Kh. Lundell et al., SKELETAL-MUSCLE ENERGY SUBSTRATES, METABOLIC PRODUCTS AND ENZYME-ACTIVITY IN INFANTS WITH SYMPTOMATIC VENTRICULAR SEPTAL-DEFECT, Acta paediatrica, 85(11), 1996, pp. 1314-1318
Muscle biopsy studies were performed on 26 infants with symptomatic ve
ntricular septal defect (VSD) (mean age 4.7 months) and 10 healthy inf
ants (mean age 7.8 months). Analyses were made of muscle energy substr
ates, metabolic products, muscle enzyme activity, fibre types and fibr
e sizes. Relatively few differences were noted between the groups. The
most important difference was a reduced ATP level in the VSD group. G
lucose 6-phosphate concentrations were also lower in the VSD group. Th
ese differences could indicate a low metabolic activity in skeletal mu
scle in infants with heart failure. Most muscle enzyme activity was co
mparable with the exception of lactate dehydrogenase (LD), which was l
ower in the VSD group. Within the VSD group, no differences were revea
led in muscle substrate concentrations or muscle enzyme activity in te
rms of the degree of heart failure. We conclude that low energy levels
are probably explained by undernourishment and/or reduced blood flow
to skeletal muscle and that the lack of other discrepancies in muscle
metabolism indicates a desirable relatively normal motor activity in t
hese infants with symptomatic VSD.