Assessment of left atrial appendage function with transthoracic tissue Doppler echocardiography

Abstract

A transthoracic echocardiographic (TTE) parameter that would stratify atrial fibrillation (AF) risk would be useful. Tissue Doppler imaging can quantify left atrial appendage contraction velocity (LAA A(M)). We studied 141 patients referred for transoesophageal echocardiogram (TEE); 48 were in AF. We obtained TEE and TTE LAA A(M) velocities from the LAA apex on the parasternal short-axis and apical two-chamber views. Adequate traces were obtained in 118 patients (84%). In these patients, we measured 5382 LAA A(M) velocity tracings. There was a strong correlation between LAA A(M) on TEE and TTE parasternal short-axis (r = 0.741; P < 0.0001) and apical two-chamber views (r = 0.729; P < 0.0001). Patients in AF had lower LAA A(M) than those with sinus rhythm on parasternal short-axis (12 +/- 5 vs. 23 +/- 7 cm/s, P < 0.0001) and apical two-chamber (14 +/- 5 vs. 23 +/- 8 cm/s, P < 0.0001) views. On parasternal short axis, LAA A(M) velocities were lower in patients with spontaneous echo contrast, 11 +/- 4 vs. 22 +/- 8 cm/s (P < 0.0001), and in those with thrombus, 8 +/- 2 cm/s (P < 0.0001). On apical two-chamber, LAA A(M) velocities were also lower with spontaneous echo contrast, 12 +/- 4 vs. 22 +/- 7 cm/s (P < 0.0001), and with thrombus, 10 +/- 4 cm/s (P < 0.0001). In patients with AF and TTE LAA A(M) < or =11 cm/s, we found that nearly one-third had LAA thrombus. In patients with AF and a history of stroke or transient ischaemic attack (TIA), LAA A(M) velocities were lower compared with those without history of stroke or TIA in the parasternal short-axis (9 +/- 3 vs. 13 +/- 5 cm/s, P = 0.02) and apical two-chamber views (11 +/- 3 vs. 15 +/- 6 cm/s, P = 0.008). Acquiring and quantifying LAA A(M) contraction velocity is feasible on TTE in a high percentage of patients and correlates with TEE. LAA A(M) was lower in AF compared with sinus rhythm, with spontaneous echo contrast compared to without spontaneous echo contrast, and in AF patients with a history of stroke or TIA. Those with LAA thrombus had the lowest LAA A(M) velocities. LAA A(M) is a novel functional parameter that may prove useful for risk stratification of AF.