Conduction system in two cases of sudden death two years after the Mustard procedure.

This report describes a serial section examination of the conduction system in two children who died suddenly 2 years following the Mustard procedure for complete transposition. The first child manifested sinus rhythm alternating with junctional rhythm in the last year of life. The second child, 2 months before death, had first-degree atrioventricular (AV) block which progressed to second-degree block with 2:1 conduction alternating with a junctional rhythm with AV dissociation. Examination of the conduction system in both cases revealed the approaches to the sinoatrial (SA) and the AV nodes to be markedly fibrosed. In addition, in Case 1 the SA node was interrupted by sutures and in Case 2 the SA node was considerably fibrosed. The arrhythmias produced and the probable cause of sudden death in both cases may be related to surgical injury to the approaches to the SA and AV nodes. This study and the review of the literature emphasize the necessity of maintaining the integrity of the SA node, the approaches to the SA and AV nodes, and the superior preferential pathway while performing the Mustard procedure for complete transposition.

Early and late results in pulmonary atresia and intact ventricular septum.

We examined the early and late results of operations in 29 consecutive neonates with pulmonary atresia and intact ventricular septum treated from 1980 to 1988. Transventricular pulmonary valvotomy and central aorta-pulmonary artery shunting were performed in 19 of 22 infants who had a patent infundibulum. Pulmonary valvotomy alone was performed in 3 of the 22 infants with a patent infundibulum, but 2 of these required subsequent systemic-pulmonary artery shunts. Primary shunting was used to palliate 7 infants who had absent infundibular portions of the right ventricle and a very diminutive right ventricular cavity. Tricuspid valve excision and atrial septectomy were also performed in 5 of these 7 infants to decompress large fistulous communications between the right ventricule and coronary artery. Two early deaths (2/29, 6.9%) occurred overall. Both were in infants who had a very small right ventricle. Definitive operation has been accomplished in 16 patients; 13 have had closure of residual interatrial communications and shunt ligation with no deaths, and 3 have undergone modified Fontan repair with 1 death. Actuarial survival rate for the entire group, including operative deaths, is 86% at 5 years. The technique of transventricular pulmonary valvotomy and systemic-pulmonary artery shunting offers a reliable means of palliating neonates with pulmonary atresia and intact ventricular septum and obtains good late right ventricular growth. Systemic-pulmonary shunting, tricuspid valvectomy, and atrial septectomy may offer a means of reducing or obliterating right ventricular-coronary artery fistulas.

Immunologic and clinical correlations in rheumatic fever and rheumatic heart disease.

The intimate relationship of Streptococcus pyogenes and rheumatic fever is well-established, but the precise pathogenesis of rheumatic fever and rheumatic heart disease continues to elude intense investigative efforts by students of the disease worldwide. Technologic advances in molecular biology, not thought possible two decades ago, have given additional insight into the immunologic aspects of the disease. On the clinical side echocardiography has proved to be a marvelous, non-invasive technique to evaluate cardiac anatomy and function. We are now able to gain a closer correlation of the clinical presentation and the autoimmune response. The increased understanding acquired both from the "bench" and the "bedside" are making this perplexing disease somewhat less mysterious. We seem tantalizingly close to grasping a complete understanding of the pathogenesis of rheumatic fever and rheumatic heart disease.

Intra-aortic balloon pumping: adaptation for pediatric use.

Commercially available equipment permits the extension of intra-aortic balloon pumping (IABP) into the pediatric age range. The special needs of the pediatric patient, however, have to be recognized and well managed if IABP is to become an accepted mode of circulatory support for children.

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.

Intra-aortic balloon pumping device for infants.

The miniature components of an intra-aortic balloon pumping system (IABP) have been successfully developed in this laboratory and have been effectively tested both in vitro and in 32 in vivo experiments using small animals weighing 3.5--18 kg. It is reasonable to assume that IABP can be successfully employed for clinical use in infants and small children.

Persistence of acute rheumatic fever in the intermountain area of the United States.

We report our 8-year experience with the resurgence of acute rheumatic fever during the years 1985 through 1992. The records of 274 confirmed cases referred to Primary Children's Medical Center were reviewed. The clinical features including the presence of the Jones criteria, demographic data, preceding streptococcal infection, and the use of echocardiographic studies were tabulated and assessed. Patients came predominantly (84%) from middle-class families with access to medical care. Only 46 patients (17%) sought medical attention for a preceding sore throat. Carditis evident by auscultation was the dominant major manifestation in 68% of the cases. Echocardiography demonstrated mitral regurgitation that was not audible in 15 (47%) of 32 patients who had only polyarthritis at onset and in 30 (57%) of the 53 who had pure chorea. The incidence of acute rheumatic fever has been declining since the peak of the outbreak in 1985 but is continuing in the intermountain area at rates comparable to those of the 1960s.

Inadvertent ligation of the left pulmonary artery.

In five patients, aged 4 days to 20 months, the left pulmonary artery was inadvertently ligated at the time of attempted closure of the patent ductus arteriosus. The complication was recognized in these patients between 1 day and 5 years later from findings of chest radiography, two-dimensional echocardiography with spectral analysis of Doppler shifted echoes, and angiography. In three patients, the presence of asymmetric pulmonary blood flow on chest radiographs obtained after surgery initially suggested the diagnosis. In the other two patients with bronchopulmonary dysplasia, the diagnosis was made by means of two-dimensional echocardiography and Doppler spectra in one and angiography in the other. On angiograms, the left pulmonary artery distal to the ligation was visualized by delayed opacification from aortic collaterals in three patients and by means of pulmonary venous wedge injection in one. Radiographic and echocardiographic examination with Doppler spectra may permit prompt diagnosis and early correction of this complication.

Rheumatic pneumonia: reappearance of a previously recognized complication of acute rheumatic fever.

The clinical diagnosis of acute rheumatic fever (ARF) may be challenging; however, a constellation of signs including new valvular insufficiency, cardiomegaly, and heart failure should readily prompt consideration of the diagnosis of rheumatic carditis. In addition, pulmonary findings are compatible with ARF, as associated pulmonary involvement may represent rheumatic pneumonia. We report the case of a young man with ARF and rheumatic pneumonia, a previously described but rare complication of ARF.

Intra-aortic balloon pumping in infants and children.

From November 1981 to November 1982, intra-aortic balloon pumping (IABP) was used after surgery in eight patients who were from 6 weeks to 6 years old and who weighed from 4.2 to 16.2 kg. In seven patients, specially constructed intra-aortic balloons with 2.5 and 5.0 ml volumes mounted on No. 5F catheters were used. In the largest and oldest patient, a two-chamber 10 ml balloon was used. The pumping module used was the Datascope System 82. Effective diastolic augmentation of arterial pressure was accomplished in seven of the eight patients and suprasystolic diastolic augmentation was accomplished in four. The two youngest and smallest patients are the only long-term survivors. There were two short-term survivors who died 5 and 10 days after successful IABP. In only one patient was there no appreciable effect of IABP. Miniaturization of the equipment has permitted IABP to be used effectively in pediatric patients.

Preclinical evaluation of intra-aortic balloon pumping for pediatric use.

Small intra-aortic balloons (0.75 ml to 5.0 ml) mounted on small catheters (4.0F and 5.0F) have undergone in vitro testing with the Utah Heart Driver and in vivo evaluation with 3 different pumping modules. In small animals with reduced cardiac output from acutely produced mitral regurgitation, intra-aortic balloon pumping effectively reduced aortic peak systolic pressure, lowered aortic end-diastolic pressure and reduced left atrial pressure. In addition, the Datascope system most effectively augmented diastolic pressure and increased aortic forward and negative flow as compared with 2 other pumping modules. The total system has been adequately and experimentally evaluated and is ready for clinical use in infants and small children.

Shunt quantification by mathematical analysis of indicator dilution curves.

Mathematical models are presented for describing and analyzing indicator dilution curves recorded in patients with intracardiac and great vessel shunts. The models treat individual segments of the circulation as linear system blocks, each having, at its output, a characteristic time response to a rapid injection of indicator at its input. These blocks are combined in feedback and feed-forward configurations to simulate left-to-right, right-to-left, and bidirectional shunts. A shunt analysis algorithm, using discrete analogs of the linear system models, was implemented in a computer program and used to analyze thermodilution curves recorded in patients with congenital heart defects. Results are presented comparing shunt fractions obtained from thermodilution curve analyses with oximetrically determined values in 20 patients. Comparing left-to-right shunts measured by the two methods, the mean systematic difference was 0.7% of pulmonary flow and the standard deviation was 7.6% of pulmonary flow. Statistical validation of the bidirectional shunt method will require acquisition and analysis of more data; however, reasonable shunt fractions were computed in five cases studied and good agreement with oximetric determinations was obtained in two cases where complete oximetric data were available.

Serologic evidence for a class I group A streptococcal infection among rheumatic fever patients.

Group A streptococci (GAS) of serotypes most commonly associated with rheumatic fever (RF) outbreaks differ from many other serotypes by the presence of a unique, surface-exposed epitope on the M protein molecule. Based on the presence or absence of this epitope, GAS are categorized as class I or II, respectively. The objective of this study was to determine whether RF patients have an altered immune response to the class I-specific epitope. Immunoreactivity to class I- and class II-specific epitopes was determined for serum IgG derived from persons with a recent history of acute RF, uncomplicated GAS pharyngitis, and no known recent GAS infection. The results indicate that only RF patients display elevated levels of serum IgG directed towards the class I-specific epitope; they lack immunoreactivity to the class II epitope. The serologic findings strongly suggest that many of the RF patients were recently infected with a class I GAS isolate.