There were no significant differences in changes in forearm blood flow between heart failure patients and healthy subjects (urocortin 2 +12% [−40 to 63%] P = 0.84, urocortin 3 −18% [−86 to +50%], P = 0.80; substance P −72% [−170 − +26%] P + 0.19). This evidence concerns the gene UCN2 and heart failure.