RESUMO
Tricuspid regurgitation (TR) in children may be secondary to congenital anomalies of the tricuspid valve complex which is composed by annulus, leaflets, commissures, chordae tendineae, and papillary muscles. The most common congenital cause is Ebstein's anomaly; however, there are less frequent causes such as abnormal number of tricuspid leaflets, tricuspid cleft, leaflet prolapse, double orifice tricuspid valve, and congenital tricuspid valve dysplasia. Identifying the precise cause is important to plan an appropriate repair surgery. In this article, the case of a 4-year-old patient with a tetracuspid valve with significant tricuspid regurgitation is presented and the morphological analysis was made by two-dimensional (2D) and three-dimensional (3D) transthoracic echocardiography. The morphological differences between a tetracuspid valve and a cleft of the anterior leaflet tricuspid valve are exposed. 3D echocardiographic evaluation of the tricuspid valve allowed a better understanding of the tricuspid valve anatomy, which includes evaluation of the tricuspid annulus, leaflets, commissures, and subvalvular apparatus. Recognizing the accurate cause of isolated tricuspid regurgitation allows better planning of the surgical technique.