Identifying the cause of heart muscle disease in children is key to effective treatment

Statement Highlights:

• A new American Heart Association scientific statement focuses on treatment strategies for pediatric cardiomyopathy (diseases of the heart muscle’s structure and function that may lead to heart failure and death) and is a companion to a 2019 scientific statement focused on diagnosis of the condition.
• There are several types of cardiomyopathies in children, and treatment should include personalized therapies based on the root cause, symptoms and progression of the condition in each child, according to the new scientific statement.

Newswise — DALLAS, June 8, 2023 —A fresh scientific statement published today in the flagship, peer-reviewed journal Circulation by the American Heart Association suggests that individualizing the treatment of pediatric cardiomyopathy should consider the underlying cause, symptoms, and disease progression specific to each child.

Pediatric cardiomyopathy is a cardiac muscle ailment that can impede the heart's ability to efficiently circulate blood throughout the body, potentially resulting in heart failure and fatality. These life-threatening conditions, which exist in various forms, are rare yet pervasive among children, affecting approximately 1 in every 100,000 individuals based on population-based studies conducted in the United States, Finland, and Australia.

The inaugural scientific statement dedicated to treating cardiomyopathy in children highlights significant distinctions between treatment approaches for pediatric cardiomyopathies and heart failure compared to adults. This statement serves as a companion to the American Heart Association's 2019 scientific statement, which primarily addressed the diagnosis of pediatric cardiomyopathy.

According to Steven E. Lipshultz, M.D., FAHA, the chair of the group responsible for crafting the statement, children's cardiomyopathies may share similar names with those found in adults, but they often stem from distinct causes, exhibit different risk factors, follow diverse progression patterns, and result in distinct outcomes. Unlike adults, children are not influenced by behavioral or environmental factors typically associated with cardiomyopathy, such as smoking, alcohol consumption, obesity, or Type 2 diabetes. Consequently, treatments for pediatric cardiomyopathy must be customized to address the underlying causes, ranging from enzyme replacement therapies to heart transplantation.

The causes of cardiomyopathy in children often stem from genetic abnormalities, which differentiates them from the causes typically associated with adults, such as Type 2 diabetes, alcoholism, long-term high blood pressure, or family history. Children with cardiomyopathy may experience symptoms like breathing difficulties, heart palpitations, fainting during physical activity, swelling in the ankles, feet, legs, abdomen, or congestion of neck veins. They may also exhibit heart failure symptoms, including difficulty breathing, poor feeding or growth, excessive sweating, low blood pressure, or fatigue.

The committee responsible for the statement concentrated on the treatment of the most prevalent cardiomyopathies observed in children. These include:

1. Dilated cardiomyopathy: This condition occurs when the heart enlarges, and the pumping chambers demonstrate poor contraction, leading to reduced efficiency in pumping blood.
2. Hypertrophic cardiomyopathy: Characterized by a thickened and stiff heart muscle, this condition hampers the heart's ability to relax and impairs the filling of blood into its chambers.
3. Restrictive cardiomyopathy: This form of heart muscle disease is rare and involves the stiffening of the heart muscle, which hinders the normal filling of blood into the ventricular chambers. Consequently, blood accumulates in the atria, lungs, and body, resulting in symptoms and signs of heart failure.

The committee emphasizes that pediatric cardiomyopathy can manifest at different stages, with some patients having a genetic abnormality but showing no symptoms, while others may experience severe symptoms or progress to the end-stage of the disease. It is crucial for physicians to conduct thorough evaluations and examinations of pediatric patients to identify the underlying cause of the condition. This comprehensive assessment is essential for devising an appropriate treatment plan tailored to the individual needs of each patient.

According to Lipshultz, who serves as a professor in the department of pediatrics and previously chaired pediatrics at the University at Buffalo's Jacobs School of Medicine and Biomedical Sciences, conducting genetic testing for all children with cardiomyopathy is a prudent approach that is expected to yield clinical benefits. He suggests that such genetic screening has the potential to generate cost savings, both in financial terms and emotional well-being.

The statement writing committee also highlighted the following key points:

1. Treatment can be initiated in pediatric patients at risk for cardiomyopathy, even before they develop symptoms, to slow down the progression of the disease.
2. Adult heart failure treatments have limited effectiveness in pediatric dilated cardiomyopathy. However, there is evidence suggesting that their use has contributed to a decrease in the mortality rate among children with the condition.
3. Therapies aimed at preventing sudden death in children with hypertrophic cardiomyopathies, such as exercise limitations or the use of an internal defibrillator, are continually evolving and have specific parameters based on age and size, in contrast to adult treatments and devices.
4. Heart transplantation is considered an acceptable treatment for end-stage pediatric cardiomyopathy. While ventricular assist devices are commonly used as a temporary measure while awaiting a heart transplant, they are associated with a low rate of ventricular recovery, similar to outcomes observed in adults.

Lipshultz expresses optimism for the future, noting that the limitations of sample size and funding in pediatric clinical trials are being addressed through the implementation of learning networks that involve multiple pediatric cardiomyopathy centers. He highlights the innovative utilization of multi-center registries and adaptive trial designs, which have the potential to advance and enhance cause-specific therapy options for pediatric cardiomyopathy in the future. These developments are expected to contribute to improved treatment outcomes and refine the understanding of the disease.

The scientific statement was created under the guidance of the American Heart Association's Young Hearts Pediatric Heart Failure and Transplantation Committee, which operates within the Council on Lifelong Congenital Heart Disease and Heart Health in the Young (Young Hearts). Scientific statements play a crucial role in raising awareness about cardiovascular diseases and stroke-related matters, aiding in informed healthcare decision-making. They provide a comprehensive overview of the current knowledge on a particular topic and identify areas that require further research. It is important to note that while scientific statements contribute to the development of guidelines, they do not provide specific treatment recommendations. The official clinical practice recommendations of the American Heart Association are established through their guidelines.

Co-authors are Vice Chair Charles E. Canter, M.D., FAHA; Carmel Bogle, M.D.; Steven D. Colan, M.D.; Shelley D. Miyamoto, M.D., FAHA; Swati Choudhry, M.D.; Nathanya Baez-Hernandez, M.D.; Molly M. Brickler, A.P.N.P.; Brian Feingold, M.D., FAHA; Ashwin K. Lal, M.D., FAHA; and Teresa M. Lee, M.D. Authors’ disclosures are listed in the manuscript.

The Association receives funding primarily from individuals. Foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers, and the Association’s overall financial information are available here.