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Ischemic myocardial necrosis and papillary muscle dysfunction in infants and children
1Department of Pathology, University of Florida, Gainesville.
Insights
Ischemic myocardial necrosis (IMN) in infants and children results from underperfusion, not coronary artery occlusion. Pathologists should consider IMN in newborns with specific clinical signs.
Area of Science:
- Pediatric Cardiology
- Neonatal Pathology
- Cardiovascular Research
Background:
- Ischemic myocardial and papillary muscle dysfunction significantly impacts infants and children, differing from adult causes like coronary artery occlusion.
- In pediatric populations, myocardial injury stems from underperfusion due to factors like birth asphyxia, congenital heart disease, and premature delivery complications.
- Unlike adults, infants and children experience ischemic injury with similar frequency in both ventricles.
Purpose of the Study:
- To highlight the distinct causes and presentations of ischemic myocardial necrosis (IMN) in newborns and children.
- To alert pathologists to clinical indicators suggestive of IMN in neonates and older infants.
- To differentiate pediatric ischemic cardiac injury from adult models.
Main Methods:
- Review of clinical presentations and pathological findings in infants and children with myocardial dysfunction.
- Analysis of etiological factors contributing to myocardial underperfusion in neonates and children.
- Comparison of pediatric ischemic injury patterns with those observed in adult models.
Main Results:
- Ischemic myocardial necrosis in infants and children is primarily caused by underperfusion, with coronary artery occlusion being rare.
- Clinical signs such as cardiogenic shock, cyanotic heart failure, or persistent fetal circulation in newborns may indicate IMN.
- Older infants may present with IMN, fibrosis, or calcification, particularly those with ventricular hypertrophy, persistent pulmonary hypertension, bronchopulmonary dysplasia, or complex congenital heart disease.
Conclusions:
- Ischemic myocardial injury in the pediatric population has unique etiologies and requires specific diagnostic considerations.
- Pathologists must be aware of the clinical context, including birth asphyxia and congenital heart disease, when evaluating myocardial damage in infants.
- Existing animal models for adult ischemic heart disease may not accurately represent the pathophysiology in newborns.
Abstract:
Ischemic myocardial and papillary muscle dysfunction has considerable implication in newborn infants and children with normal or malformed hearts. Papillary muscle dysfunction in adults primarily involves coronary artery occlusion and ischemic necrosis in the left ventricle and papillary muscles. Infants and children rarely develop coronary artery occlusion. Their myocardial dysfunction and injury occurs with nearly equal frequency in both ventricles as a result of underperfusion from a wide range of causes, including severe birth asphyxia, congenital heart disease, and complications of premature delivery. A history of cardiogenic shock, acute congestive heart failure with cyanosis and atrioventricular murmur, or persistent fetal circulation in a newborn without congenital heart disease should alert the pathologist to the possibility of ischemic myocardial necrosis (IMN). Older infants with ventricular hypertrophy, persistent pulmonary hypertension (PPHN), bronchopulmonary dysplasia (BPD), and those with malformed hearts involving severe ventricular hypertension due to outflow obstruction or pulmonary hypertension may have IMN, fibrosis, or dystrophic calcification alone or in combination. Animal models of adult ischemic cardiac injury may not be suitable for study of the newborn.