Does hypoxia and stress erythropoiesis compromise cardiac function in healthy adults? A randomized trial

Objectives To investigate whether recombinant human erythropoietin (rHuEPO) injections during an altitude training camp impact heart function. Methods Thirty-nine (16 women) moderately trained subjects stayed at 2,320 m altitude for 4 weeks while training. Subjects were randomized to placebo (isotonic saline) or rHuEPO (20 IU/kg body weight) i.v. injections. Transthoracic echocardiography imaging was acquired 3 days after arrival to altitude and prior to the first placebo or rHuEPO injection as well as one day after the last rHuEPO injection three weeks later. Results rHuEPO did not alter cardiovascular morphology parameters, systolic or diastolic function. In the placebo group, altitude exposure improved left ventricle (LV) systolic function due to an increased twist angle but rHuEPO had no additional effects. Pulmonary arterial systolic pressure was unaffected in either group. Notably, rHuEPO hampered LV untwist rate without affecting LV early filling. Conclusion rHuEPO alters LV twist rate during a high altitude training camp in a mechanism likely mediated by impaired restorative forces and/or by the haematological and metabolic effects induced rHuEPO outside the cardiovascular system. However, this alteration in heart mechanics is unlikely to have a meaningful clinical effect.