Subjects with chronic stable HF, left ventricular ejection fraction (LVEF) 鈮?5%, on optimal medical therapy were enrolled and underwent simulated altitude exposure for 10 sessions, each 3-4 hours, over a period of 22 days. Starting altitude was 1,500 m and was increased by 300 m with each subsequent session to a maximum altitude of 2,700 m. Peak oxygen consumption, 6-minute walk distance (6MW), skeletal muscle strength, quality of life scores, LVEF, and hematologic parameters were measured at baseline and 48 hours and 4 weeks after the final session. Twelve subjects (median age 52.5 y, ejection fraction 31.7%) successfully completed the protocol without any adverse effects. Peak oxygen consumption significantly improved after altitude sessions from 13.5 卤 1.8 to 14.2 卤 1.9 mL kg鈭? min鈭? (P聽= .036) and remained elevated after 4 weeks. There were significant improvements in exercise time, 6MW, skeletal muscle strength, and quality of life scores and a trend toward improvement in LVEF after completion of altitude sessions, which were sustained after 1 month.
Simulated altitude exposure up to 2,700 m is safe and well tolerated in patients with chronic stable HF and may have beneficial effects on exercise performance, muscular strength, and quality of life.