Abstract: AIM:To assess the clinical value of noncontact mapping (NCM) system in guiding radiofrequency ablation of premature ventricular contraction (PVC) arising from right ventricular outflow tract and the electrocardiogram characteristics. METHODS: A total of 58 PVC patients received radiofrequency catheter ablation (RFCA) and the origin of PVC was inferred from 12-lead surface electrocardiogram before RFCA. Conventional mapping (CM) was performed in 26 patients and guidance of noncontact mapping in 32 patients. RESULTS: Success rate with NCM was higher, recurrence rate was lower and X ray exposure time was shorter than those with CM ［100% vs. 81%; 3% vs. 19%; (3.6±1.4) min vs.(32±12) min, respectively］. Successful ablation was achieved at sites of RVOT septum in 30 patients (seven from the anterior septum, nine from the midregion septum, 14 from the posterior septum). Successful ablation was achieved at sites of RVOT freewall in 22 patients (seven from the anterior wall, four from the mid-wall, and 11 from the posterior wall). Sensitivity, specificity and accuracy of electrocardiogram for predicting PVC sites were high. CONCLUSION: Noncontact mapping system is useful for effective ablation of PVC originating from RVOT. Careful analysis of electrocardiogram characteristics is helpful in shortening the time of ablation.