Tachycardia, atrial fibrillation and premature ventricular contractions can trigger a reversible cardiomyopathy, which can result in clinical heart failure. The diagnosis is retrospective and based on recovery of left ventricular ejection fraction following appropriate arrhythmia management. The arrhythmia can be fully or partly responsible for the reduced ejection fraction depending on coexisting structural heart disease. Early and aggressive treatment targeting the arrhythmia as described in this review, is important to prevent complications including persistent pathophysiological changes.