Skeletal muscle adaptation in patients with severe heart failure: Implications for aorto- and cardiomyoplasty

Cardiomyoplasty is a surgical technique to improve cardiac pump function in patients with severe heart failure, using the Latissimus Dorsi (LD) muscle. However, intrinsic skeletal muscle alterations have been reported in patients suffering from chronic heart failure. Therefore, the aim of the present study was to compare histological characteristics of the LD muscle in patients with chronic heart failure (HF), with mild heart failure patients and non heart failure individuals. The first group (chronic-HF) were patients submitted for a cardiomyoplasty procedure (n = 6, NYHA class IV, age 57 +/- 5). The second group (mild-HF) were patients with mild heart failure (n = 7, NYHA class II, age 73 +/- 8) and the third group (non-HF) were patients without signs of heart disease and therefore considered as a reference group (n = 10, age 74 +/- 9). The LD muscle was examined for fibre type distribution, fat content, connective tissue content, and the capillary to fibre ratio. The latissimus dorsi muscle revealed a significant decrease of type I muscle fibres in chronic HF as compared to non-HF (32% +/- 11 vs 52% +/- 14). Percentage type I fibres in mild-HF was 46% +/- 13, demonstrating the tendency of reduced percentage type I fibres due to mild heart failure. In the latissimus dorsi no differences in fat content, connective tissue content or capillary to fibre ratio was observed between the three groups. In conclusion, these findings indicate that the fibre type distribution of the LD muscle in patients with chronic heart failure, is significantly altered. This reduced amount of type I fibres in the latissimus dorsi muscle is the opposit of what is required for optimal cardiac assist in aorto- and cardiomyoplasty. Therefore, it should be subject of future research whether this may retard transformation in a fatigue resistant muscle.