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Feasibility of creating estimates of left ventricular flow-volume dynamics using echocardiography
Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
Division of Clinical Physiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
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2006 (English)In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, no 4:40Article in journal (Refereed) Published
Abstract [en]

Background:This study explores the feasibility of non-invasive assessment of left ventricular volume and flow relationship throughout cardiac cycle employing echocardiographic methods.

Methods:Nine healthy individuals and 3 patients with severe left-sided valvular abnormalities were subject to resting echocardiography with automated endocardial border detection allowing real-time estimation of left ventricular volume throughout the cardiac cycle. Global and regional (6 different left ventricular segments) estimates of flow-volume loops were subsequently constructed by plotting acquired instantaneous left ventricular 2-D area data (left ventricular volume) vs. their first derivatives (flow).

Results:Flow-volume loop estimates were obtainable in 75% of all echocardiographic images and displayed in normal individuals some regional morphological variation with more pronounced isovolumic events in the paraseptal segments and significantly delayed maximal systolic flow paraapically. In patients with aortic stenosis, maximal systolic flow occurred at a lower estimated left ventricular systolic volume whereas in mitral stenosis, maximal diastolic flow was observed at a higher estimated left ventricular diastolic volume. Aortic regurgitation caused a complex alteration of the estimated flow-volume loop shape during diastole.

Conclusion:Non-invasive assessment of left ventricular flow-volume relationship with echocardiography is technically feasible and reveals the existence of regional variation in flow-volume loop morphology. Valvular abnormalities cause a clear and specific alteration of the estimates of the normal systolic or diastolic flow-volume pattern, likely reflecting the underlying pathophysiology.

Place, publisher, year, edition, pages
2006. no 4:40
National Category
Medical Laboratory and Measurements Technologies
URN: urn:nbn:se:kth:diva-6523DOI: 10.1186/1476-7120-4-40.ScopusID: 2-s2.0-33750899084OAI: diva2:11258

QC 20100922

Available from: 2006-12-06 Created: 2006-12-06 Last updated: 2016-05-12Bibliographically approved
In thesis
1. New approaches to monitoring of cardiac function
Open this publication in new window or tab >>New approaches to monitoring of cardiac function
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Left ventricular pumping performance may be described by intraventricular pressure and volume variables, usually presented as a pressure-volume plot. However, on-line monitoring of left ventricular pressure and volume with high temporal resolution requires the use of an invasive catheter technique such as, for example, the conductance catheter method. On the other hand, the very invasiveness and complexity of this approach makes it less suitable for clinical use. It is then not surprising that there has been long-felt need to make the conductance method less invasive and attempts have been made to adjust the method to clinical demands and routine in order to extract more information from pressure-volume interplay and possibly translate relevant data to their non-invasive estimates.

In the present studies, a standard five segmental conductance catheter was used in animal (pig) experiments. Segmental conductances were compared to global conductance. Since the mid-ventricular segment was shown to reflect global volume, which was also shown on theoretical basis, it was concluded that a single segmental catheter most probably could be used to estimate global left ventricular volume.

Subsequently, a thin and flexible single segmental conductance catheter was constructed and applied to an animal (pig) experimental model. Results were reproducible and very few arrythmias were detected.

At the next stage, left ventricular isovolumic phases were investigated using the standard conductance catheter method, as well as echocardiographically derived tissue velocity doppler. Conductance was shown to decrease during isovolumic contraction, and an adjustment method was proposed in order to account for the subsequent decrease in pressure-volume loop area.

In separate experiments, the left ventricular pressure wave form during left ventricular systole was examined, and an algorithm was proposed to discriminate between the changes in afterload, preload and contractility. Results showed clearly discernible patterns of the respective load and contractility alternation.

Finally, the left ventricular continuous area was monitored continuously during the entire cardiac cycle as a measure of left ventricular volume dynamics in normal subjects and three patients with left ventricular abnormalities using echocardiographic automatic boundary detection. The left ventricular area thus obtained was plotted against its first derivative, to form a flow-volume estimates loop, in accordance with the flow-volume examinations used in respiratory physiology. Data obtained from the abnormal ventricles were presented as flow-volume estimates loops, exemplifying the possible use of the method.

Place, publisher, year, edition, pages
Stockholm: KTH, 2006. 77 p.
Trita-STH : report, ISSN 1653-3836 ; 2006:04
left ventricle, pressure and volume
National Category
Medical Laboratory and Measurements Technologies
urn:nbn:se:kth:diva-4211 (URN)978-91-7178-507-7 (ISBN)
Public defence
2006-12-15, 4X, plan 4, Nobels allé 8, Huddinge, 09:00
QC 20100922Available from: 2006-12-06 Created: 2006-12-06 Last updated: 2010-09-22Bibliographically approved

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Söderqvist, EmilLind, BrittaBrodin, Lars-Åke
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