The aim of the research was to investigate the effects of prolonged use of angiotensin-converting enzyme (ACE) inhibitor enalapril and angiotensin II receptor blocker (ARB) candesartan on the levels of aldosterone, N-terminal fragment of brain natriuretic peptide (NT-proBNP), tumor necrotic factor-α (TNF-α), apoptosis inducer Fas-Ligand (FasL) and pulmonary artery systolic pressure in patients with decompensated chronic pulmonary heart disease (CPHD). 74 patients (11 women and 63 men) with decompensated CPHD with heart failure (HF) NYHA Class III were examined. Their average age was 62.8±3.7 years. The patients were randomized into two clinical groups: the first (main) group consisted of 39 patients which received ACE inhibitor enalapril and additionally the ARB candesartan, while the second (control) group consisted of 35 patients which received only basic therapy and ACE inhibitor enalapril. Increase in blood levels of aldosterone, marker of HF NT-proBNP, proinflammatory cytokine TNF-α, and apoptosis inducer FasL is marked in patients with decompensated CPHD with HF NYHA Class III, in comparison with healthy individuals. The combined use of ACE inhibitor enalapril and the ARB candesartan within 6 months promotes reduction of levels of aldosterone, NT-proBNP, TNF-α, FasL and pulmonary artery systolic pressure, that leads to the delay of HF progression in patients with decompensated CPHD.