Document Detail

Comparison of hemodynamic adaptation to orthostatic stress in patients with hypertrophic cardiomyopathy with or without syncope and in vasovagal syncope.
MedLine Citation:
PMID:  12062736     Owner:  NLM     Status:  MEDLINE    
This study was designed to investigate whether, in patients with hypertrophic cardiomyopathy (HC), tilt-induced volume unloading triggers a peripheral reflex similar to that seen in patients with a history of vasovagal syncope or rather acts through an intrinsic cardiac mechanism secondary to diastolic dysfunction. Thirty-seven patients with HC (10 with and 27 without a history of syncope), 10 patients with vasovagal syncope, and 9 controls underwent 70 degrees head-up tilt for 45 minutes during continuous radionuclide monitoring of left ventricular function. We focused on the initial 5 minutes into the tilt test, well before symptoms occurred, to exclude that the observed hemodynamic changes were the consequence rather than the cause of syncope. HC patients with previous syncope and vasovagal patients experienced significant hypotension after the initial 5 minutes of tilt. Only HC patients with a history of syncope had a significant decrease in cardiac output, which began at the initial stage of the test. Systemic vascular resistance decreased in vasovagal patients, but increased in the HC syncopal group. Baseline peak filling rate was lower (2.4 +/- 0.5 vs 3.3 +/- 1.1 stroke counts/s, p = 0.03) and a "pseudonormal" or a restrictive pattern of left ventricular filling was more frequent (70% vs 26%, p = 0.02) in HC patients with than without a history of syncope. Thus, significant hypotension or frank syncope during orthostatic stress in HC patients with a history of syncope is due to an early decrease in cardiac output, which occurs well before the onset of symptoms; such impaired hemodynamic adaptation seems to be related to diastolic dysfunction.
Fiore Manganelli; Sandro Betocchi; Quirino Ciampi; Giovanni Storto; Maria Angela Losi; Anna Violante; Carlo Briguori; Carlo Gabriele Tocchetti; Raffaella Lombardi; Alberto Cuocolo; Massimo Chiariello
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of cardiology     Volume:  89     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-06-13     Completed Date:  2002-07-10     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1405-10     Citation Subset:  AIM; IM    
Department of Clinical Medicine, Cardiovascular and Immunological Sciences, Federico II University School of Medicine, Naples, Italy.
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MeSH Terms
Adaptation, Physiological
Analysis of Variance
Cardiac Output
Cardiomyopathy, Hypertrophic / complications,  physiopathology*,  radionuclide imaging,  ultrasonography
Case-Control Studies
Chi-Square Distribution
Hemodynamics / physiology*
Hypotension / physiopathology
Syncope, Vasovagal / physiopathology*
Tilt-Table Test
Vascular Resistance

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

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