rhythm (rith´um)

1. Measured time or motion; the regular alternation of two or more different or opposite states. 2. rhythm method 3. Regular occurrence of an electrical event in the electroencephalogram. See also wave. 4. Sequential beating of the heart generated by a single beat or sequence of beats. [G. rhythmos]
agonal r. an idioventricular r., characterized by unusually wide and bizarre ventricular complexes, often seen in moribund patients.
alpha r. 1. a wave pattern in the encephalogram in the frequency band of 8 to 13 Hz; 2. the posterior dominant 8-13 Hz r. in the awake, relaxed person with closed eyes, that attenuates with eye opening.alpha wave, Berger r;
atrioventricular junctional r. the cardiac r. when the heart is controlled by the A-V junction (including node); arising in the A-V junction, the impulse ascends to the atria and descends to the ventricles, each at varying speeds depending on site of the pacemaker.A-V junctional r., nodal bradycardia, nodal r;
A-V junctional r. atrioventricular junctional r
basic electrical r. (BER) a slow wave of depolarization of smooth muscle from the fundus to the pylorus that coordinates gastric peristalsis and emptying.
Berger r. alpha r
beta r. a wave pattern in the electroencephalogram in the frequency band of 18 to 30 Hz.beta wave;
bigeminal r. that cardiac r. when each beat of the dominant rhythm (sinus or other) is followed by a premature beat, with the result that the heartbeats occur in pairs (bigeminy).coupled r;
cantering r. gallop
circadian r. See circadian.
circus r. circus movement
coronary nodal r. formerly applied by some authorities to the electrocardiographic pattern of normal upright P waves in leads I and II with a short P-R interval.
coronary sinus r. an ectopic atrial r. supposedly originating from a pacemaker at the mouth of the coronary sinus; recognized in the electrocardiogram by P-waves that are inverted in leads II, III, and a VI with a normal or prolonged P-R interval; an ectopic ("lower") atrial rhythm.
coupled r. bigeminal r
delta r. a wave pattern in the electroencephalogram in the frequency band of 1.5 to 4.0 Hz.delta wave (2);
diurnal r. See diurnal.
ectopic r. any cardiac r. arising from a center other than the normal pacemaker, the sinus node.
escape r. three or more consecutive impulses at a rate not exceeding the upper limit of the inherent pacemaker; extreme range of impulse formation at the sinoatrial node is between 40 to 180 impulses per minute, that of the atrioventricular junction is normally 40 to 60 impulses per minute, and the normal rate of the ventricular myocardium (idioventricular rhythm) is 20 to 40 impulses per minute.
gallop r. gallop
idiojunctional r. idionodal r
idionodal r. an independent r., the ventricles being under control of the A-V node (A-V junction).idiojunctional r;
idioventricular r. a slow independent ventricular r. under control of a ventricular center (which is, by definition, ectopic).ventricular r;
junctional r. r.'s originating anywhere within the A-V junction. Formerly, "A-V nodal" or simply "nodal" r.'s.
nodal r. atrioventricular junctional r
pendulum r. embryocardia
quadrigeminal r. a cardiac arrhythmia in which the heartbeats are grouped in fours, each usually composed of one sinus beat followed by three extrasystoles, but a repetitive group of four of any composition is quadrigeminal.quadrigeminy;
quadruple r. a quadruple cadence to the heart sounds due to the easy audibility of both third and fourth heart sounds, indicative of serious myocardial disease.trainwheel r;
reciprocal r. a cardiac arrhythmia in which the impulse arising in the A-V junction descends to and activates the ventricles on one intrajunctional pathway and simultaneously ascends toward the atria in parallel pathways; before reaching the atria, however, the impulse is reflected downward and again activates the ventricles, producing an echo or reciprocal beat; recognized in the electrocardiogram by the presence of an inverted P wave in lead aVF and usually II sandwiched between two ventricular complexes aberrantly, both of which may be normal or one of which may be conducted.
reciprocating r. a cardiac arrhythmia initiated by an A-V junctional beat followed in turn by a reciprocal beat; the descending impulse of the reciprocal beat, before reaching the ventricles, is also reflected backward to the atria, but before reaching the atria is reflected downward again to the ventricles, so that there is both retrograde atrial activation and orthograde ventricular activation.
reversed reciprocal r. a cardiac arrhythmia in which a normal sinus impulse, before reaching the ventricles, is reflected backward to the atria; thus in the electrocardiogram a ventricular complex is sandwiched between a normal sinus P wave and a retrograde P wave; if the dysrhythmia continues, subsequent cycles are similar to those of reciprocating r.
sinus r. normal cardiac r. proceeding from the sinoatrial node.
systolic gallop r. obsolete term for extra sounds, usually clicks, heard during systole.
theta r. a wave pattern in the electroencephalogram in the frequency band of 4 to 7 Hz.theta wave;
tic-tac r. embryocardia
trainwheel r. quadruple r
trigeminal r. a cardiac arrhythmia in which the beats are grouped in trios, usually composed of a sinus beat followed by two extrasystoles.trigeminy;
triple r. a triple cadence to the heart sounds at any heart rate, due to the easy audibility of a third (usually) or fourth heart sound, or at faster rates a summation sound due to coincidence of the third and fourth heart sounds.
ultradian r. See ultradian.
ventricular r. idioventricular r


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