Resting heart rate in first year survivors of myocardial infarction and long-term mortality: a community study

Objective: To evaluate the long-term prognostic effect of resting heart rate (HR) at index myocardial infarction (MI) and during the first year after MI among 1-year survivors.

Patients and methods: The community-based cohort consisted of 1571 patients hospitalized with an incident MI from January 1, 1983, through December 31, 2007, in Olmsted County, Minnesota, who were in sinus rhythm at index MI and had HR measurements on electrocardiography at index and during the first year after MI. Outcomes were all-cause and cardiovascular deaths.

Results: During a median follow-up of 7.0 years, 627 deaths and 311 cardiovascular deaths occurred. Using patients with HRs of 60/min or less as the referent, this study found that long-term all-cause mortality risk increased progressively with increasing HR at index (hazard ratio, 1.62; 95% CI, 1.25-2.09) and even more with increasing HR during the first year after MI (hazard ratio, 2.16; 95% CI, 1.64-2.84) for patients with HRs greater than 90/min, adjusting for clinical characteristics and β-blocker use. Similar results were observed for cardiovascular mortality (adjusted hazard ratio, 1.66; 95% CI, 1.14-2.42; and adjusted hazard ratio, 1.93; 95% CI, 1.27-2.94; for HR at index and within 1 year after MI, respectively).

Conclusion: These data from a large MI community cohort indicate that HR is a strong predictor of long-term all-cause and cardiovascular mortality not only at initial presentation of MI but also during the first year of follow-up.