The Role of Modern ECHO-methods in the Diagnostics of Left Atrium Thrombosis

Objective: Analysis of the features of the diagnostics of left atrial (LA) thrombosis in patient with atrial fibrillation (AF) and assessment of intracardiac hemodynamics on the thrombus formation using echocardiography (ECHO).

Materials and methods: Over the 11-year period (2007–2018), 770 patients with AF before ablation procedure went through ECHO examination to exclude LAA thrombosis. ECHO were performed on expert class devices (Vivid E9 and Vivid Q (GE)). Transthoracic ECHO (including 4D mode), TEE using color and PWD modes, as well as intracardiac ECHO (totally in 748 patients) has been performed.About 70% of patients had a paroxysmal AF, about 30% - persistent AF; less than 2% (n=12) - continuously recurrent AF.In 323 patients (42%) an increase of the left chamber’s volume/size was detected: LVEDV — 202 ± 58 ml, LVESV — 71 ± 12 ml; LA - 5.6 ± 1.4 cm. ECHO data was compared with the corresponding CT data. When a thrombosis was detected (or suspected), the LAA emptying speed was calculated using PWD-mode.

Results: Among 562 patients with paroxysmal AF, thrombosis of LAA was detected only in 2; in the patients with persistent AF, the frequency of LAA thrombosis was higher - 8 patients (about 4%), and in the case of continuously recurrent AF - in all –12 people (100%). The following data could be helpful in recognizing of LA thrombosis: typical localization (from the LAA) as well as clinical data such as unknown duration of AF paroxysm in the absence of adequate hypocoagulation, mitral stenosis, reduced LV systolic function.

Conclusion: Modern ECHO methods allows to detect LA thrombosis and to identify predictors of its formation.In the presence of mitral regurgitation, blood clots in the LA could be found (92%) less frequently, because of the high-speed flow of regurgitation that prevents blood from stasis and the clot formation. Decreasing in the CW- speed less than 40 cm/s results in a significant increasing of the risk of LAA thrombosis.