| 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) |
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| 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) |
| circus rhythm | A contraction or excitation wave traveling continuously in circular fashion around a ring of muscle or through the wall of the heart. Synonym: circus rhythm. (05 Mar 2000) |
| coronary nodal rhythm | 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. (05 Mar 2000) |
| coronary sinus rhythm | An ectopic atrial rhythm supposedly originating from a pacemaker at the mouth of the coronary sinus; recognised 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. (05 Mar 2000) |
| coupled 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) |
| sinus rhythm | The normal regular cardiac rhythm stimulated by the sinoatrial node. (27 Sep 1997) |
| nodal rhythm | The cardiac rhythm 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. Synonym: A-V junctional rhythm, nodal bradycardia, nodal rhythm. (05 Mar 2000) |
| systolic gallop rhythm | An obsolete term for extra sounds, usually clicks, heard during systole. (05 Mar 2000) |
| diurnal rhythm | Occurring during the day. (18 Nov 1997) |