We report a case of isolated congenital left ventricular diverticulum (LVD) with perinatal dysrhythmia, which disappeared spontaneously 1 week after birth. The LVD arose from the lateral wall of the LV, and the contraction of the LVD was synchronous with the kinetics of the main LV chamber. The LVD changed very little in size during the first 30 months after birth, and its relative size to the growing LV main chamber decreased. The patient had neither any symptoms nor complications during this time. The available literature on prenatal and neonatal cases with isolated LVD or LV aneurysm is also reviewed.