Final answer:
Epinephrine increases cardiac output by acting as a positive inotropic agent, enhancing heart contractions and heart rate. Parasympathetic stimulation and decreased calcium during contraction would reduce it, while high blood pressure is a result rather than a cause.
Step-by-step explanation:
Cardiac output is the volume of blood the heart pumps per minute, and it can be influenced by several factors. Among the options provided, epinephrine would increase cardiac output because it is a positive inotropic agent that increases the strength of heart contractions and the heart rate.
Parasympathetic stimulation, however, is a negative inotropic agent, which means it reduces the strength of heart contractions and would therefore reduce cardiac output. Reduced calcium during muscle contraction would also decrease the force of contraction, thus lowering cardiac output. High blood pressure is not a direct cause of increased cardiac output; instead, it can be a result of it.
Epinephrine, on the other hand, binds to alpha and beta receptors in the heart, increasing its metabolic rate and the force of contraction, leading to an increase in stroke volume (SV) and a reduction in the end-systolic volume (ESV), which overall raises cardiac output.