We present a case of a patient with pronounced edematous‑ascitic syndrome. Initially, its causes were considered to be alcoholic cardiomyopathy (right ventricular failure) with heart rhythm disturbances and liver cirrhosis. Targeted treatment had a low clinical effect, which served as a basis for revising the diagnostic concept. Subsequent follow‑up revealed a diffuse toxic goiter with the predominant right ventricular lesion. Achieving euthyroidism has led to a significant improvement in the patient's condition.