<prompt> Afterload is best determined by?End diastolic volumeEnd systolic volumePeripheral resistanceCompliance  <response>: Ans. c Peripheral resistance. Ref.; Gangong, Physiology, 22 ndpg.p 572PRE-LOAD AND AFTER-LOAD After-load is the pressure in the arteries against which the ventricle pumps out the blood.- After-load diastolic arterial pressure proportional to peripheral resistance.- Vasodilators e.g., hydralazine decrease after-load. The degree of filling of ventricles is pre-load.- Pre-load pumps up the heart.- Pre-load ventricular end-diastolic volume- Venous dilators e.g., nitroglycerin decrease pre-load.- Pre-load increases with exercise slightly and with increase in the blood volume overtransfusion and excitement sympathetics. 