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Detection of patent foramen ovale by contrast echocardiography is based on transient inversion (right atrial pressure higher than left atrial pressure) of the interatrial pressure gradient. Therefore, the presence of left-sided heart disease with potential elevation of left atrial pressure might obscure the diagnosis of patent foramen ovale. Accordingly, 150 patients (88 men, 62 women; mean age 51.7 +/- 15.2 years) were evaluated for a patent foramen ovale by transesophageal contrast echocardiography. Additionally, atrial septal motion during normal respiration and during the Valsalva maneuver was analyzed. Patency of the foramen ovale was observed in 20 (27%) of 74 patients without left-sided heart disease and with previous arterial embolism, in none (0%) of 25 patients with left-sided heart disease and embolism, in 7 (39%) of 18 patients without left-sided heart disease and without embolism and in 3 (9%) of 33 patients with left-sided heart disease and without embolism. The detection rate of patent foramen ovale was lower in patients with than without left-sided heart disease (5% vs. 29%, p = 0.0007) but was similar in patients with and without embolism (20% vs. 19.5%, p = NS). Abnormal atrial septal motion was more frequently observed in patients with left-sided heart disease (p = 0.0003) and was inversely correlated to detection of patent foramen ovale (p = 0.0003). Multivariate analysis revealed an independent association between the absence of left-sided heart disease and the detection of patent foramen ovale (p = 0.0003). These data suggest that in patients with left-sided heart disease, patency of the foramen ovale may be missed even by transesophageal contrast echocardiography.

Appreciation of three-dimensional relationships could be useful in cardiac diagnosis, decision making and planning of surgery. However, current ultrasound techniques provide only two-dimensional views. A recently developed echocardiographic computerized tomography unit allows reconstruction of three-dimensional images from a series of transoesophageal slices. To evaluate the potentials and limitations of this technique we performed echo computer tomographic examinations in 104 patients with a total number of 227 scans. All but two patients tolerated the procedure well and no serious complications were encountered. Indications for echo computer tomography included coronary artery disease, valvular heart disease, atrial masses, myocardial infarction, mitral and aortic valve replacement, aortic aneurysm and congenital defects. Most of the anatomical structures could be visualized with the best results obtained for the left atrium, the left ventricular outflow tract and the aortic and mitral valve apparatus. However, a variety of technical factors must be considered to achieve optimal results and to avoid misinterpretation. In 86% of patients the underlying pathology could be visualised by echo-computed tomography, particularly congenital defects such as those of the atrial or ventricular septa, but mitral valve pathologies provided the best results. In these cases three-dimensional imaging led to a better perception and understanding of structural relationships. In conclusion, despite current limitations in data acquisition, processing and computing power, echo computer tomography has the potential to provide relevant information in selected clinical settings.

Three-dimensional imaging of cardiac structures could enhance the functional understanding and the interpretation of pathologies. Limited processing capabilities, relocation problems and inadequate two-dimensional image quality have previously limited its applicability. Recently, an integrated echocardiographic computerized tomography unit (echo-CT) which uses a transesophageal approach has been developed. This system is capable of sampling and processing multiple echocardiographic images and, thus, provides three-dimensional views. To evaluate the feasibility and potential of this technique, we studied 69 patients with various cardiac disorders. All but 3 patients (96%) tolerated the procedure well allowing at least one scan to be performed. No complications were encountered. The indication for echo-CT included coronary artery disease (n = 4), mitral valve disease (n = 18), suspected arterial embolism (n = 19), masses (n = 8), congenital malformation (n = 10), postcardiac surgery (n = 8), aortic aneurysm (n = 1) and suspected left-to-right shunt (n = 1). Conventional transesophageal echocardiography revealed a pathology in 45 patients. Of these pathologies, 37 (82%) could be reconstructed and displayed in three-dimensional views. Three-dimensional imaging provided an improved spatial understanding of the pathology in 21 cases (39%). Echo-CT was especially valuable in diseases of the mitral valve (i.e. mitral valve prolapse, flail leaflets, mitral stenosis) where it had the potential to delineate the location, type and morphology of defects. In conclusion, three-dimensional transesophageal imaging enhances image interpretation and understanding. This could be of value in complex morphologies and cardiac disorders in which surgical repair is attempted.