During advanced vasodilatory shock, arginine vasopressin (AVP) is increasingly used to restore blood pressure and thus to reduce catecholamine requirements. The AVP-related rise in mean arterial pressure is due to systemic vasoconstriction, which, depending on the infusion rate, may also reduce coronary blood flow despite an increased coronary perfusion pressure. In a murine model of myocardial ischaemia, Indrambarya and colleagues now report that a 3-day infusion of AVP decreased the left ventricular ejection fraction, ultimately resulting in increased mortality, and thus compared unfavourably with a standard treatment using dobutamine. The AVP-related impairment myocardial dysfunction did not result from the increased left ventricular afterload but from a direct effect on cardiac contractility. Consequently, the authors conclude that the use of AVP should be cautioned in patients with underlying cardiac disease.