This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
End diastolic volume increases in: 
Select and explain. 
A. Decrease in total blood volume, B. Increase in intrapericardial pressure, C. Increase in negative intrathoracic pressure, D. Decrease in ventricular compliance
C: Increase in negative intrathoracic pressure
Answer: C: Increase in negative intrathoracic pressure 
Explanation: Ans. c. Increase in negative intrathoracic pressureFactors Affecting End Diastolic VolumeEnd diastolic volume increases in conditions associated with increase in negative intrathoracic pressure.Factors Decreasing EDVIncreased intra-pericardial pressuredeg (as aresult of infection of pressure from a tumor):Limits the extent to which ventricle can fillDecrease in ventricular compliancedeg:Increase in ventricular stiffness produced by MI, infiltrative disease.Standing decreases venous returndegFactors Increasing EDVIncreased total blood volume increases venous returndeg:Constriction of vein reduces the size of venous reservoirIncreased negative intrathoracic pressuredeg:Increases the pressure gradient along which blood flows to theMuscle activitydeg: Increases venous return as a result of pumping action