Changes in left ventricular systolic wall stress during biventricular circulatory assistance.
Publication/Presentation Date
5-1-1988
Abstract
Extracorporeal membrane oxygenation (ECMO) reduces the systolic stress integral (SSI) in the normal left ventricle. We tested the hypothesis that the SSI does not decrease in poorly contracting, dilated, ejecting hearts during ECMO. In 14 sheep, four pairs of ultrasonic crystals measured changes in left ventricular (LV) wall thickness and three LV diameters. Volume calculations were validated by balloon distention of the ventricles after death (slope = 0.85; r = 0.85). SSI was measured during ECMO flows of 20 to 100 ml/kg/min in both normal and dilated, poorly contracting hearts produced by 30 minutes of warm ischemia. After warm ischemia, end-systolic elastance, an index of contractility, decreased from 8.3 +/- 0.6 mm Hg/ml to 2.9 +/- 0.4 mm Hg/ml (p = 0.001) and peak systolic pressure decreased from 47.4 +/- 0.7 mm Hg to 37.5 +/- 0.08 mm Hg (p = 0.01). In normal hearts, as ECMO flow increased, SSI decreased from 10.5 +/- 2.2 mm Hg.sec to 7.7 +/- 0.8 mm Hg.sec at 60 ml/kg/min (p = 0.001). However, in postischemic hearts, SSI progressively increased from 6.6 +/- 0.3 mm Hg.sec before ECMO to 12.4 +/- 1.8 mm Hg.sec at ECMO = 100 ml/kg/min. These studies indicate that the initial effect of ECMO on the poorly contracting, dilated heart increases LV wall stress and that the increase in stress is proportional to ECMO flow. The increase in stress is primarily due to an increase in afterload, which more than offsets decreases in systolic and diastolic volumes.
Volume
45
Issue
5
First Page
526
Last Page
532
ISSN
0003-4975
Published In/Presented At
Bavaria, J. E., Ratcliffe, M. B., Gupta, K. B., Wenger, R. K., Bogen, D. K., & Edmunds, L. H., Jr (1988). Changes in left ventricular systolic wall stress during biventricular circulatory assistance. The Annals of thoracic surgery, 45(5), 526–532. https://doi.org/10.1016/s0003-4975(10)64525-0
Disciplines
Medicine and Health Sciences
PubMedID
3365043
Department(s)
Department of Surgery
Document Type
Article