title: Decreased exercise capacity and sleep-disordered breathing in patients with hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Mechanisms of decreased exercise capacity in patients with hypertrophic cardiomyopathy (HCM) are not well understood. Sleep-disordered breathing (SDB) is a highly prevalent but treatable disorder in patients with HCM. The role of comorbid SDB in the attenuated exercise capacity in HCM has not been studied previously.
  
  
  METHODS
  Overnight oximetry, cardiopulmonary exercise testing, and echocardiographic studies were performed in consecutive patients with HCM seen at the Mayo Clinic. SDB was considered present if the oxygen desaturation index (number of ≥ 4% desaturations/h) was ≥ 10. Peak oxygen consumption (VO2 peak) (the most reproducible and prognostic measure of cardiovascular fitness) was then correlated with the presence and severity of SDB.
  
  
  RESULTS
  A total of 198 patients with HCM were studied (age, 53 ± 16 years; 122 men), of whom 32% met the criteria for the SDB diagnosis. Patients with SDB had decreased VO2 peak compared with those without SDB (16 mL O2/kg/min vs 21 mL O2/kg/min, P < .001). SDB remained significantly associated with VO2 peak after accounting for confounding clinical variables (P < .001) including age, sex, BMI, atrial fibrillation, and coronary artery disease.
  
  
  CONCLUSIONS
  In patients with HCM, the presence of SDB is associated with decreased VO2 peak. SDB may represent an important and potentially modifiable contributor to impaired exercise tolerance in this unique population.
authors: Mayo Clinic, Rochester, MN; St. Anne's University Hospital, International Clinical Research Center (ICRC), Brno, Czech Republic.
authors: Tomas
authors: T
authors: Konecny
authors: Mayo Clinic, Rochester, MN.
authors: Jeffrey B
authors: JB
authors: Geske
authors: St. Anne's University Hospital, International Clinical Research Center (ICRC), Brno, Czech Republic; Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czech Republic; Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Ondrej
authors: O
authors: Ludka
authors: St. Anne's University Hospital, International Clinical Research Center (ICRC), Brno, Czech Republic; Center for Cardiovascular and Transplant Surgery (CKTCH), Brno, Czech Republic.
authors: Marek
authors: M
authors: Orban
authors: Mayo Clinic, Rochester, MN.
authors: Peter A
authors: PA
authors: Brady
authors: Mayo Clinic, Rochester, MN.
authors: Muaz M
authors: MM
authors: Abudiab
authors: Mayo Clinic, Rochester, MN; Yale University, New Haven, CT.
authors: Felipe N
authors: FN
authors: Albuquerque
authors: Mayo Clinic, Rochester, MN; Georgetown University Medical Center, Washington, DC.
authors: Alexander
authors: A
authors: Placek
authors: Mayo Clinic, Rochester, MN; Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czech Republic; Mayo Clinic, Rochester, MN; Department of Cardiology, University Hospital Olomouc, Olomouc, Czech Republic.
authors: Tomas
authors: T
authors: Kara
authors: Mayo Clinic, Rochester, MN.
authors: Karine R
authors: KR
authors: Sahakyan
authors: Mayo Clinic, Rochester, MN.
authors: Bernard J
authors: BJ
authors: Gersh
authors: Mayo Clinic, Rochester, MN.
authors: A Jamil
authors: AJ
authors: Tajik
authors: Mayo Clinic, Rochester, MN.
authors: Thomas G
authors: TG
authors: Allison
authors: Mayo Clinic, Rochester, MN.
authors: Steve R
authors: SR
authors: Ommen
authors: Mayo Clinic, Rochester, MN; St. Anne's University Hospital, International Clinical Research Center (ICRC), Brno, Czech Republic. Electronic address: somers.virend@mayo.edu.
authors: Virend K
authors: VK
authors: Somers
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000453:epidemiology* / Q000503:physiopathology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010101:Oxygen Consumption / Q000502:physiology; D015995:Prevalence; D012720:Severity of Illness Index; D020182:Sleep Apnea, Central / Q000453:epidemiology* / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology
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