Document Detail


Effects of depth and chest volume on cardiac function during breath-hold diving.
MedLine Citation:
PMID:  19424715     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cardiac response to breath-hold diving in human beings is primarily characterized by the reduction of both heart rate and stroke volume. By underwater Doppler-echocardiography we observed a "restrictive/constrictive" left ventricular filling pattern compatible with the idea of chest squeeze and heart compression during diving. We hypothesized that underwater re-expansion of the chest would release heart constriction and normalize cardiac function. To this aim, 10 healthy male subjects (age 34.2 +/- 10.4) were evaluated by Doppler-echocardiography during breath-hold immersion at a depth of 10 m, before and after a single maximal inspiration from a SCUBA device. During the same session, all subjects were also studied at surface (full-body immersion) and at 5-m depth in order to better characterize the relationship of echo-Doppler pattern with depth. In comparison to surface immersion, 5-m deep diving was sufficient to reduce cardiac output (P = 0.042) and increase transmitral E-peak velocity (P < 0.001). These changes remained unaltered at a 10-m depth. Chest expansion at 10 m decreased left ventricular end-systolic volume (P = 0.024) and increased left ventricular stroke volume (P = 0.024). In addition, it decreased transmitral E-peak velocity (P = 0.012) and increased deceleration time of E-peak (P = 0.021). In conclusion the diving response, already evident during shallow diving (5 m) did not progress during deeper dives (10 m). The rapid improvement in systolic and diastolic function observed after lung volume expansion is congruous with the idea of a constrictive effect on the heart exerted by chest squeeze.
Authors:
Claudio Marabotti; Alessandro Scalzini; Danilo Cialoni; Mirko Passera; Andrea Ripoli; Antonio L'Abbate; Remo Bedini
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-05-08
Journal Detail:
Title:  European journal of applied physiology     Volume:  106     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2009 Jul 
Date Detail:
Created Date:  2009-07-02     Completed Date:  2009-10-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  683-9     Citation Subset:  IM    
Affiliation:
UO Cardiovascolare-UTIC Ospedale di Cecina, 57023 Cecina (LI), Italy. maralbian@alice.it
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MeSH Terms
Descriptor/Qualifier:
Adult
Diving / physiology*
Echocardiography, Doppler
Heart / physiology*
Humans
Hydrostatic Pressure
Immersion
Inspiratory Reserve Volume / physiology
Lung Volume Measurements
Male
Middle Aged
Respiratory Mechanics / physiology*
Thorax / physiology*
Young Adult

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


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