The aim of the study is to determine whether discontinuation of β-blocker after at least 1 year of β-blocker therapy is noninferior to continuation of β-blocker in patients without heart failure (HF) or left ventricular systolic dysfunction after acute myocardial infarction (AMI).

Prospective, open-label, randomized, multicenter, noninferiority trial to determine whether discontinuation of β-blocker after at least 1 year of β-blocker therapy is noninferior to continuation of β-blocker in patients without HF or left ventricular systolic dysfunction after AMI.

β-blockers have anti-ischemic, anti-arrhythmic, and anti-adrenergic properties. In order to reduce cardiovascular mortality and morbidity, current major guidelines recommend that oral treatment of β-blockers should be continued during and after hospitalization in patients with acute myocardial infarction (AMI) and without contraindications to β-blocker use.

A clinically important but difficult decision on β-blocker therapy after AMI is to determine the duration of β-blocker therapy after discharge in patients without heart failure (HF) or left ventricular systolic dysfunction. Previous studies for long-term β-blocker therapy after AMI were inadequate to derive definite conclusion because of small sample size and potential selection bias.

Therefore, the SMART-DECISION trial will investigate whether discontinuation of β-blocker after at least 1 year of β-blocker therapy is noninferior to continuation of β-blocker in patients without HF or left ventricular systolic dysfunction after AMI.

Inclusion Criteria:

• Subject must be at least 19 years of age.
• Subject who have been continuing β-blocker therapy for at least 1 year after acute myocardial infarction regardless of the time of diagnosis
• Subject is able to verbally confirm understandings of risks and benefits of this trial, and he/she or his/her legally authorized representative provides written informed consent prior to any study related procedure.

Exclusion Criteria:

• Subject whose left ventricle ejection fraction was less than 40% from echocardiography performed after acute myocardial infarction or who have never received echocardiography.
• Treatment history of heart failure
• Contraindication to β-blocker therapy (history of symptomatic bronchial asthma or chronic obstructive pulmonary disease, 2nd or 3rd degree AV block, cardiac pacemaker implantation, or other cases where β-blocker cannot be used under the judgment of the clinician)
• Non-cardiac co-morbid conditions are present with life expectancy <1 year or that may result in protocol non-compliance (per site investigator's medical judgment).
• History of atrial fibrillation
• Pregnancy or breast feeding

After publication of first manuscript and trial results, the de-identified data will be shared by permission of principle investigator, when asked.