Overview Preload = ventricular EDV increases with exercise (slightly) ↑ blood volume (overtransfusion) excitement (sympathetics) preload "pumps up the heart" Afterload = mean arterial pressure proportional to peripheral resistance Drugs venodilators (e.g. nitroglycerin) ↓ preload vasodilators (e.g. hydrAlAzine) ↓ Afterload (Arterial)