Effects of exposure to altitude on men with coronary artery disease and impaired left ventricular function.

The effects of altitude on coronary patients with impaired left ventricular function are virtually unknown and the question arises whether an exposure to altitude poses a risk to such patients. Twenty-three patients with coronary artery disease (mean age 51 +/- 9 years; group H) with a mean ejection fraction of 39 +/- 6% were compared with 23 normal subjects (mean age 53 +/- 6 years; group N). Both groups underwent a maximal symptom-limited bicycle stress test at 1,000 m and 2 days later at 2,500 m. In both groups, exercise capacity decreased significantly (group H, 1,000 m 162 +/- 28 W, 2,500 m 155 +/- 28 W, p = 0.02; group N, 1,000 m 205 +/- 28 W, 2,500 m 198 +/- 25 W, p = 0.02). Maximal heart rate and blood pressure did not differ between 1,000 and 2,500 m; oxygen saturation at rest and during exercise remained unchanged. At 2,500 m, the test was terminated more often because of dyspnea, but the level of perceived exertion (Borg) was similar to that at 1,000 m. There were no complications or signs of ischemia. Thus, patients with coronary artery disease with impaired left ventricular function without residual ischemia have good tolerance to exposure to altitude. The effects in patients are comparable to those in a group of normal subjects and the risk for an adverse event is not increased.