Читать книгу Interventional Cardiology - Группа авторов - Страница 346

Agents such as milrinone and enoximone increase the intracellular concentration of cyclic adenosine mono phosphate (cAMP) by inhibiting the action of phosphodiesterase 3 [37]. Phosphodiesterase 3 is an enzyme found in the sarcoplasmic reticulum of cardiac myocytes and vascular smooth muscle cells which breaks down cAMP into AMP. The increased intracellular concentration of cAMP increases myocardial contractility, improves diastolic relaxation, and causes vasodilation. Milrinone, the most widely used phophodiesterase inhibitor has a relatively long half‐life of 2 to 4 hours. The calcium‐sensitizer levosimendan sensitizes troponin C to calcium, thereby increasing the effects of calcium on cardiac myofilaments which increases cardiac contractility at low energy costs. Levosi‐mendan also causes vasodilatation by opening ATP‐dependent potassium channels [38, 39]. Both milrinone and levosimendan have not been tested in the setting of cardiogenic shock complicating myocardial infarction and experience with these agents in this setting is limited.