Association of atrial fibrillation with rapid ventricular response and hospital mortality in intensive care unit: A retrospective cohort study

BACKGROUND: Atrial fibrillation (AF) with rapid ventricular response (RVR) is a prevalent condition among critically ill patients, frequently contributing to haemodynamic instability. However, the association between AF with RVR and hospital mortality in critically ill patients remains inconclusive. AIM: To investigate the associations between AF with RVR and hospital mortality in patients admitted to the intensive care unit (ICU). STUDY DESIGN: This study included patients from the MIMIC-IV database who experienced episodes of atrial fibrillation (AF) during their ICU stay. AF with RVR was defined as a heart rate (HR) >110 beats/min (bpm) during an episode of AF and was further classified into three categories: mild (111-130 bpm), moderate (131-150 bpm) and severe (>150 bpm) RVR. Multivariable adjusted logistic regression models and restricted cubic spline analyses were used to estimate odds ratios and 95% CIs and to explore linear and non-linear relationships of RVR and mortality, respectively. RESULTS: A total of 7027 eligible patients with AF were identified, and AF with RVR occurred in 5274 patients (75.1%). Patients with RVR had a significantly higher hospital mortality compared to those without (23.8% vs. 15.8%, adjusted OR, 1.32; 95% CI (1.13-1.54), p < .001). The adjusted ORs in mild, moderate and severe RVR were 1.11 (0.93-1.33), 1.25 (1.05-1.49) and 1.87 (1.54-2.27) for hospital mortality (p for trend <.001), respectively. Restricted cubic spline analyses showed a non-linear relationship of RVR with hospital mortality (p < .001). Additionally, hospital mortality decreased linearly with the reduction in 1-h HR following moderate and severe RVR. CONCLUSIONS: AF with moderate and severe RVR was associated with increased hospital mortality in critically ill patients, and acute HR reduction following moderate and severe RVR may be beneficial in reducing hospital mortality. RELEVANCE TO CLINICAL PRACTICE: This study emphasized the importance of individual management of AF patients in the ICU according to the severity of RVR and provided an approximate range of RVR to guide risk stratification.