Premature ventricular contractions (PVCs) stemming from the aortic sinus cusp often have preferential conduction to two exits in the outflow tract and exhibited two different morphologies of PVCs, which may render radiofrequency catheter ablation (RFCA) difficult. A 67-year-old male patient underwent RACF for premature ventricular contractions (PVCs) characterizing by bi-morphology (left and right bundle branch block) on electrocardiogram. Dynamic changes in QRS morphology during ablation and evident local voltage potentials during electro-anatomical mapping were critical for identifying the real foci of origin of PVCs. Successful ablation was achieved at the left-right coronary cusp commissure.