Enhanced Echo Intensity of Skeletal Muscle Is Associated With Exercise Intolerance in Patients With Heart Failure

Background: Skeletal muscle is quantitatively and qualitatively impaired in patients with heart failure (HF), which is closely linked to lowered exercise capacity. Ultrasonography (US) for skeletal muscle has emerged as a useful, noninvasive tool to evaluate muscle quality and quantity. Here we investigated whether muscle quality based on US-derived echo intensity (EI) is associated with exercise capacity in patients with HF. Methods and Results: Fifty-eight patients with HF (61 +/- 12 years) and 28 control subjects (58 +/- 14 years) were studied. The quadriceps femoris echo intensity (QEI) was significantly higher and the quadriceps femoris muscle thickness (QMT) was significantly lower in the patients with HF than the controls (88.3 +/- 13.4 vs 81.1 +/- 7.5, P= .010; 5.21 +/- 1.10 vs 6.54 +/- 1.34 cm, P< .001, respectively). By univariate analysis, QEI was significantly correlated with age, peak oxygen uptake (VO2), and New York Heart Association class in the HF group. A multivariable analysis revealed that the QEI was independently associated with peak VO2 after adjustment for age, gender, body mass index, and QMT: b-coefficient = -11.80, 95%CI (-20.73, -2.86), P= .011. Conclusion: Enhanced EI in skeletal muscle was independently associated with lowered exercise capacity in HF. The measurement of EI is low-cost, easily accessible, and suitable for assessment of HF-related alterations in skeletal muscle quality. (J Cardiac Fail 2020;26:685-693)