Question

Select each of the following that would result in elevated cardiac output for a given heart rate. In other words, which of the following would result in increased stroke volume?

elevated end diastolic volume

increased contractility

physiologic cardiac hypertrophy

pathologic cardiac hypertrophy

reduced ejection fraction

reduced preload

increased blood volume

increased hematocrit due to blood doping

increased afterload

increased circulating epinephrine

Answer 1

An increase in end diastolic volume increases the preload on the heart , increases the amount of blood ejected from the ventricle during systole (stroke volume).

An increase  in contractility tends to increase stroke volume and thus a secondary increase in preload.

Physiologic cardiac hypertrophy was associated with increased stroke volume.

Unaltered stroke volume is in Pathologic cardiac hypertrophy along with markedly elevated end-systolic pressure values.

Reduced ejection fraction results in an elevated left ventricular filling pressure and a drop in stroke volume with a consequent reduction of systemic blood flow.

Reduced preload decreases stroke volume by altering the force of contraction of the cardiac muscle.

An increase in blood volume increases the central venous pressure. This increases right atrial pressure, right ventricular end-diastolic pressure and volume. This increase in ventricular preload increases ventricular stroke volume.

An   increase in afterload results in increase in end-systolic volume and a decrease in stroke volume.

Increased circulatory epinephrine increases cardiac output and increased stroke volume.