clinical cohort.

BACKGROUND

Despite a relatively large body of literature on the postmortem anatomy of SMV, there is a paucity of information regarding its echocardiographic features, surgical implications and preoperative predictors of outcome.

METHODS

A retrospective review identified 46 patients with SMV between 1982 and 1999 who underwent echocardiography and surgery and had follow-up data. A detailed review of the echocardiograms, surgical reports and all pertinent records was undertaken.

RESULTS

Review of the echocardiograms revealed a widely varying anatomy among the study patients. However, four distinct groups with relatively uniform morphologic features could be distinguished on the basis of segmental analysis. Cardiac malposition associated with right ventricular hypoplasia, superior-inferior ventricles and criss-cross atrioventricular relations were common among patients with [S,D,L] (S = visceroatrial situs solitus, D = D-ventricular loop, L = L-malposition of the great arteries) (n = 6) and [S,L,D] (n = 5) segmental combinations but were rare among patients with [S,D,D] (n = 26) and [S,L,L] (n = 9) combinations. Surgical management consisted of a functional single-ventricle palliation in 38 patients (83%) and biventricular repair in 8 patients (17%). Overall mortality was 22%, but none of the seven patients who were operated on during the cohort's last five years (1994 to 1999) has died. By multivariate analysis, noncommitted ventricular septal defect was the strongest independent predictor of death (relative risk = 10.2), followed by multiple ventricular septal defects (relative risk = 4.7).

CONCLUSIONS

This study demonstrates that echocardiography provides detailed noninvasive imaging of the complex anatomic features of SMV and its associated anomalies. Anatomic classification based on segmental analysis allows the distinction of four groups with more uniform morphologic features. Although a biventricular approach is feasible in selected patients, a functional univentricular palliation is indicated in those with major straddling and markedly hypoplastic ventricles.

Predictors of outcome of biventricular repair in infants with multiple left heart obstructive lesions

BACKGROUND

Decisions regarding surgical strategy in patients with multiple left heart obstructive or hypoplastic lesions often must be made in the newborn period and are seldom reversible. Predictors of outcome of biventricular repair have not been well defined in this heterogeneous group of patients, and risk factors described for critical aortic valve stenosis have been shown to be inapplicable to patients with other left heart obstructive lesions. The goal of this study was to identify echocardiographic predictors of outcome of biventricular repair for infants with multiple left heart obstructive lesions.

METHODS AND RESULTS

Patients with >/=2 areas of left heart obstruction or hypoplasia, diagnosed at </=3 months of age, who had not previously undergone surgical or catheter intervention and maintained biventricular physiology were included (n=72). Failure of biventricular repair was defined as takedown to a univentricular repair, cardiac transplantation, and/or death (n=14; 19%). This group was compared with the patients who survived a biventricular approach (n=58). Multiple categorical, morphometric and calculated variables were examined on the basis of the initial echocardiograms. By multivariate analysis, predictors of failure included moderate/large ventricular septal defect (OR=22, P=0.001), unicommissural aortic valve (OR=16, P=0.006), and lower mitral valve dimension z-score (OR=2.2, P=0.02) or lower left ventricular end-diastolic volume z-score (OR=1.9, P=0.03).

CONCLUSIONS

Moderate/large ventricular septal defect, unicommissural aortic valve, and hypoplastic mitral valve or left ventricle are independent risk factors for failure of biventricular repair for infants with multiple left heart obstructive lesions. Combinations of these risk factors may be useful in selecting surgical strategy.

Coronary echocardiography in tetralogy of fallot: diagnostic accuracy, resource utilization and surgical implications over 13 years

OBJECTIVES

This study sought to determine the diagnostic accuracy and impact of the systematic use of coronary echocardiography in a large group of preoperative patients with tetralogy of Fallot (TOF).

BACKGROUND

Accurate preoperative identification of an anomalous coronary artery crossing the right ventricular outflow tract (RVOT) in patients with TOF is important to prevent coronary injury during surgical repair.

METHODS

A retrospective review identified 598 patients with TOF between 1983 to 1995 who underwent an echocardiogram at <2 years old before complete surgical repair. Associated diagnoses included pulmonary stenosis (n = 433), pulmonary atresia (n = 121), common atrioventricular canal (n = 17), absent pulmonary valve syndrome (n = 24) and aortopulmonary window (n = 3).

RESULTS

Based on intraoperative findings, 32 patients (5.4%) were found to have a major coronary artery crossing the RVOT. The use and diagnostic performance of coronary echocardiography increased over time, while the number of patients undergoing preoperative cardiac catheterization declined. During the most recent study period (1991 to 1995, n = 274), 97% of patients underwent coronary echocardiography yielding a sensitivity of 82%, specificity of 99% and accuracy of 98.5%. Of the 18 patients with TOF and pulmonary stenosis who had abnormal coronary arteries during this period, only 6 (33%) required an extracardiac conduit as part of their complete repair.

CONCLUSIONS

Coronary echocardiography is an accurate noninvasive tool to delineate coronary anatomy in infants with TOF before complete repair. Routine preoperative cardiac catheterization solely for diagnosis of coronary anatomy is not necessary. The use of an extracardiac conduit can be avoided in the majority of patients with TOF and pulmonary stenosis who have a major coronary artery crossing the RVOT.

3D-shaded surface rendering of gadolinium-enhanced MR angiography in congenital heart disease

BACKGROUND

Gadolinium-enhanced three-dimensional (3D) MR angiography is a useful imaging technique for patients with congenital heart disease.

OBJECTIVE

This study sought to determine the added value of creating 3D shaded surface displays compared to standard maximal intensity projection (MIP) and multiplanar reformatting (MPR) techniques when analyzing 3D MR angiography data.

MATERIALS AND METHODS

Seventeen patients (range, 3 months to 51 years old) with a variety of congenital cardiovascular defects underwent gadolinium-enhanced 3D MR angiography of the thorax. Color-coded 3D shaded surface models were rendered from the image data using manual segmentation and computer-based algorithms. Models could be rotated, translocated, or zoomed interactively by the viewer. Information available from the 3D models was compared to analysis based on viewing standard MIP/ MPR displays.

RESULTS

Median postprocessing time for the 3D models was 6 h (range, 3-25 h) compared to approximately 20 min for MIP/MPR viewing. No additional diagnostic information was gained from 3D model analysis. All major findings with MIP/MPR postprocessing were also apparent on the 3D models. Qualitatively, the 3D models were more easily interpreted and enabled adjacent vessels to be distinguished more readily.

CONCLUSION

Routine use of 3D shaded surface reconstructions for visualization of contrast enhanced MR angiography in congenital heart disease cannot be recommended. 3D surface rendering may be more useful for presenting complex anatomy to an audience unfamiliar with congenital heart disease and as an educational tool.

Minimal access approach for the repair of atrial septal defect: the initial 135 patients

BACKGROUND

From May 1996 to August 1998 a minimal access approach was used for 135 of 200 consecutive surgical atrial septal defects closures in children through young adults ranging in age from 6 months to 25 years (median 5 years).

METHODS

A 3.5- to 5-cm midline incision was centered over the xiphoid with division of the xiphoid alone (transxiphoid) or of the lower sternum (ministernotomy); both groups underwent bicaval venous cannulation through the incision. Cardioplegia and aortic cross-clamping were administered through the incision. Cephalad retraction of the sternum with a fixed-arm retractor aided exposure.

RESULTS

There have been no early or late deaths and no bleeding or wound complications. No procedure required conversion to a full sternotomy, and no cannulation attempt was abandoned for an alternate site. Cross-clamp and cardiopulmonary bypass times were equivalent to those in the full sternotomy group. The mean length of hospital stay in the ministernotomy group was 2.7 days.

CONCLUSIONS

The closure of atrial septal defects can be performed through a transxiphoid or ministernotomy approach, conferring a satisfactory cosmetic result without compromising the safety or accuracy of the repair.

Isolated ductus arteriosus aneurysm in the fetus and infant: a multi-institutional experience

OBJECTIVES

The purpose of this study was to describe the clinical characteristics and outcome and to elucidate the pathogenesis of ductus arteriosus aneurysm (DAA).

BACKGROUND

Ductus arteriosus aneurysm is a rare lesion that can be associated with severe complications including thromboembolism, rupture and death.

METHOD

We reviewed the clinical records, diagnostic imaging studies and available histology of 24 cases of DAA, diagnosed postnatally (PD) in 15 and antenatally (AD) in 9 encountered in five institutions.

RESULTS

Of PD cases, 13 presented at <2 months, and all AD cases were detected incidentally after 33 weeks of gestation during a late trimester fetal ultrasound study. Of the 24, only 4 had DAA-related symptoms and 6 had associated syndromes: Marfan, Smith-Lemli-Opitz, trisomies 21 and 13 and one possible Ehlers-Danlos. Three had complications related to the DAA: thrombus extension into the pulmonary artery, spontaneous rupture, and asymptomatic cerebral infarction. Six underwent uncomplicated DAA resection for ductal patency, DAA size or extension of thrombus. In the four examined, there was histologic evidence of reduced intimal cushions in two and abnormal elastin expression in two. Five of the 24 died, with only one death due to DAA. Of 19 survivors, all but one remain clinically asymptomatic at a median follow-up of 35 months; however, two have developed other cardiac lesions that suggest Marfan syndrome. A review of 200 consecutive third trimester fetal ultrasounds suggests an incidence of DAA of 1.5%.

CONCLUSIONS

Ductus arteriosus aneurysm likely develops in the third trimester perhaps due to abnormal intimal cushion formation or elastin expression. Although it can be associated with syndromes and severe complications, many affected infants have a benign course. Given the potential for development of other cardiac lesions associated with connective tissue disease, follow-up is warranted.

Echocardiographic predictors of coronary artery pathology in pulmonary atresia with intact ventricular septum

Coronary artery pathology is a major determinant of treatment strategy and outcome in patients with pulmonary atresia and intact ventricular septum (PA/IVS). For this reason, infants with PA/IVS routinely undergo preoperative cardiac catheterization. The goal of this study was to identify echocardiographic predictors of coronary artery pathology in infants with PA/IVS. The initial preoperative echocardiograms of 30 consecutive infants with PA/IVS (median age at diagnosis 1 day) were reviewed for indexes predicting the degree of coronary pathology. The tricuspid valve (TV) annulus diameter Z- score was determined and evidence of abnormal flow in the coronary arteries by Doppler was evaluated. Coronary pathology was defined by angiography and graded as: 0 = no fistulae; 1 = fistulae/no right ventricular (RV)-dependent coronary arteries; 2 = fistulae with 1 RV-dependent coronary; 3 = fistulae with >/=2- vessel RV-dependent coronary arteries. Outcome was classified as: 2 ventricles, "1.5" ventricles, and 1 ventricle. By angiography, 30% of the patients had grade 0 coronary pathology, 30% had grade 1, 20% had grade 2, and 20% had grade 3. There was 1 death in a patient with grade 3 coronary pathology. Among the survivors (median age at follow-up 28. 6 months), biventricular circulation existed in 12 patients (41%), 7 patients (24%) were 1.5, and 10 (34%) were 1 ventricle. All patients with TV Z-score </=-2 had coronary fistulae by angiography and 35% had grade 3 coronary pathology. None of the patients with grade 2 or 3 coronary artery pathology had a TV Z-score >-2.5. The sensitivity, specificity, positive, and negative predictive values of TV Z-score </=-2.5 in predicting RV dependent coronary arteries were 100%, 83%, 80%, and 100%, respectively. Thus, in newborns with PA/IVS the echocardiographically derived TV Z-score predicts the likelihood of coronary artery fistulae and RV-dependent coronary arteries and can be used to rationalize the need for preoperative diagnostic catheterization.

Accuracy of MRI evaluation of pulmonary blood supply in patients with complex pulmonary stenosis or atresia

Detailed imaging of pulmonary artery (PA) anatomy and significant aorto-pulmonary collaterals (APCs) is crucial for surgical planning and follow-up in patients with complex congenital heart disease (CHD) and pulmonary stenosis or atresia. Because examination by echocardiography is often technically limited and catheterization is invasive, this study evaluated the diagnostic accuracy of magnetic resonance imaging (MRI) as an alternate non-invasive tool. Thirteen patients (median age 28 years, range: 1-44 years) underwent both cardiac catheterization and MRI within a median of two months (range 0.1-8 months). Diagnoses included tetralogy of Fallot (TOF) with pulmonary atresia (n = 8), TOF with pulmonary stenosis (n = 2), single left ventricle with pulmonary stenosis (n = 2), and complex heterotaxy with pulmonary stenosis (n = 1). The MRI sequences used in this study were ECG-gated spin echo and gradient echo sequences acquired in multiple planes. Compared to catheterization, MRI had 100% sensitivity and specificity for the diagnosis of main PA (n = 6) and branch PA (n = 13) hypoplasia or stenosis, as well as discontinuous (n = 4) or absent (n = 10) branch PAs. There was complete agreement between catheterization and MRI identification of significant APCs (n = 18). Main PA atresia was noted by MRI in four patients but was not definitively seen by catheterization in any. MRI but not catheterization precisely defined the distance between discontinuous PAs and their relationship to other mediastinal structures. In conclusion, cardiac MRI is a reliable non-invasive imaging modality to define PA and APC anatomy in patients with complex pulmonary stenosis or atresia.

Phase-velocity cine magnetic resonance imaging measurement of pulsatile blood flow in children and young adults: in vitro and in vivo validation

Quantification of blood flow in vessels provides valuable information that aids management decisions in a variety of cardiac conditions. Current flow measurement techniques are often limited by accuracy, time resolution, convenience, or anatomic localization. This study examined the accuracy of a commercially available phase-velocity cine magnetic resonance imaging (PVC MRI) technique to quantify flow rate in a pulsatile flow phantom. In addition, the equivalence of PVC MRI measurements of pulmonary and systemic flow was evaluated in children and adults without any pathologic shunt. Using a pulsatile flow phantom, volume flow rates measured by PVC MRI were compared to those by a transit-time ultrasound flowmeter over a range of flow rates (1.25-3.5 L/min, 13 trials). Close agreement was found between these techniques (y = 1.02x - 0.02, r = 0.99, Bland-Altman bias = -0.045 L/min, 95% limits of agreement = -0. 19-0.10 L/min). Twenty subjects (median age 12.8 years, range 0.7-49 years) with no pathologic shunt underwent PVC MRI measurement of blood flow in the main pulmonary artery (Q(p)) and the ascending aorta (Q(s)). Data processing time for each location was 20 minutes. The Q(p)/Q(s) ratio closely approximated unity (mean = 0.99, SD = 0. 10, range 0.85-1.19). Interobserver agreement was excellent (Bland-Altman bias = 0.09 L/min, 95% limits of agreement = 0.15-0.33 L/min). PVC MRI is an accurate technique to quantify pulsatile blood flow at a specific location. It can be used to noninvasively calculate Q(p) and Q(s) under normal flow conditions.

Blood flow measurement by magnetic resonance imaging in congenital heart disease

Investigation of blood flow in the heart and vessels may provide insight into the function of the cardiovascular system and aid patient management decisions. Phase velocity cine magnetic resonance imaging (PVC MRI) is a powerful and accurate noninvasive technique to quantitate and analyze blood flow. This article describes the principles, performance, and potential limitations of PVC MRI measurements. Clinical applications of PVC MRI are then reviewed with an emphasis on the assessment of congenital heart disease.

Evolution of risk factors influencing early mortality of the arterial switch operation

OBJECTIVES

The present study was undertaken to determine the independent risk factors for early mortality in the current era after arterial switch operation (ASO).

BACKGROUND

Prior reports on factors affecting outcome of the ASO demonstrated that abnormal coronary arterial patterns were associated with increased risk of early mortality. As diagnostic, surgical and perioperative management techniques continue to evolve, the risk factors for the ASO may have changed.

METHODS

All patients who underwent the ASO at Children's Hospital, Boston between January 1, 1992 and December 31, 1996 were included. Hospital charts, echocardiographic and cardiac catheterization data and operative reports of all patients were reviewed. Demographics and preoperative, intraoperative and postoperative variables were recorded.

RESULTS

Of the 223 patients included in the study (median age at ASO = 6 days and median weight = 3.5 kg), 26 patients had aortic arch obstruction or interruption, 12 had Taussig-Bing anomaly, 12 had multiple ventricular septal defects, 8 had right ventricular hypoplasia and 6 were premature. There were 16 early deaths (7%), with 3 deaths in the 109 patients considered "low risk" (2.7%). Coronary artery pattern was not associated with an increased risk of death. Compared with usual coronary anatomy pattern, however, inverted coronary patterns and single right coronary patterns were associated with increased incidence of delayed sternal closure (p = 0.003) and longer duration of mechanical ventilation (p = 0.008). In a multivariate logistic regression model using only preoperative variables, aortic arch repair at a separate procedure before ASO and smaller birth weight were independent predictors of early mortality. In a second model that included both pre- and intraoperative variables, circulatory arrest time and right ventricular hypoplasia were independent predictors of early death.

CONCLUSIONS

The ASO can be performed in the current era without excess early mortality related to uncommon coronary artery patterns. Aortic arch repair before ASO, right ventricular hypoplasia, lower birth weight and longer intraoperative support continue to be independent risk factors for early mortality after the ASO.

Truncus arteriosus with anomalous pulmonary venous connection

The anatomic, diagnostic, and management findings of 6 patients with truncus arteriosus and anomalous pulmonary venous connections are described. Additional risk factors indicative of poor prognosis were found in 3 of 4 patients with truncus arteriosus and totally anomalous pulmonary venous connection and in 1 patient with partially anomalous pulmonary venous connection.

Feasibility study of a novel approach to sore prevention in patients with spinal cord lesions: the computerized dynamic control Matrix 200 system

OBJECTIVE

To evaluate the feasibility of a computerized mattress system based on a novel concept in sore prevention: continuous monitoring and adjustment of the interface pressure in small segments of contact between the skin and the supporting surface.

DESIGN

A preliminary observational study.

SETTING

The Spinal Department, Loewenstein Rehabilitation Hospital, Raanana, Israel.

SUBJECTS

Twelve patients with spinal cord lesions.

INTERVENTIONS

Patients were examined for signs of impending sores after lying on the mattress for up to 4 successive hours. The pressure within each of the mattress's air cells was continuously measured and adjusted.

RESULTS

No evidence of redness or excessive perspiration was found in any of the areas considered to be high risk for bed sores. Maximal interface pressure was 22-30 mm Hg in most of the examinations. Most of the patients felt comfortable on the mattress and the staff adapted easily to its operation.

CONCLUSIONS

The system is apparently safe, and at least as efficient as other existing means for preventing sores. In addition, it may allow for increased intervals between bed positionings. We conclude that this approach of pressure control has the potential to improve bed sore prevention in a rehabilitation hospital setting.

Prognostic significance of clinically silent coronary artery fistulas

Symptomatic coronary artery fistulas (CAF) are associated with significant morbidity and mortality. With the advent of high-resolution 2-dimensional and color Doppler echocardiography, the detection rate of clinically silent CAF has increased, but their clinical significance and outcome have not been defined. The clinical, echocardiographic, electrocardiographic, and angiographic findings and documented follow-up of 31 patients with an echocardiographic finding of a clinically silent coronary artery fistula from 1986 to 1997 were analyzed. Mean age at diagnosis was 7.2+/-8.4 years. Indications for echocardiography were murmur (n = 23), congenital heart disease (n = 2), cardiomegaly (n = 2), chest pain (n = 1), stridor (n = 1), syncope (n = 1), and chest trauma (n = 1). CAF were detected with color Doppler flow mapping in all patients. The origin of the fistula was from the left coronary artery system (n = 27), right coronary artery system (n = 3), and bilateral (n = 1). The exit sites were the pulmonary artery (n = 18), right ventricle (n = 8), right atrium (n = 2), and left ventricle (n = 3). Global and regional left ventricular function were normal in all patients at presentation and follow-up. Spontaneous closure of the fistula was documented in 7 patients (23%) at mean follow-up of 2.6+/-2.0 years. In 23 patients the fistula persisted without intervention. All patients remained asymptomatic, without adverse clinical events or evidence of ischemia at a mean age at follow-up of 9.3+/-9.1 years (range 4 months to 42.0). Based on this experience, there is no evidence that clinically silent CAF diagnosed incidentally by color Doppler echocardiography are associated with adverse clinical outcome in childhood and adolescence. Conservative management with continued follow-up of these patients appears to be appropriate.

In vivo evaluation of Fontan pathway flow dynamics by multidimensional phase-velocity magnetic resonance imaging

BACKGROUND

Hemodynamic efficiency of Fontan circulation is believed to be a major determinant of outcome. Prior research on flow dynamics in different modifications of Fontan circulation used in vitro models and computer-based simulation. This study was designed to compare in vivo flow dynamics in the systemic venous pathway between patients with atriopulmonary anastomosis (APA) and those with total cavopulmonary connection (TCPC).

METHODS AND RESULTS

Multidimensional phase-velocity magnetic resonance imaging (PV-MRI) studies were performed on 10 patients who had undergone a modified Fontan operation (5 with TCPC and 5 with APA) and were free of symptoms. The groups were comparable in terms of age and body surface area. The interval since surgery was longer for APA than for TCPC subjects. In each subject, the phase-velocity data sets were used to generate dynamic velocity-vector maps and to calculate quantitative flow indices describing the 3-dimensional blood-flow patterns throughout the cardiac cycle at the widest diameter of the Fontan pathway. Mean flow rate was comparable between groups. Velocity-vector maps showed areas of flow reversal, flow stagnation, and circular flow within APA but not TCPC pathways. Analysis of quantitative flow indices showed that compared with the APA group, flow velocities in the TCPC patients were significantly higher (mean velocity, 14+/-6 cm/s versus 5+/-3 cm/s; P=0.02), less variable (coefficient of variation, 19+/-2% versus 37+/-3.5%; P<0.0001), and more unidirectional (degree of unidirectionality, 89+/-7% versus 71+/-12%; P=0.03). APA pathways were significantly more dilated than were TCPC pathways (P<0.01) and showed a trend toward larger diameter with increased interval since surgery (R2=0.6, P=0.09). Fontan pathway dilatation correlated with flow velocity variability (R2=0.57, P=0.01) and inversely with flow unidirectionality (R2=0.75, P=0.001).

CONCLUSIONS

Blood flow patterns are more organized and uniform in TCPC than in APA pathways and are significantly influenced by pathway diameter. We speculate that TCPC may result in a more hemodynamically efficient circulation than APA because of differences in pathway dimension and uniformity.

Evaluation of regional differences in right ventricular systolic function by acoustic quantification echocardiography and cine magnetic resonance imaging

BACKGROUND

Accurate quantitative evaluation of right ventricular (RV) function has been limited by its complex structural geometry. Although embryological and anatomic observations suggest that the RV is composed of 2 distinct components, the RV sinus and infundibulum, most studies on RV dimensions and function viewed it as a single chamber. This study was designed to determine the volumes, relative contribution to global systolic function, and temporal course of contraction and relaxation of the RV sinus and infundibulum.

METHODS AND RESULTS

Thirty-one individuals without heart disease (aged 1 month to 17 years, 16 boys and 15 girls) participated in this study. Instantaneous area over time, its derivatives, and the temporal course of contraction and relaxation were studied by acoustic quantification echocardiography and phonocardiography in 20 individuals. Global and regional RV volumes and ejection fraction were determined by cine MRI in 11 individuals. The RV sinus made up 81+/-6% of the combined RV end-diastolic volume and 87+/-4% of the combined stroke volume. The infundibulum accounted for the remaining 19+/-6% and 13+/-4%, respectively (P<0.0001). Compared with the infundibulum, the extent of RV sinus fiber shortening was significantly greater: for ejection fraction (56+/-11% versus 38+/-13%, P<0.001), fractional area change (42+/-14% versus 28+/-9%, P<0.0001), and dA/dt (27+/-17% versus 13+/-6%, P<0.0001). Analysis of temporal course of contraction and relaxation (expressed as percentage of the cardiac cycle to adjust for differences in heart rate) showed that the infundibulum follows the RV sinus: onset of contraction 53%+/-14 versus 19+/-11% of systole, time to peak systole 115+/-16% versus 97+/-19% (P< or =0.01), indicating a peristalsis-like pattern of contraction and relaxation.

CONCLUSIONS

The results of this study demonstrate significant regional differences between the sinus and infundibulum components of the RV with regard to contribution to stroke volume, extent of fiber shortening, and sequence of mechanical activation. These data from normal individuals can be used in future research on RV function in pathological conditions.

MRI and echocardiography in children: how do they compare?

Clearly, both echocardiography and MRI play vital roles in the diagnosis and management of children with congenital heart defects. 2-D Doppler echocardiography is very easy to use in a vast array of clinical situations. The accuracy of the anatomic and hemodynamic findings are well accepted. In comparative studies, 2-D Doppler echocardiography appears preferable for intracardiac anatomy, whereas MRI appears preferable for extracardiac anatomy. In certain patients, Doppler echocardiography may not be able to optimally obtain the anatomic or hemodynamic information, and MRI should be used in these particular cases.

Development and validation of an echocardiographic model for predicting progression of discrete subaortic stenosis in children

The clinical course of discrete subaortic stenosis (DSS) varies considerably between patients. This study was performed to identify echocardiographic characteristics of DSS that distinguish progressive from nonprogressive disease. The study included 100 patients from 2 institutions and was performed in 2 stages. In phase I, a prediction model was developed based on multivariate analysis of morphometric and Doppler variables obtained from the initial echocardiogram in 52 children with DSS from Texas Children's Hospital. In phase II, the performance characteristics of the prediction model were tested in 48 patients with DSS followed at Children's Hospital in Boston. Patients were divided into 3 outcome groups: nonprogressive, progressive, and intermediate progression. In phase I, multivariate analysis identified 3 independent predictors of progressive disease: indexed aortic valve to subaortic membrane distance, anterior mitral leaflet involvement, and initial Doppler gradient. The logistic regression equation--Probability = [1 + e-(-322+0.334X1+4.06X2-0.708X3)](-1), where X = initial gradient in mm Hg; X2 = absence (0) or presence (1) of mitral leaflet involvement; and X3 = indexed distance between aortic valve and subaortic membrane in mm/body surface area0.5 were used to predict progression. When the prediction model was applied to phase II study patients, none of the patients with nonprogressive DSS had a prediction value > 0.29 and none of the patients with progressive DSS had a prediction value < 0.58. Thus, a prediction value > 0.55 yielded a 100% sensitivity and 100% specificity for distinguishing progressive from nonprogressive DSS. Patients with intermediate progression were indistinguishable from progressive DSS but were clearly separable from nonprogressing patients. We conclude that progressive subaortic obstruction in children with DSS can be predicted from morphologic, morphometric, and Doppler echocardiographic analysis of left ventricular outflow.

Accuracy of echocardiography for detection of aortic arch obstruction after stage I Norwood procedure

BACKGROUND

Echocardiography has been widely used in postoperative assessment after stage I Norwood procedure, but its accuracy in detecting aortic arch obstruction (AAO) has not been determined. This study was designed to determine the accuracy of echocardiography in the diagnosis of AAO after stage I Norwood procedure, identify echocardiographic predictors of arch obstruction, and examine the time course of its development.

METHODS

The records and echocardiography reports of 139 patients who survived stage I Norwood procedure were reviewed. Reference standard for the diagnosis of AAO was catheterization, surgery, or autopsy.

RESULTS

AAO was diagnosed by reference standard criteria in 31 (22%) patients. Echocardiography correctly diagnosed AAO in 19 patients, missed the diagnosis in five, and wrongly predicted AAO in eight, yielding a 73% sensitivity, 92% specificity, 70% positive predictive value, and 88% accuracy. Moderate or severe right ventricular dysfunction, moderate or severe tricuspid regurgitation, and an abnormal abdominal aortic Doppler flow pattern were more common in patients with AAO. The probability of AAO developing within 6 months after stage I Norwood procedure was 21.1%, with a very small likelihood after that point. Beyond the first 30 days after surgery, the risk of death was higher in patients in whom AAO developed compared with those in whom it did not (relative risk 5.9, 95% confidence interval 2.7 to 13.2).

CONCLUSIONS

Echocardiography is a highly specific modality in detecting AAO after stage I Norwood procedure but its sensitivity is limited. Because of the increased risk of death associated with AAO and because most obstructions develop between 1 and 6 months postoperatively, early cardiac catheterization with possible intervention should be considered in patients with moderate or severe right ventricular dysfunction, moderate or sever tricuspid regurgitation, or an abnormal abdominal Doppler flow pattern during that period.

Moyamoya syndrome associated with congenital heart disease

OBJECTIVE

To describe the association between moyamoya syndrome and congenital heart disease and to discuss its clinical implications. Study Design. Retrospective analysis of a case series from two institutions.

RESULTS

Five patients with moyamoya syndrome and structural congenital heart disease were identified. Coarctation of the aorta was present in 3 patients, in association with a ventricular septal defect (1 patient), aortic and mitral valve stenoses (1 patient), and tetralogy of Fallot (1 patient). Tetralogy of Fallot and a large paramembranous ventricular septal defect were found in the other 2 patients. Four patients underwent surgical repair of their congenital heart disease during the first year of life and 1 patient had balloon dilation of aortic coarctation at 5 years of age. In all patients, moyamoya syndrome was diagnosed after surgical intervention for congenital heart disease-at 6 months of age in 1 patient, at 2 years of age in 3 patients, and at 6 years in 1 patient. Strokes were the most common presenting sign (3 patients) followed by seizures (2 patients). By the age of 33 months, 4 of 5 patients had undergone cerebral revascularization surgery to halt the clinical progression of moyamoya syndrome.

CONCLUSIONS

Moyamoya syndrome should be considered in the differential diagnosis of seizures and stroke in patients with structural congenital heart disease. Prompt diagnosis and surgical management of the occlusive cerebral angiopathy should lead to improved neurological outcome in these patients.

Left ventricular mechanics and geometry in patients with congenital complete atrioventricular block

BACKGROUND

Radiographic evidence of cardiomegaly is common in patients with congenital complete atrioventricular block (CCAVB). It has been speculated that left ventricular (LV) remodeling and increased stroke volume counteract the bradycardia, but the effects of slow heart rate and atrioventricular asynchrony on LV dimensions, geometry, wall stress, and function have not been examined in detail.

METHODS AND RESULTS

Thirty patients with CCAVB without associated congenital heart disease (mean age, 8.5+/-5.3 years; range, 0.2 to 20 years) were included in a cross-sectional two-institution study. Thirty-five echocardiograms were performed using standard techniques. ECG and 24-hour ECG recordings were reviewed. Seven patients did not receive a pacemaker, whereas 23 patients underwent pacemaker implantation after the echocardiogram. Compared with normal control subjects, LV volume (Z score=1.5+/-1.3) and LV mass (Z=1.2+/-1.5) were significantly increased, whereas LV mass-to-volume ratio (1.1+/-0.3) and geometry (short-axis diameter/length ratio=0.65+/-0.09) were normal. LV end-systolic stress (ESS) (a measure of afterload) was normal (Z score=0.2+/-2.3), whereas shortening fraction (Z=3+/-2.9) and velocity of circumferential fiber shortening (VCF) (Z=3+/-3.1) were increased. The relationship between VCF and ESS (a preload-insensitive and afterload-adjusted index of contractility) was increased (Z=2.2+/-2) with only small increase in preload (Z=1.02+/-1.1). Regression analyses showed no significant change over age in LV mass, volume, geometry, loading conditions, or systolic function. Patients who ultimately met criteria for pacemaker implantation did not differ from those who did not in terms of heart rate or LV function but did have increased LV volume (Z score=1.8+/-1.4 versus 0.4+/-0.9, P=.03) and LV mass (Z score=1.7+/-1.2 versus 0.2+/-1.7, P=.001) compared to the unpaced group.

CONCLUSIONS

In most patients with CCAVB, the LV was enlarged with normal geometry and enhanced systolic function during the first two decades of life. The degree of LV dilation and enhanced function did not significantly change with age. In patients who ultimately underwent pacemaker implantation LV function did not differ from those who remained unpaced, but evidence of a slightly increased load manifested as increased end-diastolic volume and mass.

Aortic outflow obstruction in visceral heterotaxy: a study based on twenty postmortem cases

Aortic outflow tract obstruction can complicate the clinical course and surgical management of patients with heterotaxy syndromes, but its anatomic basis has not been described in detail. In 20 postmortem cases with asplenia (n = 4) or polysplenia (n = 16), the anatomic causes of aortic outflow tract obstruction were absence of the subaortic conus in association with (1) narrowing of the subaortic outflow tract between the conal septum anteriorly and the common atrioventricular (AV) valve posteriorly in six (30%) patients; (2) aortic valvar atresia in four (25%), three with asplenia and one with polysplenia; (3) redundant AV valve leaflets in four (20%); (4) excessive AV valve fibrous tissue in four (20%); (5) marked hypoplasia of the mitral valve and left ventricle in two (10%); and (6) aneurysm of membranous septum in one (5%). One patient belonged to group (1) and (4). Aortic outflow tract obstruction was much more common with polysplenia (28%) than with asplenia (4%) (p < 0.001).

Echocardiographic determinants of clinical course in infants with critical and severe pulmonary valve stenosis

OBJECTIVES

The purposes of this study were to determine the growth pattern of the pulmonary valve (PV) annulus and right heart structures in patients with critical and severe pulmonary stenosis (PS) after balloon dilation, and to determine any morphometric or hemodynamic differences between cyanotic infants with critical PS and asymptomatic infants with severe PS that may account for their varied clinical presentations.

BACKGROUND

Growth of the PV annulus and right heart structures in patients with critical PS after balloon valvuloplasty has not clearly been defined. In addition, the anatomic and hemodynamic factors that determine whether an infant with severe PS will present with cyanosis or without symptoms are not well understood.

METHODS

Measurements of the PV annulus, tricuspid valve (TV) annulus and main, right and left pulmonary arteries were obtained from initial and follow-up echocardiograms, and Z values were calculated. Hemodynamic data and balloon pulmonary valvuloplasty techniques were reviewed. Right ventricular (RV) volumes were measured from angiograms.

RESULTS

Fourteen patients with critical PS (mean [+/- SD] age 0.21 +/- 0.37 months) and 20 patients with severe PS (mean age 2.6 +/- 2.9 months) were evaluated at presentation and at 32 +/- 33 and 42 +/- 32 months of follow-up, respectively. Balloon pulmonary valvuloplasty was successful in 64% of patients with critical PS and in 90% of patients with severe PS. The PV, TV and pulmonary arteries increased in size after balloon pulmonary valvuloplasty in both groups at a rate that paralleled or exceeded the rate of somatic growth. The initial TV diameter and RV volume were smaller in patients with critical PS than in those with severe PS (p < 0.05 and p < 0.0008, respectively).

CONCLUSIONS

After balloon pulmonary valvuloplasty in infants with critical and severe PS, right heart structures increase in size at a rate that parallels or exceeds the rate of somatic growth. The primary morphometric differences between these groups are a smaller TV diameter and RV volume in infants with critical PS. This may contribute to increased right to left atrial shunting and account for the variations in clinical presentation.

Apical muscular ventricular septal defects between the left ventricle and the right ventricular infundibulum. Diagnostic and interventional considerations

BACKGROUND

Effective transcatheter or surgical closure of apical muscular ventricular septal defects (VSDs) requires accurate delineation of variable and often complex anatomy. These defects have generally been considered as communications between the apexes of both left and right ventricles.

METHODS AND RESULTS

Among 50 consecutive patients with multiple muscular VSDs referred for transcatheter device closure between October 1987 and April 1993, a subset of 10 patients (aged 7 days to 28 years) with apical muscular VSDs shared a unique set of anatomic characteristics: (1) large and often single opening in the left ventricle; (2) multiple right ventricular openings in the anterior aspect of the apical septum; and (3) separation of the right ventricular apical region into which the VSDs open from the rest of the right ventricular inflow and outflow by prominent muscle bundles. Additional analysis of the anatomy by use of echocardiography and cineangiography showed that these muscular defects were between the left ventricular apex and right ventricular infundibular apex. In 6 patients, the transcatheter devices used to create a septum in these hearts were placed in the right ventricle, straddling muscle bundles that separated the apical VSD from the rest of the right ventricular inflow and outflow, resulting in incorporation of a portion of the right ventricular infundibular apex into the physiological left ventricle. Three patients had devices placed between the apexes of the left ventricle and the infundibulum. The defect closed spontaneously within the right ventricle in 1 patient. One patient died after surgery for tetralogy of Fallot in situs inversus. The remaining 9 patients were all clinically well at the time of their most recent follow-up visit (follow-up duration, 32 +/- 11 months). This distinct type of apical VSD was identified by echocardiography in 20 of 274 patients who were followed up clinically for muscular VSDs.

CONCLUSIONS

Left ventricular-infundibular apical VSDs constitute a distinct morphological type of muscular VSD that can be distinguished by echocardiography and cineangiography. In selected cases, the infundibular apex can be separated from the rest of the right ventricular inflow and outflow to eliminate flow across these defects.

Effects of physiologic load of pregnancy on left ventricular contractility and remodeling

Left ventricular (LV) adaptation to the hemodynamic load of pregnancy has been studied with load-sensitive ejection-phase indexes, but the results of these studies are conflicting. The aim of this study was to examine the effects of the hemodynamic load of pregnancy on the contractile state of the left ventricle by using load-adjusted indexes of contractility. Thirty-four healthy women were prospectively studied by serial echo and Doppler examinations at six periods during pregnancy and after delivery. LV volume increased 10.5%, paralleling the change in stroke volume. End-systolic stress, an index of myocardial afterload, decreased 28.8% because of a decrease in end-systolic pressure and an increase in LV thickness/diameter ratio. Despite the increase in preload and the decrease in afterload, ejection phase indexes did not change during or after pregnancy. Although remaining within the normal range, the afterload-adjusted velocity of circumferential fiber shortening, an index of contractility that is relatively insensitive to preload, transiently decreased by 1.75 SDs during gestation, returning to non-pregnant values 2 to 4 weeks postpartum. Thus the increase in hemodynamic load that characterizes normal pregnancy is associated with preservation of global pump function. The transient decrease in contractile state may represent an adaptation phase of the contractile elements of the myocardium to the rapid changes in loading conditions observed during the first trimester of pregnancy.

Diagnosis and management of agenesis of the right lung and left pulmonary artery sling

The diagnostic, developmental, and surgical aspects of left pulmonary artery sling associated with right lung agenesis in 3 patients are described. Cardiac catheterization may be avoided by the combined use of echocardiography and magnetic resonance imaging and/or computed tomography.

Quantitative echocardiographic analysis of the aortic arch predicts outcome of balloon angioplasty of native coarctation of the aorta

BACKGROUND

The use of balloon angioplasty for treatment of native aortic coarctation is controversial. Cineangiographic data suggest that aortic arch hypoplasia and isthmic narrowing are associated with angioplasty failure. This study of echocardiographic measurements of preangioplasty aortic arch morphology was performed to identify potential anatomic predictors of outcome noninvasively.

METHODS AND RESULTS

The preangioplasty echocardiograms of 105 patients 3 days to 17 years old with native coarctation of the aorta were analyzed off-line. Angioplasty was considered successful if the residual coarctation gradient was < 20 mm Hg and no intervention for recoarctation occurred. Univariate analysis identified young age at angioplasty, presence of a patent ductus arteriosus, and the diameters of the aortic isthmus, distal transverse arch, and aortic valve as predictors of early and late outcomes. Multivariate analysis showed that the preangioplasty aortic isthmus z value was the best independent predictor of outcome, eliminating the effect on outcome of age and associated cardiac defects. An isthmus z value < or = -2.16 predicted early failure with 91% sensitivity and 85% specificity. Kaplan-Meier analysis demonstrated that 90% of patients with an isthmus z value > -1.0 remained free of recoarctation at late follow-up, whereas 89% of patients with a preangioplasty isthmus z value < or = -2.0 developed recoarctation within 36 months.

CONCLUSIONS

Echocardiographic measurements of the aortic arch predict both early and late outcomes of balloon angioplasty for native aortic coarctation, and the preangioplasty aortic isthmus z value was the best independent predictor. Quantitative aortic arch analysis may improve selection of angioplasty candidates who are likely to benefit from the procedure.

Quantitation of echocardiographic predictors of outcome in infants with isolated ventricular septal defect

Clinical and morphometric features such as ventricular septal defect (VSD) size and location may determine outcome in infants with an isolated VSD. However, no currently available data allow quantitative estimation of the probability of spontaneous closure or surgery in individual patients. To identify independent predictors of outcome and to quantitate the probability of spontaneous closure and surgery in patients with isolated VSD, we studied 156 consecutive infants who had a diagnosis of an isolated VSD between January 1, 1988, and December 31, 1990, and who were subsequently monitored for 28.5 +/- 15 months. Of the 149 patients with membranous (n = 100) and muscular (n = 49) defects who were studied, 46 (31%) patients had spontaneous closure, and an additional 37 (25%) patients underwent surgical repair. Univariate analysis identified defect cross-sectional area indexed to body surface area, location in the muscular septum, presence of Down syndrome, and in membranous defects the presence of aneurysmal tissue as potential predictors of spontaneous closure or surgery. Multiple logistic regression analysis with these candidate variables identified indexed defect cross-sectional area as an independent predictor of spontaneous closure and surgery (p < 0.001). An inverse nonlinear relationship was seen between indexed VSD area and the probability of spontaneous closure (probability = (1 + e[-1.74 + 4.57CSA])-1 and a positive nonlinear relationship between indexed VSD area and the probability of surgery (probability = (1 + e[3.39 - 2.31CSA])-1). Muscular defects were more likely to close spontaneously than membranous defects (odds ratio 2.6, 95% CL = 1.01 - 6.8, p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of donor-recipient size mismatch on left ventricular remodeling after pediatric orthotopic heart transplantation

Left ventricular (LV) hypertrophy has been reported after orthotopic heart transplantation. This study was designed to determine the pattern of LV remodeling in the first year after pediatric orthotopic heart transplantation and to elucidate the mechanism responsible for changes in LV dimensions. Serial echocardiograms of 20 children who underwent cardiac transplantation were analyzed off-line, and the following LV parameters were measured and indexed to body surface area (BSA): short-axis diameters, posterior wall thickness, length, mass, and volume in systole and diastole. Mass/volume and short-axis diameter/length ratios and ejection fraction were calculated. In 5 patients, the donor's echocardiogram was also available for analysis. The patient's systemic blood pressure at the time of the echocardiogram, ischemic time of the donor heart, number of rejection episodes, biopsy scores, and body size of the donor and patient were recorded. Patients were assigned to 2 groups based on their donor-recipient weight ratio:group 1, < or = 1.2 (n = 9); and group 2, > 1.2 (n = 11). In group 1, LV mass index remained within normal limits throughout the study period. In group 2, mass index was significantly increased 2 weeks after transplantation (72 +/- 24 vs 133 +/- 37 g/BSA1.5, p = 0.0008). LV volume, geometry, ejection fraction, systemic blood pressure, and number of rejection episodes did not differ significantly between groups. The excess LV mass index in group 2 regressed significantly during the first year after transplantation from 133 +/- 37 to 93 +/- 17 g/BSA1.5 (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative morphometric analysis of progressive infundibular obstruction in tetralogy of Fallot. A prospective longitudinal echocardiographic study

BACKGROUND

The morphological hallmark of tetralogy of Fallot is controversial, with much disagreement as to whether the subpulmonary infundibulum in this lesion is hypoplastic. In addition, few quantitative data are available regarding the morphometry of the subpulmonary infundibulum, what anatomic characteristics are acquired in the postnatal period, and at what rate they progress. We also sought to determine whether echocardiographic morphometric analysis of the infundibulum can predict clinical course in infants with tetralogy of Fallot.

METHODS AND RESULTS

Twenty-one infants with tetralogy of Fallot (median age at initial study, 1.6 months) were prospectively followed with serial echocardiograms until the time of first surgical intervention (median age at surgery, 10 months). Selected video still frames were digitized off-line with a computerized system. Compared with age-matched normal control infants (n = 37), the following indexed infundibular dimensions in patients with tetralogy of Fallot were significantly smaller: length (1.86 +/- 0.54 versus 2.7 +/- 0.56 cm/BSA0.5, P < .0001), cross-sectional area (1.6 +/- 0.49 versus 4.7 +/- 1.3 cm2/BSA, P < .0001), and volume (1.24 +/- 0.62 versus 7.2 +/- 3 mL/BSA1.5, P < .0001). The following measurements were increased in tetralogy patients: infundibular septal thickness (0.83 +/- 0.21 versus 0.54 +/- 0.06 cm/BSA0.5, P = .0002) and infundibular free-wall thickness (0.62 +/- 0.13 versus 0.49 +/- 0.06 cm/BSA0.5, P = .006). The angle between infundibular septum and ventricular septum had a greater degree of anterosuperior deviation in tetralogy patients, resulting in a larger infundibuloventricular septal angle (77 +/- 8.2 degrees versus 31 +/- 6.5 degrees, P < .0001). During follow-up, infundibular volume in tetralogy patients decreased from 1.24 +/- 0.62 to 0.81 +/- 0.47 mL/BSA1.5 (P = .002), correlating with infundibular septal thickness (r = -.63, P < .003). The mean rate of decrease of indexed infundibular volume was 0.1 +/- 0.13 mL.BSA-15.mo-1. Correlation analysis revealed a nonlinear correlation between the degree of infundibular septal malalignment and indexed infundibular volume (r = .93, P < .0001). Tetralogy patients who required early surgical intervention (4.8 +/- 0.9 versus 10.7 +/- 1.7 months, P < .0001) had a smaller infundibulum at presentation (0.92 +/- 0.35 versus 1.41 +/- 0.67 mL/BSA1.5, P = .04) and an accelerated rate of infundibular narrowing (0.17 +/- 0.18 versus 0.06 +/- 0.08 mL.BSA-1.5.mo-1, P = .04).

CONCLUSIONS

Compared with normal infants, the subpulmonary infundibulum in tetralogy of Fallot is characterized by a smaller volume, shorter and thicker infundibular septum, and anterosuperior deviation of the infundibular septum. Infundibular obstruction in tetralogy patients is progressive, with an average rate of decrease in indexed infundibular volume of 0.1 +/- 0.13 mL.BSA-1.5.mo-1. Infants who are likely to require early therapeutic intervention may be identified on their initial echocardiogram as having an infundibular volume of < 0.9 to 1.0 mL/BSA1.5.