Background: We aimed to describe the determinants of discharge heart rate in acute coronary syndrome patients and assess the impact of discharge heart rate on 5-year mortality in hospital survivors.
Methods: French Registry of Acute ST-Elevation or non-ST-elevation Myocardial Infarction (FAST-MI) 2005 is a nationwide French registry that included all consecutive patients with acute myocardial infarction over 1 month in 223 institutions in 2005. Discharge heart rate was recorded in 3079 patients discharged alive; all had 5-year follow-up. Logistic regression was used to detect predictors of high heart rate at discharge. Cox's proportional hazards model was used to assess the hazard ratio for mortality at 5 years. Heart rate was categorized into 4 groups by quartiles (<60, 61-67, 68-75, >75 beats per minute). High heart rate was defined as ≥75 beats per minute. Landmark analysis was performed at 1 year.
Results: Independent predictors of heart rate ≥75 beats per minute at discharge were female sex, ST-segment elevation myocardial infarction, diabetes, chronic obstructive pulmonary disease, bleeding/transfusion during hospitalization, left ventricular dysfunction, renal dysfunction, and prescription (type, but not dose category) of beta-blockers at discharge. Discharge heart rate was significantly related to mortality at 1 year (hazard ratio 1.13; 95% confidence interval, 1.03-1.24 per 10 beats per minute, P = .02); this was confirmed by landmark analysis, with a 39% increase (hazard ratio 1.39; 95% confidence interval 1.05-1.84) in the risk of 1-year death for discharge heart rate ≥75 beats per minute vs <75 beats per minute. This relationship was no longer significant between 2 and 5 years.
Conclusions: After acute myocardial infarction, patients discharged with high heart rate (≥75 beats per minute) are at higher risk of death during the first year, but not later, irrespective of beta-blocker use.
Keywords: Heart rate; Mortality; Myocardial infarction; Registry.
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