Final answer:
To calculate peak LV pressure in aortic stenosis, the aortic valve gradient is added to the left ventricular end-diastolic pressure, giving the peak pressure needed to overcome the stenotic aortic valve.
Step-by-step explanation:
To calculate peak left ventricular (LV) pressure in aortic stenosis, you add the aortic valve gradient to the left ventricular end-diastolic pressure. This is because the aortic valve gradient represents the difference in pressure between the ventricle and the aorta during ventricular systole, which must be overcome for blood to be ejected. Therefore, when this gradient is added to the LV end-diastolic pressure, which is the baseline pressure in the ventricle prior to the contraction, you obtain the peak pressure the LV must generate during systole.