Trans-esophageal Echocardiography (TEE)
Multiplane transesophageal echocardiography (TEE) was performed in all patients. The LA and LAA imaging was begun in the horizontal plane at 0°, then the transducer was rotated progressively to 60° and 90°; in the same plane, and images were also evaluated after slight and more pronounced counterclockwise rotation of the probe. Rotation of the transducer to 110° and 130° was coupled with more pronounced counterclockwise rotation of the probe. All images were recorded by optimizing the gain settings to minimize gray-noise artefacts. We examined the LAA in the short and long axis. It has been shown that transesophageal echocardiography is highly sensitive for the detection of left atrial clot, especially in the left atrial appendage.13,14
LA or LAA thrombus was diagnosed by the presence of clearly defined echogenic intracavitary mass different from the underlying endocardium. SEC was diagnosed by the presence of dynamic smoke-like echoes in the LA cavity and LAA with a characteristic swirling motion. The severity of SEC was graded from 0 to 4+ as proposed by Fatkin et al.15.
Grade 0: None (absence of echogenicity)
Grade 1+: Mild (minimal echogenicity located in the LA appendage or sparely distributed in the main cavity of the left atrium; may be detectable only transiently during the cardiac cycle; imperceptible at operating gain settings for two dimensional echocardiographic analysis)
Grade 2+: Mild to moderate (more dense swirling pattern than grade 1+ but with similar distribution; detectable without increased gain settings)
Grade 3+: Moderate (dense swirling pattern in the LAA, generally associated with somewhat lesser intensity in the main cavity; may fluctuate in intensity but detectable constantly throughout the cardiac cycle)
Grade 4+: Severe (intense echo density and very slow swirling patterns in the LAA, usually with similar density in the main cavity)
The LAA flow profiles were obtained by placing the sample volume of the pulsed Doppler 1 cm below the LAA orifice where there were no wall artefacts and a net flow could be recorded using pulse wave Doppler.  The positive flow observed after P‐wave of surface ECG, was taken as LAAEV (considered to represent the LAA contractile function). Inactive LAA was defined as late peak LAAEV <25 cm/sec7,8 (Figure 1A, B). A mean of 3 consecutive cycles was used to calculate all echocardiographic parameters.
All echocardiograms were independently evaluated by two observers and any difference of opinion was settled by mutual consensus.