Delayed contrast enhancement magnetic resonance imaging in congenital aortic stenosis.

We report a case of a 12-year-old boy with severe congenital aortic stenosis in whom magnetic resonance imaging (MRI) with delayed contrast enhancement demonstrated extensive subendocardial hyperenhancement within the left ventricle. The hyperenhancement was confirmed to be subendocardial infarct and fibrosis by histopathology. This case supports the utility of MRI with delayed contrast enhancement in evaluating myocardial viability in patients with congenital heart disease.

Costs and cost-effectiveness of routine transesophageal echocardiography in congenital heart surgery.

BACKGROUND: The safety and efficacy of transesophageal echocardiography (TEE) during congenital heart surgery is well established. The economic costs and benefits associated with its routine use in this setting are, however, uncertain. We sought to analyze the impact that routine intraoperative TEE had on echocardiographic costs in the setting of congenital heart surgery. METHODS AND RESULTS: A retrospective, case-controlled analysis of echocardiographic costs during the operative and postoperative periods was performed for 63 children undergoing elective, complex intracardiac repair. Similar analysis was performed for a smaller group of patients undergoing simple repairs. To ascertain whether any additional cost savings was realized through the use of TEE, we documented the impact that operative TEE had on altering surgical strategy as well as whether TEE use was associated with any intraoperative complications. Despite the additional expense, routine TEE, in the setting of complex repair, resulted in no significant increases in echocardiographic costs, suggesting the superior information provided may in fact reduce the need for additional postoperative studies in the intensive care setting. Although no child required a return to cardiopulmonary bypass, surgical therapy was altered by TEE findings in 2 (3%) of 63 patients. Complications were rare and self-limited, usually occurring with positioning of the probe in smaller patients. CONCLUSIONS: The findings of improved surgical outcomes in a percentage of patients, coupled with the lack of any significant increment in echocardiographic costs, confirm that intraoperative TEE is a beneficial and cost-effective intervention in children requiring complex cardiac repair.

Prospective diagnosis of alveolar capillary dysplasia in infants with congenital heart disease.

Alveolar capillary dysplasia (ACD) is a lethal pulmonary disorder found in newborns that is characterized by severe pulmonary hypertension and hypoxemia. We report on the clinical behavior of this disorder in a series of patients and its association with congenital heart disease, especially left heart obstructive disease; we also report a prospective diagnosis of ACD by lung biopsy in a newborn with congenital heart disease, which prevented futile and prolonged medical intervention.

Developmental remodeling and shortening of the cardiac outflow tract involves myocyte programmed cell death.

The embryonic outflow tract is a simple tubular structure that connects the single primitive ventricle with the aortic sac and aortic arch arteries. This structure undergoes a complex sequence of morphogenetic processes to become the portion of the heart that aligns the right and left ventricles with the pulmonary artery and aorta. Abnormalities of the outflow tract are involved in many clinically significant congenital cardiac defects; however, the cellular and molecular processes governing the development of this important structure are incompletely understood. Histologic and tissue-tagging studies indicate that the outflow tract tissues compact and are incorporated predominantly into a region of the right ventricle. The hypothesis tested in the current study was that cell death or apoptosis in the muscular portion of the outflow tract is an important cellular mechanism for outflow tract shortening. The tubular outflow tract myocardium was specifically marked by infecting myocytes of the chicken embryo heart with a recombinant replication-defective adenovirus expressing beta-galactosidase (beta-gal) under the control of the cytomegalovirus promoter. Histochemical detection of the beta -gal-labeled outflow tract myocytes revealed that the tubular structure shortened to become a compact ring at the level of the pulmonic infundibulum over several days of development (stages 25-32, embryonic days 4-8). The appearance of apoptotic cardiomyocytes was correlated with OFT shortening by two histologic assays, TUNEL labeling of DNA fragments and AnnexinV binding. The rise and fall in the number of apoptotic myocytes detected by histologic analyses paralleled the change in activity levels of Caspase-3, a protease in the apoptotic cascade, measured in outflow tract homogenates. These results suggest that the elimination of myocytes by programmed cell death is one mechanism by which the outflow tract myocardium remodels to form the proper connection between the ventricular chambers and the appropriate arterial trunks.

Severe cyanosis in a newborn after transvenous pacing wire placement.

Inadvertent disruption of tricuspid valve apposition by a pacing catheter in a neonate is described. Severe cyanosis due to atrial level shunting resulted, similar to the pathophysiologic state seen in Ebstein's anomaly.

Forced expression of the homeodomain protein Gax inhibits cardiomyocyte proliferation and perturbs heart morphogenesis.

The development of the tubular heart into a complex four-chambered organ requires precise temporal and region-specific regulation of cell proliferation, migration, death and differentiation. While the regulatory mechanisms in heart morphogenesis are not well understood, increasing attention has focused on the homeodomain proteins, which are generally linked to morphogenetic processes. The homeodomain containing gene Gax has been shown to be expressed in heart and smooth muscle tissues. In this study, the Gax protein was detected in the nuclei of myocardial cells relatively late in chicken heart development, at a time when myocyte proliferation is declining. To test the hypothesis that the Gax protein functions as a negative regulator of cardiomyocyte proliferation, a replication-defective adenovirus was used to force its precocious nuclear expression during chicken heart morphogenesis. In experiments in which Gax- and beta-galactosidase-expressing adenoviruses were co-injected, clonal expansion of myocytes was reduced, consistent with inhibition of myocyte proliferation. This effect on proliferation was corroborated by the finding that the percentage of exogenous Gax-expressing myocytes that were positive for the cell cycle marker PCNA decreased over time and was lower than in control myocytes. The precocious nuclear expression of Gax in tubular hearts resulted in abnormal heart morphology, including small ventricles with rounded apices, a thinned compact zone and coarse trabeculae. These results suggest a role for the Gax protein in heart morphogenesis causing proliferating cardiomyocytes to withdraw from the cell cycle, thus influencing the size and shape that the heart ultimately attains.

Association of systemic to pulmonary collateral arteries with tetralogy of Fallot and absent pulmonary valve syndrome.

Two patients with tetralogy of Fallot and absent pulmonary valve syndrome with significant systemic to pulmonary collateral arteries are described. Search for these rarely reported vessels should be included in the workup of these complex patients.

The value of IgM antibodies to PGL-I in the diagnosis of leprosy.

An ELISA has been used to measure IgM antibodies to phenolic glycolipid-I (PGL-I) in previously undiagnosed patients who were suspected of leprosy on purely clinical grounds. The certainty of clinical diagnosis was classified as either "firm" or "indefinite." Leprosy was confirmed in 133 of 161 patients on the basis of positive slit-skin smears and/or skin and/or nerve histopathology. All 58 patients with multibacillary leprosy (BB, BL, or LL) were correctly diagnosed clinically, as were 50 of 54 patients (93%) with a firm diagnosis of BT or TT leprosy. The firm clinical diagnoses were more accurate than either the slit-skin smear or ELISA data. However, there were 44 patients (27% of total), designated "rule out leprosy" (RO), for whom the clinical diagnosis was indefinite. The clinical suspicion of leprosy (RO) was correct in only 24 (55%) of these patients who had BT leprosy. The slit-skin smears were positive in only 20% of these patients compared to 50% for the ELISA. It was concluded that the PGL-I IgM ELISA may have its greatest diagnostic confirmatory value in paucibacillary disease because paucibacillary leprosy comprises the major source of clinical diagnostic difficulty.