Tachycardia-induced cardiomyopathy is characterised with a ventricular dysfunction caused by increased ventricular rate. It is a reversible mechanism of the heart failure. Cardiomyopathy can recover after the restoration of sinus-rhythm or after adjusting the heart rate. In the presented paper we are discussing ethiopathogenesis, diagnostics and therapy of tachycardia-induced cardiomyopathy and we are describing the case of a patient with this diagnosis, who was admitted to our department.