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

Abstract

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 IIIIV functional class (FC).
 Material and methods. A randomized prospective study included 120 men, aged 1865, hospitalized at Almazov National Medical Research Centre due to CHF IIIIV 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 p0.00001 and the strength of hand muscles increased: p=0.01 and p=0.005.
 Conclusion. In patients with CHF IIIIV 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.