Electrical muscle stimulation (EMS) is expected to be considered as an add-on therapy for the usual rehabilitation of patients with chronic heart failure (HF). However, it remains unclear whether EMS can reduce muscle volume loss in patients with acute HF (AHF) immediately after hospitalization. Therefore, the aim of this study was to investigate if EMS could reduce the lower-limb muscle volume loss in patients with AHF. In this single-center, retrospective, observational study, lower-limb skeletal muscle volume, quadriceps muscle layer thickness, and clinical events (worsening HF or kidney function) were evaluated in 45 patients with AHF (mean age, 77.4 ± 11.6 years, 31 males). All patients underwent EMS on the right leg, in addition to usual rehabilitation, for 20 minutes per day, 5 days per week, for 2 weeks. A two-factor (time × leg) analysis of variance was performed to compare the difference between the right leg (usual rehabilitation and EMS) and left leg (usual rehabilitation only). The skeletal muscle mass decreased by 11.6% ± 19.7% from baseline in the right leg and by 20.4% ± 16.1% in the left leg (interaction; F = 4.54, P = 0.036). The quadriceps muscle layer thickness decreased by 10.2% ± 7.1% from baseline in the right leg and by 13.5% ± 6.0% in the left leg (interaction; F = 10.50, P = 0.002). No clinical events were related to EMS. Results showed that EMS combined with usual rehabilitation for patients with AHF has the potential to inhibit muscle volume loss.