Incremental large and small muscle mass exercise in patients with heart failure: Evidence of preserved peripheral hemodynamics and metabolism

Aim: Doubt still remains as to whether peripheral vascular and skeletal muscle dysfunction accompany the compromised cardiac function associated with heart failure (HF). The aim was to examine the effect of HF on the hemodynamic and metabolic responses to exercise with both a large (cycle) and small (knee-extensor, KE) muscle mass in comparison to well-matched healthy controls (Ctrls). Methods: Utilizing blood sampling and thermodilution blood flow measurements we studied incremental cycle and KE exercise in 12 patients with HF (ejection fraction: 25 ± 3%) and 8 Ctrls. Results: Incremental cycle exercise in both groups (HF: 23 ± 1.3 to 116 ± 10 W; Ctrls: 22 ± 1 to 137 ± 5 W) resulted in a similar rise in leg blood flow (HF: 1525 ± 132 to 4216 ± 408 ml/min; Ctrls: 1774 ± 161 to 4713 ± 448 ml/min), oxygen consumption (HF: 206 ± 24 to 586 ± 34 ml/min; Ctrls: 252 ± 21 to 747 ± 89 ml/min), and lactate efflux across the leg (HF: 479 ± 122 to 4929 ± 1255 mM/min; Ctrls: 537 ± 155 to 5776 ± 1010 mM/min). Vascular resistance fell similarly in both groups with increasing exercise intensity (HF: 66 ± 10 to 24 ± 3 mmHg/l/min; Ctrls: 69 ± 12 to 24 ± 4 mmHg/l/min). Conclusion: Incremental KE exercise also revealed similar hemodynamic and metabolic responses in both Ctrls and patients. These data do not support the hypothesis that HF is accompanied by an intrinsic muscle myopathy that affects both vascular and metabolic responses to submaximal exercise. References Esposito F et al. (2011) Isolated quadriceps training increases maximal exercise capacity in chronic heart failure: The role of skeletal muscle convective and diffusive oxygen transport. Journal of the American College of Cardiology 58(13): 1353-1362. Esposito F et al. (2010) Limited maximal exercise capacity in patients with chronic heart failure: Partitioning the contributors. Journal of the American College of Cardiology 55(18): 1945-1954