Martín-Demiguel I, et al. - Analyzing data from the Spanish National prospective registry, researchers investigated the prevalence as well as prognostic importance of interatrial block (IAB) in patients with Takotsubo syndrome (TS). A P-wave ≥120 ms defined IAB. When the P-wave was positive in inferior leads, IAB was considered partial. An advanced IAB was defined as biphasic (+/−) P-wave. Overall participants were 246. These subjects were followed-up for a mean duration of 12 months. Findings revealed that IAB highly prevailed in patients with TS. Poor prognosis was observed in relation to advanced IAB and atrial fibrillation.