Skeletal Muscle Deoxygenation Abnormalities in Early Post-Myocardial Infarction

Abstract

Skeletal muscle deoxygenation abnormalities were observed during dynamic cycling exercise in early post-MI patients. These abnormalities were related to impaired peak aerobic capacity in early post-MI patients.

Oxygenation and neuromuscular activation of the quadriceps femoris including the vastus intermedius during a fatiguing contraction

“…A novel finding of this study is the presence of a significant correlation between ∆StO 2 and ∆MF in VI ( r = 0·745, P <0·01) at exhaustion, that is, 95% of the time to exhaustion, but the absence of a significant correlation in other muscles. In previous studies, the VL has usually been used to test the relationship between oxygenation and neuromuscular activation during a fatiguing contraction (Miura et al ., , ; Yamada et al ., ; Kime et al ., ; Takagi et al ., , ). Yamada et al ., () showed a significant relationship in the VL between the change in oxy Hb/Mb and the change in the slope of the mean power frequency ( r = 0·807, P <0·05) and a significant correlation between the change in deoxy Hb/Mb and the change in the slope of the mean power frequency of the EMG signal ( r = −0·687, P <0·05) during fatiguing knee extensions.…”

“…A spatially resolved NIRS (Hb14, Astem Co. Ltd., Kanagawa, Japan) with a two‐wavelength (770 and 830 nm) light‐emitting diode was used to measure the level of oxygenation in the VI, VL, VM and RF muscles, as previously described (Kime et al ., ; Takagi et al ., , ). The NIRS consisted of one computerized control segment (W47 × L22 × H15 mm, maximum number of channels = 8, 150 g) and probes (W20 × L45 × H5 mm with the transmission part made of silicon rubber, 10 g); the optode distances were 2·0 cm and 3·0 cm.…”

“…Subcutaneous fat thickness values, that is, path lengths, were required as input to run the NIRS program on a personal computer (VPCSE, Sony, Tokyo, Japan) and were used by the software to determine the relative change in Hb/Mb and the absolute value of StO 2 . The relative change in Hb/Mb was derived from light absorption according to a modified Beer–Lambert law (Kime et al ., ; Takagi et al ., , ). The absolute value of StO 2 was calculated using the relative absorption coefficients obtained from the slope of light attenuation over a distance measured at two focal points from the light emission.…”

“…Near‐infrared spectroscopy (NIRS) is an ideal technique to measure local muscle oxidative metabolism and blood volume during exercise in vivo (McCully & Hamaoka, ; Miura et al ., , ; Yamada et al ., ; Katayama et al ., ; Takagi et al ., , ). This technique provides the average tissue saturation in small vessels such as the capillary, arteriolar, and venular beds and the relative or absolute concentration of oxygenated haemoglobin and/or myoglobin (oxy Hb/Mb), deoxygenated Hb and/or Mb (deoxy Hb/Mb), and derived Hb and/or Mb volume (total Hb/Mb = oxy Hb/Mb + deoxy Hb/Mb) (Miura et al ., , ; Yamada et al ., ; Crenshaw et al ., ).…”

Plasma asymmetric dimethylarginine concentrations are not related to differences in maximal oxygen uptake in endurance trained and untrained men

“…Lessened vasodilatation related to ADMA could impair the ability to increase muscle blood flow and O 2 delivery in response to the increased O 2 demand of working muscle (Sperandio et al, 2012), and hence contribute to the low rate of maximal oxygen uptake (V O 2 max ) that characterizes low exercise capacity in pathological conditions (Takagi et al, 2014). Although a negative association between exercise capacity and ADMA has been showed in patients with cardiovascular diseases, it is nevertheless unknown whetherV O 2 max and muscle O 2 delivery are also negatively associated with ADMA in the absence of pathological conditions or ageing.…”