Journal article
Left Ventricular Function Depends on Previous Beat Ejection but Not Previous Beat Pressure Load
Circulation research, Vol.69(4), pp.1051-1057
10/1991
Handle:
https://hdl.handle.net/2376/114363
PMID: 1934333
Abstract
Previous beat contraction history, in which the performance of the left ventricle on any one beat is influenced by the mechanical events of the previous beat, may be important in the beat-to-beat regulation of left ventricular performance in the intact cardiovascular system. Prior studies of this phenomenon have established that mechanical events of the previous beat influence the function of the current beat, but it is not known whether the important mechanical influence is exerted by previous beat ejection or previous beat pressure. In addition, the magnitude of the effect of previous beat contraction history on left ventricular performance is unknown. To make these determinations, we performed experiments in six isolated rabbit left ventricle preparations buffer perfused at 30°C. Left ventricular pressure and volume were controlled precisely with a servo-controlled linear motor system. After steady-state ejecting conditions were established by clamping left ventricular ejection pressure at 60% of peak isovolumic pressure, single test beats, which were pressure clamped at 40%, 60%, 80%, and 100% of peak isovolumic pressure, were introduced and followed by an isovolumic reference beat. As the level of pressure clamp decreased from 100% to 40%, developed pressure on the isovolumic beat following the single test beats increased from 139±15 (mean±SD) to 151±13 mm Hg. Similarly, peak positive left ventricular dP/dt increased from 1,718±209 to 1,864±181 mm Hg · sec (both p<0.01). Multiple regression analysis showed that this increase in left ventricular function was related to previous beat ejection but not to previous beat pressure load or relaxation. These results show that previous beat contraction history, mediated by previous beat ejection, is quantitatively large enough that it could play a role in modulating the relatively small beat-to-beat adaptations that the left ventricle must continually make in the intact circulatory system. (Circulation Research 1991;69:1051–1057)
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Details
- Title
- Left Ventricular Function Depends on Previous Beat Ejection but Not Previous Beat Pressure Load
- Creators
- Bryan Slinker - Cardiology Unit (B.K.S.), Department of Medicine, University of Vermont, Burlington, Vt.; the Cardiology Section (S.G.S.), Department of Medicine, University of Chicago, Chicago, Ill.; and the Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology (R.D.K, K.B.C.), Washington State University, Pullman, WashSanjeev ShroffRobert KirkpatrickKenneth Campbell
- Publication Details
- Circulation research, Vol.69(4), pp.1051-1057
- Academic Unit
- Veterinary Medicine, College of; Integrative Physiology and Neuroscience, Department of
- Publisher
- American Heart Association, Inc
- Identifiers
- 99900548199801842
- Language
- English
- Resource Type
- Journal article