Give name of PDE inhibitor?

Milrinone is a phosphodiesterase inhibitor that increases the intracellular concentration of cAMP. Like β-adrenergic agonists, this results in an increase of intracellular calcium and, therefore, cardiac contractility. Long-term, milrinone therapy may be associated with a substantial increased risk of mortality. However, short-term use of intravenous milrinone is not associated with increased mortality in patients without a history of coronary artery disease, and some symptomatic benefit may be obtained in patients with refractory HF.