Ebner M, Rogge NIJ, Parwani AS, et al. - In 528 consecutive individuals with pulmonary embolism (PE) recruited in a single-center registry between September 2008 and September 2017, researchers examined the predominance, risk factors, and prognostic influence of atrial fibrillation (AF) on risk stratification, in-hospital adverse outcomes, and mortality. Overall, 52 participants had known AF, and 57 manifested with AF upon admission. Of these individuals, AF was recently diagnosed in 34 participants. Compared with those who did not have AF, overt hyperthyroidism was related to recently diagnosed AF, while cardiovascular risk comorbidities were more often seen in individuals with known AF. Patients with AF on admission had more comorbidities, presenting with tachycardia and high cardiac biomarkers more often, and were thus classified to higher risk classes. Nevertheless, AF on admission had no influence on the in-hospital adverse outcomes and in-hospital mortality. In multivariate logistic regression analyses adjusted for AF on admission, independent predictors of an in-hospital adverse outcome were NT-proBNP and troponin elevation, as well as greater risk classes in risk evaluation models. Hence, in PE, AF is a common finding, influencing >10% of cases. However, AF was not related to a greater risk of in-hospital adverse outcomes and did not alter the prognostic performance of risk evaluation approaches. For individuals with acute PE, the use of risk stratification tools, despite the heart rhythm on admission, was supported.