Prevention of Lower Limb Muscle Atrophy With Neuromuscular Electrical Stimulation in a Patient With Tachycardia-Induced Cardiomyopathy Secondary to Thyroid Storm: A Case Report

Tachycardia-induced cardiomyopathy (TIC) is reversible; however, the acute phase is often accompanied by hemodynamic instability, which makes conventional exercise therapy difficult to implement. Neuromuscular electrical stimulation (NMES) has been suggested as a potential alternative strategy to prevent muscle atrophy. Herein, we report a case in which NMES was used in a patient during the acute phase of TIC, secondary to thyroid storm, highlighting its safety and potential effectiveness. A male in his 40s was diagnosed with TIC associated with thyroid storm. On admission, the patient presented with atrial fibrillation, severe cardiac dysfunction with a left ventricular ejection fraction of 19%, and markedly elevated thyroid hormone levels. Due to unstable hemodynamics, conventional exercise therapy was deferred, and NMES was initiated on day nine of hospitalization, and it was continued until day 12. It was performed once daily for 20 minutes. Muscle ultrasonography revealed that quadriceps muscle thickness had decreased by approximately 5% during hospitalization. Importantly, no hemodynamic deterioration or adverse events were observed. From day 13, aerobic exercises using a cycle ergometer and resistance training were initiated. The patient achieved a six-minute walk distance of 545 m and was discharged on day 28. NMES was safely implemented without adverse events, even during periods of hemodynamic instability in a patient with TIC. In situations where conventional exercise therapy is limited due to hemodynamic instability, NMES may represent a feasible intervention option. The findings of this single case are hypothesis-generating and warrant further investigation.