Reddy YNV, Obokata M, Verbrugge FH, et al. - Researchers focused on the implications of left atrial (LA) myopathy and dysrhythmia across the spectrum of atrial fibrillation (AF) burden in heart failure with preserved ejection fraction (HFpEF). This study involved consecutive patients with HFpEF (n = 285) and controls (n = 146). More congestion with greater pulmonary vascular disease and lower cardiac output was detected in patients with permanent AF. Findings demonstrated a progressive decline in LA compliance and mechanics along with increasing AF burden in HFpEF, raising risk for new onset AF and progressive AF. The development of a unique phenotype of HFpEF, characterized by heightened ventricular interaction, right heart failure, and worsening pulmonary vascular disease, was shown to be promoted by these changes.