Spontaneous Echo Contrast in Patients with Sinus Rhythm but Poor Atrial Contraction

Spontaneous echo contrast in the left atrium in patients with sinus rhythm is unusual. The aim of this study was to assess the mechanism of this phenomenon and any clinical implications. We studied 90 consecutive patients using transesophageal echocardiography. Spontaneous echo contrast was seen within the left atrium in 29 patients, 11 of whom were in sinus rhythm. In patients with spontaneous contrast and sinus rhythm, the underlying diseases were: mitral insufficiency (5), mitral stenosis (1), mitral prostheses (2), congestive cardiomyopathy (1), hypertrophic cardiomyopathy (1), and heart transplantation (1). Spontaneous echo contrast tended to be faint in this group (10/11). The left atrium was enlarged in all, with subjective poor atrial contraction. Furthermore, reduced mitral A wave suggested an impairment of left atrial contractility. Holter monitoring demonstrated paroxysmal atrial fibrillation in five subjects. Two patients had a history of transient ischemic attacks. No atrial thrombus was observed in any patient. The demonstration of spontaneous echo contrast with transesophageal echocardiography does not seem uncommon even in patients in sinus rhythm. This may indicate an increased risk of thromboembolism.