Giornale italiano di cardiologia
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Comparative Study
Near infrared spectroscopy and changes in skeletal muscle oxygenation during incremental exercise in chronic heart failure: a comparison with healthy subjects.
Near infrared spectroscopy (NIRS) is a noninvasive technique of monitoring tissue oxygen saturation by detecting changes in tissue absorbance of two wavelengths (850 and 760 nm) reflecting the relative oxygenation of hemoglobin and myoglobin. Aim of the present study was to determine whether changes in skeletal muscle oxygen saturation during incremental exercise detected by NIRS can reflect an impared oxygen delivery and an early onset of anaerobic metabolism in patients with chronic heart failure (CHF). We studied 19 subjects (mean age 43 +/- 16 years). ⋯ However, patients with CHF had an earlier acceleration in muscle deoxygenation compared to the other group, indicating a premature onset of anaerobic metabolism. Moreover, Group A had a flatter increase in both heart rate and systolic blood pressure and a steeper slope of oxygenation profile at all matched workloads compared to normals (Group A: -0.13 +/- 0.03 ml/min; Group B: -0.06 +/- 0.015 ml/min; p < 0.0001). The LAT correlated with the work rate at which the rate of tissue O2 desaturation accelerated (r = 0.94; p < 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)