Autoimmune heart disease (AHD) describes conditions where the body’s defense system mistakenly targets and attacks healthy cardiac tissue. This immune malfunction, characterized by a loss of self-tolerance, causes the system to perceive heart cells as foreign invaders. The resulting inflammation can affect any part of the heart structure, potentially impairing its function. AHD may be localized solely to the heart or, more commonly, manifest as a complication of a broader systemic autoimmune disorder.
Understanding the Autoimmune Mechanism
The pathology of autoimmune heart disease involves the adaptive immune system, specifically T-cells and B-cells, which normally neutralize external threats. A leading theory for this mistaken attack is molecular mimicry, where a foreign antigen shares structural similarities with heart proteins. The immune response attacks the microbe, but these components then cross-react with native heart tissue, initiating the autoimmune response.
Once activated, self-reactive T-cells infiltrate the heart muscle, and B-cells produce autoantibodies that bind to cardiac cells, marking them for destruction. This sustained attack triggers chronic inflammation, damaging heart tissues. Over time, this process leads to scar tissue formation (fibrosis), which stiffens the heart and reduces its ability to pump blood effectively. This damage ultimately impairs heart function.
Specific Autoimmune Conditions Affecting the Heart
Autoimmune heart disease encompasses several distinct conditions, classified by the specific cardiac structure under attack.
Localized Conditions
When the muscular wall (myocardium) is affected, the condition is autoimmune myocarditis. This inflammation weakens the heart’s ability to contract and reduces cardiac output. If the protective sac surrounding the heart (pericardium) becomes inflamed, it results in autoimmune pericarditis. This causes chest pain and, in severe cases, can restrict heart movement due to fluid buildup or tissue thickening. Damage to the inner lining and the valves is termed autoimmune endocarditis or valvulitis, impairing the valve’s ability to open and close correctly and disrupting blood flow.
Systemic Involvement
Cardiac involvement is also a frequent consequence of systemic autoimmune disorders, where body-wide inflammation extends to the heart. Systemic Lupus Erythematosus (SLE) often targets the pericardium and heart valves, potentially causing conditions like Libman-Sacks endocarditis. Rheumatoid Arthritis (RA) and Systemic Sclerosis (Scleroderma) increase the risk of cardiac damage, including accelerated atherosclerosis and myocardial fibrosis, due to the inflammatory environment. Damage in these systemic diseases can be subtle, meaning it may be advanced before symptoms appear.
Identifying Symptoms and Seeking Care
The symptoms of an autoimmune attack on the heart are often non-specific and easily mistaken for other heart conditions. Patients frequently experience profound fatigue not relieved by rest, a hallmark of chronic inflammation. Shortness of breath is another common sign, particularly during physical activity, indicating reduced heart function.
Chest pain, which may be sharp, dull, or pressure-like, can be present, especially with pericarditis or myocarditis. Other indications include heart palpitations or an irregular heartbeat, along with swelling or fluid retention in the legs and ankles (edema). Because these symptoms signal serious cardiac issues, seeking immediate medical consultation is important. Timely evaluation can differentiate autoimmune heart disease from other causes and prevent irreversible damage.
Clinical Diagnosis and Treatment Approaches
The clinical assessment of autoimmune heart disease requires advanced imaging, laboratory testing, and tissue analysis. An initial evaluation often includes an Echocardiogram (Echo) to assess the heart’s pumping function, detect fluid accumulation, or identify damage to the valves. Cardiac Magnetic Resonance Imaging (CMR) can visualize inflammation and scar tissue (fibrosis) within the heart muscle, providing detailed evidence of the autoimmune attack.
Blood tests check for elevated inflammatory markers, such as C-reactive protein, and identify specific autoantibodies suggesting an underlying systemic disease. The most definitive diagnostic step, though rarely performed, is an Endomyocardial Biopsy. This involves examining a small sample of heart tissue under a microscope to confirm the presence of inflammatory cells and tissue damage. Treatment involves a dual strategy: managing resulting heart failure and controlling the underlying immune response. Standard cardiac medications manage symptoms and support heart function. Simultaneously, immunosuppressive therapy—including corticosteroids, disease-modifying antirheumatic drugs (DMARDs), or biologics—is used to calm the overactive immune system and prevent further damage.