Delta Wave

wave (wāv) a uniformly advancing disturbance in which the parts moved undergo a double oscillation; any wavelike pattern.

---

alpha waves  see under rhythm.

beta waves  see under rhythm.

brain waves  the fluctuations of electric potential in the brain, as recorded by electroencephalography.

delta wave 

1. an early QRS vector in the electrocardiogram in preexcitation.

2. (pl.) electroencephalographic waves with a frequency below 3.5 per second, typical in deep sleep, infancy, and serious brain disorders.

electromagnetic waves  the spectrum of waves propagated by an electromagnetic field, having a velocity of 3 × 108 m/s in a vacuum and including, in order of decreasing wavelength, radio waves, microwaves, infrared, visible, and ultraviolet light, x-rays, gamma rays, and cosmic rays.

Diagrammatic representation of electromagnetic waves.

F waves 

1. flutter w's; rapid sawtooth-edged atrial waves without isoelectric intervals between them; seen in the electrocardiogram in atrial flutter. Written also f w's .

2. f w's (1).

f waves 

1. fibrillary w's; small, irregular, rapid deflections in the electrocardiogram in atrial fibrillation. Written also F w's.

2. F w's (1).

fibrillary waves  f w's (1).

flutter waves  F w's (1).

J wave  a deflection occurring in the electrocardiogram between the QRS complex and the onset of the ST segment, occurring prominently in hypothermia and in hypocalcemia.

P wave  a deflection in the electrocardiogram produced by excitation of the atria.

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 downward (negative) deflection, related to the initial phase of depolarization of the ventricular myocardium, the depolarization of the interventricular septum.

R wave  the initial upward deflection of the QRS complex, following the Q wave in the normal electrocardiogram and representing early depolarization of the ventricles.

S wave  a downward deflection of the QRS complex following the R wave in the normal electrocardiogram and representing late depolarization of the ventricles.

T wave  the deflection of the normal electrocardiogram following the QRS complex; it represents repolarization or recovery of the ventricles.

Ta wave  a small asymmetric wave, of opposite polarity to the P wave, representing atrial repolarization; together with the P wave it defines atrial systole.

theta waves  brain waves in the electroencephalogram with a frequency of 4 to 7 per second, mainly seen in children and emotionally stressed adults.

U wave  a potential undulation of unknown origin immediately following the T wave and often concealed by it; seen in the normal electrocardiogram and accentuated in tachyarrhythmias and electrolyte disturbances.

---

delta wave

n.

1. A slurring of the R-wave upstroke in an electrocardiogram as seen in Wolff-Parkinson-White syndrome.

2. See delta rhythm.

---

delta wave,

1 also called delta rhythm. the slowest of several types of brain waves, characterized by a frequency of 4 Hz and a relatively high voltage. Delta waves are "deep-sleep waves" associated with a dreamless state from which an individual is not easily aroused. Compare alpha wave, beta wave, theta wave.

2 (in cardiology) a slurring of the QRS portion of an electrocardiogram tracing caused by preexcitation in Wolff-Parkinson-White syndrome.

---

Delta Wave

Cardiology An EKG finding in WPW syndrome, seen as a slow upstroke of the QRS wave in a background of short P-R intervals See Wolff-Parkinson-White syndrome
Sleep disorders EEG activity with a frequency of < 4 Hz; in human sleep scoring, the minimum criteria for scoring DWs is 75 µV—peak-to-peak amplitude—and 0.5 second duration—2 Hz

---

delta wave

Cardiology An EKG finding in WPW syndrome, seen as a slow upstroke of the QRS wave in a background of short P-R intervals. See Wolff-Parkinson-White syndrome.