Understanding Myocarditis and Its Impact on Children
Myocarditis, an inflammation of the heart muscle, poses a significant health risk, particularly in children. Although rare, it is the leading cause of sudden death among individuals under 20, as identified in federal databases. A recent study published in Circulation Heart Failure highlights a genetic variant that may increase the likelihood of heart failure in children suffering from myocarditis.
The Role of Genetic Variants in Heart Failure
The study reveals that 34.4% of children who developed dilated cardiomyopathy following myocarditis possessed a genetic variant predisposing them to this condition. In stark contrast, only 6.3% of control children exhibited these cardiomyopathy gene variants, marking a significant difference. Dilated cardiomyopathy is characterized by the stretching and thinning of the heart’s main pumping chamber, potentially leading to heart failure when the heart cannot adequately supply the body with oxygen.
Implications for Genetic Testing
Dr. Steven E. Lipshultz, the study’s corresponding author and a professor of pediatrics at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, advocates for genetic testing in children presenting with myocarditis and cardiomyopathy. He emphasizes that few doctors currently conduct genetic testing for cardiomyopathy-causing gene variants in children with new onset heart failure, making this study a potential game changer.
Study Methodology and Findings
The research compared 32 children with dilated cardiomyopathy and myocarditis to those with myocarditis without dilated cardiomyopathy and to heart-healthy controls. Participants with cardiomyopathy were part of the Pediatric Cardiomyopathy Registry (PCMR), a network of U.S. and Canadian centers founded and led by Lipshultz.
Historically, infections were believed to lead to myocarditis with heart failure. However, many children experience infections, especially in their first year, without developing myocarditis or heart failure. This discrepancy led Lipshultz to suspect an additional risk factor, particularly when common viruses and upper respiratory symptoms result in sudden and severe myocarditis, sometimes tragically causing sudden death.
The « Double Hit » Hypothesis
Lipshultz and his colleagues propose a « double hit » hypothesis. The first « hit » is a pathological cardiomyopathy mutation present at birth, increasing the risk for cardiomyopathy and heart failure. The second « hit » occurs when an infection affects the heart muscle cells, leading to myocarditis and inflammation.
The study found a statistically significant greater proportion of children admitted to hospitals and intensive care units for heart failure and new onset myocarditis had pathological cardiomyopathy gene mutations. These mutations reduce cardiac reserve, increasing the likelihood of heart failure compared to those with myocarditis without heart failure.
Clinical Implications and Future Directions
Identifying gene mutations in these patients is crucial, as they are at higher risk for recurrent myocarditis episodes and sudden cardiac death. Consequently, these children may be candidates for implantable cardiac defibrillators. Lipshultz stresses the importance of genetic testing to identify pathologic mutations and guide clinical management.
The study’s significance was recognized with a « Top Pediatric Cardiology Research » award at the American Heart Association Scientific Sessions, presented by first author Alicia Kamsheh, MD. Stephanie Ware, MD, Ph.D., chair of medical and molecular genetics at Indiana University School of Medicine, led all genetics studies related to this research.
The findings underscore the need for genetic testing in children with myocarditis and cardiomyopathy to identify those at higher risk for severe outcomes and inform clinical decisions.
🔗 **Fuente:** https://medicalxpress.com/news/2025-12-genetic-variant-children-myocarditis-heart.html