Questions: Cardiogenic shock can result from A myocardial infarction. B increased cardiac output. (C) increased sympathetic outflow to the heart. (D) parasympathetic antagonists.

The answer is the first one (A): a myocardial infarction.

Explanation for each option: A. Myocardial infarction: Correct. Cardiogenic shock is a condition where the heart suddenly can't pump enough blood to meet the body's needs. This is often caused by a severe heart attack (myocardial infarction), which damages the heart muscle and impairs its ability to function properly.

B. Increased cardiac output: Incorrect. Increased cardiac output means the heart is pumping more blood, which is the opposite of what happens in cardiogenic shock. In cardiogenic shock, the heart's pumping ability is compromised, leading to decreased cardiac output.

C. Increased sympathetic outflow to the heart: Incorrect. Increased sympathetic outflow typically increases heart rate and contractility, which would help improve cardiac output, not cause cardiogenic shock. Cardiogenic shock is due to the heart's inability to pump effectively, not an increase in sympathetic activity.

D. Parasympathetic antagonists: Incorrect. Parasympathetic antagonists would reduce the effects of the parasympathetic nervous system, potentially increasing heart rate and contractility. This would not cause cardiogenic shock, which is due to the heart's inability to pump blood effectively.

Summary: Cardiogenic shock can result from a myocardial infarction, which damages the heart muscle and impairs its ability to pump blood effectively.