| nodal plane | The plane corresponding to the optical centre of a simple lens. See: nodal point. (05 Mar 2000) |
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| nodal point | One of two point's in a compound optical system so related that a ray directed toward the first point will appear to have passed through the second point parallel to its original direction. Synonym: axial point. (05 Mar 2000) |
| 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) |
| nodal tachycardia | Tachycardia originating in the A-V junction. Synonym: A-V junctional tachycardia, nodal tachycardia. (05 Mar 2000) |
| nodal tissue | See: atrioventricular node, sinuatrial node. (05 Mar 2000) |
| tachycardia, atrioventricular nodal reentry | A tachycardia characterised by rates between 150 and 250 beats per minute and a qrs complex of supraventricular origin. (12 Dec 1998) |
| tachycardia, sinoatrial nodal reentry | A tachycardia arising from the sinus node region and characterised by rates between 115 and 140 beats per minute. It is paroxysmal rather than constant. (12 Dec 1998) |
| extra nodal lymphoma | <oncology, tumour> Literally outside the lymph nodes, but exhibiting the characteristics of lymph node cancer. A term used to describe the extent and site of disease. (27 Sep 1997) |
| upper nodal extrasystole | An obsolete term for a nodal extrasystole supposed to arise from the upper part of the A-V node; recognised in the electrocardiogram by a retrograde P wave preceding the QRS complex by an abnormally short P-R interval. (05 Mar 2000) |
| lower nodal extrasystole | An obsolete term for a nodal extrasystole supposed to arise from the lower part of the A-V node, recognised in the electrocardiogram by the retrograde P wave that follows the QRS complex. (05 Mar 2000) |