OME Cardiac Modules Practice Test

These drugs work as inodilators in heart failure. They boost the heart’s pumping strength (positive inotropy) and also widen the peripheral vessels (vasodilation), which lowers the afterload the heart has to push against. Dobutamine mainly stimulates beta-1 receptors to increase contractility, with some beta-2–mediated vasodilation that lowers systemic vascular resistance. Milrinone inhibits PDE-3, raising cAMP in both heart muscle and vascular smooth muscle, which directly increases contractility and causes vasodilation. The net result is higher cardiac output with reduced systemic vascular resistance, fitting the description of increasing contractility and decreasing afterload. Other options describe either reduced contractility, increased afterload, or no change in vascular resistance, which don’t match how these drugs work. These agents are typically used short-term in acute settings, with attention to potential tachycardia or hypotension.