Left ventricular lateral annulus and left atrial free-wall velocity time integral indicate thromboembolism in patients with rheumatic atrial fibrillation.

BACKGROUND

Low wall motion and stasis increase the likelihood of clot formation. We hypothesized that tissue Doppler indices of left atrial (LA) motion are reduced in the presence of LA thrombi and may be predictive for clot formation in patients with atrial fibrillation (AF).

METHODS

We did an observational study for 3 years in 118 patients with rheumatic mitral valve disease in chronic AF who had not received anticoagulation, with (Group 1, n = 36) and without (Group 2, n = 82) thromboembolism. Pulsed tissue Doppler systolic velocities and velocity time integrals (VTIs) were measured in all four chambers. A mean LA VTI was calculated. LA strain during ventricular systole was calculated using VTI and distance between two LA locations.

RESULTS

Logistic regression analysis showed that, after adjusting for age, gender, diabetes, hypertension, LA size, and left ventricular (LV) ejection fraction, mean LA VTI [Odds ratio (OR) 0.69, 95%CI (0.56-0.86, P = 0.03)] and lateral mitral annulus VTI [OR 0.15 (0.04-0.56, P = 0.03)] were associated with clot formation. The addition of these two parameters to the conventional risk factors increased the ability to predict thromboembolism (Nagelkerke R² = 0.32-0.50, P = 0.01; area under the curve 0.83 by receiver operating characteristic analysis, P = 0.01). LA strain also had potential to indicate clot formation (0.9 ± 13.8 vs. -8.2 ± 15.1%, group 1 vs. 2, respectively, P = 0.01).

CONCLUSION

Patients with chronic AF and thromboembolism have reduced LA and LV motion independently of LA size and LV ejection fraction. Tissue Doppler parameters may have potential to predict clot formation in these patients.