Hanada A, Okita K, Yonezawa K, Ohtsubo M, Kohya T, Murakami T, Nishijima H, Tamura M, Kitabatake A
Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Kita-15, Nishi-7, Kitaku, Sapporo 060-8638, Japan.
Heart. 2000 Feb;83(2):161-6. doi: 10.1136/heart.83.2.161.
To estimate muscle metabolism and oxygen delivery to skeletal muscle in patients with chronic heart failure.
13 patients with chronic heart failure and 15 controls performed calf plantar flexion for six minutes at a constant workload of 50% of one repetition maximum. During recovery from exercise, skeletal muscle content of oxygenated haemoglobin (oxy-Hb) and the level of phosphocreatine (PCr) were measured by near-infrared spectroscopy and (31)P-magnetic resonance spectroscopy, respectively.
The mean (SD) time constants of PCr and oxy-Hb during recovery from exercise were significantly greater in patients with chronic heart failure than in normal subjects (tau PCr: 76.3 (30.2) s v 36.5 (5.8) s; tau oxy-Hb: 48.3 (7.3) s v 30.1 (7.7) s; p < 0.01). Both time constants were similar in normal subjects, while the tau PCr was significantly greater than the tau oxy-Hb in patients with chronic heart failure.
The slower recovery of PCr compared with oxy-Hb in patients with chronic heart failure indicates that haemoglobin resaturation is not a major rate limiting factor of PCr resynthesis. It is suggested that muscle metabolic recovery may depend more on oxygen utilisation than on haemoglobin resaturation or oxygen delivery in patients with chronic heart failure.
评估慢性心力衰竭患者的肌肉代谢及骨骼肌的氧输送情况。
13例慢性心力衰竭患者和15名对照者以1次最大重复量的50%的恒定负荷进行6分钟的小腿跖屈运动。在运动恢复过程中，分别通过近红外光谱法和磷磁共振波谱法测量骨骼肌中氧合血红蛋白（oxy-Hb）含量和磷酸肌酸（PCr）水平。
慢性心力衰竭患者运动恢复过程中PCr和oxy-Hb的平均（标准差）时间常数显著长于正常受试者（PCr时间常数：76.3（30.2）秒对36.5（5.8）秒；oxy-Hb时间常数：48.3（7.3）秒对30.1（7.7）秒；p<0.01）。正常受试者的两个时间常数相似，而慢性心力衰竭患者的PCr时间常数显著大于oxy-Hb时间常数。
慢性心力衰竭患者PCr的恢复比oxy-Hb慢，这表明血红蛋白再饱和不是PCr再合成的主要速率限制因素。提示慢性心力衰竭患者肌肉代谢恢复可能更多地取决于氧利用，而非血红蛋白再饱和或氧输送。
