Association of follow-up change of left atrial appendage blood flow velocity with spontaneous echo contrast in nonrheumatic atrial fibrillation

Study objectives: To evaluate the time-related change of left atrial (LA) a ppendage flow velocity in chronic atrial fibrillation (AF) by follow-up tra nsesophageal echocardiography (TEE) and to investigate its association with the occurrence of LA spontaneous echo contrast. Design: Prospective follow-up study. Setting: University-based, tertiary referral medical center. Patients: Forty-seven patients with chronic nonrheumatic AF. Interventions: All studied patients underwent both a baseline and follow-up TEE during a mean period of 13 +/- 7 months. Measurements and results: Baseline TEE revealed that LA spontaneous echo co ntrast was present in 28 patients (group 1) and was absent in 19 patients ( group 2), The LA appendage flow velocity profiles at baseline tr ere signif icantly lower in group 1 than in group 2; on follow-up, the appendage flow velocities decreased significantly in group 2, but were not significantly c hanged in group 1, Follow-up TEE revealed that spontaneous echo contrast wa s persistent in all group 1 patients. In group 2, LA spontaneous echo contr ast was newly observed in 9 patients (group 2A) but was persistently absent in 10 patients (group 2B), In group 2A, all of the LA appendage flow veloc ity profiles decreased significantly at the follow-up study. In group 2B, h owever, only LA appendage inflow velocity integral showed significant decre ase on follow-up; there were no significant changes in LA appendage outflow velocity indexes and peak inflow velocity. Conclusions: LA appendage flow velocity may decrease with time in some pati ents with AF, and this change is associated with a new occurrence of LA spo ntaneous echo contrast. For patients without LA spontaneous echo contrast, serial follow-up of the LA appendage flow velocity profiles may be useful f or predicting future development of spontaneous echo contrast. Once LA spon taneous echo contrast occurs in AF patients, it tends to persist with time and the LA appendage is usually under a persistently low flow state.