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Atrial septal defect
An atrial septal defect (ASD) is a hole in the wall between the heart's two upper chambers, present at birth, allowing oxygen-rich blood to shunt into the right atrium.
Atrial septostomy
Atrial septostomy (Rashkind septostomy, balloon atrial septostomy) is a catheter procedure creating an opening between the heart's atria, used to palliate neonatal transposition of the great arteries and to decompress the right ventricle in severe pulmonary hypertension as a bridge to lung transplantation.
Atrial tachycardia
Atrial tachycardia (AT) is a supraventricular arrhythmia with regular atrial rates above 100 bpm and P waves originating outside the sinus node, caused by automaticity, triggered activity, or microreentry; classified as focal or macroreentrant, treated with drugs and catheter ablation.
Atrichia with papular lesions
Atrichia with papular lesions (papular atrichia, OMIM 209500) is a rare autosomal recessive alopecia caused by hairless (HR) gene mutations on chromosome 8p, with irreversible hair loss soon after birth and keratin papules years later.
Atrichum
Atrichum (smoothcap or starburst mosses), genus of about 15-20 acrocarpous mosses in Polytrichaceae, temperate both hemispheres; hairless calyptra, sparse lamellae, 32-toothed peristome, shady moist disturbed-soil habitats; synonym Catharinea.
Atrioventricular block
Atrioventricular block (AV block, heart block) is partial or complete interruption of electrical impulse transmission from the atria to the ventricles, classified as first-, second- (Mobitz I/II), or third-degree; diagnosed by ECG and treated with pacemakers when needed.
Atrioventricular nodal reentrant tachycardia
Atrioventricular nodal reentrant tachycardia (AVNRT) is a rapid heart rhythm caused by an electrical impulse circling two pathways at the AV node, causing sudden palpitations.
Atrioventricular node
The atrioventricular node, or AV node, is a mass of cardiac muscle at the base of the atrial septum that conducts electrical impulses from the atria to the ventricles.
Atrioventricular node ablation
Atrioventricular node ablation is a catheter procedure that destroys the AV node to permanently control rapid ventricular rates in atrial fibrillation, requiring lifelong pacemaker dependence.
Atrioventricular reentrant tachycardia
Atrioventricular reentrant tachycardia (AVRT), the reentrant arrhythmia of Wolff-Parkinson-White syndrome, uses an accessory pathway plus the AV node as a macroreentrant circuit; orthodromic forms are narrow-complex, antidromic wide-complex, and radiofrequency ablation is curative.
Atrioventricular septal defect
Atrioventricular septal defect (AVSD), also called AV canal or endocardial cushion defect, is a congenital heart defect with holes between heart chambers and a common five-leaflet AV valve, common in Down syndrome, repaired surgically in infancy.
Atrioventricular septum
Atrioventricular septum: septal heart structure between right atrium and left ventricle at the crux, partly membranous and partly muscular. Defects (AVSD) cause 0.24–0.31/1000 live-birth congenital heart disease, strongly linked to Down syndrome; repair mortality about 3%.
Atriplex
Atriplex (orache, saltbush) is the largest genus of Amaranthaceae, about 250-260 species of C3 and C4 herbs and shrubs of deserts and saline habitats, originating in Oligocene Asia with diversity centers in Australia and the New World.
Atrium (architecture)
An atrium is a large central hall or courtyard in a building, open to the sky or roofed with glazing, found in Roman houses and modern buildings.
Atrium (heart)
Atrium (heart): the two upper heart chambers (right and left atrium) that collect incoming blood. Distinct right pectinate muscles versus smooth left walls, three-phase reservoir-conduit-booster function, and the left atrial appendage as the main AF thrombus site.
Atrium Vestae
Atrium Vestae, House of the Vestals (Casa delle Vestali): residence of the six Vestal Virgins beside the temple of Vesta in the Roman Forum; visible ruins are mainly Trajanic (c. 110-113 AD), excavated by Lanciani 1882-1884.
Atrocities in the Congo Free State
Atrocities in the Congo Free State (État indépendant du Congo, 1885–1908): Leopold II's rubber and ivory quota regime enforced by hostage-taking, chicotte floggings, mutilation and punitive expeditions; estimated population decline 15–50%; exposed by Casement and Morel, ended by 1908 annexation.
Atrocitus
Atrocitus (Atros) is a DC Comics supervillain and Red Lantern Corps founder, created by Geoff Johns and Ethan Van Sciver, debuting in Green Lantern #25 (2007), based on Ysmault, seeking revenge on the Guardians for the Sector 666 massacre.
Atrocity Exhibition (album)
Atrocity Exhibition is Danny Brown's fourth studio album (Warp, September 27, 2016), named for a Joy Division song and J.G. Ballard novel, mostly produced by Paul White, 15 tracks, Metacritic 85, guests include Kendrick Lamar, Ab-Soul, and Earl Sweatshirt.
Atromitos F.C.
Atromitos F.C. (Ατρόμητος), Greek club founded 1923 in Peristeri, Athens; Super League side since 2005 Spanos era, best finish 3rd in 2013–14, two Cup finals, seven European campaigns, 8,969-seat Peristeri Stadium.
ATRON
ATRON is a lattice-based self-reconfigurable modular robot developed at the University of Southern Denmark in Odense, described in 2004, whose roughly spherical modules connect and autonomously change shape.
Atropa
Atropa is a small genus of perennial herbs in Solanaceae, tribe Hyoscyameae, named for the Greek Fate Atropos. Its six species, including deadly nightshade (Atropa bella-donna), contain toxic tropane alkaloids such as atropine and scopolamine.
Atropa belladonna
Atropa belladonna (deadly nightshade), Solanaceae perennial herb native to Europe to N. Iran and NW. Africa; purple bell flowers, black glossy berries with 0.65% tropane alkaloids; source of atropine, first isolated 1831.
Atrophia bulbi
Atrophia bulbi (eyeball atrophy, ICD-11 9C22.0) is atrophy of intraocular structures with low eye pressure from end-stage ocular disease; with shrinkage and disorganization it becomes phthisis bulbi (9C22.1).
Atrophic gastritis
Atrophic gastritis: chronic gastric inflammation causing thinning of the stomach lining; type A autoimmune (corpus, pernicious anemia) or type B H. pylori-associated; staged by OLGA/OLGIM, a gastric cancer risk factor.
Atrophic lichen planus
Atrophic lichen planus (atrophic LP, lichen planus atrophicans) is a rare variant of cutaneous lichen planus with pale, atrophic-centered papules or plaques on previously affected skin; prevalence and etiology unknown, ICD-10 L43.8.
Atrophic papulosis
Atrophic papulosis (Degos disease, Köhlmeier-Degos disease) is a rare thrombotic vasculopathy with porcelain-white skin papules; the malignant systemic form (MAP) affects gut and brain with high mortality, while benign cutaneous BAP stays skin-limited.
Atrophic rhinitis of swine
Atrophic rhinitis of swine (porcine atrophic rhinitis, sometimes called bullnose) is a pig disease with turbinate bone atrophy; nonprogressive form from Bordetella bronchiseptica, progressive form from toxigenic Pasteurella multocida, now rare after eradication programs.
Atrophic senile gingivitis
Atrophic senile gingivitis (ICD-11 DA0B.3; SNOMED CT 91949000) is an age-related form of gingivitis, gum inflammation without connective tissue loss, kept as a legacy diagnostic category in ICD-11, SNOMED CT, and MedGen.
Atrophoderma of Pasini and Pierini
Atrophoderma of Pasini and Pierini (APP), also called idiopathic atrophoderma of Pasini and Pierini, is a rare benign dermal atrophy with depressed hyperpigmented 'cliff-drop' patches on the trunk, debated as a superficial morphea variant, ICD-10 L90.3.