HISTOLOGICAL ABNORMALITIES OF MUSCLE FROM LIMB, THORAX AND DIAPHRAGM IN CHRONIC HEART-FAILURE

The aim of the study was to compare histological findings in limb and respiratory muscles from control subjects and patients with heart fail ure of two different aetiologies. Biopsies of the quadriceps femoris, strap, diaphragm and pectoralis major muscles were taken from each gro up. The control subjects all had normal left ventricular function, and comprised seven undergoing surgical ablation of electrical pathways a nd 10 undergoing coronary artery surgery. The heart failure group had severely impaired left ventricular function, and were undergoing cardi ac transplantation in all except one case. Ten patients with idiopathi c dilated cardiomyopathy and seven with heart failure of ischaemic ori gin were studied. Conventional histochemical techniques and specific a nti-myosin immunofluorescent stains were used. There were no consisten t differences in fibre type prevalence or diameter between the groups. There were no important histological abnormalities in the two control groups. There were minor/major changes in four of seven patients with ischaemic heart failure but no major abnormality, whilst in the dilat ed cardiomyopathy group there were five of 10 patients with minor/majo r changes and three of 10 with major abnormalities (P<0.001 vs control s). A variety of changes was seen in both groups of heart failure subj ects. These were more marked in the dilated cardiomyopathy than ischae mic group, and suggest the presence of fibre type regeneration and/or transformation. Amongst the findings were tubular aggregates, internal ization of nuclei, bizzare staining of myosin and staining of neonatal myosin (seven of 14) and the presence of cores (five of 14). Such cha nges were more prominent in the diaphragm than in the other muscles. I n conclusion, histological abnormalities are present in the limb and r espiratory muscles from subjects with heart failure. The changes are m ost marked in subjects with idiopathic dilated cardiomyopathy, suggest ing that there may be a generalized cardiac and skeletal myopathy in t hese subjects. The presence of histological abnormalities in the respi ratory muscles may contribute to the pathogenesis of dyspnoea in heart failure.