| A-V junctional tachycardia | Tachycardia originating in the A-V junction. Synonym: A-V junctional tachycardia, nodal tachycardia. (05 Mar 2000) |
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| A-V malformation | <anatomy, embryology> A tangled collection of abnormal blood vessels where there is an abnormal communication between the arterial and venous systems. The afferents flow directly into the venous efferents without the usual resistance of an intervening capillary bed. They are mostly congenital. If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. Common sites include; skin, liver, brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid haemorrhage). See: arteriovenous fistula, cerebral arteriovenous malformations. Synonym: haemangioma (20 Jun 2000) |
| A-V 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) |
| A-V shunt | <anatomy, surgery> A direct connection between an artery and vein. Most often due to the surgical joining of an artery and a vein under the skin for the purpose of haemodialysis. Larger arteriovenous shunts can create significant extra workload on the heart since arterial blood is diverted back to the venous circulation before it has a chance to deliver nutrients and oxygen to the body tissues. (20 Jun 2000) |
| A-V strabismus syndrome | <syndrome> Strabismus in which the angle of deviation is more marked on looking upward or downward. See: A-esotropia, V-esotropia, A-exotropia, V-exotropia. (05 Mar 2000) |
| A-V valves | <abbreviation> The cardiac atrioventricular valves; the mitral and tricuspid valves. (05 Mar 2000) |