| atrioventricular extrasystole | An extrasystole arising from the "junctional" tissues, either the A-V node or A-V bundle. Synonym: junctional extrasystole. (05 Mar 2000) |
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| atrioventricular gradient | The diastolic pressure difference between the atrium and ventricle. (05 Mar 2000) |
| atrioventricular groove | A groove on the outer surface of the heart marking the division between the atria and the ventricles. Synonym: sulcus coronarius, atrioventricular groove, atrioventricular sulcus, auriculoventricular groove, coronary sulcus. (05 Mar 2000) |
| atrioventricular interval | The time between depolarisation of the atria and of the ventricle. Synonym: atrioventricular interval. (05 Mar 2000) |
| atrioventricular junctional bigeminy | Paired beats, each pair consisting of an A-V nodal extrasystole coupled to a beat of the dominant, usually sinus, rhythm. Synonym: nodal bigeminy. (05 Mar 2000) |
| atrioventricular junctional 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) |
| atrioventricular junctional tachycardia | Tachycardia originating in the A-V junction. Synonym: A-V junctional tachycardia, nodal tachycardia. (05 Mar 2000) |
| atrioventricular nodal branch | The atrioventricular branches or the nodal branches, the small arteries supplying the atrioventricular node; they usually arise from the right coronary artery where it starts to descend the posterior interventricular sulcus. Synonym: ramus nodi atrioventricularis, atrioventricular nodal branch, branch to atrioventricular node. (05 Mar 2000) |
| atrioventricular nodal extrasystole | A premature beat arising from the A-V junction and leading to a simultaneous or almost simultaneous contraction of atria and ventricles. (05 Mar 2000) |
| atrioventricular node | <cardiology> The location in the heart's conduction system, between the atria and the ventricles, which conducts the normal electrical impulse from the atria to the ventricles. (27 Sep 1997) |
| atrioventricular septum | The small part of the membranous septum of the heart just above the septal cusp of the tricuspid valve that separates the right atrium from the left ventricle. Synonym: septum atrioventriculare, pars membranacea septi atriorum. (05 Mar 2000) |
| atrioventricular sulcus | A groove on the outer surface of the heart marking the division between the atria and the ventricles. Synonym: sulcus coronarius, atrioventricular groove, atrioventricular sulcus, auriculoventricular groove, coronary sulcus. (05 Mar 2000) |
| atrioventricular valves | See: tricuspid valve, mitral valve. (05 Mar 2000) |
| atriplicism | An intoxication caused by the ingestion of certain species of Atriplex, eaten as greens in China; it is marked by pain and swelling of the fingers, spreading to the forearm; bullae and ulcers form, and the fingers may become gangrenous. Origin: L. Atriplex (-plic-), the orach, a vegetable (05 Mar 2000) |
| atrium | <anatomy> A chamber, used in anatomical nomenclature to designate a chamber affording entrance to another structure or organ. Usually used alone to designate an atrium of the heart. Origin: L., Gr. Atrion = hall (16 Dec 1997) |