Question

If the stroke volume of the heart is \(70\ \text{mL/beat}\) and the cardiac output is \(5250\ \text{mL/min}\), what is the heart rate?

• A. \(60\) beats/min
• B. \(70\) beats/min
• C. \(75\) beats/min
• D. \(80\) beats/min

Hint:

Cardiac Output = Stroke Volume × Heart Rate. A normal resting heart rate in adults is typically around \(70-75\) beats per minute.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to calculate the Heart Rate (HR) given the Stroke Volume (SV) and the total Cardiac Output (CO).
Step 2: Key Formula or Approach:
The relationship between these variables is defined by the formula:
\[ \text{Cardiac Output (CO)} = \text{Stroke Volume (SV)} \times \text{Heart Rate (HR)} \]
Step 3: Detailed Explanation:
Given:
\( \text{SV} = 70\ \text{mL/beat} \)
\( \text{CO} = 5250\ \text{mL/min} \)
Rearranging the formula to solve for HR:
\[ \text{HR} = \frac{\text{CO}}{\text{SV}} \]
Substituting the values:
\[ \text{HR} = \frac{5250}{70} \]
\[ \text{HR} = 75\ \text{beats/min} \]
Step 4: Final Answer:
The heart rate is \(75\) beats per minute.