Idiopathic reentrant right ventricular outflow tract tachycardia with presystolic potential of central pathway.

A 12-year-old girl with recurrent palpitation due to idiopathic ventricular tachycardia (VT) with a left bundle branch block configuration and inferior axis was referred to our hospital. During the VT, a spiky presystolic potential (SP) was recorded at the septum of right ventricular outflow tract (RVOT) just below pulmonary valve. The SP was entrained with a decremental property by pacing from right ventricular apex. Concealed entrainment was observed by pacing where the SP was recorded. Delivery of radiofrequency current targeting the SP abolished the VT. The SP with the decremental property could represent the central pathway of this idiopathic RVOT reentrant VT.