Document Detail

Cardiac changes induced by immersion and breath-hold diving in humans.
MedLine Citation:
PMID:  18467547     Owner:  NLM     Status:  MEDLINE    
To evaluate the separate cardiovascular response to body immersion and increased environmental pressure during diving, 12 healthy male subjects (mean age 35.2 +/- 6.5 yr) underwent two-dimensional Doppler echocardiography in five different conditions: out of water (basal); head-out immersion while breathing (condition A); fully immersed at the surface while breathing (condition B) and breath holding (condition C); and breath-hold diving at 5-m depth (condition D). Heart rate, left ventricular volumes, stroke volume, and cardiac output were obtained by underwater echocardiography. Early (E) and late (A) transmitral flow velocities, their ratio (E/A), and deceleration time of E (DTE) were also obtained from pulsed-wave Doppler, as left ventricular diastolic function indexes. The experimental protocol induced significant reductions in left ventricular volumes, left ventricular stroke volume (P < 0.05), cardiac output (P < 0.001), and heart rate (P < 0.05). A significant increase in E peak (P < 0.01) and E/A (P < 0.01) and a significant reduction of DTE (P < 0.01) were also observed. Changes occurring during diving (condition D) accounted for most of the changes observed in the experimental series. In particular, cardiac output at condition D was significantly lower compared with each of the other experimental conditions, E/A was significantly higher during condition D than in conditions A and C. Finally, DTE was significantly shorter at condition D than in basal and condition C. This study confirms a reduction of cardiac output in diving humans. Since most of the changes were observed during diving, the increased environmental pressure seems responsible for this hemodynamic rearrangement. Left ventricular diastolic function changes suggest a constrictive effect on the heart, possibly accounting for cardiac output reduction.
Claudio Marabotti; Alessandro Scalzini; Danilo Cialoni; Mirko Passera; Antonio L'Abbate; Remo Bedini
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Publication Detail:
Type:  Journal Article     Date:  2008-05-08
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  106     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2009-01-09     Completed Date:  2009-02-19     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  293-7     Citation Subset:  IM    
Unita Operativa Cardiovascolare, Ospedale di Cecina, Via Montanara, 57023 Cecina, Italy.
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MeSH Terms
Adaptation, Physiological
Cardiac Output
Echocardiography, Doppler, Pulsed
Heart Rate
Hydrostatic Pressure
Middle Aged
Respiratory Mechanics*
Stress, Physiological
Stroke Volume
Time Factors
Ventricular Function, Left
Young Adult

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

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