A nurse is caring for a patient who is 12 hours post-op from a coronary artery bypass graft (CABG). The cardiac monitor shows new-onset atrial fibrillation with a rapid ventricular response. Which nursing actions should the nurse prioritize?

A. Hematocrit: While monitoring hematocrit is important post-CABG to detect bleeding or anemia, it does not provide immediate information about hemodynamic stability or perfusion in the setting of new-onset atrial fibrillation with rapid ventricular response. B. Blood glucose: Blood glucose management is important for overall post-operative care, particularly in cardiac surgery patients, but it is not immediately related to acute hemodynamic changes caused by atrial fibrillation. C. Urine output: Urine output is a key indicator of end-organ perfusion and cardiac output. In a patient with rapid atrial fibrillation post-CABG, decreased cardiac efficiency can reduce renal perfusion. Monitoring urine output allows early detection of hypoperfusion and guides interventions to maintain hemodynamic stability. D. Liver enzymes: Liver function tests are important in assessing organ function over time, but acute changes in liver enzymes are not immediately sensitive indicators of cardiac output or perfusion. They are not the priority in the context of acute arrhythmia with rapid ventricular response.