Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast.

Transesophageal echocardiography was performed in 314 patients over a period of 24 months using a 3.5 MHz phased-array system fitted to the distal end of a conventional 12 mm endoscope. In 12 patients (2.6%) transesophageal echocardiography could not be performed because of adverse reaction to the gastroscopic procedure. Side effects were a transient A-V block in one patient and asthmatic attack in another. Mitral valve lesions were found in 99 of 314 patients. In 9 of these 99 patients (11%), including 1 patient with mitral valve stenosis and sinus rhythm, 2 with atrial fibrillation, 3 with disc, and 3 with porcine mitral prosthesis, spontaneous echocardiographic contrast was found within the left atrium, described as faint echoes in 2 patients and dense echoes filling the whole left atrium and following turbulent flow in the other 7 patients. Only in 2 patients was left atrium shown to have additional echoes within its cavity in the four-chamber view by transthoracic echocardiography. Signs of cerebral emboli were found in 5 of 9 patients and of peripheral embolism in 3 of 9 patients. Their mechanism seems to involve red cell aggregation, which is greatest at low flow velocity such as in dilated left atria in the case of mitral valve stenosis or prosthesis. The additional effect of platelet aggregation must be discussed because increased platelet aggregation was detected in all patients with spontaneous echocardiographic contrast. Transesophageal echocardiography seems to be of great diagnostic value in patients with mitral valve lesions and cerebral and peripheral embolism, giving new insight into the pathophysiologic mechanism and possibly improving the therapeutic approach in the near future.