Usefulness of Transesophageal Echocardiography for Predicting Covert Paroxysmal Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source

Background: Covert paroxysmal atrial fibrillation (CPAF) is a major cause of embolic stroke of undetermined source (ESUS). However, detecting PAF during hospitalization in these patients is difficult. Objectives: This study aimed to determine whether findings of transesophageal echocardiography (TEE) during hospitalization are associated with later detection of PAF in patients with ESUS. Method: We retrospectively studied 348 patients with ESUS who were admitted to our hospital within 1 week of onset. These patients met the criteria of ESUS, underwent TEE during hospitalization, and were followed up for at least 1 year. Results: We found PAF in 35 (10.0%) patients. In patients with PAF, spontaneous echo contrast (SEC) and low left atrial appendage flow (LAAF) by TEE and enlargement of the left atrial dimension (LAD) by transthoracic echocardiography were identified more frequently compared with those who did not have PAF. In multivariate analysis, SEC and an LAD ≥42 mm were independently associated with later detection of PAF (p < 0.05). An association of LAAF <46.9 cm/s and PAF was marginal (p = 0.09). The specificity of the combined finding of SEC and/or LAAF with that of LAD increased up to 90%, while that of LAD alone was 70%. Conclusions: The findings of TEE during hospitalization may be useful for identifying patients at increased risk of CPAF in patients with ESUS.