Biomedical subjects

R E Shaddy

Publications and source records attributed to R E Shaddy.

At least 19 recordsLinked to original sources

PubMed1999

Influence of left ventricular cavity size on interventricular shunt timing and outcome in neonates with coarctation of the aorta and ventricular septal defect.

In this study, we reviewed the records and echocardiograms of 39 consecutive patients with coarctation of the aorta and ventricular septal defect who underwent neonatal coarctation repair to examine the influence of left heart size on ventricular shunting and outcome. We found smaller left heart structures (initial mitral and aortic annular diameters) to be associated with diastolic interventricular shunting and to be predictive of the development of mitral or aortic and/or subaortic stenosis.

Aortic Coarctation↗

PubMed1999

Pulmonary vein stenosis with normal connection: associated cardiac abnormalities and variable outcome.

BACKGROUND: Pulmonary vein (PV) stenosis with anatomically normal connection is considered rare, unresponsive to treatment, progressive, and usually fatal. METHODS: We reviewed the records of 13 children with this diagnosis at our center since 1990. RESULTS: The number of stenosed PVs ranged from all PVs (n = 5); three PVs (n = 1); two PVs (n = 5); and one PV (n = 2). All patients had associated congenital cardiac abnormalities. Operation on PV stenosis was attempted in 7 patients (54%), 2 of whom have done well and 5 of whom have not. Two patients underwent heart transplantation for inoperable associated cardiac lesions. Significantly more patients with three or four stenosed PVs died (83%) compared with patients with one or two stenosed PVs (0%). CONCLUSIONS: (1) Pulmonary vein stenosis with anatomically normal connection is associated with other congenital cardiac abnormalities, (2) presentation and outcome are contingent on the number of stenosed PVs, (3) surgical palliation may be helpful in some patients, and (4) heart transplantation for inoperable associated cardiac abnormalities may be an option in patients with only one or two stenosed PVs.

Adolescent↗

PubMed1999

Left heart hypoplasia and neonatal aortic arch obstruction: is the Rhodes left ventricular adequacy score applicable?

OBJECTIVE: Although the influence of small left heart structures on outcome of a biventricular repair in neonatal critical aortic stenosis is well documented, little is known about its effect in neonates with aortic arch obstruction and coarctation. The purpose of this study was to evaluate the influence of small left heart structures on early and late results of repair and the ability to achieve a biventricular repair in neonates with coarctation and aortic arch obstruction. PATIENTS: Neonates included in this study had a left ventricular adequacy score (as proposed by Rhodes and associates for critical aortic stenosis) that would have predicted a need for a univentricular (Norwood) repair. All were ductus dependent but had antegrade ascending aortic flow and a small but nonstenotic aortic valve (<30 mm Hg gradient). Twenty neonates aged 10 +/- 9 days were identified for the study with weights averaging 3. 1 +/- 0.6 kg. Selected left heart measurements obtained by preoperative echocardiography included the following: aortic anulus 5.3 +/- 0.3 mm, mitral anulus 8.4 +/- 1.0 mm, transverse aortic arch 3.4 +/- 0.6 mm, and left ventricular volume 25 +/- 4 mL/m2. All patients underwent coarctation repair by resection and extended end-to-end anastomosis to enlarge the transverse arch as needed. Three patients underwent simultaneous pulmonary artery banding because of a hemodynamically significant ventricular septal defect. These 3 patients have subsequently had their defects successfully closed without mortality. RESULTS: There were no early or late deaths at a follow-up of 38 +/- 16 months after the operation. Three patients (3/20, 15%) have had to undergo reintervention with balloon aortoplasty because of recurrent coarctation (gradient > 20 mm Hg) in 2 and resection of subaortic stenosis in 1. Late follow-up in the remaining patients reveals 1 with moderate subaortic stenosis (gradient = 43 mm Hg), 2 with mild aortic stenosis (gradient < 30 mm Hg), and 2 with mild to moderate mitral stenosis. At late follow-up, 16 patients (16/20, 80%) are completely free of symptoms and 4 (4/20, 20%) have mild residual symptoms. CONCLUSIONS: Biventricular physiology can be successfully achieved in neonates with small left heart structures and aortic arch obstruction with minimal mortality and excellent late functional results. Standard echocardiographic measurements used to predict the need for a univentricular repair in critical aortic stenosis are not valid for the neonate with aortic arch obstruction.

Abnormalities, Multiple↗

PubMed1999

Beta-blocker treatment of dilated cardiomyopathy with congestive heart failure in children: a multi-institutional experience.

BACKGROUND: Dilated cardiomyopathy is the primary indication for heart transplantation in children beyond infancy. Although beta-blockers improve symptoms, ejection fraction, and survival in adults with congestive heart failure, little is known of their effects in children. METHODS: This study reviews our pediatric experience with the beta-blocker, metoprolol, at 3 institutions. We gave metoprolol to 15 children, age 8.6 +/- 1.3 years (range 2.5 to 15 years), with idiopathic dilated cardiomyopathy (n = 9), anthracycline cardiomyopathy (n = 3), and Duchenne muscular dystrophy cardiomyopathy, postmyocarditis cardiomyopathy, and post-surgical cardiomyopathy (n = 1 each). All had been treated with conventional medications (digoxin, diuretics, and ACE inhibitors) for 22.5 +/- 9 months before starting metoprolol. Metoprolol was started at 0.1 to 0.2 mg/kg/ dose given twice daily and slowly increased over a period of weeks to a dose of 1.1 +/- 0.1 mg/kg/day (range 0.5 to 2.3 mg/kg/day). RESULTS: Between the time point of stabilization on conventional medications and the initiation of metoprolol therapy, there was no significant change in fractional shortening (13.1 +/- 1.2% vs 15.0 +/- 1.2%) or ejection fraction (25.6 +/- 2.1% vs 27.0 +/- 3.4%). However, after metoprolol therapy for 23.2 +/- 7 months, there was a significant increase in fractional shortening(23.3 +/- 2.6%) and ejection fraction (41.1 +/- 4.3%) (p < 0.05). CONCLUSIONS: Metoprolol improves ventricular function in some children with dilated cardiomyopathy and congestive heart failure. Further study is warranted to better define which children may benefit most from beta-blocker therapy and which beta-blockers are most efficacious.

Adolescent↗

PubMed1998

Usefulness of echocardiography for detection of coronary artery thrombi in patients with Kawasaki disease.

To evaluate the role of echocardiography for predicting and accurately detecting thrombi in patients with abnormal coronary arteries after Kawasaki disease, we reviewed the echocardiograms of 40 consecutive patients and compared echocardiographic findings with angiographic findings when available. Patients with Kawasaki disease who had coronary artery aneurysms > or =5 mm had significantly greater multivessel involvement, thrombi, and persistent coronary abnormalities than those with diameters <5 mm.

Child, Preschool↗

PubMed1998

Size of ventricular structures influences surgical outcome in Down syndrome infants with atrioventricular septal defect.

To evaluate the relation between ventricular structure size and surgical outcome in Down versus non-Down syndrome infants with an atrioventricular septal defect, we reviewed the charts and echocardiograms of 44 consecutive infants (34 with Down syndrome) who underwent atrioventricular septal defect repair. Children with Down syndrome had significantly greater aortic valve diameters, left ventricular valve areas, and left/right atrioventricular valve area ratios as well as fewer adverse outcomes than non-Down syndrome children.

Aortic Valve↗

PubMed1998

Beta-blocker therapy in young children with congestive heart failure under consideration for heart transplantation.

BACKGROUND: Although beta-blocker therapy for dilated or ischemic cardiomyopathy is now an accepted and effective treatment in adults, little is known about its efficacy in children. METHODS: We reviewed our experience with the use of metoprolol in four younger children with cardiomyopathy who were referred for consideration for heart transplantation because of severe congestive heart failure. RESULTS: Over a follow-up period of 12.6 +/- 6 months, left ventricular fractional shortening increased from 13.8% +/- 7% to 25.5% +/- 13%, and ejection fraction increased from 19.8% +/- 11% to 40.8% +/- 21% (p < 0.05). Two children became asymptomatic. CONCLUSION: Metoprolol may be effective in improving ejection fraction and symptoms in some young children with cardiomyopathy and congestive heart failure.

Adolescent↗

PubMed1998

Pulmonary vascular resistance of children treated with nitrogen during early infancy.

BACKGROUND: We have empirically used supplemental nitrogen in newborns with a functional single ventricle and ductal-dependent systemic perfusion to prevent pulmonary vasodilation and deliver a greater proportion of flow to the systemic circulation. Thus, we reviewed patient outcome to determine whether adverse pulmonary vascular effects may be associated with this therapy. METHODS: From December 1991 to December 1995, the fraction of inspired oxygen was adjusted, with supplemental nitrogen if necessary, to maintain an oxygen saturation near 75% in 20 newborns awaiting heart transplantation. Medical records were reviewed to evaluate (1) the duration of nitrogen therapy, (2) pulmonary vascular histology, (3) postoperative pulmonary hemodynamics, and (4) survival. RESULTS: Thirteen patients underwent heart transplantation, 4 patients died without surgical intervention, and 3 patients underwent late aortic reconstruction. Supplemental nitrogen was used without exceeding a fraction of inspired oxygen of 0.21 for 38 +/- 6 days. One patient had evidence of changes of potentially irreversible pulmonary vascular disease. Pulmonary vascular resistance was not increased long-term in surviving patients. CONCLUSIONS: Supplemental nitrogen can be used to maintain a systemic oxygen saturation near 75% for an extended period in newborns with ductal-dependent systemic perfusion with no long-term adverse effect on pulmonary vascular resistance.

Administration, Inhalation↗

PubMed1998

Late results and reintervention after aortic valvotomy for critical aortic stenosis in neonates and infants.

BACKGROUND: Many centers have adopted balloon valvuloplasty for treatment of infants with critical aortic stenosis because of historically poor early results and a lack of long-term results with surgical valvotomy. We evaluated our results with open aortic valvotomy over the past decade, specifically examining factors influencing survival and reintervention in the current era. METHODS: From 1986 to 1996, 37 infants in the first 3 months of life underwent open aortic valvotomy for critical aortic stenosis. All patients underwent cardiopulmonary bypass, valvotomy, and valve debridement under direct vision with standard techniques. RESULTS: Early mortality was 11% (4 of 37, 70% confidence limit 7% to 20%) and all early deaths were in neonates less than 2 weeks of age. Late death occurred in 6 patients a mean of 10 +/- 12 months (range, 2 to 36 months) after valvotomy. Actuarial survival, including operative deaths was 92% +/- 6% at 1 month, 78% +/- 9% at 1 year, and 73.4% +/- 10% at 10 years. In a multifactorial regression analysis, the best predictors of death were the presence of endocardial fibroelastosis and small body surface area and the best predictor of the need for late reintervention was preoperative aortic annular size. Thirteen patients required reintervention: repeat operation in 7 patients, balloon valvuloplasty in 3 patients, and both balloon valvuloplasty and reoperation in 3 patients. Actuarial freedom from reintervention postoperatively is 97% +/- 3% at 1 month, 73% +/- 9% at 1 year, and 55% +/- 11% at 10 years. Reintervention was for recurrent left ventricular outflow obstruction in 9 patients and mixed aortic stenosis and aortic insufficiency in 4. Echocardiography 4.3 +/- 2.5 years after aortic valvotomy in survivors who have not required reintervention (n = 20) revealed a Doppler peak instantaneous systolic gradient of 37 +/- 14 mm Hg and mild or less aortic regurgitation in 16 patients and moderate aortic regurgitation in 4 patients. CONCLUSIONS: Current surgical results with critical aortic stenosis in the neonate and young infant are acceptable in terms of both late survival, reintervention, and functional results in the majority of patients. Newer interventions, such as balloon valvuloplasty, should be carefully evaluated for long-term results and should be compared more appropriately to current surgical results to determine the best treatment modality for the neonate and infant with critical aortic stenosis.

Actuarial Analysis↗

PubMed1997

Common cardiovascular problems in the young: Part I. Murmurs, chest pain, syncope and irregular rhythms.

Cardiovascular signs and symptoms in young people are common and usually represent variants of normal physiology. However, these signs and symptoms can also indicate the presence of important cardiovascular disorders. Innocent heart murmurs can be distinguished from pathologic murmurs by the lack of associated symptoms, as well as their loudness, timing and location. Although most chest pain in this age group is of musculoskeletal or psychogenic origin, cardiac causes can include pericarditis, aortic stenosis and coronary anomalies. Syncope is usually vasovagal in origin and has a benign prognosis. Sinus arrhythmia and isolated extrasystoles are the most common causes of irregular cardiac rhythms in the young. Multiform premature ventricular contractions, couplets and ventricular tachycardia may indicate underlying cardiac disease.

Adolescent↗

PubMed1997

Doppler evaluation of aortic regurgitation in children.

Doppler indexes have been used successfully to determine the severity of aortic regurgitation (AR) in adults but have not been evaluated systematically in children. To evaluate the accuracy of specific Doppler echocardiographic indexes in assessing the degree of AR in children, 30 children underwent 2-dimensional and Doppler echocardiography within 24 hours of angiography. Patients were divided into 4 groups based on the degree of angiographic AR. Color Doppler jet width, short-axis jet area, jet length, and maximum jet area were measured. AR slope was measured using continuous-wave Doppler. Flow in the abdominal aorta was evaluated using pulsed Doppler. Doppler indexes were compared with the angiographic grade of AR. Jet width and short-axis jet area were significantly different between groups and showed strong correlation with the angiographic grade. Holodiastolic flow reversal in the abdominal aorta separated 1+ to 2+ from 3+ to 4+ AR (100% sensitivity and 100% negative predictive value for 3+ to 4+ AR). Jet length, maximum jet area, and the ratio of reverse to forward abdominal aortic velocity time integrals correlated with angiography but showed little difference between groups that differed by only 1 angiographic grade. AR slope did not correlate with the angiographic grade. We conclude that in children, color Doppler jet width, short-axis jet area, and holodiastolic abdominal aortic flow reversal are the best predictors of angiographic severity. Use of these indexes may obviate the need for angiography to determine the degree of AR in children.

Aortic Valve↗

PubMed1997

Persistence of human leukocyte antigen (HLA) antibodies after one year in children receiving cryopreserved valved allografts.

This study shows that the broad anti-HLA antibody response against cryopreserved valved allografts used for surgical repair of congenital heart disease persists beyond 1 year after implantation. In 3 patients, there were clearly defined HLA antibody specificities consistent with the HLA phenotypes of the patients, i.e., the panel-reactive antibody was directed against major alloantigen groups that were not expressed by the antibody responders.

Adolescent↗

PubMed1997

A novel approach to pediatric intraaortic balloon pump timing using M-mode echocardiography.

Timing balloon inflation and deflation is difficult in pediatric patients undergoing intraaortic balloon pumping, because the electrocardiogram and arterial pressure tracings are inadequate markers of the onset of diastole and systole. M-mode echocardiography provides a precise marker of aortic valve opening and closure, as well as balloon motion, and allows accurate timing by real-time adjustment of balloon inflation to diastole and deflation to systole.

Adolescent↗

PubMed1997

Doppler echocardiography distinguishes between physiologic and pathologic "silent" mitral regurgitation in patients with rheumatic fever.

BACKGROUND: The diagnosis of rheumatic fever is based on physical findings (major) and supporting laboratory evidence (minor) as defined by the Jones criteria. Rheumatic carditis is characterized by auscultation of a mitral regurgitant murmur. Doppler echocardiography, however, may detect mitral regurgitation when there is no murmur ("silent" mitral regurgitation), even in normal individuals. HYPOTHESIS: The hypothesis of this study was that physiologic mitral regurgitation can be differentiated from pathologic "silent" mitral regurgitation by Doppler echocardiography. METHODS: The study group consisted of 68 patients (2-27 years) with normal two-dimensional imaging and Doppler evidence of mitral regurgitation but no murmur. Patients with rheumatic fever (n = 37) met Jones criteria (chorea in 20, arthritis in 17). Patients without rheumatic fever (n = 31) were referred for innocent murmur (n = 7), abnormal electrocardiogram (n = 13), and chest pain (n = 11). Echoes were independently reviewed by two cardiologists blinded to the diagnosis. Pathologic mitral regurgitation was defined as meeting the following four criteria: (1) length of color jet > 1 cm, (2) color jet identified in at least two planes, (3) mosaic color jet, and (4) persistence of the jet throughout systole. Jet orientation was also noted. RESULTS: Using the above criteria, there was agreement in echo interpretation of pathologic versus physiologic mitral regurgitation in 67 of 68 patients (interobserver variability of 1.5%). Pathologic regurgitation was found in 25 (68%) patients with rheumatic fever but in only 2 (6.5%) patients without rheumatic fever (p < 0.001). The specificity of Doppler for detecting pathologic regurgitation was 94% with a positive predictive value of 93%. The color mitral regurgitant jet was posteriorly directed in all 25 patients with rheumatic fever. CONCLUSION: Pathologic "silent" mitral regurgitation of rheumatic fever can be distinguished from physiologic mitral regurgitation using strict Doppler criteria, particularly when the jet is directed posteriorly. These data support the use of Doppler echocardiography as a minor criterion for evaluating patients with suspected rheumatic fever.

Acute Disease↗

PubMed1997

Possibility of postnatal left ventricular growth in selected infants with non-apex-forming left ventricles.

To evaluate postnatal left ventricular growth potential, we reviewed the echocardiograms of seven infants with left ventricles that did not form an apex. Prostaglandins were used to maintain patency of the ductus arteriosus in six infants. Associated abnormalities included aortic stenosis in five, coarctation in three, and left atrial isomerism in one. Initial echocardiographic measurements (7 +/- 9 days) were compared with measurements at 1 month (36 +/- 9 days). Weight (3.0 +/- 0.1 vs 3.0 +/- 0.5 kg) and body surface area (BSA) (0.2 +/- 0.01 vs 0.2 +/- 0.01 m2) did not change. Comparing initial measurements with measurements at 1 month, there were significant increases (p < 0.05) in aortic annulus diameter (4.5 +/- 0.5 vs 5.6 +/- 0.7 mm), aortic root diameter indexed to BSA (2.9 +/- 0.5 vs 3.7 +/- 0.7 cm/m2), ratio of the long axis of the left ventricle to the long axis of the heart (0.74 +/- 0.1 vs 0.86 +/- 0.1), left ventricular end-diastolic volume indexed to BSA (10 +/- 2 vs 24 +/- 9 ml/m2), left ventricular mass indexed to BSA (27 +/- 13 vs 47 +/- 28 gm/m2), mitral valve area indexed to BSA (2.3 +/- 0.5 vs 3.2 +/- 0.7 cm2/m2), left ventricular area (2.1 +/- 0.5 vs 3.6 +/- 1.1 cm2), and Rhodes score (-2.7 +/- 0.5 vs -1.1 +/- 0.9). Tricuspid valve area indexed to BSA (5.8 +/- 1.5 vs 6.1 +/- 1.1 cm2/m2) and long axis of the heart indexed to BSA (13.0 +/- 2.8 vs 13.6 +/- 2.9 cm/m2) did not change. The increase in measurements appeared adequate for biventricular physiology in five infants (four are alive [3.9 +/- 2.6 years] and one died after not being able to wean from the ventilator). These data suggest that a non-apex-forming left ventricle may have postnatal growth potential.

Echocardiography↗

PubMed1997

Apoptosis in heart transplantation.

Apoptosis, or programmed cell death, is a mechanism of cell death that plays a major role during development, homeostasis, and in many disease states. The interaction of the cell membrance protein, Fas, with its ligand, Fas ligand, induces apoptosis in Fas-bearing cells. Several factors induce apoptosis in mammalian cardiomyocytes, including reperfusion injury, hypoxia, mechanical stretch, myocardial infarction, rapid ventricular pacing, and hypertensive heart failure. Although studies in the transplanted hearts of rodents and humans have shown the presence of Fas, Fas ligand, and apoptosis in the myocardium, there is controversy regarding which cells in the myocardium are actually undergoing apoptosis after heart transplantation. It is even less clear what type of relationship, if any, apoptosis has to allograft rejection or post-transplant graft coronary vasculopathy. This review summarizes the current knowledge regarding apoptosis in the transplanted heart and discusses some of the controversies surrounding this new and rapidly expanding area of investigation.

Apoptosis↗

PubMed1997

Cardiac transplantation for Kawasaki disease.

OBJECTIVE: Severe cardiac sequelae from Kawasaki disease include coronary ischemia and have been treated with a variety of coronary artery bypass procedures. There is only one published report of a child who underwent cardiac transplantation for severe Kawasaki disease-related cardiac complications. The purpose of this study was to gather the worldwide experience with cardiac transplantation for Kawasaki disease. METHODS: Data were obtained from the United Network for Organ Sharing Registry, the European transplant experience, and a phone survey of many Kawasaki disease investigators. Diagnostic and surgical reports as well as clinical records were reviewed. Results. We identified 13 Kawasaki disease patients who underwent cardiac transplantation and obtained data on 10. In these 10 patients, the timing of transplantation was within 6 months after diagnosis of Kawasaki disease (4 patients), 1 to 5 years after diagnosis (3 patients), and 9 to 12 years after diagnosis (3 patients). Indications for transplantation included severe myocardial dysfunction, severe ventricular arrhythmias including cardiac arrest, and severe distal multivessel occlusive coronary artery disease. Nine of the 10 patients remain alive and healthy, with up to 6 years' posttransplant follow-up. One patient died 10 months posttransplant after severe refractory rejection. In addition, 1 patient required retransplantation at 4 years for severe rejection. CONCLUSIONS: Cardiac transplantation for severe ischemic heart disease as a sequela of Kawasaki disease is feasible and can benefit the small subgroup of patients who are not candidates for revascularization because of distal coronary stenosis or aneurysms and/or those with severe irreversible myocardial dysfunction.

Adolescent↗

PubMed1997

Myocardial apoptosis in a heterotopic murine heart transplantation model of chronic rejection and graft vasculopathy.

BACKGROUND: Apoptosis has been implicated in myocardial reperfusion injury and in experimental transplantation rejection. One mechanism of apoptosis is through the interaction of the cell-surface Fas receptor on target cells and the Fas ligand that is expressed on cytotoxic T cells. The purpose of this study was to look for evidence of myocardial Fas receptor, Fas ligand, and apoptosis in a murine heterotopic heart transplantation model of chronic rejection/graft vasculopathy. METHODS: Using the nick-end labeling technique, we examined a murine heterotopic heart transplantation model of chronic rejection/graft vasculopathy (strain B10.A to B10.BR) histologically for evidence of DNA fragmentation. MRNA for the Fas receptor, Fas ligand, and beta-actin was detected with reverse transcription-polymerase chain reaction. RESULTS: Hearts harvested after 30 and 60 days showed an intimal index of the allografts (0.5 +/- 0.1) (mean +/- standard error) that was at least five times more than syngeneic grafts and native (nontransplanted) hearts (p < 0.01). In situ nick end-labeling of partially degraded DNA with terminal deoxynucleotydil transferase showed an increase in apoptotic cells in allografts and syngeneic grafts compared with native hearts. Reverse transcription-polymerase chain reaction detected equal myocardial RNA signal intensity of Fas receptor and beta-actin in allografts, syngeneic grafts, and native hearts. In contrast, allografts showed a strong signal for the Fas ligand mRNA, a signal not seen in syngeneic grafts or native hearts. CONCLUSIONS: Apoptosis is occurring in both allografts and syngeneic grafts in this murine model of chronic rejection/graft vasculopathy, although distinct mechanisms may be involved.

Animals↗