BackgroundPulmonary embolism (PE) is a critical condition characterized by the obstruction of pulmonary arteries by thrombi, which significantly contributes to morbidity and mortality globally. Although prolonged elevated heart rate (peHR) is recognized as a risk factor for adverse outcomes in critically ill patients, its specific impact on severe PE has remained unexplored. MethodsThis retrospective cohort study analyzed data from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Patients diagnosed with PE were included in the study. peHR was defined as heart rates exceeding 100 beats per minute on at least 11 occasions within any 12-h interval. Cox proportional hazards regression models were used to evaluate the impact of peHR on 30-day and 90-day mortality rates, adjusting for a broad range of demographic and clinical variables. ResultsA total of 1248 patients were included in this study, of whom 540 exhibited peHR. These patients experienced significantly longer hospital and intensive care unit (ICU) stays, as well as higher mortality rates at both 30 days (25.93 % vs. 14.97 %, P < 0.001) and 90 days (33.89 % vs. 22.74 %, P < 0.001) compared to patients without peHR. Multivariate Cox regression analysis confirmed peHR as an independent predictor of increased mortality at 30 days (HR 1.56, 95 % CI 1.19–2.07; P = 0.0014) and 90 days (HR 1.66, 95 % CI 1.32–2.10; P < 0.001). ConclusionpeHR significantly worsens outcomes in severe PE patients, underscoring the need for stringent heart rate monitoring and management. These findings advocate for integrating heart rate control within management strategies for severe PE, potentially improving survival outcomes.