A 26-year-old man suffered from recurrent palpitation and his 12-lead electrocardiogram documented the alternating narrow and wide complex tachycardia. Electrophysiologic study revealed the synchronous left fascicular ventricular tachycardia (LFVT) and slow-slow atrioventricular node reentry tachycardia (ss AVNRT), and both of them were ablated successfully.