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Changes in Subendocardial Viability Ratio With Acute High-Altitude Exposure and Protective Role of Acetazolamide.
MedLine Citation:
PMID:  23438935     Owner:  NLM     Status:  Publisher    
High-altitude tourism is increasingly frequent, involving also subjects with manifest or subclinical coronary artery disease. Little is known, however, on the effects of altitude exposure on factors affecting coronary perfusion. The aim of our study was to assess myocardial oxygen supply/demand ratio in healthy subjects during acute exposure at high altitude and to evaluate the effect of acetazolamide on this parameter. Forty-four subjects (21 men, age range: 24-59 years) were randomized to double-blind acetazolamide 250 mg bid or placebo. Subendocardial viability ratio and oxygen supply/demand ratio were estimated on carotid artery by means of a validated PulsePen tonometer, at sea level, before and after treatment, and after acute and more prolonged exposure to high altitude (4559 m). On arrival at high altitude, subendocardial viability ratio was reduced in both placebo (from 1.63±0.15 to 1.18±0.17; P<0.001) and acetazolamide (from 1.68±0.25 to 1.35±0.18; P<0.001) groups. Subendocardial viability ratio returned to sea level values (1.65±0.24) after 3 days at high altitude under acetazolamide but remained lower than at sea level under placebo (1.42±0.22; P<0.005 versus baseline). At high altitude, oxygen supply/demand ratio fell both under placebo (from 29.6±4.0 to 17.3±3.0; P<0.001) and acetazolamide (from 32.1±7.0 to 22.3±4.6; P<0.001), its values remaining always higher (P<0.001) on acetazolamide. Administration of acetazolamide may, thus, antagonize the reduction in subendocardial oxygen supply triggered by exposure to hypobaric hypoxia. Further studies involving also subjects with known or subclinical coronary artery disease are needed to confirm a protective action of acetazolamide on myocardial viability under high-altitude exposure.
Paolo Salvi; Miriam Revera; Andrea Faini; Andrea Giuliano; Francesca Gregorini; Piergiuseppe Agostoni; Carlos G Ramos Becerra; Grzegorz Bilo; Carolina Lombardi; Michael F O'Rourke; Giuseppe Mancia; Gianfranco Parati
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-2-25
Journal Detail:
Title:  Hypertension     Volume:  -     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2013 Feb 
Date Detail:
Created Date:  2013-2-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Department of Cardiology, San Luca Hospital, IRCCS Istituto Auxologico Italiano, Milan, Italy.
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