| alpha rhythm | Brain waves in the encephalogram which have a frequency of 8 to 13 per second. They are typical of the normal person awake and in a quiet resting state, and occur principally in the occipital region. (12 Dec 1998) |
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| basic electrical rhythm | A slow wave of depolarisation of smooth muscle from the fundus to the pylorus that coordinates gastric peristalsis and emptying. (05 Mar 2000) |
| Berger rhythm | Brain waves in the encephalogram which have a frequency of 8 to 13 per second. They are typical of the normal person awake and in a quiet resting state, and occur principally in the occipital region. (12 Dec 1998) |
| beta rhythm | <neurology> Brain waves in the electroencephalogram which have a frequency of 18 to 30 per second. They are typical during periods of intense activity of the nervous system, and occur principally in the parietal and frontal regions. (12 Dec 1998) |
| bigeminal rhythm | That cardiac rhythm 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). Synonym: coupled rhythm. (05 Mar 2000) |
| cantering rhythm | A triple cadence to the heart sounds; due to an abnormal third or fourth heart sound being heard in addition to the first and second sounds, and usually indicative of serious disease. Synonym: bruit de galop, cantering rhythm, gallop rhythm, Traube's bruit. (05 Mar 2000) |
| gallop rhythm | Heart rhythm like the gallop of a horse. (12 Dec 1998) |
| ventricular rhythm | A slow independent ventricular rhythm under control of a ventricular centre (which is, by definition, ectopic). Synonym: ventricular rhythm. (05 Mar 2000) |
| reciprocal rhythm | 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; recognised 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. (05 Mar 2000) |
| reciprocating rhythm | 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. (05 Mar 2000) |
| pendulum rhythm | A condition in which the cadence of the heart sounds resembles that of the foetus, the first and second sounds becoming alike and evenly spaced; a sign of serious myocardial disease. Synonym: pendulum rhythm, tic-tac rhythm, tic-tac sounds. Origin: embryo-+ G. Kardia, heart (05 Mar 2000) |
| reversed reciprocal rhythm | 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 rhythm. (05 Mar 2000) |
| rhythm | <cardiology> The regularity of the heartbeat. Can be assessed by taking the pulse. (23 Aug 1998) |
| rhythm method | <gynaecology> A contraceptive method whereby abstinence is practiced a few days before and after the estimated day of ovulation. (12 Dec 1998) |
| circadian rhythm | The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, feeding, etc. This rhythm seems to be set by a 'biological clock' which seems to be set by recurring daylight and darkness. (12 Dec 1998) |