A rare case of hypothyroid coma developed in a patient with diagnosed primary hypothyroidism, complicated by the development of rhabdomyolysis and prolonged oppression of the respiratory center is presented. The predominance of previous cardiovascular pathology, marked oedema syndrome, and hypercholesterolemia in the clinical picture of the disease initially directed the diagnostics of cardiac pathology, which delayed the diagnosis of hypothyroidism. This publication aims to draw clinicians' attention to hypothyroid coma as a rare complication of hypothyroidism, which in this case was disguised as ischemic heart disease with the development of chronic heart failure.