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Thirty two children (aged 5-19 years) with no clinical evidence of significant cardiovascular disease undertook continuous staged supine exercise on a bicycle ergometer. Multigated radionuclide ventriculography was performed at rest and during each exercise stage. Exercise duration and total workload both increased with age. Aerobic work correlated better with age than did total work. In most children the ejection fraction for both ventricles increased by at least 5% with exercise. Right ventricular ejection fraction did not decrease with exercise in any subject but left ventricular ejection fraction decreased by 2% and 9% in two. The response of end diastolic volume to exercise was variable, but there was a consistent decrease in mean (SD) end systolic volume of the left (29(22)%) and right (30(19)%) ventricles. Cardiac index (mean (SD)) increased by 234(65)% with exercise. The left ventricular:right ventricular end diastolic volume ratio (mean (SD)) at rest was 1.26(0.26). It is concluded that exercise radionuclide ventriculography is an excellent technique for a combined assessment of exercise capacity and an evaluation of ventricular size and performance in children. These values for supine bicycle exercise in children without significant cardiovascular disease will be useful for future comparisons with other groups. [ABSTRACT FROM PUBLISHER]

In the left ventriculogram in the right anterior oblique projection the plane of the mitral valve is seen in profile and the papillary muscle shadows are outlined. The distance from the middle of the papillary muscles to the plane of the mitral valve during systole was used to assess the average length of the chordae tendineae, and the area of the papillary muscle shadows was measured as an index of hypertrophy in a series of hearts with mitral valve disease. Valvar mitral stenosis is characterised by slight reduction in the length of chordae tendineae and more hypertrophy of the papillary muscles, while in subvalvar mitral stenosis there is more shortening of the chordae tendineae and less papillary muscle hypertrophy. Valvotomy may lengthen the chordae tendineae in subvalvar mitral stenosis. In rheumatic mitral regurgitation length of chordae tendineae and papillary muscle size were normal. The measurements were not useful in assessing non-rheumatic mitral regurgitation. [ABSTRACT FROM PUBLISHER]

Antinuclear antibodies are present in most patients receiving procainamide. To ascertain whether IgG antiguanosine antibodies are associated with the development of the symptoms of systemic lupus erythematosus, we compared the levels of these antibodies in the sera of 65 patients receiving procainamide: 18 with procainamide-induced symptoms and 47 asymptomatic patients. Antinuclear antibodies measured by immunofluorescence were present in the 18 patients with drug-induced symptoms but also in 24 asymptomatic patients. Similarly, elevated serum levels of antibodies to single-stranded DNA were found in 15 patients with symptoms and in 20 asymptomatic patients. In contrast, levels of IgG antiguanosine antibodies were elevated in 15 patients with drug-induced symptoms, but in only 3 asymptomatic patients. Antiguanosine antibodies binding to single-stranded DNA were found primarily in patients with arthritis, pleuritis, and pericarditis. These results suggest a strong association between IgG antiguanosine antibodies and major manifestations of procainamide-induced systemic lupus erythematosus. [ABSTRACT FROM AUTHOR]

Background: Cells with stem cell surface markers have been identified in heart tissue. Early indications suggest that these are cardiac progenitor cells that could contribute to cardiac repair/regeneration. Clinically relevant therapeutic strategies based on these cells will require improved methods for their isolation and characterization of determinants of their mobilization, proliferation and differentiation., Methods: An ex vivo culture system was developed that promotes trafficking of progenitor-like cells from mouse ventricles to a culture surface. Cells that "trafficked" from cardiac tissue were phenotyped by flow cytometry and immunohistochemistry., Results: Morphologically distinct cells spontaneously trafficked from mouse ventricular tissue, adhered in culture, and proliferated for up to 4 weeks in Dulbecco's minimal essential media supplemented with fetal calf serum. After 4 weeks in culture, cell number declined. Co-culture with unfractionated bone marrow restored the proliferation of these trafficked cells. A significant population of the trafficked cells expressed a phenotype consistent with that of a myogenic progenitor such as: c-kit+, Sca-1+, CD45-, CD34-, CD90.2-, MyoD1-, desmin-, muscle-specific actin-, and, infrequently, myogenin+. An expanded population of trafficked cells from ventricles of mice expressing green fluorescent protein (GFP+) and containing cardiac-derived progenitor cells were injected into the pericardial space of GFP- mice. GFP+ cells trafficked throughout the heart but retained a primitive undifferentiated morphology. However, when injected into the pericardial space of Apo-E-deficient mice with coronary vasculopathy, progenitor-like cells trafficked into myocardium, and GFP+ cells differentiated into vessel-lining endothelial cells and, rarely, smooth muscle and cardiomyocytes., Conclusions: Progenitor-like cells in the heart can be mobilized by tissue injury to spontaneously traffic from cardiac tissue and can expand in culture by co-culture with bone marrow. When re-infused by pericardiocentesis, these primitive cells traffic into heart, retain immature morphology, but are capable of undergoing injury-induced differentiation. The novel method described herein permits further characterization of cardiac-derived progenitor cells, which are a candidate for cardiac regeneration strategies.

Background: Infants with hypoplastic left heart syndrome (HLHS) commonly undergo cardiac transplantation as primary management., Methods: We examined outcomes of primary transplantation for unpalliated HLHS. We analyzed data from the 20 institutions of the Pediatric Heart Transplant Study Group, from January 1, 1993, through December 31, 1998, using actuarial and parametric survival analysis and competing outcomes analysis., Results: During the 6 years studied, 1,234 patients were listed for cardiac transplantation; 262 patients (21.2%) had unpalliated HLHS. The number (and percentage) of patients with HLHS decreased from 58 (27% of patients listed) in 1993 to 30 (14%) in 1998. Overall, 25% of infants with HLHS died while waiting; primary cause of death was cardiac failure (50%). Of the remaining patients awaiting transplantation, 23 (9%) underwent Norwood/Fontan-type surgeries as interim palliation: 52% died. Ultimately, 175 patients underwent cardiac transplantation (67%); 50% received organs by 2 months after listing. Post-transplant actuarial survival was 72% at 5 years, with 76% of deaths (35/46) occurring within 3 months; early mortality was caused primarily by graft failure within the first 30 days after transplantation (in 54%). Among 1-month survivors, survival at 1 and at 5 years was 92% and 85%, respectively. Of the 262 patients listed with unpalliated HLHS, overall survival, taking into account mortality after listing and after transplantation, was 68% at 3 months and 54% at 5 years., Conclusions: Cardiac transplantation offers good intermediate survival for infants with unpalliated HLHS.

Cardiac effects of anthracyclines or their metabolites may include both the stimulation and inhibition of Ca(2+) release from sarcoplasmic reticulum. In this study, the ability of daunorubicin and its primary metabolite, daunorubicinol, to stimulate and inhibit Ca(2+) release from canine sarcoplasmic reticulum (SR) vesicles was investigated. It was observed that both daunorubicin and daunorubicinol were several fold more potent at inhibiting than they were at stimulating SR Ca(2+) release. Respective IC50 inhibition of daunorubicin and daunorubicinol for caffeine-induced calcium release was 1.2 and 0.6 microM, and for spontaneous Ca(2+) release was 3 and 1 microM. EC50's for daunorubicin- and daunorubicinol-induced calcium release were 30 and 15 microM, respectively. Inhibition of either spontaneous or caffeine-induced SR Ca(2+) release was inversely related to the amount of Ca(2+) loaded into the SR before exposure to daunorubicin or daunorubicinol. The free-radical scavenger dithiothreitol did not attenuate the ability of anthracyclines to inhibit SR Ca(2+) release. A nonquinone daunorubicin derivative, 5-iminodaunorubicin, was less potent than daunorubicin at inhibiting caffeine-induced Ca(2+) release. These data suggest anthracyclines and their metabolites may produce cardiotoxicity through free-radical independent, concentration-dependent effects on SR Ca(2+) release. These effects involve either inhibition or stimulation of SR Ca(2+) release and are partly dependent upon the presence of the quinone moiety., (Copyright 2000 Academic Press.)

Background: The unique demands of cardiac transplantation in infancy have led to non-invasive rejection-surveillance strategies. ECHO-A is a multiparametric, two-dimensionally guided, M-mode analysis algorithm that assigns an empirically derived score for deviations of recipient parameters to age-adjusted, population-based normal values. A cumulative ECHO-A score > or =4 is highly predictive of endomyocardial biopsy Grade > or =3 and of cellular rejection., Methods: This study determined whether modifying ECHO-A to score for deviations of recipient parameters from the recipient's baseline would improve the predictive power of ECHO-A. We reanalyzed 701 consecutive echocardiograms of 18 pediatric cardiac transplant recipients (median age at transplantation, 142 days) and based scoring on significant (Z score > or =1) deviation from the patients' baseline means (ECHO-B)., Results: Eight episodes of treated rejection occurred during the first year after transplantation (median, 1.4 years). Approximately 10% (72) of the analyses had ECHO-A scores > or =4 that were not associated with treated rejection and were considered false positives. We identified parameters that contributed to the false-positive evaluations and calculated patient-specific baseline mean +/- standard deviation. The ECHO-B, in comparison with ECHO-A, decreased the number of false positives from 72 to 10, increased specificity from 90% to 99%, and increased the positive predictive value about 4-fold (10% to 44%). With treated rejection episodes, ECHO-B increased ECHO-A scores in 7 of 8 recipients and increased the mean score from 6 to 8., Conclusions: analysis algorithm based on change from baseline improved the positive predictive power without reducing the negative predictive value of multiparametric quantitative analyses of echocardiograms following pediatric heart transplantation.