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Titolo:
Contraction-relaxation coupling: determination of the onset of diastole
Autore:
Solomon, SB; Nikolic, SD; Frater, RWM; Yellin, EL;
Indirizzi:
Yeshiva Univ Albert Einstein Coll Med, Dept Cardiothorac Surg, Bronx, NY 10461 USA Yeshiva Univ Albert Einstein Coll Med Bronx NY USA 10461 nx, NY 10461 USA Yeshiva Univ Albert Einstein Coll Med, Dept Physiol & Biophys, Bronx, NY 10461 USA Yeshiva Univ Albert Einstein Coll Med Bronx NY USA 10461 nx, NY 10461 USA Stanford Univ, Sch Med, Palo Alto Med Fdn, Res Inst,Dept Cardiovasc & Thorac Surg, Palo Alto, CA 94306 USA Stanford Univ Palo Alto CA USA 94306 Thorac Surg, Palo Alto, CA 94306 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 1, volume: 46, anno: 1999,
pagine: H23 - H27
SICI:
0363-6135(199907)46:1<H23:CCDOTO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
LEFT-VENTRICULAR RELAXATION; SYSTOLIC PRESSURE; HEART; LOAD; MUSCLE; FAILURE; PUMP;
Keywords:
afterload; left ventricular relaxation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Solomon, SB NIH, Dept Crit Care Med, 10 Ctr Dr,Rm 7D43, Bethesda, MD 20892USA NIH 10 Ctr Dr,Rm 7D43 Bethesda MD USA 20892 esda, MD 20892 USA
Citazione:
S.B. Solomon et al., "Contraction-relaxation coupling: determination of the onset of diastole", AM J P-HEAR, 46(1), 1999, pp. H23-H27

Abstract

Left ventricular relaxation is dependent on afterload conditions during systole. An abrupt increase in afterload while the ventricle is actively contracting prolongs the duration of systole. An increase in afterload during ventricular relaxation shortens the duration of systole. Therefore, we hypothesized that the point during systole when an abrupt increase in afterload had no effect on the duration of systole represented the onset of ventricular relaxation. To determine when this point occurs, we performed aortic occlusions progressively throughout the duration of systole in six dogs. We determined the change in systolic time (t(sys)) after an intervention normalized to t(sys) Of a control beat (t(sys,i)/t(sys,c)) as a function of systolic occlusion time as a percentage of total systolic time (t(occ)/t(sys,c)),where t(sys) is the duration from time of left ventricular end-diastolic pressure to the time of minimum first derivative of left ventricular pressure. Our results show the onset of left ventricular relaxation during normal ejection occurs at 34 +/- 3% of systolic time and similar to 16% after the onset of ejection. Thus the beginning of relaxation occurs soon after the beginning of ejection, suggesting that relaxation is modulated by variable loading conditions during ejection, significantly before what has been conventionally been assumed to be the beginning of ventricular relaxation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 14:11:50