Analysing the transcriptional activity of TGF‐β1 genes and its receptors and the number of diseased coronary arteries among patients with coronary artery disease without heart failure, a statistically significant decrease in the activity of the cytokine gene was noted, along with the severity of coronary artery disease (in two‐ and multivessel coronary artery disease). This evidence concerns the gene TGFB1 and heart failure.