Microembolic signal detection in patients with symptomatic and asymptomatic lone atrial fibrillation

Background and Purpose: There are few data on the occurrence of microemboli c signals (MES) in patients with lone atrial fibrillation (LAF). The aim of this work was to systematically study the frequency of IVIES in patients w ith symptomatic and asymptomatic LAF and to compare it with that of nonvalv ular atrial fibrillation (NVAF). Methods: 37 consecutive acute stroke patie nts with LAF, 10 asymptomatic patients with LAF and 100 age-matched healthy controls were studied. Another 92 stroke patients with known NVAF were inc luded in the study to compare patients with LAF regarding the presence of M ES. Both middle cerebral arteries were monitored by transcranial Doppler ul trasound for at least 30 min at admission and after 1 week in symptomatic a nd asymptomatic patients with LAF. All patients with LAF were followed up f or a mean duration of 18 months, and recurrent strokes were registered. Res ults: MES was detected in 11 (29%) symptomatic patients with LAF but only i n 1 asymptomatic patient with LAF (chi (2) = 11.3; p = 0.0008) and in no co ntrol subjects (chi (2) = 106; p = 0.00001). There was no difference in the frequency of MES-positive patients and the number of MES between subjects with symptomatic LAF and known NVAF (29% in both groups; mean count, 16 +/- 4 vs. 17 +/- 6; p = 0.73). In patients with symptomatic LAF and NVAF who u nderwent anticoagulant therapy, there was no difference in the frequency of MES after 1 week of hospitalization (chi (2) = 1.53; p = 0.2). During a me an follow-up period of 18 months, 1 patient with symptomatic LAF and MES ha d a recurrent ischemic event 1 year after the first stroke and none of thos e with asymptomatic LAF had any events. Conclusion: Our study suggests that asymptomatic and paroxysmal LAF with a lower frequency of MES is a benign disorder compared to chronic and symptomatic LAF with a higher frequency of MES. Further studies need to justify whether MES has a predictive value in patients with chronic LAF who are prone to ischemic stroke. Copyright (C) 2001 S. Karger AG, Basel.