Rare variants of divided right ventricle with sequestered apical trabecular component

The right ventricle may be divided into two or more compartments by various structures in various ways. Rarely, the apical trabecular component may be sequestered from the rest of the right ventricle. We report 4 cases with different underlying lesions that share a common pathology of apical sequestration of the right ventricle resulting in diverse hemodynamic consequences. Case 1 had pulmonary valve stenosis. The apical sequestration of the right ventricle resulted in no significant hemodynamic consequence. Case 2 had multiple defects in the muscular ventricular septum. The volume of left-to-right shunt seemed to be reduced because of the commitment of some of the defects to the sequestered cavity. Case 3 had a large defect in the trabecular septum. As the defect involved the whole septum that was related to the sequestered right ventricular apex, the left ventricle together with the sequestered right ventricle formed a boot-shaped chamber. Hemodynamically, the muscular shelf was an interventricular septum. Case 4 had a coronary artery fistula to an isolated cavity that occupied the apical region of the right ventricle. The pathology was similar to the case that was reported as a five-chambered heart. The abnormal cavity was, in fact, the sequestered right ventricular apex.