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Titolo:
Factors affecting epicardial dispersion of repolarization: a mapping studyin the isolated porcine heart
Autore:
Lacroix, D; Extramiana, F; Delfaut, P; Adamantidis, M; Grandmougin, D; Klug, D; Kacet, S; Dupuis, B;
Indirizzi:
Univ Lille, Dept Cardiol, Lille, France Univ Lille Lille FranceUniv Lille, Dept Cardiol, Lille, France Univ Lille, Dept Pharmacol, Lille, France Univ Lille Lille FranceUniv Lille, Dept Pharmacol, Lille, France Univ Lille, Dept Cardiovasc Surg, Lille, France Univ Lille Lille FranceUniv Lille, Dept Cardiovasc Surg, Lille, France
Titolo Testata:
CARDIOVASCULAR RESEARCH
fascicolo: 3, volume: 41, anno: 1999,
pagine: 563 - 574
SICI:
0008-6363(199903)41:3<563:FAEDOR>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
TORSADE-DE-POINTES; RABBIT VENTRICULAR MYOCYTES; LONG QT SYNDROME; M-CELLS; EARLY AFTERDEPOLARIZATIONS; TRIGGERED ACTIVITY; PURKINJE-FIBERS; DELAYED RECTIFIER; CARDIAC-MUSCLE; K+ CURRENTS;
Keywords:
arrhythmia mechanisms; antiarrhythmia agents; intra/extracellular ions; mapping; QT-dispersion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Lacroix, D Hop Cardiol, Blvd Prof J Leclercq, F-59037 Lille, France Hop Cardiol Blvd Prof J Leclercq Lille France F-59037 , France
Citazione:
D. Lacroix et al., "Factors affecting epicardial dispersion of repolarization: a mapping studyin the isolated porcine heart", CARDIO RES, 41(3), 1999, pp. 563-574

Abstract

Objective: Non-uniform drug-induced prolongation of repolarization predominating in the midmyocardial (M) cell layers has been shown to be responsible for perpetuation of reentry, giving rise to torsade de pointes. However, the absence of M cells in immature animals, especially the pig, suggests other possible underlying mechanisms. We sought to examine, in this species, the effects of predisposing factors to torsade de pointes on the dispersionof epicardial repolarization and their contribution to arrhythmogenesis. Methods: Computerized mapping of repolarization and activation was conductedon the epicardial surface in 29 Langendorff-perfused hearts of eight-week-old pigs. Activation-recovery intervals were measured simultaneously from 128 unipolar electrograms. Results: Baseline iso-interval maps were dipolar (41%) or multipolar (59%). Dispersion of repolarization was reverse frequency-dependent but was unaffected by lowering [K+](o). DL-Sotalol (0.1 mmol/l) reinforced local gradients and thus increased epicardial dispersion, whereas intramural recordings did not demonstrate any predominant effect in midmyocardial layers. Phenylephrine (1 mu mol/l) notably augmented DL-sotalol effects. After [Mg++](o) lowering, although dispersion was not significantly increased, or-sotalol was associated with the spontaneous occurrence of polymorphic ventricular tachycardia in seven out of nine experiments. When maps of repolarization of escape beats were compared with activation maps offirst arrhythmic beats, an are of functional dissociation was observed in the vicinity of a steep gradient of repolarization in two out of nine tachycardias. Conclusion: Epicardial dispersion of repolarization is increased by slow rates, DL-sotalol and phenylephrine but is not the only requirement for initiation of polymorphic ventricular tachycardia. In combination with other factors, it helps continuation of the arrhythmia in this model. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/07/20 alle ore 21:47:36