| 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) |
| left atrial pressure | <radiology> 15-20 mm Hg redistribution 20-25 interstitial oedema 25-30 airspace oedema (12 Dec 1998) |
| lateral mammary branches of lateral cutaneous branches of intercostal nerves | Branches arising from the lateral cutaneous branches of the ventral primary rami of spinal nerves (intercostal nerves) T-3 to T-6 which run anteriorly to supply the lateral aspect of the breast. Synonym: rami mammarii laterales rami cutanei lateralis nervorum thoracicorum, rami mammarii laterales rami cutanei lateralis nervorum intercostalium, lateral mammary branches of lateral cutaneous branches of intercostal nerves. (05 Mar 2000) |
| lateral mammary branches of lateral cutaneous branches of thoracic spinal nerves | Branches arising from the lateral cutaneous branches of the ventral primary rami of spinal nerves (intercostal nerves) T-3 to T-6 which run anteriorly to supply the lateral aspect of the breast. Synonym: rami mammarii laterales rami cutanei lateralis nervorum thoracicorum, rami mammarii laterales rami cutanei lateralis nervorum intercostalium, lateral mammary branches of lateral cutaneous branches of intercostal nerves. (05 Mar 2000) |
| lateral mammary branches of lateral thoracic artery | <anatomy, artery> Branches of the lateral thoracic artery which extend around the lateral borders of the pectoral muscles to supply the lateral aspect of the breast and mammary gland. Synonym: rami mammarii laterales arteriae thoracicae lateralis. (05 Mar 2000) |
| accessory cephalic vein | <anatomy, vein> A variable vein that passes along the radial border of the forearm to join the cephalic vein near the elbow. Synonym: vena cephalica accessoria. (05 Mar 2000) |
| accessory hemiazygos vein | <anatomy, vein> Formed by the union of the fourth to seventh left posterior intercostal veins, passes along the side of the bodies of the fifth, sixth, and seventh thoracic vertebrae, then crosses the midline behind the aorta, oesophagus, and thoracic duct, and empties into the azygos vein, sometimes in common with the hemiazygos vein. Synonym: vena hemiazygos accessoria, vena azygos minor superior. (05 Mar 2000) |
| accessory saphenous vein | <anatomy, vein> An occasional vein running in the thigh parallel to the great saphenous vein which it joins just before the latter empties into the femoral vein. Synonym: vena saphena accessoria. (05 Mar 2000) |
| accessory vertebral vein | <anatomy, vein> A vein that accompanies the vertebral vein but passes through the foramen of the transverse process of the seventh cervical vertebra and opens independently into the brachiocephalic vein. Synonym: vena vertebralis accessoria. (05 Mar 2000) |
| accompanying vein | A vein accompanying another structure. Synonym: accompanying vein, companion vein. (05 Mar 2000) |
| accompanying vein of hypoglossal nerve | Runs with the hypoglossal nerve below and lateral to the hyoglossus muscle, emptying usually into the lingual vein. Synonym: accompanying vein of hypoglossal nerve. (05 Mar 2000) |