A research paper recently appeared on JAFIB addressing a significant but under-recognized public health problem with clinical repercussions: that a persistent tachyarrhythmia or frequent ectopic activity could induce a potentially reversible left ventricular dysfunction and cardiomyopathy. Accordingly, the present letter is focused on an ill-defined subgroup of patients with pre-existent atrial fibrillation followed by incident heart failure. This cohort of patients belongs to a discrete clinical phenotype that involves various contributing parameters and multiple pathophysiological mechanisms. The early identification of this group of patients will permit targeted preventive and therapeutic interventions.