Heart failure is a common disease with major social and economic repercussions for the health system. All potentially curable or reversible causes of heart failure should be investigated and treated if possible. Several experimental and clinical studies have demonstrated that supraventricular tachycardias can induce a form of dilated cardiomyopathy (tachycardiomyopathy), which may be reversible with ventricular frequency response control. In this article we present a clinical case, and review this clinical entity, so often underdiagnosed.