Chen et al. (1991) found a congenital aneurysm of the interventricular septum of the heart in a 29-year-old man and his 4-year-old son. Both were symptom free. Echocardiography demonstrated the aneurysm in the midmuscular trabecular portion of the ... Chen et al. (1991) found a congenital aneurysm of the interventricular septum of the heart in a 29-year-old man and his 4-year-old son. Both were symptom free. Echocardiography demonstrated the aneurysm in the midmuscular trabecular portion of the ventricular septum with considerable paradoxical motion of the aneurysmal segment. Otherwise, abnormality of structure or function of the heart was not found. Such aneurysms are rare (Fasoli et al., 1988; Magherini et al., 1988), and the familial cases reported by Chen et al. (1991) may be unique.