Oxygen Kinetics and Heart Rate Response during Early Recovery from Exercise in Patients with Heart Failure

[摘要] Background. The purpose of this study was to assess the post-exercise O2uptake and heart rate response in patients with heart failure (HF) in comparison to healthy individuals.Methods and Results. Exercise testing of all subjects was conducted according to the RITE-protocol. The study subjects were classified according to their peak oxygen uptake (peak VO2) in four groups: healthy individuals with a peak VO2>22 mL/kg/min (group 1,n: 50), and patients with HF and a peak VO2of 18–22 mL/kg/min, (group 2,n: 48), 14–18 mL/kg/min (group 3,n: 57), and <14 mL/kg/min (group 4,n: 31). Both peak VO2and HR declined more slowly in the patients with HF than in the normal subjects. Recovery of VO2and HR followed monoexponential kinetics in the early post-recovery phase. This enabled the determination of a time constant for both HR and VO2(TC VO2and TC HR). From group 1 to 4 there was a prolongation of the time constant for VO2and HR: TC VO2(group 1:110±34, group 2:197±43, group 3:238±80, and group 4:278±50 sec), and TC HR (group 1:148±82, group 2:290±65, group 3:320±58, and group 4:376±55 sec).Conclusion. The rate of decline of VO2and HR in the early post-exercise phase is inversely related to the peak VO2. The time constant for oxygen uptake (TC VO2) and heart rate (TC HR) might prove a useful parameter for more precise monitoring and grading of HF.

[学科分类] 心脏病和心血管学