Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
CYCLE LENGTH DEPENDENCE OF THE ELECTROPHYSIOLOGICAL EFFECTS OF INCREASED LOAD ON THE MYOCARDIUM
Autore:
HORNER SM; DICK DJ; MURPHY CF; LAB MJ;
Indirizzi:
CHARING CROSS & WESTMINSTER MED SCH,DEPT PHYSIOL,BRITISH HEART FDN CARDIAC ARRHYTHMIA RES GRP LONDON W6 8RF ENGLAND CHARING CROSS & WESTMINSTER MED SCH,DEPT PHYSIOL,BRITISH HEART FDN CARDIAC ARRHYTHMIA RES GRP LONDON W6 8RF ENGLAND
Titolo Testata:
Circulation
fascicolo: 5, volume: 94, anno: 1996,
pagine: 1131 - 1136
SICI:
0009-7322(1996)94:5<1131:CLDOTE>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTION-POTENTIAL DURATION; CONTRACTION-EXCITATION FEEDBACK; ACTIVATED ION CHANNELS; MAMMALIAN VENTRICULAR MUSCLE; MONOPHASIC ACTION-POTENTIALS; STRETCH-INDUCED ARRHYTHMIAS; MECHANOELECTRICAL FEEDBACK; CALCIUM-CONCENTRATION; STEADY-STATE; PIG-HEART;
Keywords:
ARRHYTHMIA; ELECTROPHYSIOLOGY; INTERVALS POTENTIALS; VAGUS NERVE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
S.M. Horner et al., "CYCLE LENGTH DEPENDENCE OF THE ELECTROPHYSIOLOGICAL EFFECTS OF INCREASED LOAD ON THE MYOCARDIUM", Circulation, 94(5), 1996, pp. 1131-1136

Abstract

Background Mechanoelectric feedback, the process by which changes in mechanical activity change the electrophysiology of the myocardium, has been linked to the genesis of arrhythmias. We investigated possible arrhythmogenic mechanisms by measuring changes in steady-state action potential duration and, more particularly, electrical restitution on atransiently applied load change, because action potential recovery may provide clues to arrhythmogenesis. Methods and Results Pigs were anesthetized and their hearts exposed. A snare was placed around the aorta, and the right atrium was paced. Ventricular pressure, monophasic action potential, and segment motion were recorded from the left ventricle. The action potential duration was measured before and during transient aortic occlusion. Electrical restitution curves were constructed from the records obtained during normal loading or during transient aortic occlusion. The degree of shortening of action potential duration on aortic occlusion decreased with decreases in the steady-state beat-to-beat interval (P=.0008). Control restitution curves had the typicalconfiguration, with a rapid initial, usually monotonic, rise toward aplateau. Some curves showed a marginal ''supernormal'' section. Increased load reduced the action potential duration at the plateau of the restitution curve (9.4 ms, P<.0001) but increased the action potentialduration at the start of the restitution curve (8.7 ms, P=.03). Increased loading increased the maximum slope of the electrical restitutioncurve by 32 ms/100 ms CP=.04). Increased load also increased the supernormal period of the electrical restitution curves. Conclusions Mechanoelectric feedback produces changes in rate-dependent electrophysiology, which could favor a matrix conducive to arrhythmogenesis.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 22:44:03