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Watson's water hammer pulse, also known as Corrigan's pulse or collapsing pulse, is the medical sign (seen in aortic regurgitation) which describes a pulse that is bounding and forceful, [1] rapidly increasing and subsequently collapsing, [2] as if it were the sound of a water hammer that was causing the pulse.
The ultrasound probe emits a high-frequency sound wave (usually a multiple of 2 MHz) that bounces off various substances in the body. These echoes are detected by a sensor in the probe. In the case of blood in an artery, the echoes have different frequencies depending on the direction and speed of the blood because of the Doppler effect. [2]
Hyperdynamic circulation is abnormally increased circulatory volume. Systemic vasodilation and the associated decrease in peripheral vascular resistance results in decreased pulmonary capillary wedge pressure and decreased blood pressure, presenting usually with a collapsing pulse, but sometimes a bounding pulse.
Doppler fetal monitors, although usually not technically -graphy but rather sound-generating, use the Doppler effect to detect the fetal heartbeat for prenatal care. These are hand-held, and some models also display the heart rate in beats per minute (BPM). Use of this monitor is sometimes known as Doppler auscultation.
De Musset's sign is a type of rhythmic bobbing of the head in synchrony with the beating of the heart, seen in severe aortic regurgitation. [1]This sign occurs as a result of blood from the aorta regurgitating into the left ventricle due to a defect in the aortic valve.
Ultrasound Doppler imaging can be used to obtain basic functional measurements of brain activity using blood flow. In functional transcranial Doppler sonography, a low frequency (1-3 MHz) transducer is used through the temporal bone window with a conventional pulse Doppler mode to estimate blood flow at a single focal location.
Pulse-Doppler begins with coherent pulses transmitted through an antenna or transducer. There is no modulation on the transmit pulse. Each pulse is a perfectly clean slice of a perfect coherent tone. The coherent tone is produced by the local oscillator. There can be dozens of transmit pulses between the antenna and the reflector.
The effect (now named Uni-Vibe) was modified to have easier access to its fuse, and a speed control foot pedal was added. It was later released in North America by Univox in 1968. [1] [3] It is commonly thought the Uni-Vibe is intended to emulate the "Doppler sound" of a Leslie speaker. However Fumio Mieda revealed in an interview the effect ...