Despite the justifiable concern about the use of oral cyclic adenosine monophosphate phosphodiesterase (cAMP PDE) inhibitors, the intravenous preparations are clearly effective in the treatment of acute heart failure, whether it occurs de novo or complicating chronic congestive heart failure (CHF), and in low output states following cardiac surgery. There are no grounds to curtail their use in these areas, though any advantages over conventional agents such as dobutamine need further investigation with regard to end-points other than haemodynamic parameters. The long term use of oral cAMP PDE inhibitors in the treatment of chronic CHF should remain restricted by the increase in mortality now confirmed in severe CHF. However, in view of the distressing nature of the condition there remain subgroups of patients in whom the benefits may outweight the risks.