Arteriovenous fistulas have high-output cardiac failure due to what peripheral resistance?

Arteriovenous fistulas have high-output cardiac failure due to what peripheral resistance?

• A. Low; high
• B. High; low
• C. High; high
• D. Low; low

Answer: (B)

Arteriovenous fistulas create a large, low-resistance pathway that shunts arterial blood directly into the venous system, bypassing the high-resistance capillary beds. This lowers systemic vascular resistance (afterload) and increases venous return. In response, the heart pumps more blood to maintain arterial pressure, so a high-output state develops. Over time, this sustained high flow can lead to high-output cardiac failure. So the key point is low peripheral (systemic) resistance driving a high-output state. The correct description is low resistance with high cardiac output, even though the other option descriptions don’t match this physiology.

Arteriovenous fistulas create a large, low-resistance pathway that shunts arterial blood directly into the venous system, bypassing the high-resistance capillary beds. This lowers systemic vascular resistance (afterload) and increases venous return. In response, the heart pumps more blood to maintain arterial pressure, so a high-output state develops. Over time, this sustained high flow can lead to high-output cardiac failure. So the key point is low peripheral (systemic) resistance driving a high-output state. The correct description is low resistance with high cardiac output, even though the other option descriptions don’t match this physiology.