Admission Heart Rate Is a Determinant of Effectiveness of Beta-Blockers in Acute Myocardial Infarction Patients.

BACKGROUND

Beta-blockers are standard therapy for acute myocardial infarction (AMI). However, despite current advances in the management of AMI, it remains unclear whether all AMI patients benefit from β-blockers. We investigated whether admission heart rate (HR) is a determinant of the effectiveness of β-blockers for AMI patients.

METHODS AND

RESULTS

We enrolled 3,283 consecutive AMI patients who were admitted to 28 participating institutions in the Japanese Registry of Acute Myocardial Infarction Diagnosed by Universal Definition (J-MINUET) study. According to admission HR, we divided patients into 3 groups: bradycardia (HR <60 beats/min, n=444), normocardia (HR 60 to ≤100 beats/min, n=2,013), and tachycardia (HR >100 beats/min, n=342). The primary endpoint was major adverse cardiac events (MACE), including all-cause death, non-fatal MI, non-fatal stroke, heart failure (HF), and urgent revascularization for unstable angina, at 3-year follow-up. Beta-blocker at discharge was significantly associated with a lower risk of MACE in the tachycardia group (23.6% vs. 33.0%; P=0.033), but it did not affect rates of MACE in the normocardia group (17.8% vs. 18.4%; P=0.681). In the bradycardia group, β-blocker use at discharge was significantly associated with a higher risk of MACE (21.6% vs. 12.7%; P=0.026). Results were consistent for multivariable regression and stepwise multivariable regression.

CONCLUSIONS

Admission HR might determine the efficacy of β-blockers for current AMI patients.