What is the likely change in myocardial oxygen consumption in a patient with aortic stenosis?

• A. A) Increased
• B. B) Decreased
• C. C) No change
• D. D) Fluctuating

Answer: (A)

In a patient with aortic stenosis, myocardial oxygen consumption is likely to increase. This increase is primarily due to the increased workload on the heart. Aortic stenosis results in a narrowing of the aortic valve, which obstructs blood flow from the left ventricle into the aorta during systole. To compensate for this obstruction, the left ventricle must generate a greater pressure to eject blood, leading to hypertrophy (thickening) of the ventricular muscle over time.

As the left ventricle hypertrophies, it requires more oxygen to support its increased mass and contractility. Additionally, the increased afterload can contribute to greater myocardial oxygen demand. As such, the heart needs to work harder, thus consuming more oxygen to maintain adequate cardiac output and meet the body’s demands, particularly during exertion.

In summary, the pathophysiology associated with aortic stenosis—specifically the increased ventricular pressure and subsequent hypertrophy—leads to elevated myocardial oxygen consumption.