Patient population. Patients with IPAH and SPAH (defined as a mean PAP >25 mm Hg at rest) not responding optimally to current medical therapy (defined as a reduction of <5mmHg in the resting mean PAP during medication, or unchanged 6-min walk test (6MWT) defined as increment of 6MW distance <50 m) will be eligible for the study. The patients will be informed that they have the right to withdraw their informed consent at any time. After signing a previously approved institutional written informed consent 20 patients with proven IPAH and 20 patients with proven SPAH and 20 control patients (10 with IPAH and 10 with SPAH) will be randomly assigned to radiofrequency denervation of pulmonary arteries or to sham group. Patients of age <18 years, patients with structural heart diseases with left-to right shunting and/or with Eisenmenger syndrome will be excluded from the trial. Medical treatment before enrollment including a diuretics sildenafil or bosentan or digoxin or any other necessary medication will not be discontinued. Blood samples will be obtained for N-terminal brain natriuretic peptide (NT-BNP), troponin T, mbCK, CK and other usually accepted biological markers of pulmonary hypertension levels before, immediately after the pulmonary artery denervation (PADN) procedure, and at 3 and 6 months following the PADN procedure. For the assessment of potential anatomical complications at the sight of PADN a multisliced computed tomography angiography of pulmonary trunk and pulmonary arteries will be obtained before and 6 months after PADN procedure. Assessment of functional capacity (9) will be determined by the six-minutes walk test (6MWT), followed by an assessment of dyspnea using the Borg scale (10). The 6MWT will be performed at 3 month and 6 months following the PADN procedure. The World Health Organization classification (11) at rest and during exercise will be recorded by a physician blinded to the study design.