NATURAL-HISTORY OF LEFT ATRIAL SPONTANEOUS ECHO CONTRAST IN NONRHEUMATIC ATRIAL-FIBRILLATION

A prospective study was designed to investigate potential changes of l eft atrial (LA) spontaneous echo contrast with time and the effects of antithrombotic therapy on its presence in 77 patients with chronic no nrheumatic atrial fibrillation (AF), using serial transesophageal echo cardiography (TEE). During a mean follow-up period of 20 +/- 15 months (range 6 to 77), a total of 197 TEE studies were performed in these p atients. Baseline TEE revealed that LA spontaneous echo contrast was a bsent in 43 patients (group 1) and present in 34 (group 2). LA thrombu s was found in 8 of group 2 but in none of the group 1 patients. Durin g the follow-up period, only 2 of the group 1 patients were receiving antithrombotic agents; the patients in group 2 without LA thrombus wer e treated with either warfarin or aspirin, whereas those with LA throm bus were treated with warfarin. On the latest TEE study, LA spontaneou s echo contrast was observed in 19 of the group 1 patients (44%) and w as persistently found in all of the group 2 patients. During the study period, no patient was found to develop new LA thrombus formation and only 4 episodes of transient ischemic attack were recorded in 4 patie nts (embolic event rate = 3.1% per year). Of these, 2 were observed in group 1 and the remaining 2 were from group 2 and under aspirin thera py (event rate = 2.2% and 4.7% per year, respectively). In the subgrou p of patients with LA thrombus receiving warfarin therapy, follow-up T EE revealed complete resolution of the thrombi in 6 and partial resolu tion in the remaining 2 in spite of the persistence of LA spontaneous echo contrast; none of these patients developed clinical thromboemboli c events during the study period. Thus, future occurrence of LA sponta neous echo contrast could be observed by serial TEE at a substantial r ate in patients with nonrheumatic AF who have no LA spontaneous echo c ontrast; follow-up TEE should be recommended for these patients to det ect early the potential occurrence of LA spontaneous echo contrast if preventive antithrombotic therapy is not considered. Although warfarin therapy is associated with resolution of LA thrombus, neither warfari n nor aspirin is effective for suppressing the presence of LA spontane ous echo contrast in nonrheumatic AF. (C) 1997 by Excerpta Medica, Inc .