Document Detail

Effects of pericardial constraint and ventricular interaction on left ventricular hemodynamics in the unloaded heart.
MedLine Citation:
PMID:  21398598     Owner:  NLM     Status:  MEDLINE    
Pericardial constraint and ventricular interaction influence left ventricular (LV) performance when preload is high. However, it is unclear if these constraining forces modulate LV filling when the heart is unloaded, such as during upright posture, in humans. Fifty healthy individuals underwent right heart catheterization to measure pulmonary capillary wedge (PCWP) and right atrial pressure (RAP). To evaluate the effects of pericardial constraint on hemodynamics, transmural filling pressure (LVTMP) was defined as PCWP-RAP. Beat-to-beat blood pressure (BP) waveforms were recorded, and stroke volume (SV) was derived from the Modelflow method. After measurements at -30 mmHg lower body negative pressure (LBNP), which approximates the upright position, LBNP was released, and beat-to-beat measurements were performed for 15 heartbeats. At -30 mmHg LBNP, RAP and PCWP were significantly decreased. During the first six beats of LBNP release, heart rate (HR) was unchanged, while BP increased from the fourth beat. RAP increased faster than PCWP resulting in an acute decrease in LVTMP from the fourth beat. A corresponding drop in SV by 3% was observed with no change in pulse pressure. From the 7th to 15th beats, LVTMP and SV increased steadily, followed by a decreased HR due to the baroreflex. A decreased TMP, but not PCWP, caused a transient drop in SV with no changes in HR or pulse pressure during LBNP release. These results suggest that the pericardium constrains LV filling during LBNP release, enough to cause a small but significant drop of SV, even at low cardiac filling pressure in healthy humans.
Naoki Fujimoto; Shigeki Shibata; Jeffery L Hastings; Graeme Carrick-Ranson; Paul S Bhella; Dean Palmer; Qi Fu; Benjamin D Levine
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-03-11
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  300     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-05-02     Completed Date:  2011-07-07     Revised Date:  2013-06-30    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1688-95     Citation Subset:  IM    
Institute for Exercise and Environmental Medicine, Dallas, TX 75231, USA.
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MeSH Terms
Blood Pressure / physiology
Cardiac Catheterization
Heart / physiology*
Heart Rate / physiology
Hemodynamics / physiology*
Lower Body Negative Pressure / methods*
Middle Aged
Pericardium / physiology*
Posture / physiology*
Pulmonary Wedge Pressure / physiology
Stroke Volume / physiology
Ventricular Function, Left / physiology*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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