What is the cause of cardiomegaly (enlarged heart) in Rheumatic Fever (RF)?

From the Guidelines

Rheumatic fever can cause an enlarged heart primarily due to inflammation of the heart tissues and subsequent valve damage, as supported by the World Heart Federation's position statement on the prevention and control of rheumatic heart disease 1. The inflammation affects the heart valves, particularly the mitral and aortic valves, leading to scarring and valve stenosis or regurgitation. Key points to consider include:

• The body's immune system mistakenly attacks heart tissues after a streptococcal infection, causing carditis (inflammation of the heart) 1.
• As the heart works harder to compensate for these valve abnormalities, the cardiac chambers enlarge and the heart muscle thickens, resulting in cardiomegaly (enlarged heart).
• The left ventricle often enlarges first as it struggles to pump blood through damaged valves.
• This cardiac remodeling is the body's attempt to maintain adequate cardiac output despite valve dysfunction.
• Over time, without proper treatment, this compensation mechanism fails, potentially leading to heart failure, as highlighted by the estimated 233,000–468,164 individuals who die from RHD each year 1. Prevention and management strategies are crucial, including:
• Prompt treatment of streptococcal throat infections with antibiotics like penicillin.
• Patients with established rheumatic heart disease require prophylactic antibiotics before dental or surgical procedures to prevent recurrent episodes.
• Emerging echocardiographic data suggest that the true prevalence of RHD might be several-fold higher than the 2005 global estimate, emphasizing the need for increased awareness and prevention efforts 1.

From the Research

Enlarged Heart in Rheumatic Fever

• Rheumatic fever can lead to an enlarged heart, also known as cardiomegaly, due to the inflammation of the heart tissue caused by the disease 2.
• The inflammation can lead to scarring and damage to the heart valves, which can result in an enlarged heart 3, 4.
• The use of anti-inflammatory agents such as aspirin and corticosteroids has been shown to reduce the inflammation and prevent further damage to the heart valves, but the evidence is not conclusive 3, 4.
• Some studies suggest that the use of corticosteroids may reduce the risk of cardiac disease at one year, but the results are not significant and should be interpreted with caution 4.

Pathogenesis of Rheumatic Fever

• Rheumatic fever is an immunologically mediated inflammatory disease that occurs as a delayed sequel to group A streptococcal throat infection, in genetically susceptible individuals 5.
• The disease is caused by an autoimmune response to the infection, which leads to inflammation and damage to the heart tissue 2, 5.
• The inflammation can lead to scarring and damage to the heart valves, which can result in an enlarged heart and other complications 3, 4, 2.

Prevention and Treatment of Rheumatic Fever

• Antibiotics have been shown to be effective in reducing the incidence of acute rheumatic fever following an episode of suspected group A streptococcal pharyngitis 6.
• The use of penicillin has been shown to be effective in preventing rheumatic fever, with a protective effect of 80% 6.
• The treatment of rheumatic fever typically involves the use of anti-inflammatory agents such as aspirin and corticosteroids, as well as antibiotics to prevent further complications 3, 4, 2.