Anatomy of the Atrioventricular Valves for Understanding Pediatric Cardiac Diseases

Abstract

Anatomical knowledge of atrioventricular valves is essential to enhance the quality of diagnosis and treatment of pediatric cardiac diseases. Basic structure and function of the mitral valve, which consists of two leaflets, annulus, chordae, and papillary muscles as well as their variations, should be properly recognized. In particular, dysplasia of the leaflets and abnormalities of subvalvar apparatus are frequently seen in congenital valvular diseases. Left circumflex coronary artery, coronary sinus, central fibrous body, and the aortic valve are located around the perimeter of the mitral valve. Basic structure of three leaflets, chordae, and papillary muscles of the tricuspid valve and its variations, which are occasionally seen in septal and anterior leaflets, should be recognized. Relationship to the aortic valve and the conduction system, including Koch’s triangle and membranous septum, are also important anatomical points. Atrioventricular septal defect and Ebstein’s anomaly are closely related to abnormalities of atrioventricular valves. Variations in common atrioventricular valve and anomalous location of the conduction system are particularly important for understanding atrioventricular septal defect. However, deformity and apical deviation of the septal and the posterior leaflets of the tricuspid valve, which may cause severe regurgitation, are pathognomonic in Ebstein’s anomaly. Accordingly, the right ventricle varies in size and shape. In single ventricle with univentricular physiology, durability of the tricuspid valve in systemic circulation and regurgitation of the common atrioventricular valve are important issues that may influence prognosis.