Watson's water hammer pulse

Watson's water hammer pulse is the medical sign which describes a pulse that is bounding and forceful,^[1] rapidly increasing and subsequently collapsing,^[2] as if it were the sound of a waterhammer that was causing the pulse. A waterhammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow.^[3]

This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.

Eponym

"Watson's water hammer pulse" and "Corrigan's pulse" refer to similar observations. However, the former usually refers to measurement of a pulse on a limb, while the latter refers to measurement of the pulse of the carotid artery.^[1]

• "Corrigan's pulse" is named for Sir Dominic Corrigan, the Irish physician, who characterized it in 1832.^[4][5]
• "Watson's water hammer pulse" is named for Thomas Watson, who characterized it in 1844.^[1]

Observation

To feel a water hammer pulse: with the patient reclining, the examiner raises the patient's arm vertically upwards. The examiner grasps the muscular part of the patient's forearm. A water hammer pulse is felt as a tapping impulse which is transmitted through the bulk of the muscles. This happens because the blood that is pumped to the arm during systole is emptied very quickly due to the gravity effect on the raised arm. This results in the artery emptying back into the heart during diastole, therefore causing a palpable pulse.

Causes

Water hammer pulse is commonly found when a patient has aortic regurgitation. It can also be seen in other conditions which are associated with a hyperdynamic circulation. A more comprehensive list of causes follows:

• Physiological
  • Fever
  • Pregnancy
• Cardiac lesions
  • Aortic regurgitation
  • Patent ductus arteriosus
  • Systolic hypertension
  • Bradycardia
  • Aortopulmonary window
  • Aneurysm of sinus of Valsalva
• Syndromes or high-output states
  • Anemia
  • Cor pulmonale
  • Cirrhosis of liver
  • Beriberi
  • Thyrotoxicosis
  • Arteriovenous fistula
  • Paget's disease
• Other causes
  • Chronic alcoholism

See also

• Blood hammer

References

1. Suvarna JC (2008). "Watson's water hammer pulse". J Postgrad Med 54 (2): 163–5. doi:10.4103/0022-3859.40791. PMID 18480541.
2. Elizabeth D Agabegi; Agabegi, Steven S. (2008). Step-Up to Medicine (Step-Up Series). Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN 0-7817-7153-6.
3. https://www.youtube.com/watch?v=Kb6feUfHgAU
4. synd/3006 at Who Named It?
5. D. J. Corrigan. On permanent patency of the mouth of the aorta, or inadequacy of the aortic valves. The Edinburgh Medical and Surgical Journal, 1832, 37: 225-245.