Estimation of left atrial blood stasis using diastolic late mitral annular velocity.

Aims: Diastolic late mitral annular velocity (a') measured by transthoracic echocardiography (TTE) is reported to represent left atrial (LA) pump function and the severity of LA remodelling. The purpose of this study is to investigate the association between a' and LA blood stasis in patients with non-valvular paroxysmal atrial fibrillation.
Methods and Results: We enrolled 138 consecutive patients with non-valvular paroxysmal atrial fibrillation who had spontaneous sinus rhythm at the time of echocardiography. Using TTE, a' was determined as an average of tissue Doppler velocities measured at septal and lateral mitral annuli. Transoesophageal echocardiography was also performed on the same day as TTE, and spontaneous echo contrast (SEC) and LA appendage flow velocity were examined. Spontaneous echo contrast was observed in 21 (15%) patients. Patients in the lowest quartile of a' (≤6.4 cm/s) demonstrated SEC more frequently (44 vs. 6%, P < 0.0001) and had lower LA appendage flow velocity (39 ± 13 vs. 53 ± 16 cm/s, P < 0.0001) than those in the other quartiles. Receiver-operating characteristic curve analysis showed that the best cut-off value of a' was 7.0 cm/s for the prediction of SEC with a sensitivity of 80%, specificity of 81%, and predictive accuracy of 80%. Multivariate analysis revealed that decreased a' (OR = 0.61, P = 0.0026) was independently associated with SEC.
Conclusion: Decreased a' may be a useful parameter for the estimation of LA blood stasis in patients with paroxysmal atrial fibrillation.