In a group of 300 patients (stage B—n = 76, age 68.58 ± 8.63, LVEF 54.95 ± 9.82%), it was shown that the concentration of CST decreased from stage A, through stage B, to stage C. The CST cutoff value for detection of stage B HF was 19.73 ng/ml with 90% sensitivity (higher in this study than for BNP) and a specificity of 50.9%. This evidence concerns the gene NPPB and hydrops fetalis.