- 1. Measured time or motion; the regular alternation of two or more different or opposite states. 2. SYN: r. method. 3. Regular or irregular occurrence of an electrical event in the electrocardiogram or 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 8–13 Hz; 2. the posterior dominant 8–13 Hz r. in the awake, relaxed person with closed eyes, that attenuates with eye opening. SYN: alpha wave, Berger r..- atrioventricular junctional r. the cardiac r. when the heart is controlled by the AV junction (including node); arising in the AV junction, the impulse ascends to the atria and descends to the ventricles, each at varying speeds depending on the site of the pacemaker; only descends to the ventricles in the common form of atrioventricular dissociation and in idiojunctional r.. SYN: AV junctional r., nodal bradycardia, nodal r..- AV junctional r. SYN: 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.- beta r. a wave pattern in the electroencephalogram in the frequency band of 18–30 Hz. SYN: beta wave.- bigeminal r. that cardiac r. when each beat of the dominant r. (sinus or other) is followed by a premature beat, with the result that the heartbeats occur in pairs (bigeminy). SYN: coupled r..- cantering r. SYN: gallop.- circus r. SYN: 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 aVF with a normal or prolonged P-R interval; an ectopic (“lower”) atrial r..- coupled r. SYN: bigeminal r..- 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 and 180 impulses per minute, that of the atrioventricular junction is normally 40–60 impulses per min, and the normal rate of the ventricular myocardium (idioventricular r.) is 20–40 impulses per min.- idiojunctional r. SYN: idionodal r..- idionodal r. an independent r., the ventricles being under control of the AV node (AV junction). SYN: idiojunctional r..- idioventricular r. a slow independent ventricular r. under control of a ventricular center (which is, by definition, ectopic). SYN: ventricular r..- junctional r. rhythms originating anywhere within the AV junction. Formerly, “AV nodal” or simply “nodal” rhythms.- pendulum r. SYN: 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. SYN: 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. SYN: trainwheel r..- reciprocal r. a cardiac arrhythmia in which the impulse arising in the AV 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 AV 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; in healthy adults its rate is 60–90 beats/min.- theta r. a wave pattern in the electroencephalogram in the frequency band of 4–7 Hz. SYN: theta wave.- tic-tac r. SYN: embryocardia.- trainwheel r. SYN: 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. SYN: trigeminy.- triple r. a triple cadence to the heart sounds at any heart rate, due to the easy audibility of a third (S3) (usually) or fourth (S4) heart sound, or at faster rates a summation sound due to coincidence of the third and fourth heart sounds (“S7” = S3 + S4).
* * *rhythm 'rith-əm n1) a regularly recurrent quantitative change in a variable biological process: asa) the pattern of recurrence of the cardiac cycle <an irregular \rhythm>b) the recurring pattern of physical and functional changes associated with the mammalian and esp. human sexual cycle2) RHYTHM METHOD
* * *(rithґəm) [L. rhythmus; Gr. rhythmos] a measured movement; the recurrence of an action or function at regular intervals. rhythmic, rhythmical adj
Medical dictionary. 2011.