Figure 1.

 Left ventricular (LV) and aortic pressure waveforms obtained in a pig of group A (A) at normal aortic pressure and (B) during mild and (C) severe systemic hypertension induced by banding of the aorta. (D) In this pig, in an additional stage after the removal of the aorta banding, phenylephrine was administered to produce severe hypertension (protocol similar to the one used in group B). Note the major decrease in pressure gradients during hypertension despite the presence of severe aortic stenosis (in this animal, effective orifice area (EOA) varies between 0.47–0.65 cm² and EOA indexed for body surface area varies between 0.43–0.59 cm²/m²).