Table 2

Transesophageal Echocardiographic Evaluation of the LAA

PathophysiologyEchocardiographic AppearanceTreatmentFigure
SECLow blood flow velocities.
Composed of activated platelets and leukocytes or aggregated red blood cells.
Swirling echodensity within the atrium.Anticoagulation does not reduce SEC but reduces the development of LAA thrombus.
Cardioversion is acceptable. SEC can initially increase, but eventually decreases after cardioversion.
SludgeLow blood flow velocities.Viscous, gelatinous morphology, not well formed. Represents an intermediate stage between SEC and formed thrombus.Anticoagulation. Cardioversion in the setting of sludge is controversial and associated with a higher risk of thrombus being present.5D
ThrombusLow blood flow velocities.Organized formed thrombus.Anticoagulation. Cardioversion contraindicated with this finding.5E, F
Pectinate musclePart of the normal LAA morphology.No treatments, normal finding.5A, B

LAA = left atrial appendage; SEC = spontaneous echocardiographic contrast.