**Question:** All of the following are the actions of β-blockers in CHF except:

A. Reduction in heart rate
B. Improvement in cardiac output
C. Increase in systemic vascular resistance
D. Improvement in heart failure symptoms

**Core Concept:** β-blockers are a class of medications used in the treatment of cardiovascular diseases, particularly in heart failure (CHF). They work by blocking β-adrenergic receptors, which are stimulated by the sympathetic nervous system and lead to increased cardiac contractility, heart rate, and vascular resistance.

**Why the Correct Answer is Right:**

Correct Answer: C. Increase in systemic vascular resistance

In CHF, the heart is unable to pump blood efficiently due to structural or functional abnormalities. β-blockers work by reducing the afferent feedback loop (sympathetic nervous system) to the heart and vasculature, which leads to:

1. **Reduction in heart rate:** By blocking β-adrenergic receptors, β-blockers decrease the heart's rate and contractility, reducing the heart's workload and oxygen demand.
2. **Improvement in cardiac output:** Although β-blockers initially reduce heart rate and contractility, over time, the heart adapts by increasing its efficiency and contractility, ultimately improving cardiac output.
3. **Improvement in heart failure symptoms:** The reduction in heart rate and contractility leads to mild symptoms relief and improved quality of life.
4. **Improvement in heart failure prognosis:** By reducing the heart's oxygen demand and improving cardiac output, β-blockers can potentially improve the overall prognosis of CHF patients.

**Why Each Wrong Option is Incorrect:**

A. **Reduction in heart rate:** As mentioned above, reducing heart rate and contractility is a mechanism of action for β-blockers, making this option incorrect.
B. **Improvement in cardiac output:** As explained, β-blockers initially reduce heart rate and contractility, not improve cardiac output.
D. **Improvement in heart failure symptoms:** Although β-blockers can provide mild symptom relief, this option is not entirely accurate because they also improve prognosis and reduce oxygen demand.

**Why the Correct Answer is Right:**

C. **Increase in systemic vascular resistance:** This option is incorrect because β-blockers, by reducing heart rate and contractility, decrease the heart's oxygen demand and improve cardiac output. This leads to a reduction in afterload (systemic vascular resistance) and improves the heart's workload.

In conclusion, the correct answer (C) is incorrect because β-blockers do not increase systemic vascular resistance. Instead, they reduce it by decreasing the heart's oxygen demand and improving cardiac output in CHF patients.