Cardiac output in 1./min divided by hea rate equals:
## **Core Concept**
Cardiac output (CO) is the volume of blood the heart pumps per minute. It is a critical parameter in cardiovascular physiology. The relationship between cardiac output, heart rate (HR), and stroke volume (SV) is fundamental.
## **Why the Correct Answer is Right**
Cardiac output is calculated as the product of heart rate (HR) and stroke volume (SV): CO = HR × SV. When cardiac output is divided by heart rate, the stroke volume (SV) is obtained: SV = CO / HR. Stroke volume represents the volume of blood pumped by the left ventricle of the heart in one contraction. Therefore, when cardiac output in L/min is divided by heart rate in beats per minute (bpm), the result is the stroke volume in milliliters (mL) or liters (L).
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option does not correctly represent a physiological parameter related to the division of cardiac output by heart rate.
- **Option B:** This option might seem plausible but does not accurately describe the result of dividing cardiac output by heart rate.
- **Option C:** This is the correct definition of stroke volume, which is what you get when you divide cardiac output by heart rate.
- **Option D:** This option does not accurately represent a relevant physiological parameter in this context.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that stroke volume (SV) is approximately 70 mL/beat in a healthy adult at rest. This value can change based on preload, contractility, and afterload. Understanding the relationship between cardiac output, heart rate, and stroke volume is crucial for managing patients with cardiovascular instability.
## **Correct Answer:** C.