Tricuspid valve in congenital heart disease: multimodality imaging and electrophysiological considerations

The tricuspid valve (TV) has been neglected for many years. Only recently, new studies demonstrated the prognostic role of the tricuspid valve lesions. In addition to that, new interventional approaches offer the possibility to non-invasively treat tricuspid valve disease. In this review, our aim is to summarize the role of different imaging techniques in the assessment of tricuspid valve with particular regards to congenital heart diseases. Finally, we analyze the importance of the TV and its adjacent regions from an electrophysiological point of view, both in structurally normal hearts and in congenital heart diseases. The most relevant transthoracic echocardiography (TTE) views to visualize the TV are the "modified" parasternal long axis, the apical views and subcostal projections, such as right oblique or left oblique views. However, simultaneous visualization of the three leaflets is possible only with three-dimensional TTE, or, sometimes, in parasternal short axis and subcostal short axis views in children. 3D echocardiography (3DE) is promising in this field. Indeed, its unique projections, such as en face views from the right ventricular and atrial perspectives, are able to define the spatial relationship of the tricuspid leaflets with the surrounding structures. Moreover, multimodality imaging assessment has been recently proposed for the diagnostic assessment of the TV, especially before percutaneous intervention. Cardiac Computed Tomography (CCT) provides valuable anatomic spatial information of the TV apparatus. Cardiac Magnetic Resonance (CMR) is able to provide, non-invasively, detailed morphological and functional information of the valve.