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Titolo:
ELECTROPHYSIOLOGICAL EFFECTS OF ACUTE DILATATION IN THE ISOLATED RABBIT HEART - CYCLE LENGTH-DEPENDENT EFFECTS ON VENTRICULAR REFRACTORINESS AND CONDUCTION-VELOCITY
Autore:
REITER MJ; LANDERS M; ZETELAKI Z; KIRCHHOF CJH; ALLESSIE MA;
Indirizzi:
UNIV COLORADO,HLTH SCI CTR,DIV CARDIOL,DEPT MED,BOX B-130,4200 E 9TH AVE DENVER CO 80262 MAASTRICHT UNIV,DEPT PHYSIOL MAASTRICHT NETHERLANDS
Titolo Testata:
Circulation
fascicolo: 11, volume: 96, anno: 1997,
pagine: 4050 - 4056
SICI:
0009-7322(1997)96:11<4050:EEOADI>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONTRACTION-EXCITATION FEEDBACK; ACTION-POTENTIALS; MECHANOELECTRICAL FEEDBACK; CANINE HEARTS; LOAD; REPOLARIZATION; TACHYCARDIA; ARRHYTHMIAS; HUMANS; PROLONGATION;
Keywords:
HEART FAILURE; CONDUCTION; REENTRY; REFRACTORINESS; ARRHYTHMIAS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
37
Recensione:
Indirizzi per estratti:
Citazione:
M.J. Reiter et al., "ELECTROPHYSIOLOGICAL EFFECTS OF ACUTE DILATATION IN THE ISOLATED RABBIT HEART - CYCLE LENGTH-DEPENDENT EFFECTS ON VENTRICULAR REFRACTORINESS AND CONDUCTION-VELOCITY", Circulation, 96(11), 1997, pp. 4050-4056

Abstract

Background Acute ventricular dilatation has important electrophysiological effects: Dilatation shortens action potential duration and refractoriness without an apparent effect on conduction velocity. These effects have been implicated as a potential mechanism of arrhythmias in patients with congestive failure. Because the influence of cycle lengthon these phenomena has not been studied, we examined the effects of dilatation during ventricular pacing at cycle lengths from 1000 to 150 ms. Methods and Results Thin epicardial layers were created in isolated, perfused rabbit left ventricles (n=7). A fluid filled latex balloonwas secured in the left ventricle to dilate the left ventricle. Mapping was performed with 248 epicardial electrodes. Longitudinal conduction velocity (76+/-1 cm/s; mean+/-SEM) and transverse conduction velocity (26+/-1 cm/s) were not influenced by dilatation at any cycle length. In contrast, the effects of dilatation in decreasing left ventricular effective refractory period (ERP) were significantly greater at shorter drive cycle lengths: The decrease in ERP was 2+/-2 ms (a 1% change) at a drive cycle length of 1000 ms and 18+/-4 ms (a 20% change) at adrive cycle length of 150 ms. In 10 additional intact, isolated perfused rabbit hearts, dilatation decreased ERP to a greater degree during250 ms drive cycle length pacing than during pacing at 400 ms (25+/-4versus 16+/-3 ms; P=.01). Conclusions Acute dilatation exaggerates the normal rate-dependent shortening of refractoriness but does not influence transverse or longitudinal conduction velocity. This observationsuggests that the electrophysiological effects of acute dilatation may be greater during tachycardia than at slower cycle lengths. This mayhave implications for arrhythmias in patients with congestive heart failure.

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Documento generato il 24/11/20 alle ore 09:47:50