Heart rate and mortality in myocardial infarction: incremental or bimodal correlation?

Abstract Introduction Risk prediction scores adopted in acute coronary syndromes use incremental models to estimate mortality for heart rate (HR) above 60 bpm. Nonetheless, a non-linear, bimodal relationship, with higher event rates at low or high HR, has been described, potentially hampering risk accuracy. Purpose Our aim was assess the prognostic impact of bradycardia, defined as admission HR <50 bpm, myocardial infarction (MI) among patients enrolled large nationwide registry. Methods Data between 1999 and 2021 stratified by were retrospectively analysed. The primary endpoint in-hospital mortality. secondary composite death, cerebrovascular event, reinfarction. Associations outcomes assessed univariate multivariable logistic regression analyses, then verified after sequential propensity-score matchings groups. Results 51001 (median age 66 years, IQR 56–76) included. Crude estimates showed distribution endpoints peaks HR. Association bpm recognised only analysis (OR 1.49; 95% CI 1.01–2.13 p=0.038) but not multiple sensitivity analyses exclusion on negative chronotropic therapy. Three matching performed those 50–75 76–100 >100 admission, identifying 1159, 1159 1158 matched pairs, respectively. After matching, equalled groups <100 Conclusions Bradycardia (HR bpm) MI identified group crude adverse events. signal supporting an independent association bradycardia short-term is weak confirmed correction relevant baseline differences propensity score matching. These findings support hypothesis that lower might be causative worse outcomes, rather serves marker underlying morbidity. Funding Acknowledgement Type funding sources: Other. Main source(s): AMIS Plus registry funded unrestricted grants from Swiss Heart Foundation Abbot AG, Amgen AstraZeneca Bayer (Schweiz) Biotronik Boston Scientific B. Braun Medical Daiichi-Sankyo/Lilly Cordis Cardinal Health GmbH, Medtronic Novartis Pharma Schweiz Sanofi-Aventis SIS Terumo Vascular all Switzerland, Working Group Interventional Cardiology. sponsors did play any role design, data collection, analysis, interpretation data.