water hammer pulse

Water hammer pulse occurs due to a large stroke volume ejected rapidly into the aorta during systole (causing a sharp upstroke) followed by rapid diastolic runoff back into the left ventricle or peripheral vasodilation, causing a quick collapse of the pulse. This produces a widened pulse pressure (systolic - diastolic), which is the hemodynamic hallmark of aortic regurgitation (AR). It is best appreciated by palpating the radial artery while elevating the patient's arm above the heart, which accentuates the collapsing quality due to gravity aiding diastolic runoff. Water hammer pulse is part of a constellation of eponymous physical exam findings in AR, including: Corrigan's pulse (bounding carotid pulse), de Musset's sign (head bobbing with each heartbeat), Müller's sign (uvular pulsation), Quincke's sign (visible capillary pulsations in nail beds), Duroziez's sign (to-and-fro murmur over femoral artery with light compression), and Traube's sign (pistol-shot sounds over femoral artery). Causes of AR leading to water hammer pulse include bicuspid aortic valve, rheumatic heart disease, infective endocarditis, aortic root dilation (e.g., from syphilis, Marfan syndrome, ankylosing spondylitis), and aortic dissection. Other conditions with wide pulse pressure and bounding pulses include patent ductus arteriosus, arteriovenous fistulas, severe anemia, thyrotoxicosis, and febrile states—all high-output states with low systemic vascular resistance or rapid diastolic runoff. Clinically, recognizing water hammer pulse should prompt further cardiac auscultation for a diastolic decrescendo murmur at the left sternal border (best heard with patient leaning forward, breath held in expiration), echocardiography to assess valve morphology and regurgitant fraction, and evaluation for the underlying etiology. Chronic severe AR can lead to left ventricular volume overload, eccentric hypertrophy, and eventually heart failure if untreated; surgical valve replacement is indicated based on symptoms, LV dimensions, and ejection fraction criteria.