The blood samples from the superior vena cava and PA will be obtained for the measurements of oxygen pressure and saturation. PADN procedure. A baseline PA angiography will be performed to identify the PA bifurcation level and calculate the PA diameter. An 8-F long sheath will be inserted through the femoral vein and advanced to the main PA (MPA). The PADN catheter will be advanced along this long sheath. After gently withdrawing the sheath and pushing the PADN catheter, the tip will be released from the sheath. Then, by slightly rotating and pushing the handle the tip will be positioned first at the ostium of the left PA (Level 1 of ablation, <2 mm distal to orifice. After ablation at this level, the catheter tip will be positioned at the ostium of right PA (Level 2 of ablation, <2mm proximal to the bifurcation level). Finally, denervation of main pulmonary artery will be done by pulling the denervation catheter back into Level 3 of ablation (<2 mm proximal to both ostia of right and left PA-s) into main pulmonary artery.Three criteria will be used to ensure that the electrodes were tightly in contact with the endovascular surface: 1) strong manual resistance when rotating the handle; 2) inability to advance distally or ease in, withdrawing proximally 3) angiographic confirmation and 4) actual electrode contact pressure (gm) readings provided by RF denervation system used. The procedure will be stopped if the patient complained of intolerable chest pain. The electrocardiogram and hemodynamic pressure will be monitored and continuously recorded throughout the procedure. Procedural success will be defined as a reduction in the mean PAP >10 mm Hg (as measured by the Swan-Ganz catheter), and there were no complications. The patients will be monitored in the intensive cardiac care unit for at least 24 h after the PADN procedure. Commercially available and approved radiofrequency technology for pulmonary vein isolation will be utilized for new clinical indication.