Objective to investigate the mapping and ablation strategy of premature ventricular contraction(PVC)originating from the free wall of tricuspid annulus.Methods With the Carto3 three-dimensional electro-anatomical mapping system and long sheath supporting,the PVC originating from the free wall of the tricuspid annulus was mapped and ablated by inverted U-shaped catheter via the femoral vein access.Results In 19 patients with PVC originating from the free wall of the tricuspid annulus,mapping and ablation with an inverted U-shaped catheter under the free wall of tricuspid annulus was carried out.The treatment was immediately successful in all the 19 patients,and no complications occurred.During the 6-month follow-up period,one patient developed recurrence of PVC.Conclusion The PVC originating from the free wall of the tricuspid annulus can be roughly judged by the features of the electrocardiogram of the body surface before operation,and the mapping and ablation treatment by using inverted U-shaped catheter is technically-simple and clinically-safe with reliable therapeutic efficacy.