Question
Which of the following is the right order for the changes depicted in this graphical representation?
| A. |
Increased preload, Decreased afterload & Increased contractility
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| B. |
Increased preload, Increased afterload & Increased contractility
|
| C. |
Decreased preload, Increased afterload & decreased contractility
|
| D. |
Decreased preload, Decreased afterload & Decreased contractility
|
Show Answer
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Correct Answer � B
Explanation
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|
Ans. B. Increased preload, Increased afterload & Increased contractility.
This illustrates the normal, resting left ventricular pressure-volume relationship during a cardiac cycle.
- An increase in preload (end-diastolic volume) results in greater stroke volume through the Frank-Starling mechanism.
- An increase in afterload results in the opening of the aortic valve at a higher left ventricular pressure; stroke volume is reduced.
- An increase in contractility produces a greater stroke volume that is not dependent on a change in end-diastolic volume.
