Abstract
Water hammer may occur in a closed conduit when there is a rapid retardation of the flow with the closure of a valve. In an aorta with an artificial aortic valve, substantial regurgitation of the blood flow occurs just before the valve is closed, and when the valve is closed the regurgitating flow is stopped suddenly. This causes a pulse of high pressure to be propagated along the aorta. These water hammer pulses were measured in the aorta of a dog with an artificial aortic valve. In the vicinity of thh valve, the peak of the water hammer pressure exceeded the peak systolic pressure. Water hammer pulses were measured also in a forty-four-year-old male after valve replacement for annulo-aortic ectasia.
