Introduction The development of chest pain associated with intermittent left bundle branch block (LBBB) in the absence of coronary artery disease has been described in the literature as painful left bundle branch block syndrome. The mechanism responsible for the chest pain is unknown, but the main current hypothesis is related to acute cardiac dyssynchrony. In this syndrome, the LBBB occurs when the cycle length is equal to or less than the refractory period of the left bundle, mainly during physical […]

Abstract In 2016, the European Society of Cardiology (ESC) recognized heart failure (HF) with ejection fraction between 40 and 49% as a new HF phenotype, HF with mid-range ejection fraction (HFmrEF), with the main purpose of encouraging studies on this new category. In 2018, the Brazilian Society of Cardiology adhered to this classification and introduced HFmrEF in Brazil. This paper presents a narrative review of what the literature has described about HFmrEF. The prevalence of patients with HFmrEF ranged from […]