From the Guidelines
Atrial masses can be caused by several conditions, with the most common being thrombi (blood clots), primary cardiac tumors, metastatic tumors, and vegetations. Thrombi typically form in the left atrial appendage in patients with atrial fibrillation or mitral valve disease due to blood stasis. Primary cardiac tumors affecting the atria include myxomas (the most common primary cardiac tumor, usually in the left atrium), lipomas, fibromas, and papillary fibroelastomas, as noted in the guidelines for the primary prevention of stroke 1. Metastatic tumors can spread to the heart from lung, breast, melanoma, lymphoma, or renal cell carcinoma. Vegetations result from infective endocarditis, with bacteria or fungi colonizing heart valves and extending into the atrial chamber. Less common causes include anatomical variants like Chiari network or prominent crista terminalis, which can mimic masses on imaging. Diagnostic evaluation typically includes echocardiography, cardiac MRI, or CT to characterize the mass, with treatment depending on the underlying cause, ranging from anticoagulation for thrombi to surgical resection for tumors or antibiotics for vegetations.
Some key points to consider when evaluating atrial masses include:
- The majority of myxomas occur in the left atrium and about 30% to 40% of them embolize, as stated in the guidelines for the primary prevention of stroke 1
- Surgical excision of atrial myxomas is recommended, and surgical intervention is also recommended for symptomatic fibroelastomas and for fibroelastomas that are >1 cm in diameter or appear mobile, even if asymptomatic 1
- The management of patients with atrial fibrillation, which can be related to acute temporary causes, including alcohol intake, surgery, electrocution, MI, pericarditis, myocarditis, pulmonary embolism or other pulmonary diseases, hyperthyroidism, and other metabolic disorders, is crucial in preventing the formation of atrial masses 1
Given the potential for embolization and the importance of early treatment, it is essential to promptly diagnose and manage atrial masses to prevent morbidity and mortality. The most recent and highest quality study, which is the guidelines for the primary prevention of stroke 1, provides the most relevant information for making a definitive recommendation. Therefore, the diagnosis and treatment of atrial masses should be guided by the latest evidence-based guidelines, prioritizing the prevention of stroke and other complications.
From the Research
Causes of Atrial Mass
The causes of an atrial mass can be attributed to several factors, including:
- Thrombi formation, which can occur in the left or right atrial appendage, particularly in patients with atrial fibrillation 2, 3
- Organized thrombosis, which can mimic the imaging features of tumors 2
- Atrial fibrillation, which can lead to ineffective atrial contraction and increased risk of thrombi formation 4, 5, 3, 6
- Hemodynamic factors, such as blood stasis, which can contribute to thrombus formation in the atria and atrial appendage 6
- Systemic factors, such as inflammation and hypercoagulability, which can also play a role in thrombus formation 6
Risk Factors
Certain risk factors can increase the likelihood of developing an atrial mass, including:
- Atrial fibrillation, particularly in patients with a history of stroke or transient ischemic attack 4, 5, 3, 6
- Age, with older adults being more susceptible to atrial fibrillation and thrombi formation 3
- Presence of other cardiovascular conditions, such as heart failure or valvular disease 6
- Lack of anticoagulation therapy, which can increase the risk of thrombi formation and subsequent embolic events 2, 3