This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Mechanism of action of levosimendon include 
Select and explain. 
A. Na channel opener, B. Potassium channel opener, C. Beta blockers, D. Beta 1 agonist
B: Potassium channel opener
Answer: B: Potassium channel opener 
Explanation: Mechanism of action Levosimendan exes its positive inotropic effect by increasing calcium sensitivity of myocytes by binding to cardiac troponin C in a calcium-dependent manner. ... The combined inotropic and vasodilatoryactions result in an increased force of contraction, decreased preload and decreased afterload. Refer katzung 11e p221