Initial heart rate and cardiovascular outcomes in patients presenting with acute coronary syndrome.

Objectives: To assess the impact of on-admission heart rate (HR) in patients presenting with acute coronary syndrome (ACS).

Methods: Data were collected retrospectively from the second Gulf Registry of Acute Coronary Events. Patients were divided according to their initial HR into: (I: < 60, II: 60-69, III: 70-79, IV: 80-89 and V: ≥ 90 bpm). Patients' characteristics and hospital and one- and 12-month outcomes were analyzed and compared.

Results: Among 7939 consecutive ACS patients, groups I to V represented 7%, 13%, 20%, 23.5%, and 37%, respectively. Mean age was higher in groups I and V. Group V were more likely males, diabetic and hypertensive. ST-elevation myocardial infarction was the main presentation in groups I and V. Reperfusion therapies were less likely given to group V. Beta blockers were more frequently prescribed to group III in comparison to groups with higher HR. Groups I and V were associated with worse hospital outcomes. Multivariate analysis showed initial tachycardia as an independent predictor for heart failure (OR 2.2; 95%CI: 1.39-3.32), while bradycardia was independently associated with higher one-month mortality (OR 2.0; 95%CI: 1.04-3.85) CONCLUSION: The majority of ACS patients present with tachycardia. However, low or high HR is a marker of high risk that needs more attention and management.