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Titolo:
Effect of physiological mechanical perturbations on intact human myocardial repolarization
Autore:
Nanthakumar, K; Dorian, P; Paquette, M; Hutchison, S; Andrews, J; Newman, D;
Indirizzi:
Univ Toronto, St Michaels Hosp, Div Cardiol, Toronto, ON M5B 1W8, Canada Univ Toronto Toronto ON Canada M5B 1W8 rdiol, Toronto, ON M5B 1W8, Canada
Titolo Testata:
CARDIOVASCULAR RESEARCH
fascicolo: 2, volume: 45, anno: 2000,
pagine: 303 - 309
SICI:
0008-6363(20000114)45:2<303:EOPMPO>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONTRACTION-EXCITATION FEEDBACK; MONOPHASIC ACTION-POTENTIALS; VALSALVA MANEUVER; MECHANOELECTRICAL FEEDBACK; VENTRICULAR REFRACTORINESS; HEART-FAILURE; VOLUME; VALIDATION; RELEVANCE; MUSCLE;
Keywords:
pacemaker/AICD; autonomic nervous system; stretch/m-e coupling; ventricular arrhythmias; ventricular function;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
31
Recensione:
Indirizzi per estratti:
Indirizzo: Newman, D Univ Toronto, St Michaels Hosp, Div Cardiol, 30 Bond St, Toronto, ON M5B 1W8, Canada Univ Toronto 30 Bond St Toronto ON Canada M5B 1W8 5B 1W8, Canada
Citazione:
K. Nanthakumar et al., "Effect of physiological mechanical perturbations on intact human myocardial repolarization", CARDIO RES, 45(2), 2000, pp. 303-309

Abstract

Objective: The objective of this study was to investigate the relationshipbetween acute decreases in right ventricular volume during Valsalva strain(with resultant changes in autonomic neural tone) and measures of local endocardial repolarization. time independent of heart rate and autonomic neural tone. Methods: Patients implanted with a Stimulus to T wave (Stim-T) sensing pacemaker specially adapted to output a validated measure of beat to beat local repolarization (n=9) performed Valsalva manoeuvers (40 mmHg for 15 s) while paced at a cycle length of 500 ms. Stim-T intervals were measured before and after autonomic blockade (Block: 0.03 mg/kg i.v. atropine+/-0.15 mg/kg propranolol). Right ventricular end diastolic volume was estimatedby simultaneous 2D-echocardiography, Results: Without autonomic blockade, compared to baseline, repolarization significantly prolonged during Valsalva strain (1.1+/-0.7%) and shortened during release (-1.4+/-1.0%). After block, strain related repolarization prolongation was also observed (1.0+/-0.6%), with significantly less release related repolarization shortening (-0.8/-0.8%) compared to pre-block (P<0.05). Right ventricular end diastolic volume decreased during strain by 11+/-10 and 9+/-16% from baseline, pre- andpost-block respectively (P<0.05). Conclusion: In a chronically instrumented human model, an acute physiologic volume reduction modestly prolongs right ventricular repolarization independent of changes in rate or autonomic tone. (C) 2000 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 02/12/20 alle ore 14:22:08