Case Presentation
A 54-year-old man with a history of mitral valve repair nine years ago
due to a flail posterior mitral valve leaflet was admitted to our
hospital. He also had a history of permanent atrial fibrillation (AF)
and was taking warfarin, but his International Normalized Ratio (INR)
was subtherapeutic. Transesophageal echocardiography (TEE) for
assessment of LA thrombosis was performed. Interestingly, different
echocardiographic presentations of the increased thrombogenicity in the
left atrium (LA) have been detected in just one biplane view (Figure 1,
Video S1). A large LA thrombosis, LA appendage sludge, severe
spontaneous echo contrast (smoke) in the LA, and normal structures, such
as pectinate muscles and Coumadin ridge, were detected.
Spontaneous echo contrast (SEC) or smoke is defined as an
echogenic, dynamic, swirling blood flow pattern mainly observed as a
marker of a low-flow state in the LA. The presence and the grade of SEC
are related to an increased risk of thrombosis formation in the LA. The
severity is graded from 0 to 4+, with grade 0 indicating the absence of
echogenicity and grade 4+ indicating severe echogenicity and very slow
swirling patterns in the LAA, usually with similar density in the LA
cavity (1).
Among patients with AF, the prevalence of spontaneous echo contrast in
LA was 8 percent, and the rate of sludge was 1-3.4 percent based on
different studies. Between 2 to 12.4 percent of patients with AF taking
vitamin k antagonists (VKA) may have LA or LAA thrombosis depending on
the study population (2).
Pectinate muscles are normal ridge-like structures within the LAA wall
that may be difficult to distinguish from LAA thrombosis, specifically
at the tip of the LAA. Coumadin ridge is a band-like structure between
LAA and the left upper pulmonary vein that may cause a reverberation
artifact resembling a thrombosis in the LAA (3).