Aneurysm of the muscular septum associated with Wolf-Parkinson-White syndrome presenting as dilated cardiomyopathy; A report of two cases.

Muscular septal aneurysms are extremely rare without a ventricular septal defect and are diagnosed accidentally in most cases. Reported cases generally have rhythm disturbance or electrocardiographic findings of Wolf-Parkinson-White (WPW) syndrome. Presently described are 2 cases of ventricular septal aneurysm associated with WPW syndrome, which presented as dilated cardiomyopathy. Pre-excitation disappeared gradually in first patient. There was also concurrent decrease in degree of bulging of the interventricular septum and improvement of left ventricular systolic function. Second patient had complaints of palpitation and was referred for ablation of accessory pathway. Our findings suggest that presence of pre-excitation may lead to ventricular dyssynchrony and abnormal ventricular septal movement, resulting in appearance of aneurysm.