What is the appropriate diagnostic work‑up and management for a left atrial myxoma?

Left Atrial Myxoma: Diagnostic Work-Up and Management

Surgical excision should be performed urgently once a left atrial myxoma is diagnosed, as it is the only definitive treatment and prevents life-threatening complications including stroke, sudden death, and recurrent syncope. 1, 2, 3

Diagnostic Work-Up

Initial Imaging

Transthoracic echocardiography (TTE) is the first-line diagnostic modality and is sufficient to establish the diagnosis in most cases. 2, 3, 4

• TTE provides critical information about tumor location, attachment site (typically the interatrial septum at the fossa ovalis), size, mobility, and surface characteristics 3, 5
• Transesophageal echocardiography (TEE) should be added when TTE images are suboptimal or when detailed surgical planning is needed, as it offers superior resolution for smaller tumors and better visualization of the attachment site 2, 3
• Two-dimensional echocardiography can evaluate both atria simultaneously, detect the tumor stalk, assess mobility, and determine the extent of obstruction 4

Advanced Imaging

• Cardiac MRI or CT may be obtained for additional tumor characterization and surgical planning, particularly to define anatomic relationships and rule out other pathology 2, 3
• These modalities are adjunctive rather than essential for diagnosis 3

Cardiac Catheterization

• Coronary angiography should be performed only in older patients at risk for coronary artery disease who may require concomitant coronary artery bypass grafting 6
• Routine cardiac catheterization is not necessary, as surgery can be undertaken based solely on echocardiographic findings 6, 4

Clinical Presentation and Risk Assessment

Symptom Recognition

Left atrial myxomas present through three principal mechanisms 1:

1. Mechanical obstruction causing dyspnea, syncope, heart failure symptoms, or sudden death from mitral valve obstruction during diastole 1, 2, 6
2. Embolic complications with an overall embolism rate of 25%, presenting as stroke in up to 50% of cases 1, 2, 3
3. Constitutional symptoms including fever and weight loss from cytokine release 1

High-Risk Features

Myxomas with villous or papillary surface architecture have markedly higher embolic potential due to friable surfaces that generate thrombus and shed tumor fragments 1, 2, 3

Management

Surgical Intervention

All symptomatic left atrial myxomas require urgent surgical resection (Class I recommendation). 1, 2

Surgical Approach

• The right atrial trans-septal approach is preferred, as it allows inspection of all four cardiac chambers, limits tumor manipulation, and facilitates complete excision 6, 5
• Complete tumor removal with adequate margin of atrial septum is essential to prevent recurrence 1, 6, 5
• Surgery should include excision of the tumor base and resection of the portion of interatrial septum to ensure complete removal 4
• The procedure is performed via median sternotomy with cardiopulmonary bypass 7

Timing

Surgery should be performed as soon as possible after diagnosis due to the high risk of valvular obstruction (which can cause sudden death) and systemic embolization 6, 5

Critical Management Pitfalls

Do not use anticoagulation or antiplatelet therapy alone as definitive treatment—these do not address mechanical obstruction and do not prevent embolic complications 1, 2

Avoid pericardiocentesis if pericardial effusion is present, as this may worsen hemodynamics 2

Histopathologic Confirmation

• Mandatory histopathologic examination should be performed on all resected specimens 1
• Characteristic findings include myxoma cells (polygonal to stellate-shaped with eosinophilic cytoplasm), abundant myxoid matrix rich in mucopolysaccharides, vascular channels, and often hemorrhage with hemosiderin deposition 1, 2
• Immunohistochemistry is positive for vimentin and calretinin, negative for cytokeratin and S100 1

Follow-Up

Long-term surveillance with periodic echocardiography is mandatory to monitor for recurrence, which occurs in 1-5% of sporadic cases and is higher in familial myxomas 1, 6, 5

• Annual echocardiographic evaluation is recommended 5
• Recurrence typically occurs years after initial surgery (reported at 3-4 years in some series) 6, 5

Prognosis

• Surgical mortality is low in experienced centers, with excellent long-term outcomes in most patients 6, 5, 7
• Surgical excision reduces stroke risk compared to conservative management 1
• Most patients (94%) remain asymptomatic following surgery 5
• Recurrence after complete excision is extremely rare (1.9-3.7%) 5, 7