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How can you find out if someone has hardened arteries without cutting them
open? Micro Medical of Rochester, Kent (GB 2356251) says you push a special
thimble over a patient’s fingertip, and an LED on one side shines infrared light
through the flesh to a sensor. Pressure waves in the blood caused by the
heartbeat show up as small changes in the amount of infrared you can detect. The
peaks come in pairs, a strong peak directly from the heart and a second, weaker
peak as the pressure wave bounces back from small arteries in the patient’s
lower body. The faster the pressure wave travels, the harder the arterial
walls.