Atrial Myxoma

Account for 50% of benign cardiac tumours

Most commonly present in 30-60yrs age group, more common in females

Seen in 0.0017% - 0.03% of cases in autopsy studies (rare)

May be familial as part of the “Carney Complex” which is an autosomal dominant condition associated with PRKAR1A gene mutation. Results in abnormal skin pigmentation and multiple tumours in heart, skin and lungs.

Histology

Features of lepidic cells with "myxoid" stromal findings
Arise from cells in fossa ovalis

Pedunculated gelatinous mass
May be friable or villous in 35% of cases

Clinical features

Characteristic “plop” heard in early diastole as myxoma obstructs the mitral valve
“Platypnoea” where breathlessness improves on lying flat as the myxoma moves out of the mitral valve entrance
Clinical features of mitral stenosis (Loud S1, pedal oedema, pleural effusions etc…)
Constitutional symptoms such as fever and weight loss seen in 30% with associated rises in CRP and ESR. These are caused by IL-6 release from the myxoma itself and is associated with larger myxoma size
Arrhythmias and heart block due to myocardial invasion
Pericardial effusion with possible progression to tamponade
Usually attached to the interatrial septum as derived from embryonic fossa ovalis tissue

TOE findings

Locations - LA = 75%, RA 20%, elsewhere = 5%

May resemble a thrombus on echo
Be wary of TOE insertion as this has been noted in case reports to dislodge atrial masses in some case reports

Reference [1] Relationship of left atrium to adjacent structures and the oesophagus

Atrial myxoma vs thrombus

Feature	Atrial Myxoma	Atrial Thrombus
Typical Location	Within the body of the atrium	Often in the left atrial appendage
Attachment	Has a stalk or pedicle	Has a wider base
Mobility	Mobile and free-moving	Immobile
Vascularity	Show some vascularity (enhancement on contrast imaging)	Avascular (no enhancement)
Clinical Symptoms	Can present with constitutional symptoms like fever, weight loss, arthralgia, or myalgia	Does not present with constitutional symptoms. Increased association with AF

Atrial myxoma originating from the left atrium and obstructing the mitral valve

Anaesthetic Management Considerations

Potential for pre-operative deconditioning secondary to constitutional symptoms
Assess for evidence of obstruction
Document pre-operative neurological deficit if previous embolic events
Pre-op management of anticoagulation
Assessment of mitral or tricuspid inflow obstruction
Caution on insertion of TOE probe
Careful fluid management and inotrope titration in post-operative phase as loading conditions can alter dramatically following excision of obstructive lesions.

References

https://www.sciencedirect.com/science/article/pii/S2214854X19300512