a wave

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1. a uniformly advancing disturbance in which the parts undergo a change in direction, such as a progressing disturbance on the surface of a liquid.
2. variation in the transmission of electromagnetic energy, especially the periodic change in direction of a reading on a monitoring device.
A wave the wave on a His bundle electrogram that represents atrial activation.
alpha w's brain waves having a frequency of 8 to 13 per second, typical of a normal person awake in a quiet resting state; they occur primarily in the occipital region.
B wave a sharp rhythmic oscillation with a sawtooth pattern, occurring every 30 seconds to two minutes during intracranial pressure monitoring, associated with unstable increases in pressure.
beta w's brain waves having a frequency of 18 to 30 per second, typical during periods of intense central nervous system activity; they occur primarily in the parietal and frontal regions.
brain w's changes in electric potential of different areas of the brain, as recorded by electroencephalography. See also alpha, beta, delta, and theta waves.
C wave in intracranial pressure monitoring, a small rhythmic oscillation in pressure that occurs every four to eight minutes.
delta w's
1. brain waves having a frequency below 3½ per second, typical in deep sleep, in infancy, and in serious brain disorders.
2. an early QRS vector in the electrocardium in wolff-parkinson-white syndrome.
dicrotic wave the second portion of the tracing of a sphygmograph of the arterial pulse or arterial pressure after the dicrotic notch, attributed to the reflected impulse of closure of the aortic valves. Called also recoil wave
electromagnetic w's the entire series of ethereal waves, which are similar in character and move at the speed of light but vary enormously in wavelength. The unbroken series is known from radio waves that may be many kilometers in length through light waves, ultraviolet rays, x-rays, and gamma rays, to the cosmic rays, whose wavelength may be as short as 40 femtometers (4 × 10−14 m).
light w's the electromagnetic waves that produce sensations on the retina; see also vision.
P wave a positive deflection in the normal surface electrocardiogram produced by the wave of excitation passing over the atria; it represents atrial depolarization, an intrinsic atrial event.
papillary wave (percussion wave) the chief ascending portion of the tracing of a sphygmograph.
plateau wave a wave seen during intracranial pressure monitoring in advanced stages of increased pressure, signaling hypoxia of the brain cells.
pulse wave the elevation of the pulse felt by the finger or shown graphically in a recording of pulse pressure.
Q wave in the QRS complex, the initial electrocardiographic downward (negative) deflection, related to the initial phase of depolarization.
QRS wave QRS complex.
R wave in the normal surface electrocardiogram, the initial upward deflection of the QRS complex, following the Q wave; it represents ventricular depolarization. In cardiac pacing, it may be the entire native or intrinsic QRS complex.
radio w's electromagnetic waves of wavelength between 10−1 and 106 cm and frequency of about 1011 to 104 hertz.
recoil wave dicrotic wave.
S wave a downward deflection of the QRS complex following the R wave in the normal surface electrocardiogram.
sonic w's audible sound waves.
sound w's longitudinal waves of mechanical energy that transmit the vibrations interpreted as sound (def. 2).
T wave the second major deflection of the normal surface electrocardiogram, reflecting the potential variations occurring with repolarization of the ventricles.
theta w's brain waves having a frequency of 4 to 7 per second, occurring mainly in children but also seen in adults under emotional stress.
tidal wave the wave after the percussion wave on a sphygmograph recording; the second elevation of the tracing, preceding the dicrotic wave.
ultrasonic w's waves similar to sonic waves but of such high frequency (20,000 hertz or higher) that the human ear does not perceive them as sound; see ultrasonics.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

A wave

1. the initial negative deflection in the electroretinogram, presumably reflecting retinal photoreceptor activity;
2. an atrial deflection in an electrogram recorded from within the atrium of the heart;
3. the first positive deflection of the atrial and venous pulses due to atrial systole.
Farlex Partner Medical Dictionary © Farlex 2012

A Wave

A waveform which is part of a normal jugular phlebogram produced by retrograde transmission of the pressure pulse, and corresponds to atrial systole. The a wave begins before the first heart sound, peaking at the moment the first sound begins. Abnormalites of the a wave indicate cardiopulmonary disease. It may disappear in atrial fibrillation or be "swallowed" in the v-y descent of a prolonged P-Q interval. It may be very large—giant—when the atrium is contracting against resistance (e.g., tricuspid valve stenosis or atresia, pulmonary hypertension or pulmonary oedema) or have a presystolic "notch" in pulmonary oedema.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

a wave

A component of a normal jugular phlebogram produced by retrograde transmission of the pressure pulse, corresponding to atrial systole; the a wave begins before the first heart sound peaking at the moment the first sound begins; abnormalites of the a wave indicate cardiopulmonary disease; it may disappear in A Fib, be 'swallowed' in the v-y descent of a prolonged P-Q interval, it may be very large–giant when the atrium is contracting against resistance–eg tricuspid valve stenosis or atresia, pulmonary HTN or pulmonary edema or bear a presystolic 'notch'–pulmonary edema. Cf Cannon wave.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
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a wave

1. A venous neck wave produced by atrial contraction.
2. A component of right atrial and pulmonary artery wedge pressure tracings produced by atrial contraction. The a wave just precedes the first heart sound. It is absent in atrial fibrillation and is larger in atrioventricular dissociation and in conditions causing dilation of the right atrium.
See also: wave
Medical Dictionary, © 2009 Farlex and Partners