Answer:
• Decrease in cardiac output causes an increase in preload.
• Diuretics reduce blood volume and myocardial oxygen demand.
• Excessive stretch on the ventricular wall will decrease preload.
Frank-starling mechanism showing the relation of the end diastolic pressure (EDP) and the contraction power(calculated by stroke volume).
In heart failure, failure to pump the blood(decrease in cardiac output) will increase the preload/EDP. The diuretic can decrease blood volume which will reduce the amount of blood the heart has to pump. Stretching of muscle will decrease the EDP and decrease the preload as well.
