Stroke Volume (SV) equals

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Stroke Volume (SV) equals

The key relationship here is that cardiac output equals the product of stroke volume and heart rate. In other words, the amount of blood pumped per minute (cardiac output) is the volume per beat (stroke volume) times how many beats occur each minute. So stroke volume is cardiac output divided by heart rate. Using QT to mean cardiac output, SV = QT / HR. For example, if cardiac output is 5 L/min and heart rate is 75 beats/min, then SV ≈ 5 L/min ÷ 75 beats/min ≈ 0.0667 L/beat (about 67 mL per beat). The other forms don’t fit this relationship: multiplying by heart rate would give a value that’s too large and not the stroke volume; dividing heart rate by cardiac output would yield a nonsensical unit; and subtracting the two values has no physiological basis.

The key relationship here is that cardiac output equals the product of stroke volume and heart rate. In other words, the amount of blood pumped per minute (cardiac output) is the volume per beat (stroke volume) times how many beats occur each minute. So stroke volume is cardiac output divided by heart rate.

Using QT to mean cardiac output, SV = QT / HR. For example, if cardiac output is 5 L/min and heart rate is 75 beats/min, then SV ≈ 5 L/min ÷ 75 beats/min ≈ 0.0667 L/beat (about 67 mL per beat).

The other forms don’t fit this relationship: multiplying by heart rate would give a value that’s too large and not the stroke volume; dividing heart rate by cardiac output would yield a nonsensical unit; and subtracting the two values has no physiological basis.

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