Cardiac Catheterization Practice Test

When a valve is stenotic, the obstruction causes resistance to forward flow, so the pressure builds up in the chamber immediately upstream of the narrowed opening. That proximal chamber has to generate higher pressure to push blood through the narrowed valve, especially during systole in cases like aortic stenosis, where the left ventricle must overcome the increased afterload. The downstream chamber experiences less pressure rise because the flow is impeded after the valve. Apical or basal are anatomical regions, not the site of the pressure increase due to the valve narrowing. So the chamber right before the stenosis experiences the pressure rise.