UCN2 and heart failure: However, in patients with stable heart failure, there was no difference in terms of forearm vasodilatation within groups of patients infused with UCN 2 (3.6–36 pmol/min), UCN3 (360–3600 pmol/min) and substance P (2–8 pmol/min), while UCN3 caused a transient tachycardia at the highest dose infused, suggesting that vasodilator effects of UCN2 and UCN3 were upheld in patients with heart failure [86].