Investigation On The Relationship Between The Average Heart Rate Within 24-hour After Admission And Cardiovascular Events In Patients With Acute Myocardial Infarction

Objective To investigate the relationship between the average heart rate within 24-hour after admission and cardiovascular events in patients with acute myocardial infarction.Methods A prospective observational study was conducted in patients with acute myocardial infarction hospitalized in the Hangzhou first people’s hospital from July 2013 to Dec 2015. A total of 200 patients were consecutively enrolled, all of them were routinely treated and monitored by ECG at frist day after admission. We recorded heart rate once per hour and calculated the average heart rate in the frist whole day. The patients were divided into three groups as A group (HR≤70 bpm), B group (>70 and ≤90 bpm) and C group (>90 bpm) according to the average heart rate within 24-hour after admission.The occurrence frequency of composite major adverse cardiac events (MACE, including cardiovascular death, non-fatal myocardial infarction, heart failure, malignant arrhythmias and cardiogenic shock) during hospitalization were recorded. Logistic regression analysis was used to detect the risk factors for MACE.Results The occurrence frequency of MACE in A group and C group were all significantly higher than that of B group (all P<0.05), however the difference of occurrence frequency of MACE between A group and C group was not significant (P=0.264). Logistic regression analysis indicated that the average heart rate within 24-hour after admission was an independent risk factor for predicting occurrence of MACE during hospitalization in patients with acute myocardial infarction (OR=0.976, 95%CI:0.850-0.998, P=0.010). The optimal cutoff point of the average heart rate within 24-hour after admission for predicting occurrence of MACE during hospitalization was 76 bpm, with a sensibility of 85.3%, nd a specificity of 88.9%,the area under curve (AUC) was 0.624.Conclusion As to patients with AMI, who with an average heart rate within 24-hour after admission of ≤70 or>90 bpm have a lower risk of MACE during hospitalization. The average heart rate within 24-hour after admission was a good indicator for predicting occurrence of MACE during hospitalization.