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Background: Previous studies have demonstrated that surgical patches comprised of small intestinal submucosa-derived extracellular matrix (ECM) have biological remodeling potential. This pilot study investigated histological, mechanical, and bioelectrical properties of an ECM patch implanted in the ovine right-ventricular outflow tract (RVOT)., Materials and Methods: ECM patches (2 × 2 cm 2 ) were implanted in four Western Range sheep (wether males, 37-49 kg, age <1 year) and explanted at 5 months (n = 2) and 8 months (n = 2). In vivo analysis included epicardial echocardiography and contact electrical mapping. Optical mapping was used to map electrical activity of two hearts on a Langendorff preparation. Mechanical testing quantified stiffness. Histological stains characterized structure, neovascularization, and calcification; immunohistochemistry (IHC) assessed cell phenotype., Results: In vivo analysis showed that ECM patch tissue was contractile by M-mode and two-dimensional echocardiographic evaluation. In vivo electrical mapping, and optical mapping confirmed that ECM conducted an organized electrical signal. Mechanical testing of native and ECM patched RVOT tissue showed an elastic modulus of the implanted patch comparable to native tissue stiffness., Conclusions: At 5 and 8 months, the ECM had undergone extracellular matrix remodeling and neovascularization without calcification. The ECM was populated with locally aligned muscle cells positive for sarcomeric alpha-actinin, CD45, and troponin I and T. In sheep, the ECM patch appears to have the potential of remodeling to resemble native, functional ventricular tissue as evidenced by histological, mechanical, and electrical properties. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1713-1720, 2016., (© 2015 Wiley Periodicals, Inc.)

Ventricular septal defects account for up to 40% of all congenital cardiac malformations. The diagnosis encompasses a broad range of anomalies, including isolated defects and those associated with other congenital cardiac malformations. Presentation, symptoms, natural history, and management of ventricular septal defects depend on size and anatomical associations of the anomaly, patient's age, and local diagnostic and interventional expertise. In this Seminar, we describe the anatomical range of ventricular septal defects and discuss present management of these malformations. Genetic determinants, diagnostic techniques, physiological considerations, and management challenges are examined in detail. Unfortunately, in many circumstances, evidence on which to guide optimum management is scarce. We present some longer term considerations of ventricular septal defects in adolescents and adults, with particular emphasis on patients with raised pulmonary vascular resistance and Eisenmenger's syndrome., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Heart failure is an important cause of morbidity and mortality in individuals of all ages. The many-faceted nature of the clinical heart failure syndrome has historically frustrated attempts to develop an overarching explanative theory. However, much useful information has been gained by basic and clinical investigation, even though a comprehensive understanding of heart failure has been elusive. Heart failure is a growing problem, in both adult and pediatric populations, for which standard medical therapy, as of 2010, can have positive effects, but these are usually limited and progressively diminish with time in most patients. If we want curative or near-curative therapy that will return patients to a normal state of health at a feasible cost, much better diagnostic and therapeutic technologies need to be developed. This review addresses the vexing group of heart failure etiologies that include cardiomyopathies and other ventricular dysfunctions of various types, for which current therapy is only modestly effective. Although there are many unique aspects to heart failure in patients with pediatric and congenital heart disease, many of the innovative approaches that are being developed for the care of adults with heart failure will be applicable to heart failure in childhood., (Copyright © 2010 Elsevier Inc. All rights reserved.)

We tested the accuracy and reproducibility of knowledge-based reconstruction (KBR) for measuring right ventricular (RV) volume and function. KBR enables rapid assessment of the right ventricle from sparse user input by referencing a database. KBR generates a 3-dimensional surface to fit points that the user enters at anatomic landmarks. We measured the RV volume using KBR from magnetic resonance images in 20 patients with repaired tetralogy of Fallot at end-diastole and end-systole. We entered points in the long- and short-axis and/or oblique views. The true volume was computed by manually tracing the RV borders for 3-dimensional reconstruction using the piecewise smooth subdivision surface method. The reference database included 54 patients with tetralogy of Fallot patients. The KBR values agreed closely with the true values for the end-diastolic volume (r = 0.993), end-systolic volume (r = 0.992), and ejection fraction (EF; r = 0.930). KBR slightly overestimated the end-diastolic volume (4 +/- 10 ml, p = NS), end-systolic volume (1 +/- 9 ml, p = NS), and EF (4 +/- 3%, p = NS). No bias in the error was found by Bland-Altman analysis (p = NS for end-diastolic and end-systolic volume and EF). The KBR volumes had approached the true volumes (235 +/- 93 vs 243 +/- 93, p = 0.012, r = 0.978 for end-diastolic and end-systolic volumes combined) already after the first run and the entry of 19 +/- 3 points. In conclusion, KBR provided accurate measurement of the RV volume and EF with minimal user input. KBR is a clinically feasible alternative to full manual tracing of the heart borders from imaging data., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: Danon disease is an X-linked dominant disorder characterized by the clinical triad of hypertrophic cardiomyopathy, skeletal myopathy, and variable mental retardation. Pathologically, autophagic vacuoles are noted in both skeletal and cardiac muscle. It exhibits an X-linked dominant mode of inheritance, and male carriers are severely affected, whereas female carriers develop milder and later-onset cardiac symptoms. Danon disease has been associated with mutations in the lysosome-associated membrane glycoprotein 2 (LAMP2) gene located at Xq24, typically resulting in splicing defects or protein truncation affecting the LAMP2. Because of its rarity, the full spectrum of genetic mutation resulting in Danon disease has not been elucidated., Methods and Results: We analyzed 3 male cases with clinical and pathological findings consistent with Danon disease. Comprehensive mutational analysis failed to yield detectable products for selected LAMP2 exons, and genomic DNA deletion was suspected. Genomic junction fragment polymerase chain reaction analysis in case 1 identified a novel Alu-mediated 34-kb microdeletion encompassing the entire 5'-untranslated region and exon 1 of LAMP2. In case 2 and 3, junctional polymerase chain reaction and Southern blot analyses mapped the breakpoint to an MIRb and (TA)(n) simple repeats present in intron 3, which determined a 64-kb and a 58-kb deletion, respectively, thereby ablating exons 4 to 10. Western blot analysis confirmed the absence of LAMP2 in protein extract from lymphocytes of index case 2., Conclusions: This article is the first report of Danon disease caused by microdeletions at Xq24, which functionally ablate LAMP2. The microdeletion mechanism appears to involve 1 Alu-mediated unequal recombination and 2 chromosomal breakage points involving TA-rich repeat sequences.

Background: Mechanical support using a left ventricular assist device (LVAD) can lead to functional recovery of the myocardium in patients with end-stage heart failure (HF). Molecular remodeling, cytoskeletal disruption, and apoptosis activation are associated with abnormal gene expression in the failing ventricular myocardium of HF subjects and can normalize in response to medium- and long-term mechanical unloading in adults. However, there is little knowledge of the changes in gene expression after short-term mechanical support in children with HF., Methods: We evaluated left ventricular biopsies from 4 children with HF. The children had implantation of a continuous- or a pulsatile-flow LVAD for 8 to 16 days before undergoing heart transplantation. At the time of LVAD insertion and removal, we performed quantitative real-time polymerase chain reaction (QPCR) to study the expression of 326 genes encoding for structural, transcriptional, and signaling pathways proteins, and immunoblot analysis on dystrophin and apoptotic factors., Results: Short-term LVAD therapy significantly decreased brain natriuretic peptide (BNP) levels from pre-LVAD (3,584.5 +/- 378.3 pg/ml [95% CI]) to post-LVAD (447.5 +/- 52.7 pg/ml [95% CI]) in 2 patients in whom comparative BNP measurements were available. In addition, short-term LVAD therapy reduced HF and apoptosis markers, whereas it upregulated structural proteins, including dystrophin, as well as pro-hypertrophic and pro-inotropic markers. Furthermore, LVAD therapy normalized expression of genes involved in calcium homeostasis, cell growth, and differentiation., Conclusions: Our pilot study suggests that even short-term LVAD therapy in children with severe HF can reverse molecular remodeling. This favorable effect should be taken into consideration in eligible children with significant ventricular dysfunction., (Copyright (c) 2010 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: The purpose of this article is to provide an overview of investigational work which has demonstrated the ability of MRI to define abnormalities caused by coronary heart disease. There have been numerous recent advances in the MRI assessment of coronary heart disease which warrant review., Recent Findings: Newly implemented techniques have made MRI a rapid and definitive method for delineating cardiac gross morphology, global and regional cardiac function, cardiac muscle viability, and cardiac muscle perfusion. Significant advances have been made in characterizing coronary artery anatomical course and lumen size, coronary artery flow, coronary artery plaque, cardiac metabolism, and cardiac molecular characteristics with MRI in patients with coronary heart disease., Summary: MRI is a clinically valuable technique for cardiac evaluation which is steadily becoming more widely utilized. In many areas of assessment it is the clinical gold standard for noninvasive imaging in coronary heart disease.

Background: Mutations in the transforming growth factor beta receptor type I and II genes (TGFBR1 and TGFBR2) cause Loeys-Dietz syndrome (LDS), characterised by thoracic aortic aneurysms and dissections (TAAD), aneurysms and dissections of other arteries, craniosynostosis, cleft palate/bifid uvula, hypertelorism, congenital heart defects, arterial tortuosity, and mental retardation. TGFBR2 mutations can also cause TAAD in the absence of features of LDS in large multigenerational families, yet only sporadic LDS cases or parent-child pairs with TGFBR1 mutations have been reported to date., Methods: The authors identified TGFBR1 missense mutations in multigenerational families with TAAD by DNA sequencing. Clinical features of affected individuals were assessed and compared with clinical features of previously described TGFBR2 families., Results: Statistical analyses of the clinical features of the TGFBR1 cohort (n = 30) were compared with clinical features of TGFBR2 cohort (n = 77). Significant differences were identified in clinical presentation and survival based on gender in TGFBR1 families but not in TGFBR2 families. In families with TGFBR1 mutations, men died younger than women based on Kaplan-Meier survival curves. In addition, men presented with TAAD and women often presented with dissections and aneurysms of arteries other than the ascending thoracic aorta. The data also suggest that individuals with TGFBR2 mutations are more likely to dissect at aortic diameters <5.0 cm than individuals with TGFBR1 mutations., Conclusion: This study is the first to demonstrate clinical differences between patients with TGFBR1 and TGFBR2 mutations. These differences are important for the clinical management and outcome of vascular diseases in these patients.

The correlation between right ventricular ejection fraction (RVEF) and tricuspid annular plane systolic excursion (TAPSE) by two-dimensional (2-D) echo has been repeatedly validated, but not by magnetic resonance imaging (MRI) nor in patients with congenital heart disease. We tested whether TAPSE measurements by MRI correlate with RVEF in surgically repaired tetralogy of Fallot (TOF) patients. TAPSE was measured from systolic displacement of the RV-freewall/tricuspid annular plane junction in the apical 4-chamber view in 7 normal subjects and 14 TOF patients. The RV was reconstructed in 3-D from manually traced borders on MR images to compute true EF. Because we previously observed discrepancy between TAPSE and RVEF in the presence of regional dysfunction, we also analyzed RV wall motion in terms of regional stroke volume at 20 short axis slices from apex to tricuspid annulus. RVEF was 52 +/- 3% in normal subjects and 41 +/- 9% in TOF (P < 0.01). TAPSE correlated weakly (r = 0.50, P < 0.05) with RVEF. TOF patients exhibited increased regional stroke volume from apical portions of the RV and decreased regional stroke volume at the base compared to normal (P < 0.05 at 15 of 20 slices). Regional stroke volume in apical slices correlated inversely with RVEF such that patients with higher apical stroke volume had lower RVEF (P < 0.05). TAPSE is not a reliable measure of RVEF in TOF by MRI. TAPSE may be of limited use in conditions that exhibit abnormal regional contraction.

Isolated anomalous origin of the right coronary artery from the main pulmonary artery (ARCAPA) is a rare congenital cardiac malformation. We reviewed the current literature and found only 31 patients with ARCAPA. We report the first case that was diagnosed and followed on a noninvasive basis with cardiovascular magnetic resonance after surgical re-implantation. This report of a patient with ARCAPA showed resolving coronary artery sizes secondary to decreased pulmonary steal. Cardiovascular magnetic resonance is an accurate and reliable imaging modality that allows serial noninvasive follow up in patients with coronary artery anomalies.

Background: Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play a central role in arterial wall remodeling, affecting stability of fibrous caps covering atherosclerotic plaques. The objective of this study was to determine the spatial distribution of TIMP mass and MMP mass and activity of carotid endarterectomy (CEA) tissues and relate it to the distribution of atherosclerotic lesions., Methods and Results: Fresh CEA tissues were imaged by multicontrast MRI to generate 3D reconstructions. Tissue segments were cut transversely from the common, bifurcation, internal, and external regions. Segments were subjected to total protein extractions and analyzed by ELISA for MMP-2 and -9 and TIMP-1 and -2 mass and by zymography for gelatinase activity. Segments at or near the bifurcation with highly calcified lesions contained higher MMP levels and activity than segments distant from the bifurcation; highly fibrotic or necrotic plaque contained lower MMP levels and activity and higher TIMP levels. Fatty streak, fibroatheroma with hemorrhage and calcification, and fully occluded lesions were enriched in MMP-2, MMP-9, and TIMP-1 and TIMP-2, respectively., Conclusions: The spatial distribution of MMPs and TIMPs in carotid atherosclerotic lesions is highly heterogeneous, reflecting lesion location, size, and composition. This study provides the first semi-quantitative maps of differential distribution of MMPs and TIMPs over atherosclerotic plaques.

Navigator coronary magnetic resonance imaging (MRI) was evaluated in assessing coronary artery origins in a pediatric and adolescent population. Sixty-five consecutive infants, children, or adolescents (age range 11 days to 21 years) were referred for MRI evaluations to assess coronary artery origins. Coronary artery origins were unambiguously delineated in 62 of 65 patients. In 3 patients, irregular arrhythmias precluded cardiac gating of the magnetic resonance acquisition. Two patients had anomalous coronary artery origins detected. Twenty-six patients required sedation for the studies. Free-breathing 3-dimensional MRI with real-time navigator correction is a robust method for delineating the coronary artery origins in pediatric and adolescent patients.

Background and Purpose: Magnetic resonance imaging (MRI) can accurately and reproducibly measure the volume of atherosclerotic plaque in human carotid arteries. Atherosclerotic plaques may either progress or regress over time, depending on individual risk factors and treatment regimens. This study was designed to determine if regression or progression of human carotid atherosclerosis in patients receiving statin therapy over 24 months can be detected by high-resolution MRI., Methods: In 11 subjects who had undergone unilateral carotid endarterectomy and were on statin therapy, volumes for total carotid artery, concentric wall (normal wall), eccentric wall (plaque), and lumen were quantified at 0, 16 and 24 months using a 1.5-T human imager equipped with 6-cm phased array coils., Results: The interobserver mean coefficient of variation (CV) was lowest for the lumen volume (3.1%) and highest for the plaque volume (9.8%). The interscan mean CV was lowest for the total artery volume (3.2%) and highest for the plaque volume (9.9%). As much as 26% regression and 35% progression were observed in individual subject's carotid artery eccentric wall (plaque) volumes over time. Mean eccentric wall volume increased 5% by 16 months and 8% by 24 months. Mean total wall volume increased slightly at both 16 and 24 months (+1.2% and +1.8%)., Conclusions: High-resolution MRI provides a noninvasive reproducible method of tracking changes in carotid atherosclerosis. This pilot study detected changes in individual subjects at both 16 and 24 months. MRI tracking of changes in atherosclerotic plaques should prove useful in assessing vascular disease risk and monitoring the efficacy of interventions designed to induce regression or retard progression.

During the last few decades, significant strides have been made in the field of noninvasive imaging for the patient with congenital heart disease. Echocardiography and MRI continue to provide improved means of anatomic and functional assessment in children and adults with congenital heart lesions. This review reports some of the recent advances in tissue Doppler, strain rate, and integrated backscatter, and highlights exciting current and future potential developments in their application. We also discuss advances in MR in evaluation of cardiac anatomy and function in congenital heart disease.

Purpose: To evaluate the role of time-resolved contrast-enhanced magnetic resonance angiography (CE-MRA) using sensitivity encoding in imaging the thoraco-abdominal vessels in pediatric patients., Materials and Methods: Thoraco-abdominal vessels of 22 pediatric patients (median age = 5 years) were evaluated with a 3D CE-MRA technique in combination with SENSE following a 0.2 mmol/kg injection of Gd-chelate. The acquisition parameters were as follows: TR/TE = 5/1.1 msec; flip angle = 40 degrees; in-plane phase encoding steps were reduced by a factor of 2 using sensitivity encoding (SENSE); 3D volume acquisition was repeated four to eight times consecutively during free breathing (four to eight dynamics) with a mean temporal resolution of 6.8 seconds/dynamic; and mean acquired voxel size = 1.4 x 1.7 x 3.1 mm (reconstructed as 1.4 x 1.4 x 1.55 mm). Arterial-to-venous signal intensity ratios (AVRs) were computed for each dynamic., Results: All images were successfully reconstructed and were of diagnostic quality. The AVRs of prepeak, peak, and postpeak arterial volumes were 1.0 +/- 0.5, 6.1 +/- 3.3, and 1.3 +/-0.9, respectively, indicating good arterial-to-venous separation. The signal-to-noise ratio (SNR) of the peak arterial volume was 41 +/- 26., Conclusion: Our results suggest that it is feasible to apply SENSE to a conventional 3D CE-MRA technique in a time-resolved fashion for imaging the thoraco-abdominal vessels in pediatric patients during free breathing., (Copyright 2003 Wiley-Liss, Inc.)

Background and Purpose: Atherosclerosis is a principal cause of stroke and myocardial infarction. The carotid arteries provide a site at which progression of atherosclerosis can be monitored reproducibly and noninvasively. This study was conducted to determine the similarity of atherosclerotic plaques in the left and right carotid arteries. This question was explored with the use of perfusion-fixed cadaveric carotid arteries and 2 noninvasive clinical imaging techniques, MRI and electron-beam CT., Methods: Fifty pairs of carotid arteries from cadaveric donors (aged 48 to 98 years) were imaged with MRI and electron-beam CT. Thirty-eight of the pairs met the criteria for rigorous analysis. Carotid artery wall volumes were measured from the MRI images, and calcification scores were computed from the electron-beam CT images., Results: Total wall volumes of the left (972.5+/-241.6 mm3) and right (1016.3+/-275.0 mm3) carotid arteries were moderately correlated (concordance correlation coefficient [r(c)]=0.71). Calcification scores were highly correlated, with r(c)=0.95 for the Agatston scores and r(c)=0.94 for the calcium volume scores., Conclusions: Total wall volume and plaque calcification in the left and right human carotid arteries are substantially similar. These results suggest that atherosclerosis of the human carotid arteries is generally a bilaterally symmetrical disease. This evidence of symmetry suggests that diagnostic information about atherosclerotic plaque in one carotid artery can be used to infer information about the composition and volume of atherosclerotic plaque in the contralateral artery.

We report a case of a healthy, asymptomatic 6-year-old boy in whom an anomalous right pulmonary vein was noted to drain into both the inferior vena cava and left atrium in association with findings consistent with scimitar syndrome. The anomalous pulmonary vein took a very circuitous route through the lungs before draining into the left atrium, a condition previously termed "meandering pulmonary vein." To aid in the diagnosis, cardiovascular magnetic resonance imaging and magnetic resonance angiography were used to delineate this complex course and the connection of the anomalous pulmonary vein. To our knowledge, this is the 1st reported case of a meandering pulmonary vein with dual drainage to the inferior vena cava and left atrium in association with other anomalies.

Magnetic resonance imaging (MRI) can provide important information on patients with congenital heart defects. There is some reluctance to perform MRI acutely following intravascular stent implant, due to concerns of distortion or movement of the stent in the magnetic field. We report on three patients who underwent MRI evaluation less than 14 days following Palmaz stent implant in the pulmonary arteries and superior vena cava, with no acute adverse outcome or long-term problems., (Copyright 2001 Wiley-Liss, Inc.)

Over the last two decades, surgical separation of thoracopagus conjoined twins has become increasingly feasible. Delineation of the degree of cardiac involvement is essential to establish the feasibility of surgical separation. We describe our experience of cardiac catheterization both in the diagnosis and management of nine sets of thoracopagus twins who presented to a single center over three decades and discuss its role in conjunction with other modern diagnostic modalities.

We report the case of a female infant who had the rare combination of double aortic arch and D-transposition of the great arteries. The double aortic arch was diagnosed at the time of her arterial switch procedure. Magnetic resonance imaging identified the left arch as dominant, and the right arch was successfully ligated.

The purpose of medical imaging technology in pediatric cardiology is to provide clear representations of the underlying anatomy and physiology of the cardiovascular system--representations that are easily understood and that facilitate clinical decision making. However, standard projective and tomographic imaging methods often yield results that are intelligible only to imaging specialists. Three- and four-dimensional reconstructions from projective and tomographic data sets are an alternative form of image display. Often, these reconstructions are more readily comprehensible as representations of the reality apparent in the operating room or the pathology laboratory than are the original data sets. Furthermore, viewing of these reconstructions is much more time efficient than viewing hundreds of separate tomographic images. Magnetic resonance imaging inherently provides three-, four-, and even higher dimensional data, and magnetic resonance data sets are commonly used to generate volumetric reconstructions. This review will focus on the practical application of magnetic resonance imaging to yield three- and four-dimensional reconstructions of pediatric cardiovascular disorders.

Background: Whether left ventricular function can be assessed accurately by gated single photon emission computed tomography (SPECT) in patients with myocardial infarction and severe perfusion defects is not well known., Methods and Results: Twenty-five patients with an acute myocardial infarction underwent 99mTc-labeled tetrofosmin (99mTc-tetrofosmin) gated SPECT and cine magnetic resonance imaging (MRI). Wall motion was assessed in 13 left ventricular segments using a 5-point scoring system ranging from 3 (normal) to -1 (dyskinetic). Exact agreement for wall motion scores between gated SPECT and MRI was excellent (92%, kappa = 0.82). Furthermore, correlations between the two techniques were also good for end-diastolic volume (r = 0.81, P < .0001), end-systolic volume (r = 0.92, P < .0001), and ejection fraction (r = 0.93, P < .0001)., Conclusion: In patients with a recent myocardial infarction, 99mTc-tetrofosmin gated SPECT provides reliable evaluation of global and regional ventricular function and volumes.

Advances in ultrasound technology will continue to expand the utility of echocardiography in the assessment of structural and functional cardiac disease in children. Tissue Doppler imaging and dobutamine stress echocardiography are 2 promising clinical applications that are expected to become increasingly used with time. Advances in data compression technology, including JPEG and MPEG techniques, will significantly affect digital archival and transmission of echocardiograms, which also have clinical implications, particularly in the expanding use of telemedicine. Continued research and clinical experience will further define the ultimate roles of these technologies in the future.

Background: Balloon-expandable intravascular stents are well accepted in the management of arterial obstructions. This study was undertaken to detail the immediate and short-term results of intravascular stent implantation in systemic venous and systemic venous baffle obstructions in children., Methods and Results: Between September 1991 and June 1994, 12 patients had 21 stents implanted in 13 systemic venous obstructions, 1 patient having stents placed in 2 separate obstructions. In the baffle group, 4 of 13 obstructions were at the superior vena cava/right atrial junction after atrial baffling for transposition of the great arteries. One of 4 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 12 +/- 8.4 mm Hg (range, 4 to 20 mm Hg) to 1.3 +/- 1.9 mm Hg (range, 0 to 4 mm Hg, P = .05). The obstructed segment diameter increased from 3.5 +/- 3.9 mm (range, 0 to 8.5 mm) to 16 +/- 2.7 mm (range, 14 to 20 mm, P = .002). In the central vein group, 9 of 13 obstructions were in large central veins. Three of 9 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 10.3 +/- 8.5 mm Hg (range, 0 to 20 mm Hg) to 0.8 +/- 1.1 mm Hg (range, 0 to 3 mm Hg, P = .005). The obstructed segment diameter increased from 1.3 +/- 1.1 mm (range, 0 to 2.8 mm) to 9.4 +/- 1.7 mm (range, 7.6 to 12 mm, P < .001). There were no acute complications in either group. In the follow-up group, patients were scheduled for clinical follow-up at 3, 6, and 12 months with echocardiography or magnetic resonance imaging (MRI) at 3 or 6 months and for repeat cardiac catheterization at 12 months. All stents were patent by echocardiography or MRI when studied at follow-up. Cardiac catheterization in 6 of 12 patients, 2 to 13 months after stent, demonstrated that all stents remained patent without compression or fracture. Follow-up and immediate poststent gradients were not significantly different (1 +/- 1.6 versus 0.7 +/- 1.2 mm Hg, P = NS). Neointimal hyperplasia (5 of 6 patients) reduced the stent lumen only from 12.5 +/- 4.7 mm (range, 8 to 20 mm) to 10.6 +/- 4.7 mm (range, 4.5 to 17.7 mm, P = NS). No stents required redilation. One of 18 stents placed in series had "unlocked" and rotated in the venous lumen but remained fully patent to flow., Conclusions: Balloon-expandable intravascular stents can be safely and effectively used to relieve systemic venous and systemic venous baffle obstructions, even when obstruction is complete. Short-term follow-up suggests excellent continued patency, but further follow-up is required to observe for progression of neointimal hyperplasia. We postulate that balloon-expandable intravascular stents will become the treatment of choice for the relief of selected systemic venous and venous baffle obstructions in the pediatric population.

Background: Patients with heterotaxy syndrome frequently have complex congenital cardiac and noncardiac malformations requiring detailed diagnostic evaluation by noninvasive as well as invasive imaging modalities for management planning. Recent advances in magnetic resonance imaging (MRI) techniques allow detailed delineation of cardiovascular anatomy and blood flow in young infants with rapid heart rates. The present study was undertaken to prospectively evaluate the role of MRI in the presurgical evaluation of patients with heterotaxy syndrome., Methods and Results: Between January 1 and December 31, 1992, 14 consecutive patients with heterotaxy syndrome and complex congenital heart disease were enrolled in a prospective protocol. After evaluation by echocardiography and cardiac catheterization, a tentative management plan was recorded. Subsequently, a MRI study was performed and surgical planning was reevaluated. MRI was found to be comparable to echocardiography in terms of length of examination and sedation requirements. Surgical planning was altered in four patients because MRI provided additional data not evident on echocardiography and catheterization. Comparison of diagnostic yield between echocardiography, catheterization, and MRI showed that MRI is superior to echocardiography and often to catheterization in delineation of systemic and pulmonary venous anatomy and their relation to mediastinal structures. When the anatomic and hemodynamic data obtained by echocardiography and MRI were considered together, cardiac catheterization data were necessary only to determination of pulmonary vascular resistance before Fontan operation., Conclusions: MRI provides excellent anatomic and functional information that in some patients was not available by echocardiography or catheterization. Combined with echocardiography, MRI provides the high-quality diagnostic information necessary for management planning in most patients with heterotaxy syndrome. Cardiac catheterization is indicated when determination of pulmonary vascular resistance is necessary for decision making or when an interventional procedures is indicated.

This study compared gradient echo magnetic resonance imaging, spin echo magnetic resonance imaging, echocardiography, and echocardiography with x-ray cineangiography in the evaluation of major aortopulmonary collateral arteries. Twelve patients (ages 9 months to 35 years, mean 11 +/- 11 years) with known or suspected major aortopulmonary collateral arteries were studied. The aortic insertion and proximal course of 29 major aortopulmonary collateral arteries demonstrated by x-ray contrast angiography were shown in all 29 cases by gradient echo magnetic resonance imaging but in only 23 of the 29 cases by spin echo magnetic resonance imaging. Color Doppler-echocardiography detected aortopulmonary collateral arteries in four patients but did not define the proximal course or distal anatomy. Gradient echo images of distal aortopulmonary collateral anatomy were qualitatively superior to spin echo images. The contrast-to-noise ratio between the vessel lumen and adjacent lung was greater for gradient echo (6.06 +/- 2.91) than for spin echo (1.45 +/- 1.13)(p < 0.05). Gradient echo magnetic resonance imaging is a useful method for identification and characterization of aortopulmonary collateral arteries in patients of all ages and is superior to spin echo magnetic resonance imaging and echocardiography.

Intravascular stents have been implanted in children with congenital and acquired vascular stenoses. Little information is known regarding the long-term results in growing patients, the implantation of multiple stents (in series), and the feasibility of further dilation. Nine stents were implanted in the abdominal aortas of 6 mini-pigs; in 3 pigs, 2 stents were implanted in series. Five pigs were recatheterized 196 +/- 17 days after stent implant. All stents were patent, with mild narrowing at the stent relative to the adjacent aorta; further stent dilation was performed. The stent diameter increased from 8.3 +/- 0.6 mm to 11.2 +/- 1.3 mm (p = 0.002), and the narrowing was relieved. These five pigs were catheterized 253 +/- 73 days after stent redilation. Each stent was patent without narrowing or pressure gradient. We conclude that intravascular stents do not interfere with normal growth, can be implanted in series, and can be further dilated.

Background: The Pediatric Electrophysiology Society studied children with the long QT syndrome (LQTS) to describe the features of LQTS in patients less than 21 years old, define potential "low-risk" and "high-risk" subpopulations, and determine optimal treatment., Methods and Results: Patients less than 21 years old were included if either QTc was more than 0.44; they had unexplained syncope, seizures, or cardiac arrest preceded by emotion or exercise; or family history of LQTS. We found 287 patients from 26 centers in seven countries. Mean +/- SD age at presentation was 6.8 +/- 5.6; 9% presented with cardiac arrest, 26% with syncope, and 10% with seizures. Of those with symptoms, 67% had symptoms related to exercise. Family history was positive for long QT interval in 39% and for sudden death in 31%. Hearing loss was present in 4.5%. A normal QTc was present in 6%, and QTc of more than 0.60 was in 13%. Atrioventricular block occurred in 5%, but 13 of 15 patients had second-degree atrioventricular block (2:1), and only two of 287 had complete atrioventricular block. Ventricular arrhythmias were found on 16% of initial routine ECGs: 4% uniform premature ventricular contractions, 5% multiform premature ventricular contractions, 1% monomorphic ventricular tachycardia, and 6% torsade de pointes. Overall, treatment was effective for symptoms in 76% and for ventricular arrhythmias in 60%. There was no difference between propranolol and other beta-blockers in effective treatment. Left stellectomy was performed in nine patients, and defibrillators were implanted in four; no sudden death occurred in these 13 patients. In follow-up (duration, 5.0 +/- 4 years; age, 10.9 +/- 6.3 years), 5% had cardiac arrest, 4% had syncope, and 1% had seizures. The two multivariate predictors of symptoms at follow-up were symptoms at presentation and propranolol failure. Sudden death occurred in 8%; multivariate predictors of sudden death were length of QTc at presentation of more than 0.60 and medication noncompliance., Conclusions: The appearance of 2:1 atrioventricular block, multiform premature ventricular contractions, and torsade de pointes are relatively more common in children with LQTS than other children and should raise the index of suspicion for LQTS. Because 9% of patients presented with cardiac arrest and no preceding symptoms, perhaps prophylactic treatment in asymptomatic children is indicated. Asymptomatic patients with normal QTc and positive family history may be a low-risk group. Patients with QTc of more than 0.60 are at particularly high risk for sudden death, and if treatment is not effective, consideration should be given to cardiac sympathetic denervation, pacemaker implantation, and perhaps implantation of a defibrillator.

A versatile gating device for magnetic resonance (MR) spectroscopy and imaging is presented. The device uses electrocardiograph (ECG) and respiration signals as input, applies appropriate signal conditioning, and generates control signals for ECG, respiration, or combined gating studies. In the combined ECG and respiration mode, in conjunction with a proper MR pulse program, one can acquire MR data gated by the ECG signal within a selected window of the respiration cycle, while maintaining a steady level of magnetization saturation during the remainder of the respiration cycle, by gating the radio-frequency excitation with the ECG while inhibiting data acquisition.

An experimental canine model of pericardial effusion was designed to validate previous clinical nuclear magnetic resonance imaging (NMR) studies. Saline (n = 7), serum (n = 4), blood (10% hematocrit [n = 5]; 20% hematocrit [n = 5]), and lipid (n = 4) effusions were chosen to resemble: (1) transudative/exudative, (2) nonhemorrhagic/hemorrhagic, and (3) chylous effusions, respectively. There was a linear correlation between the infused volume and the pericardial/epicardial distance measurements on the nuclear magnetic resonance images. Hemorrhagic and nonhemorrhagic exudative effusions were distinguished from transudative effusions by the low signal intensity of transudative effusions images obtained at a TR (repetition time) of 400 and 800 msec. Nonhemorrhagic effusions had significantly lower effusion-to-myocardial signal intensity ratio at TR of 400 msec than did hemorrhagic effusions. Differences in hematocrit were not appreciated qualitatively or quantitatively. Compared with other effusion types, only chylous effusions were hyperintense to myocardium at a TR of 400 msec. Chylous effusions were further uniquely characterized by a decreasing effusion-to-myocardial signal intensity ratio with increasing TR. These experimental findings corroborate the findings of earlier clinical reports and suggest that NMR can provide important assistance in the evaluation of pericardial effusions.

Twelve patients more than 8 years of age with complex congenital heart disease were evaluated prospectively with nuclear magnetic resonance (NMR) imaging and with echocardiographic and angiographic imaging techniques. The subpulmonary region, main pulmonary artery, right and left pulmonary arteries, and aorticopulmonary shunts were clearly visualized by means of NMR imaging in all patients. Angiography defined the subpulmonary region and main pulmonary artery in all patients, the right and left pulmonary arteries along their length in 11 of 12 patients, and aorticopulmonary shunts in seven of eight patients. Except for the right pulmonary artery, echocardiography defined the remaining structures in less than or equal to 50% of patients. Measurement of the pulmonary artery diameters on NMR images correlated well with the angiographic measurements of both the left (r = 0.96) and right (r = 0.94) pulmonary arteries. These results suggest that NMR imaging may be the preferable noninvasive imaging technique for defining the anatomy of the subpulmonary region, main and left pulmonary arteries, and aorticopulmonary shunts in older patients with congenital cardiovascular disease and that it compares well with the angiographic standard.

Despite the generally excellent success with balloon dilation for the stenotic lesions of congenital and acquired heart disease, technical difficulties sometimes prevent satisfactory results. Such technical difficulties include: a large diameter of the anulus of the stenotic lesion relative to available balloon diameter, difficulty in the insertion or removal of the larger balloon catheters, and permanent damage to or obstruction of the femoral vessels by the redundant deflated balloon material of the large balloons. A double balloon technique was initiated to resolve these difficulties. With this method, percutaneous balloon angioplasty catheters were inserted in right and left femoral vessels, placed side by side across the stenotic lesion and inflated simultaneously. Dilation procedures using the two balloon technique were performed in 41 patients: 18 with pulmonary valve stenosis, 14 with aortic valve stenosis, 5 with mitral valve stenosis, 3 with vena caval obstruction following the Mustard or Senning procedure and 1 with tricuspid valve stenosis. Patient ages ranged from 1 to 75 years (mean 17.8) and patient weights ranged from 8.9 to 89 kg (mean 42.3). Balloon catheter sizes ranged from 10 to 20 mm in diameter. Average maximal pressure gradient in mm Hg before dilation was 61 in pulmonary stenosis, 68 in aortic stenosis, 21 in mitral stenosis, 12 in tricuspid stenosis and 25 in vena caval stenosis. Average maximal valvular pressure gradient after dilation was 13 in pulmonary stenosis, 24 in aortic stenosis, 4 in mitral stenosis, 0 in tricuspid stenosis, and 1 in vena caval stenosis. No major complications were encountered with the procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-dimensional echocardiography can diagnose hypoplastic left heart syndrome. However, with the advent of the possibility of palliative open heart surgery, complete anatomic diagnosis is necessary. The anatomic findings of 15 neonates with hypoplastic left heart syndrome (age 1 to 10 days, mean 4.1) who had two-dimensional Doppler echocardiographic studies were compared with the results obtained by angiography (6 cases), surgery (11 cases) and autopsy (8 cases). Complete two-dimensional echocardiographic examination of the aortic arch, pulmonary and systemic venous return, atrial septum, ductus arteriosus and proximal coronary arteries was possible in all 15 neonates and correctly diagnosed hypoplastic left heart syndrome in each. Anatomic two-dimensional echocardiographic assessment was accurate in 13 (86%) of the 15 neonates and there were no false positive results. Undiagnosed associated abnormalities were hypoplasia of a left pulmonary artery in one patient and left superior vena cava in another. Accurate quantitation of the size of the tricuspid valve anulus, ascending aorta, pulmonary anulus and right and left pulmonary arteries was possible. Doppler examination was performed in seven patients and confirmed retrograde aortic arch flow and right to left systolic shunting in the patent ductus arteriosus. In selected neonates, surgical palliation can be attempted without angiography.

The purpose of this investigation was to evaluate the efficacy, technique, and follow-up results of balloon dilation angioplasty for valvular pulmonary stenosis. Percutaneous dilation was performed on 63 patients with pulmonary stenosis (ages 3 months to 76 years, mean = 4.3 years). In 43 patients, a single balloon was used; in 20 patients two balloons were used simultaneously. The pressure gradient across the pulmonary valve was determined with right ventricular and main pulmonary artery catheters. Pressure gradients simultaneously were estimated by continuous wave Doppler (CWD) during catheterization. The peak systolic ejection gradient was obtained by both techniques both pre- and postangioplasty. There was excellent linear correlation between the simultaneous catheter pressure gradient and the pressure gradient estimated by Doppler (r = 0.99). Follow-up pressure gradient estimations by Doppler echocardiogram were obtained in 30 patients between 6 months and 30 months postcatheterization (mean = 13 months). The mean preangioplasty gradient of 64 mm Hg (range 30-160 mm Hg) was reduced to 22 mm Hg (range 2-31 mm Hg). A significant reduction of transvalvular gradient (52-95%, mean 68%) occurred in each patient. A linear correlation was found between the predilation gradient and the pressure gradient drop (r = 0.92). Mean follow-up gradient by Doppler was 20 mm Hg (range 0-31 mm Hg), and there was no significant difference between these gradients and the postdilation gradient. No important complications were noted. These data confirm that balloon dilation angioplasty for valvular pulmonary stenosis is safe and effective, and suggest that stenosis does not recur.

Radionuclide angiograms were compared with radiographic and physical findings and with echocardiographic left atrial to aortic ratios in 30 neonates clinically suspected of having a persistent ductus arteriosus. In three infants without clinical signs and with normal LA/Ao ratios (10%), radionuclide angiograms provided evidence of a large left-to-right shunt, which was confirmed by the finding of a large ducts arteriosus at surgery. Whereas routine physical, radiographic, and echocardiographic criteria fail to identify some neonates with large PDA's, the present study suggests that radionuclide angiography can be performed in a neonatal intensive care unit setting and may be a valuable addition to currently employed diagnostic techniques.

Evaluation for patent ductus arteriosus by both Doppler examination and direct two-dimensional echocardiographic visualization has been reported in infants and children. However, visualization of a patent ductus arteriosus in preterm infants with lung disease has been difficult. Using a recently developed 7.5 MHz mechanical scanner with interfaced two-dimensional directed pulsed Doppler ultrasonography, 36 examinations were performed from a suprasternal approach in 27 patients (age range 1 day to 3 months, mean 18 days; weight range 490 to 2,500 g, mean 1,260). Complete imaging for evaluation of patency of the ductus arteriosus was successful in 33 (92%) of 36 examinations, and imaging of the pulmonary end of the ductus arteriosus was successful in all. In 18 examinations, the ductus arteriosus was closed by both two-dimensional echocardiography and Doppler examination. In four cases the ductus arteriosus was widely patent by both two-dimensional echocardiography and Doppler examination. Eleven echocardiographic examinations revealed a narrowed ductus arteriosus, and of these, 10 (91%) showed Doppler findings of patent ductus arteriosus. It is concluded that combined two-dimensional/Doppler echocardiographic assessment allows confident detection of both a large unrestrictive and a small, stenotic patent ductus arteriosus in preterm infants with lung disease.

Obstruction to pulmonary venous return may be associated with a number of congenital cardiovascular abnormalities occurring both before and after surgery. Hemodynamic assessment by cardiac catheterization is often difficult. A noninvasive method for detection and quantitation of obstruction to systemic ventricular inflow would be clinically useful. Two-dimensionally directed pulsed and continuous wave Doppler echocardiography was performed before cardiac catheterization in 31 patients thought clinically to have possible obstruction to left ventricular inflow or pulmonary venous return. Primary diagnoses included transposition of the great arteries after the Mustard or Senning procedure in nine patients, total anomalous pulmonary venous connection in nine (in two after surgical repair), cor triatriatum in eight (in four after surgical repair), congenital mitral stenosis in four (in one after surgical repair) and mitral atresia in one. Severe obstruction was defined as a mean pressure gradient at catheterization of greater than or equal to 16 mm Hg at any level of the pulmonary venous return or of the systemic ventricular inflow. Severe obstruction was predicted if Doppler examination measured a flow velocity of greater than or equal to 2 m/s across any area of inflow obstruction. At catheterization, 12 patients (39%) had severe obstruction to left ventricular inflow or pulmonary venous return and all obstructions were correctly detected by Doppler echocardiography. The site of pulmonary venous obstruction was localized by two-dimensionally directed pulsed Doppler study. Patients with a lesser degree of obstruction had a lower Doppler velocity, but none had a maximal Doppler velocity of greater than or equal to 2 ms/s.(ABSTRACT TRUNCATED AT 250 WORDS)