P743Left atrial appendage deformation in patients with atrial fibrillation: a new marker of prothrombotic susceptibility?


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Abstract

Introduction: Recent techniques for the study of cardiac deformation have been developed but their used has remained almost exclusively reserved for the assessment of ventricular function. Left atrial appendage (LAA) is the place where most thrombi (T) are formed in patients with atrial fibrillation (AF) and has only been assessed through the measurement of flow velocities and presence of spontaneous echo contrast (SEC). Strain (S) and strain rate (SR) haven't been used for this purpose.Purpose: to assess the viability and role of LAA S and SR measurement in stroke risk prediction when compared to previously used parameters.Methods: prospective study of 76 consecutive patients in AF (age 68.9±10.6; 35.5% women; CHADS 2.0±1.1; CHADSVasc 3.6±1.6) using conventional transthoracic and transesophageal echocardiogram (TTE and TEE) and LAA segmental longitudinal S, SR, velocity and displacement assessment obtained through speckle tracking with a GE Vivid 7 echocardiograph. The presence of LAA thrombi (T) and SEC and LAA empyting and filling velocities (EV and FV) were measured with TEE. Comparisons were performed according to the presence of LAA T and dense SEC and correlations were estimated with EV, FV and degree of SEC.Results: LAA T were detected in 14.5% and dense SEC in 22.4%. Patients with LAA T had lower values of LAA peak systolic segmental velocity (SV) (2.91±0.79 vs 3.94±1.33; p0.02) and diastolic SV (2.51±1.19 vs 3.69±1.41; p 0.01), less negative longitudinal peak S (-5.99±3.97 vs -9.03±5.83; p 0.04) and lower values of systolic longitudinal SR (1.33±0.44 vs 2.00±1.32; p 0.09) and diastolic SR (1.15±0.49 vs 1.91±1.05; p 0.02). Correlations were found between: LAA peak systolic SV and FV (r 0.443 p<0.001), EV (r 0.351; p<0.003) and SEC (-0.439; p 0.0001); peak diastolic SV and FV (r 0.431; p<0.001), EV (0.512; p<0.001) and SEC (r-0.312 p0.006); peak negative longitudinal S and EV (r -0.29; p 0.017) and SEC (r 0.279; p 0.015); peak systolic longitudinal SR and FV (r 0.336; p 0.005), EV (r 0.368; p 0.002) and SEC (-0.348; p 0.002); peak longitudinal diastolic SR and FV (r 0.367; p 0.002), EV (r 0.374; p 0.002) and SEC (r -0.335; p 0.003).Conclusion: compromised LAA S and SR seem to be related to a higher risk of stroke and are correlated to previously used parameters like SEC, EV and FV. More studies will be necessary to demonstrate the utility or possible advantages of this technique when compared to previously available methods.

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