Influence of baroreflex on volume elasticity of heart and aorta in the rabbit

Johannes-Müller-Institut für Physiologie, Humboldt Universität (Charité), D-10117 Berlin, Germany Optimal ventriculoaortic coupling includes tuning of elastic properties. The ratio of effective arterial elastance and left ventricular endsystolic elastance is often taken as a measure for mechanical a...

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Bibliographic Details
Published in:American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2002-03, Vol.282 (3), p.842-R849
Main Authors: Wronski, T, Seeliger, E, Persson, P. B, Harnath, A, Flemming, B
Format: Article
Language:English
Subjects:
Animals
Aorta - physiology
Aorta - physiopathology
Arteriosclerosis - chemically induced
Arteriosclerosis - physiopathology
Baroreflex - physiology
Blood Volume - physiology
Cholesterol, Dietary
Coronary Circulation - physiology
Elasticity
Female
Male
Myocardial Contraction - physiology
Rabbits
Reference Values
Stroke Volume - physiology
Ventricular Function
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Summary:Johannes-Müller-Institut für Physiologie, Humboldt Universität (Charité), D-10117 Berlin, Germany Optimal ventriculoaortic coupling includes tuning of elastic properties. The ratio of effective arterial elastance and left ventricular endsystolic elastance is often taken as a measure for mechanical and energetical efficiency. The present study determined the time course of ventricular and aortic volume elasticity (VE   = dp/dV) throughout a complete heartbeat. This was achieved by using changes of eigenfrequency of two catheter-transducer systems under closed chest conditions in rabbits. Short-term VE modulation was studied by a baroreflex response, as induced by pressure changes applied to the carotid sinus. Long-term changes were studied in atherosclerotic rabbits (12 wk of high-cholesterol feeding). The time course and mean values of ventricular and aortic VE were changed by the baroreflex stimulus. Cholesterol feeding diminished the response. The degree of ventriculoaortic coupling, as quantified by VE Aorta /VE Ventricle ratio, varied during a single ejection period. The large span allows either maximal energetical efficiency or maximal stroke work. Although normal rabbits adjusted their ventriculoaortic coupling during baroreflex input, the cholesterol-fed rabbits failed to do so. compliance; ventriculoarterial coupling; eigenfrequency; cholesterol; atherosclerosis
ISSN:0363-6119
1522-1490
DOI:10.1152/ajpregu.00474.2001