Cardiovascular angiography is one of the most important means of diagnosing cardiovascular diseases. It is a complicated special examination method, which has a certain degree of danger and needs to strictly grasp the indications. Then, what are the causes of cardiovascular angiography see double ball sign? Here is a brief introduction: Double ball syndrome on cardiovascular angiography is a manifestation of the stenotic form of Ebstein’s syndrome, which requires surgical treatment. The main anatomic features of this abnormality are tricuspid valve downstaging, atrialization of the right ventricle, and functional right ventricular cavity narrowing. The right atrioventricular annulus is normal (often enlarged), and the anterior tricuspid valve often attaches normally to the annulus, whereas the attachment points of the diaphragmatic and posterior valves are markedly displaced on the endocardium of the right ventricular wall. The degree of displacement and the mode of attachment vary from person to person, and even though the attachment points of the affected valves are adjacent to the annulus, the leaflets are often adhered to the wall of the right ventricle at various sites distal to the annulus because of the excessively long lengths of the leaflets. In addition, these leaflets may attach to the septum and the apical portion of the right ventricle with the aid of malformed tendons. The posterior tricuspid valve is often underdeveloped or completely absent, and all of the above can lead to tricuspid valve closure insufficiency. In a few patients, the tricuspid valve is fused into a diaphragm in the ventricular cavity, with an orifice in the center or lateral margin through which right atrial blood flow must be injected into the ventricle, thus impeding atrial emptying. As a result of tricuspid valve subluxation, the right atrium seizes part of the right ventricle, and the ventricular wall of this seized area thins and becomes atrialized, resulting in a marked enlargement of the right atrial cavity. The atrialized right ventricle is functionally part of the right atrium but retains the characteristics of the right ventricular myocardium in terms of electrical activity. The larger the atrialized right ventricular component, the smaller the functional right ventricular cavity. The atrialized right ventricle does not participate in right ventricular emptying; instead, it acts as a ventricular wall tumor and paradoxically dilates during ventricular contraction, thus interfering with right ventricular ejection.