Correlation of Admission Heart Rate With Angiographic and Clinical Outcomes in Patients With Right Coronary Artery ST‐Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: HORIZONS‐AMI (The Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

BACKGROUND Bradycardia on presentation is frequently observed in patients with right coronary artery ST-segment elevation myocardial infarction, but it is largely unknown whether it predicts poor angiographic or clinical outcomes in that patient population. We sought to determine the prognostic implications of admission heart rate (AHR) in patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion. METHODS AND RESULTS We analyzed 1460 patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion enrolled in the randomized HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial who underwent primary percutaneous coronary intervention. Patients presenting with high-grade atrioventricular block were excluded. Outcomes were examined according to AHR range (AHR <60, 61-79, 80-99, and ≥100 beats per minute). Baseline and procedural characteristics did not vary significantly with AHR except for a more frequent history of diabetes mellitus, longer symptom-to-balloon time, more frequent cardiogenic shock, and less frequent restoration of thrombolysis in myocardial infarction 3 flow in patients with admission tachycardia (AHR >100 beats per minute). Angiographic analysis showed no significant association between AHR and lesion location or complexity. On multivariate analysis, admission bradycardia (AHR <60 beats per minute) was not associated with increased 1-year mortality (hazard ratio 1.33; 95% CI 0.41-4.34, P=0.64) or major adverse cardiac events (hazard ratio 1.08; 95% CI 0.62-1.88, P=0.78), whereas admission tachycardia was a strong independent predictor of mortality (hazard ratio 5.02; 95% CI 1.95-12.88, P=0.0008) and major adverse cardiac events (hazard ratio 2.20; 95% CI 1.29-3.75, P=0.0004). CONCLUSIONS In patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion undergoing primary percutaneous coronary intervention, admission bradycardia was not associated with increased mortality or major adverse cardiac events at 1 year. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov. Unique identifier: NCT00433966.