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Typification of atrial organization in electrogram recordings

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• adrenergic AF occurs as a result of excessive adrenaline that comes from sympathetic stimulation; sympathetic effects on the heart include increased rate and force of contraction. This type of AF is most likely occurring during the day and may be associated with emotional or physical stress. 2.1.2 Complications The tachycardia per se and the associated atrial contraction failure lead to profound alterations in atrial anatomy and function, establishing two differ- ent vicious circles sustaining AF and worsening eventual pre-existing heart failure. The non contracting atrium may lead to remodeling of the atrial body, in- creasing atrial size and causing intra-atrial flow velocity to decrease, leading to sluggish flow and increasing the risk of thrombus formation. AF patients with a large left atrium are thus threatened with both thromboembolic com- plications and worsening congestive heart failure. Cognitive defects increasingly develop in AF even in the absence of clinical stroke, and may relate to small, silent, deep lacunar and cortical infarcts. Furthermore, significant deficits in attention, memory, and language have been reported with no evidence of cerebral ischaemia. The increased heart rate in AF and the severity of the underlying ven- tricular disease, determine the overall hemodynamic derangement: hemody- namically, the loss of atrial transport and the impaired diastolic filling can reduce resting cardiac output by up to 20% if uncontrolled and long lasting, the irregular tachycardia may by itself precipitate cardiomyopathy and lead to congestive heart failure. Thromboembolic disease and stroke are the most important complica- tions of AF and their occurrence strikingly increases in both paroxysmal and chronic AF. However, because of a low rate of stroke among patients with lone AF, the causal link between AF and stroke has still to be proved. Complications are also heavily dependent on the effectiveness of the ther- apy, which strongly varies according to the duration of time since the onset of AF. As it is normally difficult to isolate AF onset, studies showed that eval- uation of atrial size may be of some help to assess the approximate duration of a patients AF [3-4]. 2.1.3 Therapy The initial management of patients with AF should address potential pre- cipitating illnesses while clinical assessment should moreover address those 9

Anteprima della Tesi di Alberto Zaffaroni

Anteprima della tesi: Typification of atrial organization in electrogram recordings, Pagina 7

Laurea liv.II (specialistica)

Facoltà: Ingegneria

Autore: Alberto Zaffaroni Contatta »

Composta da 93 pagine.


Questa tesi ha raggiunto 482 click dal 06/12/2005.

Disponibile in PDF, la consultazione è esclusivamente in formato digitale.