SKELETAL-MUSCLE PHOSPHATE-METABOLISM ABNORMALITIES IN VOLUME-OVERLOADEXPERIMENTAL HEART-FAILURE

We studied skeletal muscle phosphate metabolism abnormalities to exami ne their contribution at an early stage of congestive heart failure (C HF) in rats with aortocaval fistula (ACF) 4 wk after the procedure. In a group of 26 rats (13 with ACF and 13 sham operated), we assessed th e degree of CHF. The ACF produced a significant rise in heart weight a nd plasma atrial natriuretic peptide. In a second group of 26 rats (13 ACF and 13 sham operated), we performed P-31-magnetic resonance spect roscopy in the gastrocnemius muscle during motor activity produced by electrical stimulation. The rate of phosphocreatine depletion, express ed by its initial slope, was higher in the ACF rats compared with cont rols (0.078 +/- 0.01 vs. 0.041 +/- 0.007; P < 0.03). pH and ATP decrea sed and phosphodiesters increased in all rats during electrical stimul ation, with no difference between ACF rats and controls. The kinetics of phosphocreatine recovery were not different between ACF rats and co ntrols. Together with previous studies, our present results suggest th at muscle metabolism abnormalities in CHF may vary according to the ex perimental model and may be observed early in the course of the diseas e.