The relationship between exercise capacity and muscle oxygenation in patients after heart open surgery.

Purpose:The aim of this study was to investigate whether recovery of muscle oxygenation from constant work exercise is correlated with exercise capacity in patients after open heart surgery. Methods:Six patients underwent incremental cycle ergometer exercise test with gas exchange analysis to determine anaerobic threshold(AT). After I or 2week, 6-min constant work exercise at 90% of AT was performed. Oxygenation of the vastus lateralis muscle was monitored during exercise and recovery by near infrared spectroscopy. Results and Discussion:No significant correlation was observed between AT and recovery of muscle oxygenation. Left ventricular ejection fraction was significantly correlated with recovery of muscle oxygenation(r=-0.93, P<0.05). The patient with most delayed recovery of muscle oxygenation was obesity and had low left ventricular function. This suggests that thick subcutaneous fat layers and decrease of oxygen delivery tend to be slower recovery of muscle oxygenation. [ABSTRACT FROM AUTHOR]