Preoperative Resting Heart Rate and 30-Day Heart Failure After Off-Pump Coronary Artery Bypass Grafting

BACKGROUND: Postoperative heart failure complicates off-pump coronary artery bypass grafting. Whether preoperative resting heart rate (RHR) is associated with 30-day heart failure, and how intraoperative physiologic patterns relate to this association, remains unclear. METHODS: This secondary cohort analysis included adults aged 60 or older undergoing elective off-pump coronary artery bypass grafting in a randomized trial. Preoperative RHR was the mean of three resting, supine measurements taken 24-48 hours preoperatively. The primary outcome was 30-day heart failure. The association between preoperative RHR and 30-day heart failure was assessed using Firth logistic regression, restricted cubic splines, and change-point models; exploratory, hypothesis-generating mediation analyses evaluated intraoperative physiologic patterns. RESULTS: Among 1,952 patients, 69 (3.5%) developed 30-day heart failure. Higher RHR was independently associated with heart failure (adjusted odds ratio 1.47 per 10 beats/min; 95% confidence interval 1.16-1.86; P = .002). The association was nonlinear, with the risk rising steeply beyond approximately 80 beats/min. Sensitivity analyses yielded consistent adjusted odds ratios ranging from 1.42 to 1.53. In exploratory mediation analyses, intraoperative heart rate metrics showed stronger indirect associations with the observed relationship between preoperative RHR and 30-day heart failure than hypotension metrics; other intraoperative variables were not statistically significant. CONCLUSIONS: Preoperative RHR, particularly above 80 beats/min, may serve as a practical complementary marker for 30-day heart failure after off-pump coronary artery bypass grafting. Exploratory mediation analyses identified intraoperative heart rate and hypotension patterns that may warrant further study.