Search results for "atrium"
showing 10 items of 69 documents
Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline
2020
This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfus…
Positive inotropic response to 5-HT in human atrial but not in ventricular heart muscle
1992
The effects of 5-hydroxytryptamine (5-HT) on force of contraction (FC), action potential (AP) and calcium current (ICa) were studied in human right atrial and left ventricular heart muscle. 5-HT exerted a concentration-dependent increase in FC in multicellular atrial preparations; the EC50 was approximately 3 x 10(-7) mol/l. Maximal increases in FC (252 +/- 58% of control values; mean +/- SEM, n = 6) were obtained at 5-HT 10(-5) mol/l. At this concentration, ICa was increased four- to sevenfold in enzymatically isolated atrial myocytes. In contrast, ventricular preparations did not respond to 5-HT; FC, AP and ICa remained unaffected. In the same preparations, FC was increased by isoprenalin…
Effect of intravenous flecainide on atrial vulnerability in man.
1983
Sixteen patients were investigated by means of programmed atrial stimulation at two different driving rates: 100 and 120/min. All patients had an increased atrial vulnerability at both driving rates. After intravenous flecainide application (1 mg/kg body weight as a bolus followed by the same amount given by infusion over a period of 20 min) the increased vulnerability was abolished in 11 and 9 patients respectively. In the remaining patients the rate of induced atrial tachyarrhythmia decreased. These findings correlate with a significant prolongation of the effective refractory period of the right atrium and a significant shortening of the relative refractory period of the right atrium. It…
Wave similarity mapping shows the spatiotemporal distribution of fibrillatory wave complexity in the human right atrium during paroxysmal and chronic…
2005
Introduction: The complexity of waveforms during atrial fibrillation may reflect critical activation patterns for the arrhythmia perpetuation. In this study, we introduce a novel concept of map, based on the analysis of the wave morphology, which gives a direct evidence in the human right atrium on the spatiotemporal distribution of fibrillatory wave complexity in paroxysmal (PAF) and chronic (CAF) atrial fibrillation. Methods and Results: Electrograms were recorded from a 64-electrode catheter in the right atrium of 15 patients during PAF (n = 8) and CAF (n = 7). Wave similarity maps were constructed by calculating the degree of morphological similarity of activation waves (S) at each atri…
Implantation Strategy of the Atrial Dipole Impacts Atrial Sensing Performance of Single Lead VDD Pacemakers
2002
WIEGAND, U.K.H., et al.: Implantation Strategy of the Atrial Dipole Impacts Atrial Sensing Perfor-mance of Single Lead VDD Pacemakers. Intermittent atrial undersensing is observed in a considerable percentage of patients with single lead VDD pacemakers. Analyzing the 2-year data of the Saphir Multicenter Follow-Up Study, the authors investigated predictors for the occurrence of undersensing. The study included 194 patients with high degree AV block who received a VDD pacemaker system with an identical sensing amplifier. Placement strategy of the atrial dipole was left to the discretion of the implanting physician. At the final position, atrial potential amplitudes were measured during deep …
Per una lettura socio-economica dei contesti abitativi: L’insula I del Quartiere ellenistico-romano di Agrigento. La domus I A – I B
2021
In linea con le ultime ricerche organizzate dal Parco Archeologico Regionale Valle dei Templi di Agrigento, il cui scopo è la conoscenza dell'antica città di Akragas/Agrigentum come sistema integrato e unitario, si è dedicata nuova attenzione alle forme dell'abitare, in particolare nell'area del cosiddetto "Quartiere ellenistico-romano". Quest'area fu scavata negli anni '50 e '60 del secolo scorso, ma è con la pubblicazione di E. De Miro, avvenuta solo nel 2009, che è stato possibile conoscere i risultati delle indagini. In questo contributo ci si vuole concentrare sull'isolato I del Quartiere, contraddistinto da due grandi abitazioni (I A/B e I E/F) che dominano l'area pubblica dell'agorà.…
H2-Antihistaminika, 36. Mitt. Isolamtidin und Analoge
1987
Isolamtidin (9a), ein Stellungsisomer des Lamtidins (8a), sowie die analogen N3-substituierten 1-Methyl-1H-1,2,4-triazol-3,5-diamine 9e-i, k wurden durch spezifische Synthese dargestellt und am isolierten Meerschweinchenvorhof und an der histaminstimulierten Sauresekretion der narkotisierten Ratte auf H2-antagonistische Wirkung untersucht. H2-Antihistaminics, XXXVI: Isolamitidine and Analogues Isolamitidine (9a), a position isomer of lamtidine (8a), as well as the analogous N3-substituted 1-methyl-1H-1,2,4-triazole-3,5-diamines 9e-i, k were prepared and tested for H2-antagonistic activity on the isolated guinea-pig atrium and towards the histamine-stimulated acid secretion of the anaestheti…
Isomeric arrangement of the left atrial appendages and visceral heterotaxy: two atypical cases.
2000
AbstractWe present two cases in which there was isomeric arrangement oi the left atrial appendages in association with multiple spleens and complete heart block. In both of these, the venous connections were normal. In one case the arrangement of the bronchial tree and the lungs was normal, the liver was left-sided, and the stomach was right-sided. In the other case, there was left isomeric broncho-pulmonary morphology, and both liver and stomach were right-sided. These unusual combinations show the need for full description of the morphology of other organs, and the venoatrial connections, in cases with isomeric arrangement of the atrial appendages. They also demonstrate that connection of…
Modi di abitare, tipi e varianti: alcune riflessioni sulla cultura abitativa ellenistico-romana in Sicilia
2020
After a brief survey on the previous studies on the Sicilian domestic architecture of the hellenistic and Roman periods, this paper questions the idea of a continuous development of the Greek house's central space, from the simple court to the peristyle, as well as the opposition between “centripetal”and “axial” (i.e. the Greek peristyle house and the Roman atrium house). This rigid distinction doesn't take in account the existence of an hybrid form of the court that doesn't fit well in these comfortable cathegories: the “tetrastylon”. Sicilian houses are reconsidered in order to establish if this and other single houses' features can be labelled as “Punic”, “Greek” or “Roman” or if this is…
CVG-ICP-OES -menetelmän käyttö elohopean analysointiin eläinkudoksesta
2015
Tässä Pro gradu –tutkielmassa käsitellään elohopean määritystä eläinkudoksesta kemiallinen höyryn muodostus induktiivisesti kytketty plasma optinen emissio spektrometria –menetelmällä (CVG-ICP-OES) ja siihen liittyvää näytteenkäsittelyä. Tutkimuksen kirjallisessa osassa käydään läpi muun muassa eri näytteenliuotusmenetelmiä, analyysimenetelmiä, tutkittavien metallien pelkistämistä CVG-ICP-OES –analyysiä varten ja CVG-ICP-OES –analyysissä esiintyviä häiriöitä. Näytteenliuotusosassa keskitytään pääasiassa tutkimuksessa käytetyn ultraäänihajotuksen esittelyyn, tämän lisäksi myös muita yleisiä näytteenliuotusmenetelmiä esitetään. Analyysimenetelmä osiossa suurin huomio keskittyy ICP-OES –laitte…