Influence of physical rehabilitation on oxygen and lactate status in "inotrope-dependent" patients with chronic heart failure in class III–IV

Aim. To assess the effect of physical rehabilitation on dynamics of oxygen and lactate status indicators in “inotrope-dependent” patients with stable chronic heart failure (CHF) of III–IV functional class (FC).

Material and methods. A randomized prospective study included 120 men, aged 18–65, hospitalized at Almazov National Medical Research Centre due to CHF III–IV FC, left ventricular ejection fraction (LVEF) ≤30%; with blood pressure (BP)≥90/60 mm Hg. Patients who received dobutamine or dopamine for ≥2 weeks were randomized into 3 groups: 1st – participating in the program of physical training (PPT), 2nd – not participating; 3rd group – patients without inotropic support participating in PPT.

Results. Oxygen extraction ratio (O₂ER) at rest was increased, while central venous oxygen saturation (ScvO₂) was decreased in all groups at baseline, after 3 and 6 months. Initially, at rest, central venous blood lactate (lactate) was normal in all groups. By the 6th month, lactate in group 2 became higher than in group 1 (p=0.005) and group 3 (p=0.008). Initially, after 3 and 6 months, at peak of exercise in groups 1 and 3, lactate and O₂ER increased, and ScvO₂ decreased without development of life-threatening adverse events. By the 6th month, in groups 1 and 3, the distance of 6-minute walk test increased: p=0.004 and p<0.00001 and the strength of hand muscles increased: p=0.01 and p=0.005.

Conclusion. In patients with CHF III–IV FC at rest, regardless of participation in PPT and inotropic therapy, there were comparable disturbances of oxygen status, characterized by decreased level of ScvO₂ and increased level of O₂ER, in the absence of decrease in arterial blood saturation. At peak of aerobic exercise of mild and moderate intensity in patients with advanced CHF, regardless of inotropic support, there was a comparable increase in the level of lactate and O₂ER, as well as a decrease in ScvO₂, which was not accompanied by life-threatening adverse events. The participation of “inotrope-dependent” patients in PPT is associated with decrease in blood lactate at rest, which, along with increase in hand muscle strength and exercise tolerance, may indicate an improvement in condition of muscle tissue.