Significance of the tendency for relative bradycardia during induction therapy for acute myeloid leukemia

This study explored the relationship between body temperature (BT) and heart rate (HR) data during acute myeloid leukemia (AML) treatment, using relative bradycardia (RB) as an index. RB trends were also assessed in confirmed infections and during intensive chemotherapy. Data from AML patients who received induction therapy (anthracycline and cytarabine) at Jichi Medical University Hospital between May 2015 and December 2023 were analyzed. A total of 1000 febrile events (axillary temperature ≥ 37.8 °C) in 97 patients were included. Multivariate analysis showed an HR increase of 6.57 bpm (95% CI 4.44-8.70) per 1 °C rise in BT. RB, defined as BT ≥ 37.8 °C with HR < 90 bpm, was observed in 630 events (63.0%). RB was more likely with age ≥ 44 years, hemoglobin ≥ 6.5 g/dL, and reduced-intensity regimens. In contrast, BT ≥ 38.6 °C, diastolic BP ≥ 70 mmHg, oxygen therapy, CRP ≥ 7.13 mg/dL, and incomplete hematologic recovery decreased the likelihood of RB. In addition, RB was significantly associated with documented infection (OR = 2.32, 95% CI 1.17-4.61, p = 0.016). RB frequently occurred during AML induction therapy, and may serve as an indicator of infection.