AimsRight atrial (RA) dilation and stretch provide prognostic information in patients with cardiovascular diseases. We investigated the prevalence, confounding factors and prognostic relevance of RA dilation in patients with pulmonary embolism (PE).MethodsOverall, 609 PE patients were consecutively included in a prospective single-centre registry between September 2008 and August 2017. Volumetric measurements of heart chambers were performed on routine non-electrocardiographic-gated computed tomography and plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) measured on admission. An in-hospital adverse outcome was defined as PE-related death, cardiopulmonary resuscitation, mechanical ventilation or catecholamine administration.ResultsPatients with an adverse outcome (11.2%) had larger RA volumes (median 120 (interquartile range 84–152) versus 102 (78–134) mL; p=0.013), RA/left atrial (LA) volume ratios (1.7 (1.2–2.4) versus 1.3 (1.1–1.7); p<0.001) and MR-proANP levels (282 (157–481) versus 129 (64–238) pmol·L⁻¹; p<0.001) compared to patients with a favourable outcome. Overall, 499 patients (81.9%) had a RA/LA volume ratio ≥1.0 and a calculated cut-off value of 1.8 (area under the curve 0.64, 95% CI 0.56–0.71) predicted an adverse outcome, both in unselected (OR 3.1, 95% CI 1.9–5.2) and normotensive patients (OR 2.7, 95% CI 1.3–5.6). MR-proANP ≥120 pmol·L⁻¹ was identified as an independent predictor of an adverse outcome, both in unselected (OR 4.6, 95% CI 2.3–9.3) and normotensive patients (OR 5.1, 95% CI 1.5–17.6).ConclusionsRA dilation is a frequent finding in patients with PE. However, the prognostic performance of RA dilation appears inferior compared to established risk stratification markers. MR-proANP predicted an in-hospital adverse outcome, both in unselected and normotensive PE patients, integrating different prognostic relevant information from comorbidities.