Water hammer pulse seen in

Aoic regurgitation Water hammer pulse It is a large bounding pulse, associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance, leading to a wide pulse pressure. The pulse strikes the palpating finger with a rapid, forcefid jerk and quickly disappears. It is best felt in the radial aery with the patients arm elevated. It is seen in Aoic regurgitation. Pathophysiology of water hammer pulse In Aoic regurgitation the stroke volume is high, so the systolic pressure is high and this is responsible for sharp rise in the pulse. The stroke volume is high because the left ventricle gets blood from two sources during the diastole i.e. blood leaking from the Aoa and the blood it receives from left atria. The collapse occurs because Diastolic leak of blood into the left ventricle from the Aoa Rapid run off to the periphery as a result of low systemic vascular resistance (the increased cardiac output stimulates the baroreceptors in the aoic arch and the result is reflex vasodilatation of the peripheral vessels into which the blood flows rapidly). Wiry are arms elevated in the examination ? When the arm is raised there is fall of blood column resulting in vasodilation and thus helps to reduce the diastolic pressure more, so the pulse pressure widens. It may be so that the aery palpated becomes more in the line of Aoa after elevation of the arm and thus allows the direct systolic ejection and diastolic backward flow.