title: Safety and exercise tolerance of acute high altitude exposure (3454 m) among patients with coronary artery disease.
abstract: OBJECTIVE
  To assess the safety and cardiopulmonary adaptation to high altitude exposure among patients with coronary artery disease.
  
  
  METHODS
  22 patients (20 men and 2 women), mean age 57 (SD 7) years, underwent a maximal, symptom limited exercise stress test in Bern, Switzerland (540 m) and after a rapid ascent to the Jungfraujoch (3454 m). The study population comprised 15 patients after ST elevation myocardial infarction and 7 after a non-ST elevation myocardial infarction 12 (SD 4) months after the acute event. All patients were revascularised either by percutaneous coronary angioplasty (n = 15) or by coronary artery bypass surgery (n = 7). Ejection fraction was 60 (SD 8)%. beta blocking agents were withheld for five days before exercise testing.
  
  
  RESULTS
  At 3454 m, peak oxygen uptake decreased by 19% (p < 0.001), maximum work capacity by 15% (p < 0.001) and exercise time by 16% (p < 0.001); heart rate, ventilation and lactate were significantly higher at every level of exercise, except at maximum exertion. No ECG signs of myocardial ischaemia or significant arrhythmias were noted.
  
  
  CONCLUSIONS
  Although oxygen demand and lactate concentrations are higher during exercise at high altitude, a rapid ascent and submaximal exercise can be considered safe at an altitude of 3454 m for low risk patients six months after revascularisation for an acute coronary event and a normal exercise stress test at low altitude.
authors.affiliation: Swiss Cardiovascular Centre Bern, Cardiovascular Prevention & Rehabilitation, University Hospital (Inselspital), Bern, Switzerland. jean-paul.schmid@insel.ch
authors.forename: J-P
authors.initials: JP
authors.lastname: Schmid
authors.forename: M
authors.initials: M
authors.lastname: Noveanu
authors.forename: R
authors.initials: R
authors.lastname: Gaillet
authors.forename: G
authors.initials: G
authors.lastname: Hellige
authors.forename: A
authors.initials: A
authors.lastname: Wahl
authors.forename: H
authors.initials: H
authors.lastname: Saner
mesh_terms: D000368:Aged; D000531:Altitude; D001794:Blood Pressure / Q000502:physiology; D003324:Coronary Artery Disease / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology; D017079:Exercise Tolerance; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012119:Respiration; D012307:Risk Factors; D012449:Safety
chemical_list: D007773:Lactates