Relationship Between Leg Muscle Strength and Muscle Oxygenation Dynamics During Incremental Exercise in Patients With Heart Failure

Figures

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  Central Figure.

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  Figure 1.. Study flowchart of the patient selection process. CPX, cardiopulmonary exercise testing.

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  Figure 2.. Changes in muscle oxygenation and blood volume dynamics during incremental exercise by absolute work rate (WR) in high and low leg muscle strength groups. (A) Changes in muscle oxygen saturation (SmO2). (B) Changes in total hemoglobin (THb). Solid line, high leg muscle strength group; dashed line, low leg muscle strength group. Data are presented as mean±standard error. *P<0.05, **P<0.01. Because ≤3 patients remained at ≥140 W, the interaction analysis was conducted using data from 0 W to 130 W.

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  Figure 3.. Changes in muscle oxygenation and blood volume dynamics during incremental exercise by relative exercise intensity in high and low leg muscle strength groups. (A) Changes in muscle oxygen saturation (SmO2) expressed as %peak V̇O2. (B) Changes in total hemoglobin (THb) expressed as %peak V̇O2. Solid line, high leg muscle strength group; dashed line, low leg muscle strength group. Data are presented as mean±standard error. *P<0.05, **P<0.01. Exercise intensity was normalized to individual peak V̇O2 (30% to 100% peak V̇O2). A linear mixed-effects model was applied with the change in SmO2 as the dependent variable, patients as a random effect, and group and exercise intensity (% peak V̇O2) as fixed effects.