| IAS | immunosuppressive acidic substance; infant apnea syndrome; insulin autoimmune syndrome; interatrial ... |
|---|---|
| IS | ileal segment; immediate sensitivity; immune serum; immunosuppression; impingement syndrome; incenti... |
| IVS | inappropriate vasopressin secretion; intervening sequence; interventricular septum; intervillous spa... |
| LS | lateral suspensor; left sacrum; left septum; left side; legally separated; leiomyosarcoma; length of... |
| RS | radioscaphoid; random sample; rating schedule; Raynaud syndrome; recipient's serum; rectal sinus; re... |
| septal defect, atrial | A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an asd. Asds are a major class of heart deformity that is present at birth (congenital cardiac malformation). (12 Dec 1998) |
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| subsidiary atrial pacemaker | Secondary source for rhythmic control of the heart, available for controlling cardiac activity if the sinoatrial pacemaker fails; located within the crista terminalis and atrial free wall near the inferior vena cava. (05 Mar 2000) |
| defect, atrial septal | A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs are a major class of congenital cardiac malformation. (12 Dec 1998) |
| intra-atrial | Within one or both of the atria of the heart. (05 Mar 2000) |
| intra-atrial block | Impaired conduction through the atria, manifested by widened and often notched P waves in the electrocardiogram. (05 Mar 2000) |
| intra-atrial conduction | Conduction of the cardiac impulse through the atrial myocardium, represented by the P wave in the electrocardiogram. (05 Mar 2000) |
| intra-atrial conduction time | The total duration of electrical activity of the atria in one cardiac cycle. (05 Mar 2000) |
| tachycardia, ectopic atrial | A tachycardia originating in the atrial myocardium and characterised by rates between 135 and 175 beats per minute. (12 Dec 1998) |
| tachycardia, paroxysmal atrial | Bouts of rapid, regular heart beating originating in the atrium (upper chamber of the heart). Often due to abnormalities in the av node relay station that lead to rapid firing of electrical impulses from the atrium which bypass the av node under certain conditions. These conditions include alcohol excess, stress, caffeine, overactive thyroid or excessive thyroid hormone intake, and certain drugs. Pat is an example of an arrhythmia where the abnormality is in the electrical system of the heart, while the heart muscle and valves may be normal. (12 Dec 1998) |
| fibrillation, atrial | An abnormal irregular heart rhythm whereby electrical signals are generated chaotically throughout the upper chambers (atria) of the heart. Although many persons with atrial fibrillation have no symptoms, the most common symptom is palpitations, an uncomfortable awareness of the rapid and irregular heartbeat. Atrial fibrillation can cause blood clots that travel from the heart to the brain, causing stroke. Treatment of atrial fibrillation involves controlling the risk factors, medications to slow the heart rate and/or convert the heart to normal rhythm, and preventing complications of blood clotting. (12 Dec 1998) |
| lateral atrial vein | A vein draining deep portions of the temporal and parietal lobes; it runs in the lateral wall of the lateral ventricle to terminate in the superior thalamostriate vein. Synonym: vena ventriculi lateralis lateralis, lateral atrial vein, lateral vein of lateral ventricle. (05 Mar 2000) |
| left atrial pressure | <radiology> 15-20 mm Hg redistribution 20-25 interstitial oedema 25-30 airspace oedema (12 Dec 1998) |
| absent nasal septum | <radiology> Cocaine, Wegener's (midline lethal granuloma), surgery, trauma, syphilis, sarcoid (12 Dec 1998) |
| alveolar septum | The tissue intervening between two adjacent pulmonary alveoli; it consists of a close-meshed capillary network covered on both surfaces by very thin alveolar epithelial cells, one of the bony partitions between the tooth sockets. Synonym: septum interalveolare, alveolar septum, septal bone. (05 Mar 2000) |
| anterior vein of septum pellucidum | Vein draining the anterior part of the transparent septum; it empties into the superior thalamostriate vein. Synonym: vena septi pellucidi anterior. (05 Mar 2000) |