How is QT calculated when given stroke volume?

The correct approach to calculating QT when given stroke volume involves understanding the relationship between stroke volume and heart rate in the context of cardiac output.

Cardiac output (CO) is defined as the volume of blood pumped by the heart per minute and is calculated using the formula:

Cardiac Output = Stroke Volume x Heart Rate.

In this case, QT, or the total time it takes to complete one cardiac cycle, can be viewed in terms of heart rate and stroke volume. Heart rate indicates how many times the heart beats in one minute, while stroke volume indicates how much blood is pumped with each beat. By multiplying heart rate by stroke volume, you get the total volume of blood pumped in a minute, thus providing a direct relation to how QT can be approached in a more integrative way.

This is why multiplying heart rate by stroke volume is the correct method to relate these two parameters in the context of QT calculation. The other options involve incorrect operations (such as division or addition of these two separate values), which do not accurately represent the relationship in physiological terms.