The positive inotropic agents, including beta-adrenergic receptor agonists and PDE III inhibitors, are reviewed to explain their mechanisms of action, pharmacology, and clinical usage. New cardiotonic drugs, such as dopexamine and dobutamine (beta-adrenergic receptor agonists) and amrinone, milrinone, and enoximone (PDE III inhibitors), have important roles for the treatment of perioperative acute heart failure or acute deterioration of congestive heart failure. PDE III inhibitors have important roles as effective inodilator agents, and understanding their actions, pharmacology, and appropriate usage is important. Nicardipine, the first dihydropyridine calcium-channel blocker available for intravenous use, represents an arterial-specific vasodilator that offers an important therapeutic approach to treat perioperative hypertension.