Association of Long-Term Oral β-Blocker Use With Cardiac Troponin I and B-Type Natriuretic Peptide in Septic Myocardial Injury: A Retrospective Cohort Study.

Background and Aims: Septic myocardial injury, characterized by elevated levels of cardiac troponin I (cTnI) and B-type natriuretic peptide (BNP), is associated with increased mortality in sepsis. This study aimed to evaluate whether chronic oral β-blocker use is associated with reduced cardiac biomarker levels and improved short-term outcomes. Methods: We conducted a retrospective cohort study of 289 patients diagnosed with septic myocardial injury admitted to the ICU/EICU from January 2015 to June 2020. Patients were stratified into chronic β-blocker users (n = 102) and non-users (n = 187). Associations between β-blocker use and serum cTnI and BNP levels were analyzed using univariate and multivariate linear regression, adjusting for age, severity scores (SOFA, APACHE II), infection site, and vasopressor use. Secondary outcomes included 28-day mortality and ICU length of stay. Subgroup analyses were performed by age and infection site. Results: Chronic β-blocker use was independently associated with significantly lower serum levels of cTnI (0.19 vs. 0.29 μg/L; β = -0.07; 95% CI: -0.12 to -0.02; p < 0.001) and BNP (627 vs. 690 ng/L; β = -36.6; 95% CI: -69.6 to -3.5; p = 0.03). However, no significant differences were observed in 28-day mortality or ICU length of stay. Subgroup analysis revealed greater biomarker reductions in patients under 60 years old and those with pulmonary infections, though sample sizes were limited. Conclusion: Long-term β-blocker therapy is associated with lower levels of cardiac injury biomarkers in patients with septic myocardial injury. Subgroup analyses revealed greater reductions in younger patients and those with pulmonary infections, though these findings are exploratory. However, these biochemical improvements did not translate into short-term survival benefits. Prospective trials are needed to determine whether myocardial protection translates into clinical benefit.