Heart failure and arrhythmias are pathogenetically closely interconnected and they are mutually aggravating each other. At the same time, tachycardia-induced cardiomyopathy is particularly a reversible disease with proper treatment. This article presents a case report of an elderly patient with hypertension and atrial fibrillation, which are associated to an advanced heart failure and complicating the management of a decreasing kidneys filtration capacity, hematuria and brain stroke. In this case report, tachycardia-induced cardiomyopathy is caused by persistent atrial fibrillation. A complex approach to diagnosis and evidence-based treatment (in particular cardioversion and radiofrequency ablation) made it possible to restore sinus rhythm and compensate heart failure. Dynamics of the clinical state of the patient, laboratory indicators, echocardiographic characteristics allowed us to retrospectively verify atrial fibrillation-mediated cardiomyopathy as the main cause of heart failure progression, and classify this clinical case as heart failure with improved ejection fraction.