“…Moreover, ventricular tachycardia or fibrillation sometimes occurs in patients with this tumor. 2,3,6 Tumor size varies from 0.5 mm to 30 mm, and there is no relationship between size and the occurrence of lethal arrhythmia. It is thus important to consider the possibility of cystic tumor of the atrioventricular nodal region in patients with electrocardiographic evidence of heart block limited to the atrioventricular node (ie, with a narrow QRS), particularly in women.…”